/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.apache.nifi.cdc.mysql.processors;

import com.github.shyiko.mysql.binlog.BinaryLogClient;
import com.github.shyiko.mysql.binlog.GtidSet;
import com.github.shyiko.mysql.binlog.event.Event;
import com.github.shyiko.mysql.binlog.event.EventHeaderV4;
import com.github.shyiko.mysql.binlog.event.EventType;
import com.github.shyiko.mysql.binlog.event.GtidEventData;
import com.github.shyiko.mysql.binlog.event.MySqlGtid;
import com.github.shyiko.mysql.binlog.event.QueryEventData;
import com.github.shyiko.mysql.binlog.event.RotateEventData;
import com.github.shyiko.mysql.binlog.event.TableMapEventData;
import com.github.shyiko.mysql.binlog.network.SSLMode;
import org.apache.commons.lang3.StringUtils;
import org.apache.nifi.annotation.behavior.InputRequirement;
import org.apache.nifi.annotation.behavior.PrimaryNodeOnly;
import org.apache.nifi.annotation.behavior.RequiresInstanceClassLoading;
import org.apache.nifi.annotation.behavior.Stateful;
import org.apache.nifi.annotation.behavior.TriggerSerially;
import org.apache.nifi.annotation.behavior.WritesAttribute;
import org.apache.nifi.annotation.behavior.WritesAttributes;
import org.apache.nifi.annotation.documentation.CapabilityDescription;
import org.apache.nifi.annotation.documentation.Tags;
import org.apache.nifi.annotation.lifecycle.OnStopped;
import org.apache.nifi.annotation.notification.OnPrimaryNodeStateChange;
import org.apache.nifi.annotation.notification.PrimaryNodeState;
import org.apache.nifi.cdc.CDCException;
import org.apache.nifi.cdc.event.ColumnDefinition;
import org.apache.nifi.cdc.event.RowEventException;
import org.apache.nifi.cdc.event.TableInfo;
import org.apache.nifi.cdc.event.TableInfoCacheKey;
import org.apache.nifi.cdc.mysql.event.BinlogEventInfo;
import org.apache.nifi.cdc.mysql.event.BinlogEventListener;
import org.apache.nifi.cdc.mysql.event.BinlogLifecycleListener;
import org.apache.nifi.cdc.mysql.event.DataCaptureState;
import org.apache.nifi.cdc.event.io.EventWriterConfiguration;
import org.apache.nifi.cdc.event.io.FlowFileEventWriteStrategy;
import org.apache.nifi.cdc.mysql.event.RawBinlogEvent;
import org.apache.nifi.cdc.mysql.event.io.AbstractBinlogEventWriter;
import org.apache.nifi.cdc.mysql.event.handler.BeginEventHandler;
import org.apache.nifi.cdc.mysql.event.handler.CommitEventHandler;
import org.apache.nifi.cdc.mysql.event.handler.DDLEventHandler;
import org.apache.nifi.cdc.mysql.event.handler.DeleteEventHandler;
import org.apache.nifi.cdc.mysql.event.handler.InsertEventHandler;
import org.apache.nifi.cdc.mysql.event.handler.UpdateEventHandler;
import org.apache.nifi.cdc.mysql.processors.ssl.BinaryLogSSLSocketFactory;
import org.apache.nifi.cdc.mysql.processors.ssl.ConnectionPropertiesProvider;
import org.apache.nifi.cdc.mysql.processors.ssl.StandardConnectionPropertiesProvider;
import org.apache.nifi.components.AllowableValue;
import org.apache.nifi.components.PropertyDescriptor;
import org.apache.nifi.components.PropertyValue;
import org.apache.nifi.components.ValidationContext;
import org.apache.nifi.components.ValidationResult;
import org.apache.nifi.components.resource.ResourceCardinality;
import org.apache.nifi.components.resource.ResourceType;
import org.apache.nifi.components.state.Scope;
import org.apache.nifi.components.state.StateManager;
import org.apache.nifi.components.state.StateMap;
import org.apache.nifi.distributed.cache.client.DistributedMapCacheClient;
import org.apache.nifi.expression.ExpressionLanguageScope;
import org.apache.nifi.flowfile.FlowFile;
import org.apache.nifi.logging.ComponentLog;
import org.apache.nifi.processor.AbstractSessionFactoryProcessor;
import org.apache.nifi.processor.ProcessContext;
import org.apache.nifi.processor.ProcessSession;
import org.apache.nifi.processor.ProcessSessionFactory;
import org.apache.nifi.processor.Relationship;
import org.apache.nifi.processor.exception.ProcessException;
import org.apache.nifi.processor.util.StandardValidators;
import org.apache.nifi.reporting.InitializationException;
import org.apache.nifi.security.util.TlsConfiguration;
import org.apache.nifi.ssl.SSLContextService;

import javax.net.ssl.SSLContext;
import java.io.IOException;
import java.net.InetSocketAddress;
import java.sql.Connection;
import java.sql.Driver;
import java.sql.DriverManager;
import java.sql.DriverPropertyInfo;
import java.sql.ResultSet;
import java.sql.ResultSetMetaData;
import java.sql.SQLException;
import java.sql.SQLFeatureNotSupportedException;
import java.sql.Statement;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.HashMap;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Properties;
import java.util.Set;
import java.util.concurrent.BlockingQueue;
import java.util.concurrent.LinkedBlockingQueue;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.TimeoutException;
import java.util.logging.Logger;
import java.util.regex.Pattern;

import static com.github.shyiko.mysql.binlog.event.EventType.DELETE_ROWS;
import static com.github.shyiko.mysql.binlog.event.EventType.EXT_DELETE_ROWS;
import static com.github.shyiko.mysql.binlog.event.EventType.EXT_WRITE_ROWS;
import static com.github.shyiko.mysql.binlog.event.EventType.FORMAT_DESCRIPTION;
import static com.github.shyiko.mysql.binlog.event.EventType.PRE_GA_DELETE_ROWS;
import static com.github.shyiko.mysql.binlog.event.EventType.PRE_GA_WRITE_ROWS;
import static com.github.shyiko.mysql.binlog.event.EventType.ROTATE;
import static com.github.shyiko.mysql.binlog.event.EventType.WRITE_ROWS;
import static com.github.shyiko.mysql.binlog.event.EventType.XID;
import static org.apache.nifi.cdc.event.io.EventWriter.CDC_EVENT_TYPE_ATTRIBUTE;
import static org.apache.nifi.cdc.event.io.EventWriter.SEQUENCE_ID_KEY;
import static org.apache.nifi.cdc.event.io.FlowFileEventWriteStrategy.MAX_EVENTS_PER_FLOWFILE;


/**
 * A processor to retrieve Change Data Capture (CDC) events and send them as flow files.
 */
@TriggerSerially
@PrimaryNodeOnly
@InputRequirement(InputRequirement.Requirement.INPUT_FORBIDDEN)
@Tags({"sql", "jdbc", "cdc", "mysql", "transaction", "event"})
@CapabilityDescription("Retrieves Change Data Capture (CDC) events from a MySQL database. CDC Events include INSERT, UPDATE, DELETE operations. Events "
        + "are output as either a group of a specified number of events (the default is 1 so each event becomes its own flow file) or grouped as a full transaction (BEGIN to COMMIT). All events "
        + "are ordered by the time at which the operation occurred. NOTE: If the processor is stopped before the specified number of events have been written to a flow file, "
        + "the partial flow file will be output in order to maintain the consistency of the event stream.")
@Stateful(scopes = Scope.CLUSTER, description = "Information such as a 'pointer' to the current CDC event in the database is stored by this processor, such "
        + "that it can continue from the same location if restarted.")
@WritesAttributes({
        @WritesAttribute(attribute = SEQUENCE_ID_KEY, description = "A sequence identifier (i.e. strictly increasing integer value) specifying the order "
                + "of the CDC event flow file relative to the other event flow file(s)."),
        @WritesAttribute(attribute = CDC_EVENT_TYPE_ATTRIBUTE, description = "A string indicating the type of CDC event that occurred, including (but not limited to) "
                + "'begin', 'insert', 'update', 'delete', 'ddl' and 'commit'."),
        @WritesAttribute(attribute = "mime.type", description = "The processor outputs flow file content in JSON format, and sets the mime.type attribute to "
                + "application/json")
})
@RequiresInstanceClassLoading
public class CaptureChangeMySQL extends AbstractSessionFactoryProcessor {

    // Random invalid constant used as an indicator to not set the binlog position on the client (thereby using the latest available)
    private static final int DO_NOT_SET = -1000;

    private static final int DEFAULT_MYSQL_PORT = 3306;

    // A regular expression matching multiline comments, used when parsing DDL statements
    private static final Pattern MULTI_COMMENT_PATTERN = Pattern.compile("/\\*.*?\\*/", Pattern.DOTALL);

    // Relationships
    public static final Relationship REL_SUCCESS = new Relationship.Builder()
            .name("success")
            .description("Successfully created FlowFile from SQL query result set.")
            .build();

    protected static Set<Relationship> relationships;

    private static final AllowableValue SSL_MODE_DISABLED = new AllowableValue(SSLMode.DISABLED.toString(),
            SSLMode.DISABLED.toString(),
            "Connect without TLS");

    private static final AllowableValue SSL_MODE_PREFERRED = new AllowableValue(SSLMode.PREFERRED.toString(),
            SSLMode.PREFERRED.toString(),
            "Connect with TLS when server support enabled, otherwise connect without TLS");

    private static final AllowableValue SSL_MODE_REQUIRED = new AllowableValue(SSLMode.REQUIRED.toString(),
            SSLMode.REQUIRED.toString(),
            "Connect with TLS or fail when server support not enabled");

    private static final AllowableValue SSL_MODE_VERIFY_IDENTITY = new AllowableValue(SSLMode.VERIFY_IDENTITY.toString(),
            SSLMode.VERIFY_IDENTITY.toString(),
            "Connect with TLS or fail when server support not enabled. Verify server hostname matches presented X.509 certificate names or fail when not matched");


    // Properties
    public static final PropertyDescriptor DATABASE_NAME_PATTERN = new PropertyDescriptor.Builder()
            .name("capture-change-mysql-db-name-pattern")
            .displayName("Database/Schema Name Pattern")
            .description("A regular expression (regex) for matching databases (or schemas, depending on your RDBMS' terminology) against the list of CDC events. The regex must match "
                    + "the database name as it is stored in the RDBMS. If the property is not set, the database name will not be used to filter the CDC events. "
                    + "NOTE: DDL events, even if they affect different databases, are associated with the database used by the session to execute the DDL. "
                    + "This means if a connection is made to one database, but the DDL is issued against another, then the connected database will be the one matched against "
                    + "the specified pattern.")
            .required(false)
            .addValidator(StandardValidators.NON_EMPTY_VALIDATOR)
            .build();

    public static final PropertyDescriptor TABLE_NAME_PATTERN = new PropertyDescriptor.Builder()
            .name("capture-change-mysql-name-pattern")
            .displayName("Table Name Pattern")
            .description("A regular expression (regex) for matching CDC events affecting matching tables. The regex must match the table name as it is stored in the database. "
                    + "If the property is not set, no events will be filtered based on table name.")
            .required(false)
            .addValidator(StandardValidators.NON_EMPTY_VALIDATOR)
            .build();

    public static final PropertyDescriptor CONNECT_TIMEOUT = new PropertyDescriptor.Builder()
            .name("capture-change-mysql-max-wait-time")
            .displayName("Max Wait Time")
            .description("The maximum amount of time allowed for a connection to be established, zero means there is effectively no limit.")
            .defaultValue("30 seconds")
            .required(true)
            .addValidator(StandardValidators.TIME_PERIOD_VALIDATOR)
            .expressionLanguageSupported(ExpressionLanguageScope.VARIABLE_REGISTRY)
            .build();

    public static final PropertyDescriptor HOSTS = new PropertyDescriptor.Builder()
            .name("capture-change-mysql-hosts")
            .displayName("MySQL Nodes")
            .description("A list of hostname (and optional port) entries corresponding to nodes in a MySQL cluster. The entries should be comma separated "
                    + "using a colon (if the port is to be specified) such as host1:port,host2:port,....  For example mysql.myhost.com:3306. The port need not be specified, "
                    + "when omitted the default MySQL port value of 3306 will be used. This processor will attempt to connect to "
                    + "the hosts in the list in order. If one node goes down and failover is enabled for the cluster, then the processor will connect "
                    + "to the active node (assuming its node entry is specified in this property).")
            .required(true)
            .addValidator(StandardValidators.NON_EMPTY_VALIDATOR)
            .expressionLanguageSupported(ExpressionLanguageScope.VARIABLE_REGISTRY)
            .build();

    public static final PropertyDescriptor DRIVER_NAME = new PropertyDescriptor.Builder()
            .name("capture-change-mysql-driver-class")
            .displayName("MySQL Driver Class Name")
            .description("The class name of the MySQL database driver class")
            .defaultValue("com.mysql.jdbc.Driver")
            .required(true)
            .addValidator(StandardValidators.NON_EMPTY_VALIDATOR)
            .expressionLanguageSupported(ExpressionLanguageScope.VARIABLE_REGISTRY)
            .build();

    public static final PropertyDescriptor DRIVER_LOCATION = new PropertyDescriptor.Builder()
            .name("capture-change-mysql-driver-locations")
            .displayName("MySQL Driver Location(s)")
            .description("Comma-separated list of files/folders and/or URLs containing the MySQL driver JAR and its dependencies (if any). "
                    + "For example '/var/tmp/mysql-connector-java-5.1.38-bin.jar'")
            .defaultValue(null)
            .required(false)
            .identifiesExternalResource(ResourceCardinality.MULTIPLE, ResourceType.FILE, ResourceType.DIRECTORY, ResourceType.URL)
            .expressionLanguageSupported(ExpressionLanguageScope.VARIABLE_REGISTRY)
            .dynamicallyModifiesClasspath(true)
            .build();

    public static final PropertyDescriptor USERNAME = new PropertyDescriptor.Builder()
            .name("capture-change-mysql-username")
            .displayName("Username")
            .description("Username to access the MySQL cluster")
            .required(false)
            .addValidator(StandardValidators.NON_EMPTY_VALIDATOR)
            .expressionLanguageSupported(ExpressionLanguageScope.VARIABLE_REGISTRY)
            .build();

    public static final PropertyDescriptor PASSWORD = new PropertyDescriptor.Builder()
            .name("capture-change-mysql-password")
            .displayName("Password")
            .description("Password to access the MySQL cluster")
            .required(false)
            .sensitive(true)
            .addValidator(StandardValidators.NON_EMPTY_VALIDATOR)
            .expressionLanguageSupported(ExpressionLanguageScope.VARIABLE_REGISTRY)
            .build();

    public static final PropertyDescriptor EVENTS_PER_FLOWFILE_STRATEGY = new PropertyDescriptor.Builder()
            .name("events-per-flowfile-strategy")
            .displayName("Event Processing Strategy")
            .description("Specifies the strategy to use when writing events to FlowFile(s), such as '" + MAX_EVENTS_PER_FLOWFILE.getDisplayName() + "'")
            .required(true)
            .sensitive(false)
            .addValidator(StandardValidators.NON_EMPTY_VALIDATOR)
            .allowableValues(FlowFileEventWriteStrategy.class)
            .defaultValue(MAX_EVENTS_PER_FLOWFILE.getValue())
            .expressionLanguageSupported(ExpressionLanguageScope.NONE)
            .build();

    public static final PropertyDescriptor NUMBER_OF_EVENTS_PER_FLOWFILE = new PropertyDescriptor.Builder()
            .name("number-of-events-per-flowfile")
            .displayName("Events Per FlowFile")
            .description("Specifies how many events should be written to a single FlowFile. If the processor is stopped before the specified number of events has been written,"
                    + "the events will still be written as a FlowFile before stopping.")
            .required(true)
            .sensitive(false)
            .addValidator(StandardValidators.POSITIVE_INTEGER_VALIDATOR)
            .defaultValue("1")
            .expressionLanguageSupported(ExpressionLanguageScope.VARIABLE_REGISTRY)
            .dependsOn(EVENTS_PER_FLOWFILE_STRATEGY, MAX_EVENTS_PER_FLOWFILE.getValue())
            .build();

    public static final PropertyDescriptor SERVER_ID = new PropertyDescriptor.Builder()
            .name("capture-change-mysql-server-id")
            .displayName("Server ID")
            .description("The client connecting to the MySQL replication group is actually a simplified replica (server), and the Server ID value must be unique across the whole replication "
                    + "group (i.e. different from any other Server ID being used by any primary or replica). Thus, each instance of CaptureChangeMySQL must have a Server ID unique across "
                    + "the replication group. If the Server ID is not specified, it defaults to 65535.")
            .required(false)
            .addValidator(StandardValidators.POSITIVE_LONG_VALIDATOR)
            .expressionLanguageSupported(ExpressionLanguageScope.VARIABLE_REGISTRY)
            .build();

    public static final PropertyDescriptor DIST_CACHE_CLIENT = new PropertyDescriptor.Builder()
            .name("capture-change-mysql-dist-map-cache-client")
            .displayName("Distributed Map Cache Client - unused")
            .description("This is a legacy property that is no longer used to store table information, the processor will handle the table information (column names, types, etc.)")
            .identifiesControllerService(DistributedMapCacheClient.class)
            .required(false)
            .build();

    public static final PropertyDescriptor RETRIEVE_ALL_RECORDS = new PropertyDescriptor.Builder()
            .name("capture-change-mysql-retrieve-all-records")
            .displayName("Retrieve All Records")
            .description("Specifies whether to get all available CDC events, regardless of the current binlog filename and/or position. If binlog filename and position values are present "
                    + "in the processor's State, this property's value is ignored. This allows for 4 different configurations: 1) If binlog data is available in processor State, that is used "
                    + "to determine the start location and the value of Retrieve All Records is ignored. 2) If no binlog data is in processor State, then Retrieve All Records set to true "
                    + "means start at the beginning of the binlog history. 3) If no binlog data is in processor State and Initial Binlog Filename/Position are not set, then "
                    + "Retrieve All Records set to false means start at the end of the binlog history. 4) If no binlog data is in processor State and Initial Binlog Filename/Position "
                    + "are set, then Retrieve All Records set to false means start at the specified initial binlog file/position. "
                    + "To reset the behavior, clear the processor state (refer to the State Management section of the processor's documentation).")
            .required(true)
            .allowableValues("true", "false")
            .defaultValue("true")
            .addValidator(StandardValidators.BOOLEAN_VALIDATOR)
            .build();

    public static final PropertyDescriptor INCLUDE_BEGIN_COMMIT = new PropertyDescriptor.Builder()
            .name("capture-change-mysql-include-begin-commit")
            .displayName("Include Begin/Commit Events")
            .description("Specifies whether to emit events corresponding to a BEGIN or COMMIT event in the binary log. Set to true if the BEGIN/COMMIT events are necessary in the downstream flow, "
                    + "otherwise set to false, which suppresses generation of these events and can increase flow performance.")
            .required(true)
            .allowableValues("true", "false")
            .defaultValue("false")
            .addValidator(StandardValidators.BOOLEAN_VALIDATOR)
            .build();

    public static final PropertyDescriptor INCLUDE_DDL_EVENTS = new PropertyDescriptor.Builder()
            .name("capture-change-mysql-include-ddl-events")
            .displayName("Include DDL Events")
            .description("Specifies whether to emit events corresponding to Data Definition Language (DDL) events such as ALTER TABLE, TRUNCATE TABLE, e.g. in the binary log. Set to true "
                    + "if the DDL events are desired/necessary in the downstream flow, otherwise set to false, which suppresses generation of these events and can increase flow performance.")
            .required(true)
            .allowableValues("true", "false")
            .defaultValue("false")
            .addValidator(StandardValidators.BOOLEAN_VALIDATOR)
            .build();

    public static final PropertyDescriptor STATE_UPDATE_INTERVAL = new PropertyDescriptor.Builder()
            .name("capture-change-mysql-state-update-interval")
            .displayName("State Update Interval")
            .description("DEPRECATED. This property is no longer used and exists solely for backward compatibility purposes. Indicates how often to update the processor's state with binlog "
                    + "file/position values. A value of zero means that state will only be updated when the processor is "
                    + "stopped or shutdown. If at some point the processor state does not contain the desired binlog values, the last flow file emitted will contain the last observed values, "
                    + "and the processor can be returned to that state by using the Initial Binlog File, Initial Binlog Position, and Initial Sequence ID properties.")
            .defaultValue("0 seconds")
            .required(true)
            .addValidator(StandardValidators.TIME_PERIOD_VALIDATOR)
            .expressionLanguageSupported(ExpressionLanguageScope.VARIABLE_REGISTRY)
            .build();

    public static final PropertyDescriptor INIT_SEQUENCE_ID = new PropertyDescriptor.Builder()
            .name("capture-change-mysql-init-seq-id")
            .displayName("Initial Sequence ID")
            .description("Specifies an initial sequence identifier to use if this processor's State does not have a current "
                    + "sequence identifier. If a sequence identifier is present in the processor's State, this property is ignored. Sequence identifiers are "
                    + "monotonically increasing integers that record the order of flow files generated by the processor. They can be used with the EnforceOrder "
                    + "processor to guarantee ordered delivery of CDC events.")
            .required(false)
            .addValidator(StandardValidators.NON_NEGATIVE_INTEGER_VALIDATOR)
            .expressionLanguageSupported(ExpressionLanguageScope.VARIABLE_REGISTRY)
            .build();

    public static final PropertyDescriptor INIT_BINLOG_FILENAME = new PropertyDescriptor.Builder()
            .name("capture-change-mysql-init-binlog-filename")
            .displayName("Initial Binlog Filename")
            .description("Specifies an initial binlog filename to use if this processor's State does not have a current binlog filename. If a filename is present "
                    + "in the processor's State or \"Use GTID\" property is set to false, this property is ignored. "
                    + "This can be used along with Initial Binlog Position to \"skip ahead\" if previous events are not desired. "
                    + "Note that NiFi Expression Language is supported, but this property is evaluated when the processor is configured, so FlowFile attributes may not be used. Expression "
                    + "Language is supported to enable the use of the Variable Registry and/or environment properties.")
            .required(false)
            .addValidator(StandardValidators.NON_EMPTY_VALIDATOR)
            .expressionLanguageSupported(ExpressionLanguageScope.VARIABLE_REGISTRY)
            .build();

    public static final PropertyDescriptor INIT_BINLOG_POSITION = new PropertyDescriptor.Builder()
            .name("capture-change-mysql-init-binlog-position")
            .displayName("Initial Binlog Position")
            .description("Specifies an initial offset into a binlog (specified by Initial Binlog Filename) to use if this processor's State does not have a current "
                    + "binlog filename. If a filename is present in the processor's State or \"Use GTID\" property is false, this property is ignored. "
                    + "This can be used along with Initial Binlog Filename to \"skip ahead\" if previous events are not desired. Note that NiFi Expression Language "
                    + "is supported, but this property is evaluated when the processor is configured, so FlowFile attributes may not be used. Expression Language is "
                    + "supported to enable the use of the Variable Registry and/or environment properties.")
            .required(false)
            .addValidator(StandardValidators.NON_NEGATIVE_INTEGER_VALIDATOR)
            .expressionLanguageSupported(ExpressionLanguageScope.VARIABLE_REGISTRY)
            .build();

    public static final PropertyDescriptor USE_BINLOG_GTID = new PropertyDescriptor.Builder()
            .name("capture-change-mysql-use-gtid")
            .displayName("Use Binlog GTID")
            .description("Specifies whether to use Global Transaction ID (GTID) for binlog tracking. If set to true, processor's state of binlog file name and position is ignored. "
                    + "The main benefit of using GTID is to have much reliable failover than using binlog filename/position.")
            .required(true)
            .allowableValues("true", "false")
            .defaultValue("false")
            .addValidator(StandardValidators.BOOLEAN_VALIDATOR)
            .build();

    public static final PropertyDescriptor INIT_BINLOG_GTID = new PropertyDescriptor.Builder()
            .name("capture-change-mysql-init-gtid")
            .displayName("Initial Binlog GTID")
            .description("Specifies an initial GTID to use if this processor's State does not have a current GTID. "
                    + "If a GTID is present in the processor's State or \"Use GTID\" property is set to false, this property is ignored. "
                    + "This can be used to \"skip ahead\" if previous events are not desired. "
                    + "Note that NiFi Expression Language is supported, but this property is evaluated when the processor is configured, so FlowFile attributes may not be used. "
                    + "Expression Language is supported to enable the use of the Variable Registry and/or environment properties.")
            .required(false)
            .addValidator(StandardValidators.NON_EMPTY_VALIDATOR)
            .expressionLanguageSupported(ExpressionLanguageScope.VARIABLE_REGISTRY)
            .build();

    public static final PropertyDescriptor SSL_MODE = new PropertyDescriptor.Builder()
            .name("SSL Mode")
            .displayName("SSL Mode")
            .description("SSL Mode used when SSL Context Service configured supporting certificate verification options")
            .required(true)
            .defaultValue(SSLMode.DISABLED.toString())
            .allowableValues(SSL_MODE_DISABLED,
                    SSL_MODE_PREFERRED,
                    SSL_MODE_REQUIRED,
                    SSL_MODE_VERIFY_IDENTITY)
            .build();

    public static final PropertyDescriptor SSL_CONTEXT_SERVICE = new PropertyDescriptor.Builder()
            .name("SSL Context Service")
            .displayName("SSL Context Service")
            .description("SSL Context Service supporting encrypted socket communication")
            .required(false)
            .identifiesControllerService(SSLContextService.class)
            .dependsOn(SSL_MODE,
                    SSL_MODE_PREFERRED,
                    SSL_MODE_REQUIRED,
                    SSL_MODE_VERIFY_IDENTITY)
            .build();

    private static final List<PropertyDescriptor> propDescriptors;

    private volatile BinaryLogClient binlogClient;
    private volatile BinlogEventListener eventListener;
    private volatile BinlogLifecycleListener lifecycleListener;
    private volatile GtidSet gtidSet;

    // Set queue capacity to avoid excessive memory consumption
    private final BlockingQueue<RawBinlogEvent> queue = new LinkedBlockingQueue<>(1000);

    private final Map<TableInfoCacheKey, TableInfo> tableInfoCache = new HashMap<>();

    private volatile ProcessSession currentSession;
    private DataCaptureState currentDataCaptureState = new DataCaptureState();

    private volatile BinlogResourceInfo binlogResourceInfo = new BinlogResourceInfo();

    private volatile Pattern databaseNamePattern;
    private volatile Pattern tableNamePattern;
    private volatile boolean skipTable = false;
    private int currentHost = 0;
    private volatile JDBCConnectionHolder jdbcConnectionHolder = null;

    private final BinlogEventState binlogEventState = new BinlogEventState();

    private final BeginEventHandler beginEventHandler = new BeginEventHandler();
    private final CommitEventHandler commitEventHandler = new CommitEventHandler();
    private final DDLEventHandler ddlEventHandler = new DDLEventHandler();
    private final InsertEventHandler insertEventHandler = new InsertEventHandler();
    private final DeleteEventHandler deleteEventHandler = new DeleteEventHandler();
    private final UpdateEventHandler updateEventHandler = new UpdateEventHandler();

    private volatile EventWriterConfiguration eventWriterConfiguration;


    static {

        final Set<Relationship> r = new HashSet<>();
        r.add(REL_SUCCESS);
        relationships = Collections.unmodifiableSet(r);

        final List<PropertyDescriptor> pds = new ArrayList<>();
        pds.add(HOSTS);
        pds.add(DRIVER_NAME);
        pds.add(DRIVER_LOCATION);
        pds.add(USERNAME);
        pds.add(PASSWORD);
        pds.add(EVENTS_PER_FLOWFILE_STRATEGY);
        pds.add(NUMBER_OF_EVENTS_PER_FLOWFILE);
        pds.add(SERVER_ID);
        pds.add(DATABASE_NAME_PATTERN);
        pds.add(TABLE_NAME_PATTERN);
        pds.add(CONNECT_TIMEOUT);
        pds.add(DIST_CACHE_CLIENT);
        pds.add(RETRIEVE_ALL_RECORDS);
        pds.add(INCLUDE_BEGIN_COMMIT);
        pds.add(INCLUDE_DDL_EVENTS);
        pds.add(STATE_UPDATE_INTERVAL);
        pds.add(INIT_SEQUENCE_ID);
        pds.add(INIT_BINLOG_FILENAME);
        pds.add(INIT_BINLOG_POSITION);
        pds.add(USE_BINLOG_GTID);
        pds.add(INIT_BINLOG_GTID);
        pds.add(SSL_MODE);
        pds.add(SSL_CONTEXT_SERVICE);
        propDescriptors = Collections.unmodifiableList(pds);
    }


    @Override
    public Set<Relationship> getRelationships() {
        return relationships;
    }

    @Override
    protected List<PropertyDescriptor> getSupportedPropertyDescriptors() {
        return propDescriptors;
    }

    @Override
    protected Collection<ValidationResult> customValidate(final ValidationContext validationContext) {
        final Collection<ValidationResult> results = new ArrayList<>();

        final Map<PropertyDescriptor, String> properties = validationContext.getProperties();

        final String sslContextServiceProperty = properties.get(SSL_CONTEXT_SERVICE);
        final String sslModeProperty = properties.get(SSL_MODE);
        if (StringUtils.isBlank(sslModeProperty) || SSLMode.DISABLED.toString().equals(sslModeProperty)) {
            results.add(new ValidationResult.Builder()
                    .subject(SSL_MODE.getDisplayName())
                    .valid(true)
                    .build());
        } else if (StringUtils.isBlank(sslContextServiceProperty)) {
            final String explanation = String.format("SSL Context Service is required for SSL Mode [%s]", sslModeProperty);
            results.add(new ValidationResult.Builder()
                    .subject(SSL_CONTEXT_SERVICE.getDisplayName())
                    .valid(false)
                    .explanation(explanation)
                    .build());
        }

        return results;
    }

    @OnPrimaryNodeStateChange
    public synchronized void onPrimaryNodeChange(final PrimaryNodeState state) throws CDCException {
        if (state == PrimaryNodeState.PRIMARY_NODE_REVOKED) {
            stop();
        }
    }

    public void setup(ProcessContext context) {

        final ComponentLog logger = getLogger();

        final StateManager stateManager = context.getStateManager();
        final StateMap stateMap;

        try {
            stateMap = stateManager.getState(Scope.CLUSTER);
        } catch (final IOException ioe) {
            logger.error("Failed to retrieve observed maximum values from the State Manager. Will not attempt "
                    + "connection until this is accomplished.", ioe);
            context.yield();
            return;
        }

        // Get inTransaction value from state
        binlogResourceInfo.setInTransaction("true".equals(stateMap.get("inTransaction")));

        // Build a event writer config object for the event writers to use
        final FlowFileEventWriteStrategy flowFileEventWriteStrategy = FlowFileEventWriteStrategy.valueOf(context.getProperty(EVENTS_PER_FLOWFILE_STRATEGY).getValue());
        eventWriterConfiguration = new EventWriterConfiguration(
                flowFileEventWriteStrategy,
                context.getProperty(NUMBER_OF_EVENTS_PER_FLOWFILE).evaluateAttributeExpressions().asInteger()
        );

        PropertyValue dbNameValue = context.getProperty(DATABASE_NAME_PATTERN);
        databaseNamePattern = dbNameValue.isSet() ? Pattern.compile(dbNameValue.getValue()) : null;

        PropertyValue tableNameValue = context.getProperty(TABLE_NAME_PATTERN);
        tableNamePattern = tableNameValue.isSet() ? Pattern.compile(tableNameValue.getValue()) : null;

        boolean getAllRecords = context.getProperty(RETRIEVE_ALL_RECORDS).asBoolean();

        if (binlogResourceInfo == null) {
            binlogResourceInfo = new BinlogResourceInfo();
        }
        currentDataCaptureState.setUseGtid(context.getProperty(USE_BINLOG_GTID).asBoolean());

        if (currentDataCaptureState.isUseGtid()) {
            // Set current gtid to whatever is in State, falling back to the Retrieve All Records then Initial Gtid if no State variable is present
            currentDataCaptureState.setGtidSet(stateMap.get(BinlogEventInfo.BINLOG_GTIDSET_KEY));
            if (currentDataCaptureState.getGtidSet() == null) {
                if (!getAllRecords && context.getProperty(INIT_BINLOG_GTID).isSet()) {
                    currentDataCaptureState.setGtidSet(context.getProperty(INIT_BINLOG_GTID).evaluateAttributeExpressions().getValue());
                } else {
                    // If we're starting from the beginning of all binlogs, the binlog gtid must be the empty string (not null)
                    currentDataCaptureState.setGtidSet("");
                }
            }
            currentDataCaptureState.setBinlogFile("");
            currentDataCaptureState.setBinlogPosition(DO_NOT_SET);
        } else {
            // Set current binlog filename to whatever is in State, falling back to the Retrieve All Records then Initial Binlog Filename if no State variable is present
            final String currentBinlogFile = stateMap.get(BinlogEventInfo.BINLOG_FILENAME_KEY);
            if (currentBinlogFile == null) {
                if (!getAllRecords) {
                    if (context.getProperty(INIT_BINLOG_FILENAME).isSet()) {
                        currentDataCaptureState.setBinlogFile(context.getProperty(INIT_BINLOG_FILENAME).evaluateAttributeExpressions().getValue());
                    }
                } else {
                    // If we're starting from the beginning of all binlogs, the binlog filename must be the empty string (not null)
                    currentDataCaptureState.setBinlogFile("");
                }
            } else {
                currentDataCaptureState.setBinlogFile(currentBinlogFile);
            }

            // Set current binlog position to whatever is in State, falling back to the Retrieve All Records then Initial Binlog Filename if no State variable is present
            final String binlogPosition = stateMap.get(BinlogEventInfo.BINLOG_POSITION_KEY);
            if (binlogPosition != null) {
                currentDataCaptureState.setBinlogPosition(Long.parseLong(binlogPosition));
            } else if (!getAllRecords) {
                if (context.getProperty(INIT_BINLOG_POSITION).isSet()) {
                    currentDataCaptureState.setBinlogPosition(context.getProperty(INIT_BINLOG_POSITION).evaluateAttributeExpressions().asLong());
                } else {
                    currentDataCaptureState.setBinlogPosition(DO_NOT_SET);
                }
            } else {
                currentDataCaptureState.setBinlogPosition(-1);
            }
        }

        // Get current sequence ID from state
        String seqIdString = stateMap.get(SEQUENCE_ID_KEY);
        if (StringUtils.isEmpty(seqIdString)) {
            // Use Initial Sequence ID property if none is found in state
            PropertyValue seqIdProp = context.getProperty(INIT_SEQUENCE_ID);
            if (seqIdProp.isSet()) {
                currentDataCaptureState.setSequenceId(seqIdProp.evaluateAttributeExpressions().asInteger());
            }
        } else {
            currentDataCaptureState.setSequenceId(Long.parseLong(seqIdString));
        }

        final SSLContextService sslContextService = context.getProperty(SSL_CONTEXT_SERVICE)
                .asControllerService(SSLContextService.class);
        final SSLMode sslMode = SSLMode.valueOf(context.getProperty(SSL_MODE).getValue());

        // Save off MySQL cluster and JDBC driver information, will be used to connect for event enrichment as well as for the binlog connector
        try {
            List<InetSocketAddress> hosts = getHosts(context.getProperty(HOSTS).evaluateAttributeExpressions().getValue());

            String username = context.getProperty(USERNAME).evaluateAttributeExpressions().getValue();
            String password = context.getProperty(PASSWORD).evaluateAttributeExpressions().getValue();

            // BinaryLogClient expects a non-null password, so set it to the empty string if it is not provided
            if (password == null) {
                password = "";
            }

            long connectTimeout = context.getProperty(CONNECT_TIMEOUT).evaluateAttributeExpressions().asTimePeriod(TimeUnit.MILLISECONDS);

            String driverLocation = context.getProperty(DRIVER_LOCATION).evaluateAttributeExpressions().getValue();
            String driverName = context.getProperty(DRIVER_NAME).evaluateAttributeExpressions().getValue();

            Long serverId = context.getProperty(SERVER_ID).evaluateAttributeExpressions().asLong();

            connect(hosts, username, password, serverId, driverLocation, driverName, connectTimeout, sslContextService, sslMode);
        } catch (IOException | IllegalStateException e) {
            if (eventListener != null) {
                eventListener.stop();
                if (binlogClient != null) {
                    binlogClient.unregisterEventListener(eventListener);
                }
            }
            context.yield();
            binlogClient = null;
            throw new ProcessException(e.getMessage(), e);
        }
    }


    @Override
    public synchronized void onTrigger(ProcessContext context, ProcessSessionFactory sessionFactory) throws ProcessException {

        ComponentLog log = getLogger();

        // Create a client if we don't have one
        if (binlogClient == null) {
            setup(context);
        }

        // If no client could be created, try again
        if (binlogClient == null) {
            return;
        }

        // If the client has been disconnected, try to reconnect
        if (!binlogClient.isConnected()) {
            Exception e = lifecycleListener.getException();
            // If there's no exception, the listener callback might not have been executed yet, so try again later. Otherwise clean up and start over next time
            if (e != null) {
                // Communications failure, disconnect and try next time
                log.error("Binlog connector communications failure: " + e.getMessage(), e);
                try {
                    stop();
                } catch (CDCException ioe) {
                    throw new ProcessException(ioe);
                }
            }

            // Try again later
            context.yield();
            return;
        }

        if (currentSession == null) {
            currentSession = sessionFactory.createSession();
        }

        try {
            outputEvents(currentSession, context, log);
        } catch (Exception eventException) {
            getLogger().error("Exception during event processing at file={} pos={}", currentDataCaptureState.getBinlogFile(), currentDataCaptureState.getBinlogPosition(), eventException);
            try {
                // Perform some processor-level "rollback", then rollback the session
                binlogResourceInfo.setInTransaction(false);
                stop();
            } catch (Exception e) {
                // Not much we can recover from here
                log.error("Error stopping CDC client", e);
            } finally {
                queue.clear();
                currentSession.rollback();
            }
            context.yield();
        }
    }

    /**
     * Get a list of hosts from a NiFi property, e.g.
     *
     * @param hostsString A comma-separated list of hosts (host:port,host2:port2, etc.)
     * @return List of InetSocketAddresses for the hosts
     */
    private List<InetSocketAddress> getHosts(String hostsString) {

        if (hostsString == null) {
            return null;
        }
        final String[] hostsSplit = hostsString.split(",");
        List<InetSocketAddress> hostsList = new ArrayList<>();

        for (String item : hostsSplit) {
            String[] addresses = item.split(":");
            if (addresses.length > 2 || addresses.length == 0) {
                throw new ArrayIndexOutOfBoundsException("Not in host:port format");
            } else if (addresses.length > 1) {
                hostsList.add(new InetSocketAddress(addresses[0].trim(), Integer.parseInt(addresses[1].trim())));
            } else {
                // Assume default port of 3306
                hostsList.add(new InetSocketAddress(addresses[0].trim(), DEFAULT_MYSQL_PORT));
            }
        }
        return hostsList;
    }

    protected void connect(List<InetSocketAddress> hosts, String username, String password, Long serverId,
                           String driverLocation, String driverName, long connectTimeout,
                           final SSLContextService sslContextService, final SSLMode sslMode) throws IOException {

        int connectionAttempts = 0;
        final int numHosts = hosts.size();
        InetSocketAddress connectedHost = null;
        Exception lastConnectException = new Exception("Unknown connection error");

        try {
            // Ensure driverLocation and driverName are correct before establishing binlog connection
            // to avoid failing after binlog messages are received.
            // Actual JDBC connection is created after binlog client gets started, because we need
            // the connect-able host same as the binlog client.
            registerDriver(driverLocation, driverName);
        } catch (InitializationException e) {
            throw new RuntimeException("Failed to register JDBC driver. Ensure MySQL Driver Location(s)" +
                    " and MySQL Driver Class Name are configured correctly. " + e, e);
        }

        while (connectedHost == null && connectionAttempts < numHosts) {
            if (binlogClient == null) {

                connectedHost = hosts.get(currentHost);
                binlogClient = createBinlogClient(connectedHost.getHostString(), connectedHost.getPort(), username, password);
            }

            // Add an event listener and lifecycle listener for binlog and client events, respectively
            if (eventListener == null) {
                eventListener = createBinlogEventListener(binlogClient, queue);
            }
            eventListener.start();
            binlogClient.registerEventListener(eventListener);

            if (lifecycleListener == null) {
                lifecycleListener = createBinlogLifecycleListener();
            }
            binlogClient.registerLifecycleListener(lifecycleListener);

            binlogClient.setBinlogFilename(currentDataCaptureState.getBinlogFile());
            if (currentDataCaptureState.getBinlogPosition() != DO_NOT_SET) {
                binlogClient.setBinlogPosition(currentDataCaptureState.getBinlogPosition());
            }

            binlogClient.setGtidSet(currentDataCaptureState.getGtidSet());
            binlogClient.setGtidSetFallbackToPurged(true);

            if (serverId != null) {
                binlogClient.setServerId(serverId);
            }

            binlogClient.setSSLMode(sslMode);
            if (sslContextService != null) {
                final SSLContext sslContext = sslContextService.createContext();
                final BinaryLogSSLSocketFactory sslSocketFactory = new BinaryLogSSLSocketFactory(sslContext.getSocketFactory());
                binlogClient.setSslSocketFactory(sslSocketFactory);
            }

            try {
                if (connectTimeout == 0) {
                    connectTimeout = Long.MAX_VALUE;
                }
                binlogClient.connect(connectTimeout);
                binlogResourceInfo.setTransitUri("mysql://" + connectedHost.getHostString() + ":" + connectedHost.getPort());

            } catch (IOException | TimeoutException te) {
                // Try the next host
                connectedHost = null;
                binlogResourceInfo.setTransitUri("<unknown>");
                currentHost = (currentHost + 1) % numHosts;
                connectionAttempts++;
                lastConnectException = te;
            }
        }
        if (!binlogClient.isConnected()) {
            if (eventListener != null) {
                eventListener.stop();
                if (binlogClient != null) {
                    binlogClient.unregisterEventListener(eventListener);
                }
            }
            binlogClient.disconnect();
            binlogClient = null;
            throw new IOException("Could not connect binlog client to any of the specified hosts due to: " + lastConnectException.getMessage(), lastConnectException);
        }

        final TlsConfiguration tlsConfiguration = sslContextService == null ? null : sslContextService.createTlsConfiguration();
        final ConnectionPropertiesProvider connectionPropertiesProvider = new StandardConnectionPropertiesProvider(sslMode, tlsConfiguration);
        final Map<String, String> jdbcConnectionProperties = connectionPropertiesProvider.getConnectionProperties();
        jdbcConnectionHolder = new JDBCConnectionHolder(connectedHost, username, password, jdbcConnectionProperties, connectTimeout);
        try {
            // Ensure connection can be created.
            getJdbcConnection();
        } catch (SQLException e) {
            getLogger().error("Error creating binlog enrichment JDBC connection to any of the specified hosts", e);
            if (eventListener != null) {
                eventListener.stop();
                if (binlogClient != null) {
                    binlogClient.unregisterEventListener(eventListener);
                }
            }
            if (binlogClient != null) {
                binlogClient.disconnect();
                binlogClient = null;
            }
            return;
        }

        gtidSet = new GtidSet(binlogClient.getGtidSet());
    }


    public void outputEvents(ProcessSession session, ProcessContext context, ComponentLog log) throws IOException {
        RawBinlogEvent rawBinlogEvent;
        DataCaptureState dataCaptureState = currentDataCaptureState.copy();
        final boolean includeBeginCommit = context.getProperty(INCLUDE_BEGIN_COMMIT).asBoolean();
        final boolean includeDDLEvents = context.getProperty(INCLUDE_DDL_EVENTS).asBoolean();

        // Drain the queue
        while (isScheduled() && (rawBinlogEvent = queue.poll()) != null) {
            Event event = rawBinlogEvent.getEvent();
            EventHeaderV4 header = event.getHeader();
            long timestamp = header.getTimestamp();
            EventType eventType = header.getEventType();
            // Advance the current binlog position. This way if no more events are received and the processor is stopped, it will resume at the event about to be processed.
            // We always get ROTATE and FORMAT_DESCRIPTION messages no matter where we start (even from the end), and they won't have the correct "next position" value, so only
            // advance the position if it is not that type of event. ROTATE events don't generate output CDC events and have the current binlog position in a special field, which
            // is filled in during the ROTATE case
            if (eventType != ROTATE && eventType != FORMAT_DESCRIPTION && !currentDataCaptureState.isUseGtid()) {
                dataCaptureState.setBinlogPosition(header.getPosition());
            }
            log.debug("Message event, type={} pos={} file={}", eventType, dataCaptureState.getBinlogPosition(), dataCaptureState.getBinlogFile());
            switch (eventType) {
                case TABLE_MAP:
                    // This is sent to inform which table is about to be changed by subsequent events
                    TableMapEventData data = event.getData();

                    // Should we skip this table? Yes if we've specified a DB or table name pattern and they don't match
                    skipTable = (databaseNamePattern != null && !databaseNamePattern.matcher(data.getDatabase()).matches())
                            || (tableNamePattern != null && !tableNamePattern.matcher(data.getTable()).matches());

                    if (!skipTable) {
                        TableInfoCacheKey key = new TableInfoCacheKey(this.getIdentifier(), data.getDatabase(), data.getTable(), data.getTableId());
                        binlogResourceInfo.setCurrentTable(tableInfoCache.get(key));
                        if (binlogResourceInfo.getCurrentTable() == null) {
                            // We don't have an entry for this table yet, so fetch the info from the database and populate the cache
                            try {
                                binlogResourceInfo.setCurrentTable(loadTableInfo(key));
                                tableInfoCache.put(key, binlogResourceInfo.getCurrentTable());
                            } catch (SQLException se) {
                                // Propagate the error up, so things like rollback and logging/bulletins can be handled
                                throw new IOException(se.getMessage(), se);
                            }
                        }
                    } else {
                        // Clear the current table, to force reload next time we get a TABLE_MAP event we care about
                        binlogResourceInfo.setCurrentTable(null);
                    }
                    break;
                case QUERY:
                    QueryEventData queryEventData = event.getData();
                    binlogResourceInfo.setCurrentDatabase(queryEventData.getDatabase());

                    String sql = queryEventData.getSql();

                    // Is this the start of a transaction?
                    if ("BEGIN".equals(sql)) {
                        // If we're already in a transaction, something bad happened, alert the user
                        if (binlogResourceInfo.isInTransaction()) {
                            getLogger().debug("BEGIN event received at pos={} file={} while already processing a transaction. This could indicate that your binlog position is invalid "
                                    + "or the event stream is out of sync or there was an issue with the processor state.", dataCaptureState.getBinlogPosition(), dataCaptureState.getBinlogFile());
                        }

                        if (databaseNamePattern == null || databaseNamePattern.matcher(binlogResourceInfo.getCurrentDatabase()).matches()) {
                            beginEventHandler.handleEvent(queryEventData, includeBeginCommit, currentDataCaptureState, binlogResourceInfo,
                                    binlogEventState, sql, eventWriterConfiguration, currentSession, timestamp);
                        }
                        // Whether we skip this event or not, it's still the beginning of a transaction
                        binlogResourceInfo.setInTransaction(true);

                        // Update inTransaction value to state
                        updateState(session, dataCaptureState);
                    } else if ("COMMIT".equals(sql)) {
                        // InnoDB generates XID events for "commit", but MyISAM generates Query events with "COMMIT", so handle that here
                        if (!binlogResourceInfo.isInTransaction()) {
                            getLogger().debug("COMMIT event received at pos={} file={} while not processing a transaction (i.e. no corresponding BEGIN event). "
                                    + "This could indicate that your binlog position is invalid or the event stream is out of sync or there was an issue with the processor state "
                                    + "or there was an issue with the processor state.", dataCaptureState.getBinlogPosition(), dataCaptureState.getBinlogFile());
                        }
                        if (databaseNamePattern == null || databaseNamePattern.matcher(binlogResourceInfo.getCurrentDatabase()).matches()) {
                            commitEventHandler.handleEvent(queryEventData, includeBeginCommit, currentDataCaptureState, binlogResourceInfo,
                                    binlogEventState, sql, eventWriterConfiguration, currentSession, timestamp);
                        }
                        // Whether we skip this event or not, it's the end of a transaction
                        binlogResourceInfo.setInTransaction(false);
                        updateState(session, dataCaptureState);
                        // If there is no FlowFile open, commit the session
                        if (eventWriterConfiguration.getCurrentFlowFile() == null) {
                            // Commit the NiFi session
                            session.commitAsync();
                        }
                        binlogResourceInfo.setCurrentTable(null);
                        binlogResourceInfo.setCurrentDatabase(null);
                    } else {
                        // Check for DDL events (alter table, e.g.). Normalize the query to do string matching on the type of change
                        String normalizedQuery = normalizeQuery(sql);

                        if (isQueryDDL(normalizedQuery)) {
                            if (databaseNamePattern == null || databaseNamePattern.matcher(binlogResourceInfo.getCurrentDatabase()).matches()) {
                                if (queryEventData.getDatabase() == null) {
                                    queryEventData.setDatabase(binlogResourceInfo.getCurrentDatabase());
                                }
                                ddlEventHandler.handleEvent(queryEventData, includeDDLEvents, currentDataCaptureState, binlogResourceInfo,
                                        binlogEventState, sql, eventWriterConfiguration, currentSession, timestamp);

                                // The altered table may not be the "active" table, so clear the cache to pick up changes
                                tableInfoCache.clear();
                            }

                            // If not in a transaction, commit the session so the DDL event(s) will be transferred
                            if (includeDDLEvents && !binlogResourceInfo.isInTransaction()) {
                                updateState(session, dataCaptureState);
                                if (FlowFileEventWriteStrategy.ONE_TRANSACTION_PER_FLOWFILE.equals(eventWriterConfiguration.getFlowFileEventWriteStrategy())) {
                                    if (currentSession != null) {
                                        FlowFile flowFile = eventWriterConfiguration.getCurrentFlowFile();
                                        if (flowFile != null && binlogEventState.getCurrentEventWriter() != null) {
                                            // Flush the events to the FlowFile when the processor is stopped
                                            binlogEventState.getCurrentEventWriter().finishAndTransferFlowFile(currentSession, eventWriterConfiguration, binlogResourceInfo.getTransitUri(),
                                                    dataCaptureState.getSequenceId(), binlogEventState.getCurrentEventInfo(), REL_SUCCESS);
                                        }
                                    }
                                }
                                // If there is no FlowFile open, commit the session
                                if (eventWriterConfiguration.getCurrentFlowFile() == null) {
                                    session.commitAsync();
                                }
                            }
                        }
                    }
                    break;

                case XID:
                    if (!binlogResourceInfo.isInTransaction()) {
                        getLogger().debug("COMMIT (XID) event received at pos={} file={} /while not processing a transaction (i.e. no corresponding BEGIN event). "
                                        + "This could indicate that your binlog position is invalid or the event stream is out of sync or there was an issue with the processor state.",
                                dataCaptureState.getBinlogPosition(), dataCaptureState.getBinlogFile());
                    }
                    if (databaseNamePattern == null || databaseNamePattern.matcher(binlogResourceInfo.getCurrentDatabase()).matches()) {
                        commitEventHandler.handleEvent(event.getData(), includeBeginCommit, currentDataCaptureState, binlogResourceInfo,
                                binlogEventState, null, eventWriterConfiguration, currentSession, timestamp);
                    }
                    // Whether we skip this event or not, it's the end of a transaction
                    binlogResourceInfo.setInTransaction(false);
                    dataCaptureState.setBinlogPosition(header.getNextPosition());
                    updateState(session, dataCaptureState);
                    // If there is no FlowFile open, commit the session
                    if (eventWriterConfiguration.getCurrentFlowFile() == null) {
                        // Commit the NiFi session
                        session.commitAsync();
                    }
                    binlogResourceInfo.setCurrentTable(null);
                    binlogResourceInfo.setCurrentDatabase(null);
                    break;

                case WRITE_ROWS:
                case EXT_WRITE_ROWS:
                case PRE_GA_WRITE_ROWS:
                case UPDATE_ROWS:
                case EXT_UPDATE_ROWS:
                case PRE_GA_UPDATE_ROWS:
                case DELETE_ROWS:
                case EXT_DELETE_ROWS:
                case PRE_GA_DELETE_ROWS:
                    // If we are skipping this table, then don't emit any events related to its modification
                    if (skipTable) {
                        break;
                    }
                    if (!binlogResourceInfo.isInTransaction()) {
                        // These events should only happen inside a transaction, warn the user otherwise
                        log.info("Event {} occurred outside of a transaction, which is unexpected.", eventType.name());
                    }
                    if (binlogResourceInfo.getCurrentTable() == null) {
                        // No Table Map event was processed prior to this event, which should not happen, so throw an error
                        throw new RowEventException("No table information is available for this event, cannot process further.");
                    }

                    if (eventType == WRITE_ROWS
                            || eventType == EXT_WRITE_ROWS
                            || eventType == PRE_GA_WRITE_ROWS) {

                        insertEventHandler.handleEvent(event.getData(), true, currentDataCaptureState, binlogResourceInfo,
                                binlogEventState, null, eventWriterConfiguration, currentSession, timestamp);

                    } else if (eventType == DELETE_ROWS
                            || eventType == EXT_DELETE_ROWS
                            || eventType == PRE_GA_DELETE_ROWS) {

                        deleteEventHandler.handleEvent(event.getData(), true, currentDataCaptureState, binlogResourceInfo,
                                binlogEventState, null, eventWriterConfiguration, currentSession, timestamp);
                    } else {
                        // Update event
                        updateEventHandler.handleEvent(event.getData(), true, currentDataCaptureState, binlogResourceInfo,
                                binlogEventState, null, eventWriterConfiguration, currentSession, timestamp);
                    }
                    break;

                case ROTATE:
                    if (!currentDataCaptureState.isUseGtid()) {
                        // Update current binlog filename
                        RotateEventData rotateEventData = event.getData();
                        dataCaptureState.setBinlogFile(rotateEventData.getBinlogFilename());
                        dataCaptureState.setBinlogPosition(rotateEventData.getBinlogPosition());
                    }
                    updateState(session, dataCaptureState);
                    break;

                case GTID:
                    if (currentDataCaptureState.isUseGtid()) {
                        // Update current binlog gtid
                        GtidEventData gtidEventData = event.getData();
                        MySqlGtid mySqlGtid = gtidEventData.getMySqlGtid();
                        if (mySqlGtid != null) {
                            gtidSet.add(mySqlGtid.toString());
                            dataCaptureState.setGtidSet(gtidSet.toString());
                            updateState(session, dataCaptureState);
                        }
                    }
                    break;

                default:
                    break;
            }

            // Advance the current binlog position. This way if no more events are received and the processor is stopped, it will resume after the event that was just processed.
            // We always get ROTATE and FORMAT_DESCRIPTION messages no matter where we start (even from the end), and they won't have the correct "next position" value, so only
            // advance the position if it is not that type of event.
            if (eventType != ROTATE && eventType != FORMAT_DESCRIPTION && !currentDataCaptureState.isUseGtid() && eventType != XID) {
                dataCaptureState.setBinlogPosition(header.getNextPosition());
            }
        }
    }

    private boolean isQueryDDL(String sql) {
        return sql.startsWith("alter table")
                || sql.startsWith("alter ignore table")
                || sql.startsWith("create table")
                || sql.startsWith("truncate table")
                || sql.startsWith("rename table")
                || sql.startsWith("drop table")
                || sql.startsWith("drop database");
    }

    protected void clearState() throws IOException {
        if (currentSession == null) {
            throw new IllegalStateException("No current session");
        }

        currentSession.clearState(Scope.CLUSTER);
    }

    protected String normalizeQuery(String sql) {
        String normalizedQuery = sql.toLowerCase().trim().replaceAll(" {2,}", " ");

        //Remove comments from the query
        normalizedQuery = MULTI_COMMENT_PATTERN.matcher(normalizedQuery).replaceAll("").trim();
        normalizedQuery = normalizedQuery.replaceAll("#.*", "");
        normalizedQuery = normalizedQuery.replaceAll("-{2}.*", "");
        return normalizedQuery;
    }

    @OnStopped
    public void stop() throws CDCException {
        try {
            if (eventListener != null) {
                eventListener.stop();
                if (binlogClient != null) {
                    binlogClient.unregisterEventListener(eventListener);
                }
            }
            if (binlogClient != null) {
                binlogClient.disconnect();
            }

            if (currentSession != null) {
                FlowFile flowFile = eventWriterConfiguration.getCurrentFlowFile();
                if (flowFile != null && binlogEventState.getCurrentEventWriter() != null) {
                    // Flush the events to the FlowFile when the processor is stopped
                    binlogEventState.getCurrentEventWriter().finishAndTransferFlowFile(
                            currentSession,
                            eventWriterConfiguration,
                            binlogResourceInfo.getTransitUri(),
                            currentDataCaptureState.getSequenceId(), binlogEventState.getCurrentEventInfo(), REL_SUCCESS);
                }
                currentSession.commitAsync();
            }

            currentDataCaptureState.setBinlogPosition(-1);
        } catch (IOException e) {
            throw new CDCException("Error closing CDC connection", e);
        } finally {
            binlogClient = null;

            if (jdbcConnectionHolder != null) {
                jdbcConnectionHolder.close();
            }
        }
    }

    private void updateState(ProcessSession session, DataCaptureState dataCaptureState) throws IOException {
        updateState(session, dataCaptureState, binlogResourceInfo.isInTransaction());
    }

    private void updateState(ProcessSession session, DataCaptureState dataCaptureState, boolean inTransaction) throws IOException {
        // Update state with latest values
        final Map<String, String> newStateMap = new HashMap<>(session.getState(Scope.CLUSTER).toMap());

        // Save current binlog filename, position and GTID to the state map
        if (dataCaptureState.getBinlogFile() != null) {
            newStateMap.put(BinlogEventInfo.BINLOG_FILENAME_KEY, dataCaptureState.getBinlogFile());
        }

        newStateMap.put(BinlogEventInfo.BINLOG_POSITION_KEY, Long.toString(dataCaptureState.getBinlogPosition()));
        newStateMap.put(SEQUENCE_ID_KEY, String.valueOf(dataCaptureState.getSequenceId()));
        //add inTransaction value into state
        newStateMap.put("inTransaction", inTransaction ? "true" : "false");

        if (dataCaptureState.getGtidSet() != null) {
            newStateMap.put(BinlogEventInfo.BINLOG_GTIDSET_KEY, dataCaptureState.getGtidSet());
        }

        session.setState(newStateMap, Scope.CLUSTER);
        currentDataCaptureState = dataCaptureState;
    }


    /**
     * Creates and returns a BinlogEventListener instance, associated with the specified binlog client and event queue.
     *
     * @param client A reference to a BinaryLogClient. The listener is associated with the given client, such that the listener is notified when
     *               events are available to the given client.
     * @param q      A queue used to communicate events between the listener and the NiFi processor thread.
     * @return A BinlogEventListener instance, which will be notified of events associated with the specified client
     */
    BinlogEventListener createBinlogEventListener(BinaryLogClient client, BlockingQueue<RawBinlogEvent> q) {
        return new BinlogEventListener(client, q);
    }

    /**
     * Creates and returns a BinlogLifecycleListener instance, associated with the specified binlog client and event queue.
     *
     * @return A BinlogLifecycleListener instance, which will be notified of events associated with the specified client
     */
    BinlogLifecycleListener createBinlogLifecycleListener() {
        return new BinlogLifecycleListener();
    }


    protected BinaryLogClient createBinlogClient(String hostname, int port, String username, String password) {
        return new BinaryLogClient(hostname, port, username, password);
    }

    /**
     * Retrieves the column information for the specified database and table. The column information can be used to enrich CDC events coming from the RDBMS.
     *
     * @param key A TableInfoCacheKey reference, which contains the database and table names
     * @return A TableInfo instance with the ColumnDefinitions provided (if retrieved successfully from the database)
     */
    protected TableInfo loadTableInfo(TableInfoCacheKey key) throws SQLException {
        TableInfo tableInfo = null;
        if (jdbcConnectionHolder != null) {

            try (Statement s = getJdbcConnection().createStatement()) {
                s.execute("USE `" + key.getDatabaseName() + "`");
                ResultSet rs = s.executeQuery("SELECT * FROM `" + key.getTableName() + "` LIMIT 0");
                ResultSetMetaData rsmd = rs.getMetaData();
                int numCols = rsmd.getColumnCount();
                List<ColumnDefinition> columnDefinitions = new ArrayList<>();
                for (int i = 1; i <= numCols; i++) {
                    // Use the column label if it exists, otherwise use the column name. We're not doing aliasing here, but it's better practice.
                    String columnLabel = rsmd.getColumnLabel(i);
                    columnDefinitions.add(new ColumnDefinition(rsmd.getColumnType(i), columnLabel != null ? columnLabel : rsmd.getColumnName(i)));
                }

                tableInfo = new TableInfo(key.getDatabaseName(), key.getTableName(), key.getTableId(), columnDefinitions);
            }
        }

        return tableInfo;
    }

    protected Connection getJdbcConnection() throws SQLException {
        return jdbcConnectionHolder.getConnection();
    }

    private class JDBCConnectionHolder {
        private final String connectionUrl;
        private final Properties connectionProps = new Properties();
        private final long connectionTimeoutMillis;

        private Connection connection;

        private JDBCConnectionHolder(InetSocketAddress host, String username, String password, Map<String, String> customProperties, long connectionTimeoutMillis) {
            this.connectionUrl = "jdbc:mysql://" + host.getHostString() + ":" + host.getPort();
            connectionProps.putAll(customProperties);
            if (username != null) {
                connectionProps.put("user", username);
                if (password != null) {
                    connectionProps.put("password", password);
                }
            }

            this.connectionTimeoutMillis = connectionTimeoutMillis;
        }

        private Connection getConnection() throws SQLException {
            if (connection != null && connection.isValid((int) (connectionTimeoutMillis / 1000))) {
                getLogger().trace("Returning the pooled JDBC connection.");
                return connection;
            }

            // Close the existing connection just in case.
            close();

            getLogger().trace("Creating a new JDBC connection.");
            connection = DriverManager.getConnection(connectionUrl, connectionProps);
            return connection;
        }

        private void close() {
            if (connection != null) {
                try {
                    getLogger().trace("Closing the pooled JDBC connection.");
                    connection.close();
                } catch (SQLException e) {
                    getLogger().warn("Failed to close JDBC connection due to " + e, e);
                }
            }
        }
    }

    /**
     * using Thread.currentThread().getContextClassLoader(); will ensure that you are using the ClassLoader for you NAR.
     *
     * @throws InitializationException if there is a problem obtaining the ClassLoader
     */
    protected void registerDriver(String locationString, String drvName) throws InitializationException {
        if (locationString != null && locationString.length() > 0) {
            try {
                final Class<?> clazz = Class.forName(drvName);
                if (clazz == null) {
                    throw new InitializationException("Can't load Database Driver " + drvName);
                }
                final Driver driver = (Driver) clazz.newInstance();
                DriverManager.registerDriver(new DriverShim(driver));

            } catch (final InitializationException e) {
                throw e;
            } catch (final Exception e) {
                throw new InitializationException("Can't load Database Driver", e);
            }
        }
    }

    private static class DriverShim implements Driver {
        private final Driver driver;

        DriverShim(Driver d) {
            this.driver = d;
        }

        @Override
        public boolean acceptsURL(String u) throws SQLException {
            return this.driver.acceptsURL(u);
        }

        @Override
        public Connection connect(String u, Properties p) throws SQLException {
            return this.driver.connect(u, p);
        }

        @Override
        public int getMajorVersion() {
            return this.driver.getMajorVersion();
        }

        @Override
        public int getMinorVersion() {
            return this.driver.getMinorVersion();
        }

        @Override
        public DriverPropertyInfo[] getPropertyInfo(String u, Properties p) throws SQLException {
            return this.driver.getPropertyInfo(u, p);
        }

        @Override
        public boolean jdbcCompliant() {
            return this.driver.jdbcCompliant();
        }

        @Override
        public Logger getParentLogger() throws SQLFeatureNotSupportedException {
            return driver.getParentLogger();
        }
    }

    public static class BinlogEventState {
        private BinlogEventInfo currentEventInfo;
        private AbstractBinlogEventWriter<? extends BinlogEventInfo> currentEventWriter;

        public BinlogEventInfo getCurrentEventInfo() {
            return currentEventInfo;
        }

        public void setCurrentEventInfo(BinlogEventInfo currentEventInfo) {
            this.currentEventInfo = currentEventInfo;
        }

        public AbstractBinlogEventWriter<? extends BinlogEventInfo> getCurrentEventWriter() {
            return currentEventWriter;
        }

        public void setCurrentEventWriter(AbstractBinlogEventWriter<? extends BinlogEventInfo> currentEventWriter) {
            this.currentEventWriter = currentEventWriter;
        }
    }

    public static class BinlogResourceInfo {
        private TableInfo currentTable = null;
        private String currentDatabase = null;

        private boolean inTransaction = false;

        private String transitUri = "<unknown>";

        public BinlogResourceInfo() {

        }

        public TableInfo getCurrentTable() {
            return currentTable;
        }

        public void setCurrentTable(TableInfo currentTable) {
            this.currentTable = currentTable;
        }

        public String getCurrentDatabase() {
            return currentDatabase;
        }

        public void setCurrentDatabase(String currentDatabase) {
            this.currentDatabase = currentDatabase;
        }

        public boolean isInTransaction() {
            return inTransaction;
        }

        public void setInTransaction(boolean inTransaction) {
            this.inTransaction = inTransaction;
        }

        public String getTransitUri() {
            return transitUri;
        }

        public void setTransitUri(String transitUri) {
            this.transitUri = transitUri;
        }
    }
}
