Add ability to use Kafka's sinks as Pulsar sinks (apache#9927)

* Add ability to use Kafka's sinks as Pulsar sinks

* Get topic/partition from the record

* Making use of GenericObject

* Added SubscriptionType check and tests

* support for topic/partition pause/resume/seek

* added comment; only one flush in progress is allowed

pulsar-io/kafka-connect-adaptor-nar/src/main/resources/META-INF/services/pulsar-io.yaml

@@ -20,3 +20,4 @@
 name: kafka-connect-adaptor
 description: Kafka source connect adaptor
 sourceClass: org.apache.pulsar.io.kafka.connect.KafkaConnectSource
+sinkClass: org.apache.pulsar.io.kafka.connect.KafkaConnectSink

pulsar-io/kafka-connect-adaptor/src/main/java/org/apache/pulsar/io/kafka/connect/KafkaConnectSink.java

@@ -0,0 +1,353 @@
+/**
+ * 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.pulsar.io.kafka.connect;
+
+import com.google.common.annotations.VisibleForTesting;
+import com.google.common.base.Preconditions;
+import com.google.common.collect.ImmutableMap;
+import com.google.common.collect.Lists;
+import com.google.common.collect.Maps;
+import com.google.common.util.concurrent.ThreadFactoryBuilder;
+import lombok.extern.slf4j.Slf4j;
+import org.apache.kafka.clients.consumer.OffsetAndMetadata;
+import org.apache.kafka.common.TopicPartition;
+import org.apache.kafka.common.record.TimestampType;
+import org.apache.kafka.connect.connector.Task;
+import org.apache.kafka.connect.data.Schema;
+import org.apache.kafka.connect.sink.SinkConnector;
+import org.apache.kafka.connect.sink.SinkRecord;
+import org.apache.kafka.connect.sink.SinkTask;
+import org.apache.pulsar.client.api.Message;
+import org.apache.pulsar.client.api.SubscriptionType;
+import org.apache.pulsar.client.api.schema.GenericObject;
+import org.apache.pulsar.client.impl.schema.KeyValueSchema;
+import org.apache.pulsar.common.schema.SchemaType;
+import org.apache.pulsar.functions.api.Record;
+import org.apache.pulsar.io.core.KeyValue;
+import org.apache.pulsar.io.core.Sink;
+import org.apache.pulsar.io.core.SinkContext;
+
+import java.util.List;
+import java.util.Map;
+import java.util.Objects;
+import java.util.Properties;
+import java.util.concurrent.ConcurrentLinkedDeque;
+import java.util.concurrent.Executors;
+import java.util.concurrent.ScheduledExecutorService;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.atomic.AtomicBoolean;
+import java.util.concurrent.atomic.AtomicLong;
+
+import static org.apache.pulsar.io.kafka.connect.PulsarKafkaWorkerConfig.OFFSET_STORAGE_TOPIC_CONFIG;
+import static org.apache.pulsar.io.kafka.connect.PulsarKafkaWorkerConfig.PULSAR_SERVICE_URL_CONFIG;
+
+@Slf4j
+public class KafkaConnectSink implements Sink<GenericObject> {
+
+    private boolean unwrapKeyValueIfAvailable;
+
+    private final static ImmutableMap<Class<?>, Schema> primitiveTypeToSchema;
+    private final static ImmutableMap<SchemaType, Schema> pulsarSchemaTypeTypeToKafkaSchema;
+
+    static {
+        primitiveTypeToSchema = ImmutableMap.<Class<?>, Schema>builder()
+                .put(Boolean.class, Schema.BOOLEAN_SCHEMA)
+                .put(Byte.class, Schema.INT8_SCHEMA)
+                .put(Short.class, Schema.INT16_SCHEMA)
+                .put(Integer.class, Schema.INT32_SCHEMA)
+                .put(Long.class, Schema.INT64_SCHEMA)
+                .put(Float.class, Schema.FLOAT32_SCHEMA)
+                .put(Double.class, Schema.FLOAT64_SCHEMA)
+                .put(String.class, Schema.STRING_SCHEMA)
+                .put(byte[].class, Schema.BYTES_SCHEMA)
+                .build();
+        pulsarSchemaTypeTypeToKafkaSchema = ImmutableMap.<SchemaType, Schema>builder()
+                .put(SchemaType.BOOLEAN, Schema.BOOLEAN_SCHEMA)
+                .put(SchemaType.INT8, Schema.INT8_SCHEMA)
+                .put(SchemaType.INT16, Schema.INT16_SCHEMA)
+                .put(SchemaType.INT32, Schema.INT32_SCHEMA)
+                .put(SchemaType.INT64, Schema.INT64_SCHEMA)
+                .put(SchemaType.FLOAT, Schema.FLOAT32_SCHEMA)
+                .put(SchemaType.DOUBLE, Schema.FLOAT64_SCHEMA)
+                .put(SchemaType.STRING, Schema.STRING_SCHEMA)
+                .put(SchemaType.BYTES, Schema.BYTES_SCHEMA)
+                .build();
+    }
+
+    private PulsarKafkaSinkContext sinkContext;
+    @VisibleForTesting
+    PulsarKafkaSinkTaskContext taskContext;
+    private SinkConnector connector;
+    private SinkTask task;
+
+    private long maxBatchSize;
+    private final AtomicLong currentBatchSize = new AtomicLong(0L);
+
+    private long lingerMs;
+    private final ScheduledExecutorService scheduledExecutor =
+            Executors.newSingleThreadScheduledExecutor(new ThreadFactoryBuilder()
+                    .setNameFormat("pulsar-io-kafka-adaptor-sink-flush-%d")
+                    .build());
+    private final ConcurrentLinkedDeque<Record<GenericObject>> pendingFlushQueue = new ConcurrentLinkedDeque<>();
+    private final AtomicBoolean isFlushRunning = new AtomicBoolean(false);
+    private volatile boolean isRunning = false;
+
+    private final Properties props = new Properties();
+    private PulsarKafkaConnectSinkConfig kafkaSinkConfig;
+
+    protected String topicName;
+
+    @Override
+    public void write(Record<GenericObject> sourceRecord) {
+        if (log.isDebugEnabled()) {
+            log.debug("Record sending to kafka, record={}.", sourceRecord);
+        }
+
+        if (!isRunning) {
+            log.warn("Sink is stopped. Cannot send the record {}", sourceRecord);
+            sourceRecord.fail();
+            return;
+        }
+
+        // while sourceRecord.getMessage() is Optional<>
+        // it should always be present in Sink which gets instance of PulsarRecord
+        // let's avoid checks for .isPresent() in teh rest of the code
+        Preconditions.checkArgument(sourceRecord.getMessage().isPresent());
+        try {
+            SinkRecord record = toSinkRecord(sourceRecord);
+            task.put(Lists.newArrayList(record));
+        } catch (Exception ex) {
+            log.error("Error sending the record {}", sourceRecord, ex);
+            sourceRecord.fail();
+            return;
+        }
+        pendingFlushQueue.add(sourceRecord);
+        currentBatchSize.addAndGet(sourceRecord.getMessage().get().size());
+        flushIfNeeded(false);
+    }
+
+    @Override
+    public void close() throws Exception {
+        isRunning = false;
+        flushIfNeeded(true);
+        scheduledExecutor.shutdown();
+        if (!scheduledExecutor.awaitTermination(10 * lingerMs, TimeUnit.MILLISECONDS)) {
+            log.error("scheduledExecutor did not terminate in {} ms", 10 * lingerMs);
+        }
+
+        task.stop();
+        connector.stop();
+        taskContext.close();
+
+        log.info("Kafka sink stopped.");
+    }
+
+    @Override
+    public void open(Map<String, Object> config, SinkContext ctx) throws Exception {
+        kafkaSinkConfig = PulsarKafkaConnectSinkConfig.load(config);
+        Objects.requireNonNull(kafkaSinkConfig.getTopic(), "Kafka topic is not set");
+        Preconditions.checkArgument(ctx.getSubscriptionType() == SubscriptionType.Failover
+                || ctx.getSubscriptionType() == SubscriptionType.Exclusive,
+                "Source must run with Exclusive or Failover subscription type");
+        topicName = kafkaSinkConfig.getTopic();
+        unwrapKeyValueIfAvailable = kafkaSinkConfig.isUnwrapKeyValueIfAvailable();
+
+        String kafkaConnectorFQClassName = kafkaSinkConfig.getKafkaConnectorSinkClass();
+        kafkaSinkConfig.getKafkaConnectorConfigProperties().forEach(props::put);
+
+        Class<?> clazz = Class.forName(kafkaConnectorFQClassName);
+        connector = (SinkConnector) clazz.getConstructor().newInstance();
+
+        Class<? extends Task> taskClass = connector.taskClass();
+        sinkContext = new PulsarKafkaSinkContext();
+        connector.initialize(sinkContext);
+        connector.start(Maps.fromProperties(props));
+
+        List<Map<String, String>> configs = connector.taskConfigs(1);
+        Preconditions.checkNotNull(configs);
+        Preconditions.checkArgument(configs.size() == 1);
+
+        configs.forEach(x -> {
+            x.put(OFFSET_STORAGE_TOPIC_CONFIG, kafkaSinkConfig.getOffsetStorageTopic());
+            x.put(PULSAR_SERVICE_URL_CONFIG, kafkaSinkConfig.getPulsarServiceUrl());
+        });
+        task = (SinkTask) taskClass.getConstructor().newInstance();
+        taskContext =
+                new PulsarKafkaSinkTaskContext(configs.get(0), ctx, task::open);
+        task.initialize(taskContext);
+        task.start(configs.get(0));
+
+        maxBatchSize = kafkaSinkConfig.getBatchSize();
+        lingerMs = kafkaSinkConfig.getLingerTimeMs();
+
+        isRunning = true;
+        scheduledExecutor.scheduleWithFixedDelay(() ->
+                this.flushIfNeeded(true), lingerMs, lingerMs, TimeUnit.MILLISECONDS);
+
+        log.info("Kafka sink started : {}.", props);
+    }
+
+    private void flushIfNeeded(boolean force) {
+        if (isFlushRunning.get()) {
+            return;
+        }
+        if (force || currentBatchSize.get() >= maxBatchSize) {
+            scheduledExecutor.submit(this::flush);
+        }
+    }
+
+    // flush always happens on the same thread
+    public void flush() {
+        if (log.isDebugEnabled()) {
+            log.debug("flush requested, pending: {}, batchSize: {}",
+                    currentBatchSize.get(), maxBatchSize);
+        }
+
+        if (pendingFlushQueue.isEmpty()) {
+            return;
+        }
+
+        if (!isFlushRunning.compareAndSet(false, true)) {
+            return;
+        }
+
+        final Record<GenericObject> lastNotFlushed = pendingFlushQueue.getLast();
+        try {
+            Map<TopicPartition, OffsetAndMetadata> currentOffsets = taskContext.currentOffsets();
+            task.flush(currentOffsets);
+            taskContext.flushOffsets(currentOffsets);
+            ackUntil(lastNotFlushed, Record::ack);
+        } catch (Throwable t) {
+            log.error("error flushing pending records", t);
+            ackUntil(lastNotFlushed, Record::fail);
+        } finally {
+            isFlushRunning.compareAndSet(true, false);
+        }
+    }
+
+    private void ackUntil(Record<GenericObject> lastNotFlushed, java.util.function.Consumer<Record<GenericObject>> cb) {
+        while (!pendingFlushQueue.isEmpty()) {
+            Record<GenericObject> r = pendingFlushQueue.pollFirst();
+            cb.accept(r);
+            currentBatchSize.addAndGet(-1 * r.getMessage().get().size());
+            if (r == lastNotFlushed) {
+                break;
+            }
+        }
+    }
+
+    /**
+     * org.apache.kafka.connect.data.Schema for the object
+     * @param obj - Object to get schema of.
+     * @return org.apache.kafka.connect.data.Schema
+     */
+    private static Schema getKafkaConnectSchemaForObject(Object obj) {
+        if (obj != null && primitiveTypeToSchema.containsKey(obj.getClass())) {
+            return primitiveTypeToSchema.get(obj.getClass());
+        }
+        return null;
+    }
+
+    public static Schema getKafkaConnectSchema(org.apache.pulsar.client.api.Schema pulsarSchema, Object obj) {
+        if (pulsarSchema != null && pulsarSchema.getSchemaInfo() != null
+                && pulsarSchemaTypeTypeToKafkaSchema.containsKey(pulsarSchema.getSchemaInfo().getType())) {
+            return pulsarSchemaTypeTypeToKafkaSchema.get(pulsarSchema.getSchemaInfo().getType());
+        }
+
+        Schema result = getKafkaConnectSchemaForObject(obj);
+        if (result == null) {
+            throw new IllegalStateException("Unsupported kafka schema for Pulsar Schema "
+                    + (pulsarSchema == null || pulsarSchema.getSchemaInfo() == null
+                        ? "null"
+                        : pulsarSchema.getSchemaInfo().toString())
+                    + " object class "
+                    + (obj == null ? "null" : obj.getClass().getCanonicalName()));
+        }
+        return result;
+    }
+
+
+    @SuppressWarnings("rawtypes")
+    private SinkRecord toSinkRecord(Record<GenericObject> sourceRecord) {
+        final int partition = sourceRecord.getPartitionIndex().orElse(0);
+        final String topic = sourceRecord.getTopicName().orElse(topicName);
+        final Object key;
+        final Object value;
+        final Schema keySchema;
+        final Schema valueSchema;
+
+        // sourceRecord is never instanceof KVRecord
+        // https://github.com/apache/pulsar/pull/10113
+        if (unwrapKeyValueIfAvailable && sourceRecord.getSchema() != null
+                && sourceRecord.getSchema().getSchemaInfo() != null
+                && sourceRecord.getSchema().getSchemaInfo().getType() == SchemaType.KEY_VALUE) {
+            KeyValueSchema kvSchema = (KeyValueSchema) sourceRecord.getSchema();
+            KeyValue kv = (KeyValue) sourceRecord.getValue().getNativeObject();
+            key = kv.getKey();
+            value = kv.getValue();
+            keySchema = getKafkaConnectSchema(kvSchema.getKeySchema(), key);
+            valueSchema = getKafkaConnectSchema(kvSchema.getValueSchema(), value);
+        } else {
+            if (sourceRecord.getMessage().get().hasBase64EncodedKey()) {
+                key = sourceRecord.getMessage().get().getKeyBytes();
+                keySchema = Schema.BYTES_SCHEMA;
+            } else {
+                key = sourceRecord.getKey().orElse(null);
+                keySchema = Schema.STRING_SCHEMA;
+            }
+            value = sourceRecord.getValue().getNativeObject();
+            valueSchema = getKafkaConnectSchema(sourceRecord.getSchema(), value);
+        }
+
+        long offset = sourceRecord.getRecordSequence()
+                .orElse(-1L);
+        if (offset < 0) {
+            log.error("Message without sequenceId. Key: {} Value: {}", key, value);
+            throw new IllegalStateException("Message without sequenceId");
+        }
+        taskContext.updateLastOffset(new TopicPartition(topic, partition), offset);
+
+        Long timestamp = null;
+        TimestampType timestampType = TimestampType.NO_TIMESTAMP_TYPE;
+        if (sourceRecord.getEventTime().isPresent()) {
+            timestamp = sourceRecord.getEventTime().get();
+            timestampType = TimestampType.CREATE_TIME;
+        } else {
+            // publishTime is not a log append time.
+            // keep timestampType = TimestampType.NO_TIMESTAMP_TYPE
+            timestamp = sourceRecord.getMessage().get().getPublishTime();
+        }
+        return new SinkRecord(topic,
+                partition,
+                keySchema,
+                key,
+                valueSchema,
+                value,
+                offset,
+                timestamp,
+                timestampType);
+    }
+
+    @VisibleForTesting
+    protected long currentOffset(String topic, int partition) {
+        return taskContext.currentOffset(topic, partition);
+    }
+
+}