davyam commented on a change in pull request #4065: URL: https://github.com/apache/nifi/pull/4065#discussion_r697956122
########## File path: nifi-nar-bundles/nifi-cdc/nifi-cdc-postgresql-bundle/nifi-cdc-postgresql-processors/src/main/java/org/apache/nifi/cdc/postgresql/processors/CaptureChangePostgreSQL.java ########## @@ -0,0 +1,468 @@ +/* + * 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.postgresql.processors; + +import java.io.IOException; +import java.io.OutputStream; +import java.net.MalformedURLException; +import java.nio.charset.StandardCharsets; +import java.sql.Connection; +import java.sql.Driver; +import java.sql.DriverManager; +import java.sql.DriverPropertyInfo; +import java.sql.SQLException; +import java.sql.SQLFeatureNotSupportedException; +import java.util.ArrayList; +import java.util.Collections; +import java.util.HashMap; +import java.util.HashSet; +import java.util.LinkedList; +import java.util.List; +import java.util.Map; +import java.util.Properties; +import java.util.Set; +import java.util.concurrent.atomic.AtomicBoolean; +import java.util.logging.Logger; + +import org.apache.nifi.annotation.behavior.InputRequirement; +import org.apache.nifi.annotation.behavior.PrimaryNodeOnly; +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.OnScheduled; +import org.apache.nifi.annotation.lifecycle.OnShutdown; +import org.apache.nifi.annotation.lifecycle.OnStopped; +import org.apache.nifi.cdc.CDCException; +import org.apache.nifi.cdc.postgresql.pgEasyReplication.ConnectionManager; +import org.apache.nifi.cdc.postgresql.pgEasyReplication.PGEasyReplication; +import org.apache.nifi.cdc.postgresql.pgEasyReplication.Event; +import org.apache.nifi.components.PropertyDescriptor; +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.expression.ExpressionLanguageScope; +import org.apache.nifi.flowfile.FlowFile; +import org.apache.nifi.flowfile.attributes.CoreAttributes; +import org.apache.nifi.logging.ComponentLog; +import org.apache.nifi.processor.AbstractProcessor; +import org.apache.nifi.processor.ProcessContext; +import org.apache.nifi.processor.ProcessSession; +import org.apache.nifi.processor.ProcessorInitializationContext; +import org.apache.nifi.processor.Relationship; +import org.apache.nifi.processor.exception.ProcessException; +import org.apache.nifi.processor.io.OutputStreamCallback; +import org.apache.nifi.processor.util.StandardValidators; +import org.apache.nifi.reporting.InitializationException; +import org.apache.nifi.util.file.classloader.ClassLoaderUtils; + +/* A processor to Capture Data Change (CDC) events and return them as flow files. */ + +@TriggerSerially + +@InputRequirement(InputRequirement.Requirement.INPUT_FORBIDDEN) + +@PrimaryNodeOnly + +@Tags({ "sql", "jdbc", "cdc", "postgresql" }) + +@CapabilityDescription("Retrieves Change Data Capture (CDC) events from a PostgreSQL database. Works for PostgreSQL version 10+. CDC Events include INSERT, UPDATE, DELETE operations. Events " + + "are output as individual flow files ordered by the time at which the operation occurred. This processor use a replication connection to stream data and sql connection to snapshot.") + +@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 = "last.lsn.received", description = "A Log Sequence Number (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 = "mime.type", description = "The processor outputs flow file content in JSON format, and sets the mime.type attribute to " + "application/json") }) + +public class CaptureChangePostgreSQL extends AbstractProcessor { + // Relationships + public static final Relationship REL_SUCCESS = new Relationship.Builder().name("success").description("Successfully created FlowFile from CDC event.").build(); + // Properties + public static final PropertyDescriptor HOST = new PropertyDescriptor.Builder().name("cdc-postgresql-host").displayName("PostgreSQL Host") + .description("A list of hostname/port entries corresponding to nodes in a PostgreSQL cluster. The entries should be comma separated " + + "using a colon such as host1:port,host2:port,.... For example postgresql.myhost.com:5432. 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 host entry is specified in this property. The default port for PostgreSQL connections is 5432.") + .required(true).addValidator(StandardValidators.NON_EMPTY_VALIDATOR).build(); + + public static final PropertyDescriptor DRIVER_NAME = new PropertyDescriptor.Builder().name("cdc-postgresql-driver-class").displayName("PostgreSQL Driver Class Name") + .description("The class name of the PostgreSQL database driver class").defaultValue("org.postgresql.Driver").required(true).addValidator(StandardValidators.NON_EMPTY_VALIDATOR) + .expressionLanguageSupported(ExpressionLanguageScope.VARIABLE_REGISTRY).build(); + + public static final PropertyDescriptor DRIVER_LOCATION = new PropertyDescriptor.Builder().name("cdc-postgresql-driver-locations").displayName("PostgreSQL Driver Location(s)") + .description("Comma-separated list of files/folders and/or URLs containing the PostgreSQL driver JAR and its dependencies (if any)." + "For example '/var/tmp/postgresql-42.2.9.jar'") + .defaultValue(null).required(false).addValidator(StandardValidators.createListValidator(true, true, StandardValidators.createURLorFileValidator())) + .expressionLanguageSupported(ExpressionLanguageScope.VARIABLE_REGISTRY).build(); + + public static final PropertyDescriptor DATABASE_NAME = new PropertyDescriptor.Builder().name("cdc-postgresql-database").displayName("Database") + .description("Specifies the name of the database to connect to.").required(true).addValidator(StandardValidators.NON_EMPTY_VALIDATOR).build(); + + public static final PropertyDescriptor USERNAME = new PropertyDescriptor.Builder().name("cdc-postgresql-user").displayName("Username").description("Username to access PostgreSQL cluster.") + .required(true).addValidator(StandardValidators.NON_EMPTY_VALIDATOR).build(); + + public static final PropertyDescriptor PASSWORD = new PropertyDescriptor.Builder().name("cdc-postgresql-password").displayName("Password").description("Password to access PostgreSQL cluster.") + .required(false).sensitive(true).addValidator(StandardValidators.NON_EMPTY_VALIDATOR).build(); + + public static final PropertyDescriptor PUBLICATION = new PropertyDescriptor.Builder().name("cdc-postgresql-publication").displayName("Publication") + .description("PostgreSQL publication name. A publication is essentially a group of tables whose data changes are intended to be replicated through logical replication.").required(true) + .addValidator(StandardValidators.NON_EMPTY_VALIDATOR).build(); + + public static final PropertyDescriptor SLOT_NAME = new PropertyDescriptor.Builder().name("cdc-postgresql-slot-name").displayName("Slot Name") + .description("A unique, cluster-wide identifier for the replication slot. Each replication slot has a name, which can contain lower-case letters, numbers, " + + "and the underscore character. Existing replication slots and their state can be seen in the pg_replication_slots view.") + .required(true).addValidator(StandardValidators.NON_EMPTY_VALIDATOR).build(); + + public static final PropertyDescriptor SNAPSHOT = new PropertyDescriptor.Builder().name("cdc-postgresql-snapshot").displayName("Make Snapshot") + .description("The initial data in existing subscribed tables are snapshotted and copied in a parallel instance of a special kind of apply " + + "process. This process will create its own temporary replication slot and copy the existing data. Once existing data is copied, " + + "the worker enters synchronization mode, which ensures that the table is brought up to a synchronized state with the main apply " + + "process by streaming any changes that happened during the initial data copy using standard logical replication. Once the " + + "synchronization is done, the control of the replication of the table is given back to the main apply process where the replication " + "continues as normal.") + .required(true).allowableValues("true", "false").defaultValue("false").addValidator(StandardValidators.BOOLEAN_VALIDATOR).build(); + + public static final PropertyDescriptor INCLUDE_BEGIN_COMMIT = new PropertyDescriptor.Builder().name("cdc-postgresql-include-begin-commit").displayName("Include Begin/Commit Events") + .description("Specifies whether to emit events corresponding to a BEGIN or COMMIT event. 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 INIT_LSN = new PropertyDescriptor.Builder().name("cdc-postgresql-init-lsn").displayName("Initial Log Sequence Number - LSN") + .description("Specifies an initial Log Sequence Number - LSN to use if this processor's State does not have a current " + + "sequence identifier. If a Log Sequence Number - LSN is present in the processor's State, this property is ignored. Log Sequence Number - LSN 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.POSITIVE_LONG_VALIDATOR).build(); + + public static final PropertyDescriptor DROP_SLOT_IF_EXISTS = new PropertyDescriptor.Builder().name("cdc-postgresql-drop-slot-if-exists").displayName("Drop If Exists Replication Slot") + .description("The initial data in existing subscribed tables are snapshotted and copied in a parallel instance of a special kind of apply " + + "process. This process will create its own temporary replication slot and copy the existing data. Once existing data is copied, " + + "the worker enters synchronization mode, which ensures that the table is brought up to a synchronized state with the main apply " + + "process by streaming any changes that happened during the initial data copy using standard logical replication. Once the " + + "synchronization is done, the control of the replication of the table is given back to the main apply process where the replication " + "continues as normal.") + .required(true).allowableValues("true", "false").defaultValue("false").addValidator(StandardValidators.BOOLEAN_VALIDATOR).build(); + + private List<PropertyDescriptor> descriptors; + private Set<Relationship> relationships; + + // Attribute keys + public static final String MIME_TYPE_VALUE = "application/json"; + public static final String LAST_LSN_RECEIVED = "last.lsn.received"; + + // Attributes of Processor + private AtomicBoolean hasRun = new AtomicBoolean(false); + private volatile Long lastLSNReceived = null; + private volatile Boolean includeBeginCommit = false; + private Long initialLSN = 0L; + private PGEasyReplication pgEasyReplication = null; + boolean hasSnapshot = false; + private ConnectionManager connectionManager; + + // Update lastLSNReceived on processor state + private void updateState(StateManager stateManager) throws IOException { + // Update state with latest values + if (stateManager != null) { + Map<String, String> newStateMap = new HashMap<>(stateManager.getState(Scope.CLUSTER).toMap()); + + newStateMap.put(LAST_LSN_RECEIVED, String.valueOf(this.lastLSNReceived)); + stateManager.setState(newStateMap, Scope.CLUSTER); + } + } + + /** + * 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 { + // Split and trim the entries + final ClassLoader classLoader = ClassLoaderUtils.getCustomClassLoader(locationString, this.getClass().getClassLoader(), (dir, name) -> name != null && name.endsWith(".jar")); + + // Workaround which allows to use URLClassLoader for JDBC driver loading. + // Because the DriverManager will refuse to use a driver not loaded by the + // system ClassLoader. + final Class<?> clazz = Class.forName(drvName, true, classLoader); + if (clazz == null) { + throw new InitializationException("Can't load Database Driver " + drvName + " location" + locationString + "classLoader" + classLoader.toString()); + } + final Driver driver = (Driver) clazz.newInstance(); + DriverManager.registerDriver(new DriverShim(driver)); + + } catch (final InitializationException e) { + throw e; + } catch (final MalformedURLException e) { + throw new InitializationException("Invalid Database Driver Jar Url", e); + } catch (final Exception e) { + throw new InitializationException("Can't load Database Driver", e); + } + } + } + + private static class DriverShim implements Driver { + private 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(); + } + + } + + protected void stop(StateManager stateManager) throws CDCException { + try { + this.connectionManager.closeReplicationConnection(); + this.connectionManager.closeSQLConnection(); + this.pgEasyReplication = null; + + if (this.lastLSNReceived != null) + updateState(stateManager); + } catch (Exception e) { + throw new CDCException("Error closing CDC connection", e); + } + } + + @OnStopped + public void onStopped(ProcessContext context) { + try { + stop(context.getStateManager()); + } catch (CDCException ioe) { + throw new ProcessException(ioe); + } + } + + @OnShutdown + public void onShutdown(ProcessContext context) { + try { + // In case we get shutdown while still running, save off the current state, + // disconnect, and shut down gracefully + stop(context.getStateManager()); + } catch (CDCException ioe) { + throw new ProcessException(ioe); + } + } + + @Override + protected void init(final ProcessorInitializationContext context) { + final List<PropertyDescriptor> descriptors = new ArrayList<PropertyDescriptor>(); + descriptors.add(HOST); + descriptors.add(DRIVER_NAME); + descriptors.add(DRIVER_LOCATION); + descriptors.add(DATABASE_NAME); + descriptors.add(USERNAME); + descriptors.add(PASSWORD); + descriptors.add(PUBLICATION); + descriptors.add(SLOT_NAME); + descriptors.add(SNAPSHOT); + descriptors.add(INCLUDE_BEGIN_COMMIT); + descriptors.add(INIT_LSN); + descriptors.add(DROP_SLOT_IF_EXISTS); + + this.descriptors = Collections.unmodifiableList(descriptors); + + final Set<Relationship> relationships = new HashSet<Relationship>(); + relationships.add(REL_SUCCESS); + this.relationships = Collections.unmodifiableSet(relationships); + } + + @Override + public Set<Relationship> getRelationships() { + return this.relationships; + } + + @Override + public final List<PropertyDescriptor> getSupportedPropertyDescriptors() { + return descriptors; + } + + @OnScheduled + public void onScheduled(final ProcessContext context) { + + } + + // Runs the initial configuration of processor + public void setup(ProcessContext context) { + + final ComponentLog logger = getLogger(); + final StateManager stateManager = context.getStateManager(); + final StateMap stateMap; + + final String host = context.getProperty(HOST).evaluateAttributeExpressions().getValue(); + final String database = context.getProperty(DATABASE_NAME).evaluateAttributeExpressions().getValue(); + final String username = context.getProperty(USERNAME).evaluateAttributeExpressions().getValue(); + final boolean dropSlotIfExists = context.getProperty(DROP_SLOT_IF_EXISTS).evaluateAttributeExpressions().asBoolean(); + final String publicationName = context.getProperty(PUBLICATION).evaluateAttributeExpressions().getValue(); + final String replicationSlotName = context.getProperty(SLOT_NAME).evaluateAttributeExpressions().getValue(); + + // Save off PostgreSQL cluster and JDBC driver information, will be used to + // connect for event + final String driverName = context.getProperty(DRIVER_NAME).evaluateAttributeExpressions().getValue(); + final String driverLocation = context.getProperty(DRIVER_LOCATION).evaluateAttributeExpressions().getValue(); + + String password = context.getProperty(PASSWORD).evaluateAttributeExpressions().getValue(); + + // Connection expects a non-null password, so set it to the empty string if it + // is not provided + if (password == null) { + password = ""; + } + + this.hasSnapshot = context.getProperty(SNAPSHOT).asBoolean(); + this.includeBeginCommit = context.getProperty(INCLUDE_BEGIN_COMMIT).asBoolean(); + this.initialLSN = context.getProperty(INIT_LSN).asLong() == null ? null : context.getProperty(INIT_LSN).asLong(); + + try { + + // Ensure driverLocation and driverName are correct before establishing + // PostgreSQL connection to avoid failing after PostgreSQL messages are received. + // Actual JDBC connection is created after PostgreSQL client gets started, + // because we need the connect-able host same as the PostgreSQL client. + registerDriver(driverLocation, driverName); + this.connectionManager = new ConnectionManager(); + this.connectionManager.setProperties(host, database, username, password, driverName); + this.connectionManager.createSQLConnection(); + this.connectionManager.createReplicationConnection(); + + stateMap = stateManager.getState(Scope.CLUSTER); + + this.pgEasyReplication = new PGEasyReplication(publicationName, replicationSlotName, this.connectionManager); + this.pgEasyReplication.initializeLogicalReplication(dropSlotIfExists); + + if (stateMap.get(LAST_LSN_RECEIVED) != null) { + this.lastLSNReceived = Long.parseLong(stateMap.get(LAST_LSN_RECEIVED)); + this.hasRun.set(true); + } else { + this.hasRun.set(false); + } + + } catch (final Exception ioe) { + logger.error("Failed to retrieve values from the State Manager. Will not attempt " + "connection until this is accomplished.", ioe); + context.yield(); + throw new ProcessException(ioe.getMessage(), ioe); + } + } + + List<Event> getData() { Review comment: This method was included in onTrigger aiming for cleaner code. About events per flow file, I totally agree. Currently, each captured event becomes a flow file. So, with the record-based components we can improve this processor in several aspects. But, as you suggested, I believe it can be developed in a new JIRA. -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: issues-unsubscr...@nifi.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org
