diff --git a/.github/workflows/ydb-tech.yml b/.github/workflows/ydb-tech.yml new file mode 100644 index 000000000..a1bfcf6f2 --- /dev/null +++ b/.github/workflows/ydb-tech.yml @@ -0,0 +1,34 @@ +name: ydb.tech examples + +on: + pull_request: + push: + branches: [master, docs/topic-snippets] + +concurrency: + group: ydb-tech-examples-${{ github.head_ref || github.ref_name }} + cancel-in-progress: true + +permissions: + contents: read + +jobs: + examples: + name: Examples (ydb_tech) + runs-on: ubuntu-latest + timeout-minutes: 20 + services: + ydb: + image: ydbplatform/local-ydb:trunk + ports: ["2136:2136", "8765:8765"] + env: + YDB_USE_IN_MEMORY_PDISKS: true + options: '-h localhost' + steps: + - uses: actions/checkout@v5 + - uses: actions/setup-java@v5 + with: + java-version: '17' + distribution: temurin + cache: maven + - run: bash ydb_tech/run.sh diff --git a/ydb_tech/README.md b/ydb_tech/README.md new file mode 100644 index 000000000..62e80e87f --- /dev/null +++ b/ydb_tech/README.md @@ -0,0 +1,26 @@ +# Executable documentation examples + +`ydb_tech` contains the executable sources used by ydb.tech documentation. +The `Examples (ydb_tech)` CI job builds and runs every registered example against +this checkout and a local YDB instance. + +Run all examples from the repository root: + +```sh +bash ydb_tech/run.sh +``` + +Each example has its own directory and a `run.sh` entry point. The common runner +finds these entry points automatically and fails if any example fails or times out. +It requires Python 3 for portable process timeouts. Set `YDB_TECH_TIMEOUT_SECONDS` +to change the default 180-second limit per example. + +To add an example: + +1. Add a directory with executable source and a `run.sh` entry point. +2. Register its project in the SDK build if the language requires it. +3. Mark documentation regions with `[BEGIN name]` and `[END name]` comments. +4. Keep each region nonempty, unique within its file, and free of nested regions. + +No workflow changes are needed for a new example. The topic example is the first +scenario; its README describes SDK-specific build and connection settings. diff --git a/ydb_tech/run.sh b/ydb_tech/run.sh new file mode 100755 index 000000000..1b4bdcbb5 --- /dev/null +++ b/ydb_tech/run.sh @@ -0,0 +1,26 @@ +#!/usr/bin/env bash +set -euo pipefail +examples_root="$(cd "$(dirname "$0")" && pwd)" +repo_root="$(dirname "$examples_root")" +cd "$repo_root" +example_count=0 +for entry in "$examples_root"/*/run.sh; do + [[ -f "$entry" ]] || continue + example_count=$((example_count + 1)) + printf 'Running %s\n' "${entry%/run.sh}" + python3 - "$entry" "${YDB_TECH_TIMEOUT_SECONDS:-180}" <<'PYTHON' +import subprocess +import sys + +try: + result = subprocess.run(["bash", sys.argv[1]], timeout=int(sys.argv[2]), check=False) +except subprocess.TimeoutExpired: + print("Example exceeded its time limit: " + sys.argv[1], file=sys.stderr) + raise SystemExit(124) +raise SystemExit(result.returncode) +PYTHON +done +if [[ "$example_count" == 0 ]]; then + printf 'No executable examples found in %s\n' "$examples_root" >&2 + exit 1 +fi diff --git a/ydb_tech/topic/README.md b/ydb_tech/topic/README.md new file mode 100644 index 000000000..ffb4dd1f6 --- /dev/null +++ b/ydb_tech/topic/README.md @@ -0,0 +1,16 @@ +# Topic examples for ydb.tech + +This application supplies the Java snippets in the topic reference on ydb.tech. +The runner builds and installs this checkout, reads its SDK version and passes that +version to the example. No SDK version is hardcoded in the example POM. + +With JDK 8 or newer, Maven and a local YDB instance, run from the repository root: + +```sh +bash ydb_tech/topic/run.sh +``` + +`YDB_CONNECTION_STRING` defaults to `grpc://localhost:2136/local`. +The application checks management, sync and async writers/readers, acknowledgments, +metadata, compression, selectors, external commits and transactions. Topics have unique names. +The offset callback uses an in-memory store; use persistent storage for production recovery. diff --git a/ydb_tech/topic/pom.xml b/ydb_tech/topic/pom.xml new file mode 100644 index 000000000..443f9cb52 --- /dev/null +++ b/ydb_tech/topic/pom.xml @@ -0,0 +1,41 @@ + + 4.0.0 + tech.ydb.examples + ydb-tech-topic + 1.0-SNAPSHOT + + 8 + UTF-8 + + + + tech.ydb + ydb-sdk-topic + ${ydb.sdk.version} + + + tech.ydb + ydb-sdk-table + ${ydb.sdk.version} + + + + + + org.apache.maven.plugins + maven-compiler-plugin + 3.14.1 + + + org.codehaus.mojo + exec-maven-plugin + 3.5.0 + + tech.ydb.examples.topic.TopicExample + + + + + diff --git a/ydb_tech/topic/run.sh b/ydb_tech/topic/run.sh new file mode 100755 index 000000000..b80fdcdd2 --- /dev/null +++ b/ydb_tech/topic/run.sh @@ -0,0 +1,6 @@ +#!/usr/bin/env bash +set -euo pipefail +cd "$(dirname "$0")/../.." +topic_sdk_version=$(mvn -q -Dstyle.color=never help:evaluate -Dexpression=project.version -DforceStdout) +mvn -B -DskipTests install +mvn -B -f ydb_tech/topic/pom.xml -Dydb.sdk.version="$topic_sdk_version" compile exec:java diff --git a/ydb_tech/topic/src/main/java/tech/ydb/examples/topic/TopicExample.java b/ydb_tech/topic/src/main/java/tech/ydb/examples/topic/TopicExample.java new file mode 100644 index 000000000..5c118b887 --- /dev/null +++ b/ydb_tech/topic/src/main/java/tech/ydb/examples/topic/TopicExample.java @@ -0,0 +1,539 @@ +package tech.ydb.examples.topic; + +import java.nio.charset.StandardCharsets; +import java.time.Duration; +import java.time.Instant; +import java.util.Arrays; +import java.util.HashSet; +import java.util.Set; +import java.util.UUID; +import java.util.concurrent.CompletableFuture; +import java.util.concurrent.ConcurrentHashMap; +import java.util.concurrent.ConcurrentMap; +import java.util.concurrent.CountDownLatch; +import java.util.concurrent.TimeUnit; +import java.util.concurrent.atomic.AtomicReference; + +import tech.ydb.common.transaction.TxMode; +import tech.ydb.core.grpc.GrpcTransport; +import tech.ydb.table.Session; +import tech.ydb.table.TableClient; +import tech.ydb.table.transaction.TableTransaction; +import tech.ydb.topic.TopicClient; +import tech.ydb.topic.description.Codec; +import tech.ydb.topic.description.Consumer; +import tech.ydb.topic.description.MetadataItem; +import tech.ydb.topic.description.TopicDescription; +import tech.ydb.topic.description.SupportedCodecs; +import tech.ydb.topic.read.AsyncReader; +import tech.ydb.topic.read.SyncReader; +import tech.ydb.topic.read.events.AbstractReadEventHandler; +import tech.ydb.topic.read.events.DataReceivedEvent; +import tech.ydb.topic.read.events.PartitionSessionClosedEvent; +import tech.ydb.topic.read.events.StartPartitionSessionEvent; +import tech.ydb.topic.read.events.StopPartitionSessionEvent; +import tech.ydb.topic.settings.AlterTopicSettings; +import tech.ydb.topic.settings.CommitOffsetSettings; +import tech.ydb.topic.settings.CreateTopicSettings; +import tech.ydb.topic.settings.PartitioningSettings; +import tech.ydb.topic.settings.ReadEventHandlersSettings; +import tech.ydb.topic.settings.ReaderSettings; +import tech.ydb.topic.settings.ReceiveSettings; +import tech.ydb.topic.settings.SendSettings; +import tech.ydb.topic.settings.StartPartitionSessionSettings; +import tech.ydb.topic.settings.TopicReadSettings; +import tech.ydb.topic.settings.UpdateOffsetsInTransactionSettings; +import tech.ydb.topic.settings.WriterSettings; +import tech.ydb.topic.write.AsyncWriter; +import tech.ydb.topic.write.Message; +import tech.ydb.topic.write.SyncWriter; +import tech.ydb.topic.write.WriteAck; + +/** Executable source of the Java topic snippets on ydb.tech. */ +public final class TopicExample { + private static final Set EXPECTED = new HashSet<>(Arrays.asList( + "sync-one", "sync-two", "async-one", "acknowledged", "metadata-one", "metadata-two", "compressed")); + private static final String[] CONSUMERS = { + "one", "commit_one", "batch", "commit_batch", "offset", "selectors", "outside" + }; + + private TopicExample() { } + + public static void main(String[] args) throws Exception { + String connectionString = System.getenv("YDB_CONNECTION_STRING"); + if (connectionString == null) { + connectionString = "grpc://localhost:2136/local"; + } + String topicPath = "ydb_tech_" + UUID.randomUUID().toString().replace("-", ""); + // [BEGIN topic_init] + try (GrpcTransport transport = GrpcTransport.forConnectionString(connectionString).build(); + TopicClient topicClient = TopicClient.newClient(transport).build(); + TableClient tableClient = TableClient.newClient(transport).build()) { + // [END topic_init] + createTopic(topicClient, topicPath); + try { + // [BEGIN topic_alter] + topicClient.alterTopic(topicPath, AlterTopicSettings.newBuilder() + .addAddConsumer(Consumer.newBuilder().setName("another-consumer").build()) + .build()).get(30, TimeUnit.SECONDS).expectSuccess(); + // [END topic_alter] + // [BEGIN topic_describe] + TopicDescription description = topicClient.describeTopic(topicPath) + .get(30, TimeUnit.SECONDS).getValue(); + System.out.println("Consumers: " + description.getConsumers().size()); + // [END topic_describe] + require(description.getConsumers().size() == CONSUMERS.length + 1, "Unexpected consumers"); + + write(topicClient, topicPath); + readSync(topicClient, topicPath, "one", false); + readSync(topicClient, topicPath, "commit_one", true); + readAsync(topicClient, topicPath, "batch", false, false); + readAsync(topicClient, topicPath, "commit_batch", true, false); + readAsync(topicClient, topicPath, "offset", false, true); + readWithoutConsumer(topicClient, topicPath); + readSelectors(topicClient, topicPath); + commitOutside(topicClient, topicPath); + transactions(topicClient, tableClient, topicPath + "_tx"); + } finally { + // [BEGIN topic_drop] + topicClient.dropTopic(topicPath).get(30, TimeUnit.SECONDS).expectSuccess(); + // [END topic_drop] + } + } + System.out.println("All topic scenarios completed"); + } + + private static void createTopic(TopicClient topicClient, String topicPath) throws Exception { + // [BEGIN topic_create] + CreateTopicSettings.Builder settings = CreateTopicSettings.newBuilder() + .setPartitioningSettings(PartitioningSettings.newBuilder() + .setMinActivePartitions(3).setMaxActivePartitions(3).build()) + .setSupportedCodecs(SupportedCodecs.newBuilder() + .addCodec(Codec.RAW).addCodec(Codec.GZIP).addCodec(Codec.ZSTD).build()); + for (String name : CONSUMERS) { + settings.addConsumer(Consumer.newBuilder().setName(name).build()); + } + topicClient.createTopic(topicPath, settings.build()).get(30, TimeUnit.SECONDS).expectSuccess(); + // [END topic_create] + } + + private static WriterSettings writerSettings(String topicPath, String producerId) { + // [BEGIN topic_writer_settings] + return WriterSettings.newBuilder().setTopicPath(topicPath) + .setProducerId(producerId).setPartitionId(0).build(); + // [END topic_writer_settings] + } + + private static void write(TopicClient topicClient, String topicPath) throws Exception { + WriterSettings settings = writerSettings(topicPath, "ydb-tech-sync"); + // [BEGIN topic_sync_writer] + SyncWriter writer = topicClient.createSyncWriter(settings); + // [END topic_sync_writer] + try { + // [BEGIN topic_sync_writer_init] + writer.init(); + // [END topic_sync_writer_init] + // [BEGIN topic_write_sync] + writer.send(Message.of(bytes("sync-one"))); + writer.send(Message.newBuilder().setData(bytes("sync-two")) + .setCreateTimestamp(Instant.now().minusSeconds(5)).build(), 30, TimeUnit.SECONDS); + writer.flush(); + // [END topic_write_sync] + } finally { + writer.shutdown(30, TimeUnit.SECONDS); + } + + // [BEGIN topic_async_writer] + AsyncWriter asyncWriter = topicClient.createAsyncWriter(writerSettings(topicPath, "ydb-tech-async")); + asyncWriter.init().get(30, TimeUnit.SECONDS); + // [END topic_async_writer] + try { + // [BEGIN topic_write_async] + CompletableFuture pending = asyncWriter.send(Message.of(bytes("async-one"))); + // [END topic_write_async] + pending.get(30, TimeUnit.SECONDS); + // [BEGIN topic_write_ack] + asyncWriter.send(Message.of(bytes("acknowledged"))).thenAccept(ack -> { + require(ack.getState() == WriteAck.State.WRITTEN, "The message was not written"); + require(ack.getDetails() != null, "Written acknowledgment has no offset"); + System.out.println("Acknowledged offset: " + ack.getDetails().getOffset()); + }).get(30, TimeUnit.SECONDS); + // [END topic_write_ack] + // [BEGIN topic_write_metadata] + asyncWriter.send(Message.newBuilder().setData(bytes("metadata-one")) + .setMetadataItems(Arrays.asList(new MetadataItem("meta-key", bytes("meta-value")))) + .build()).get(30, TimeUnit.SECONDS); + // [END topic_write_metadata] + // [BEGIN topic_write_metadata_add] + asyncWriter.send(Message.newBuilder().setData(bytes("metadata-two")) + .addMetadataItem(new MetadataItem("meta-key", bytes("meta-value"))) + .build()).get(30, TimeUnit.SECONDS); + // [END topic_write_metadata_add] + } finally { + asyncWriter.shutdown().get(30, TimeUnit.SECONDS); + } + + // [BEGIN topic_codec] + WriterSettings compressedSettings = WriterSettings.newBuilder().setTopicPath(topicPath) + .setProducerId("ydb-tech-compressed").setPartitionId(0).setCodec(Codec.ZSTD).build(); + // [END topic_codec] + AsyncWriter compressedWriter = topicClient.createAsyncWriter(compressedSettings); + try { + compressedWriter.init().get(30, TimeUnit.SECONDS); + compressedWriter.send(Message.of(bytes("compressed"))).get(30, TimeUnit.SECONDS); + } finally { + compressedWriter.shutdown().get(30, TimeUnit.SECONDS); + } + } + + private static ReaderSettings readerSettings(String topicPath, String consumerName) { + // [BEGIN topic_reader_settings] + return ReaderSettings.newBuilder().setConsumerName(consumerName) + .addTopic(TopicReadSettings.newBuilder().setPath(topicPath) + .setReadFrom(Instant.EPOCH).setMaxLag(Duration.ofHours(1)).build()).build(); + // [END topic_reader_settings] + } + + private static void readSync(TopicClient topicClient, String topicPath, String consumer, boolean commit) + throws Exception { + ReaderSettings settings = readerSettings(topicPath, consumer); + // [BEGIN topic_sync_reader] + SyncReader reader = topicClient.createSyncReader(settings); + // [END topic_sync_reader] + try { + // [BEGIN topic_sync_reader_init] + reader.initAndWait(); + // [END topic_sync_reader_init] + Set received = new HashSet<>(); + while (received.size() < EXPECTED.size()) { + // [BEGIN topic_read_one] + tech.ydb.topic.read.Message message = reader.receive(30, TimeUnit.SECONDS); + received.add(checkMessage(message)); + // [END topic_read_one] + if (commit) { + // [BEGIN topic_read_commit] + message.commit().get(30, TimeUnit.SECONDS); + // [END topic_read_commit] + } + } + require(received.equals(EXPECTED), "Unexpected topic payloads"); + } finally { + reader.shutdown(); + } + } + + private static void readAsync(TopicClient topicClient, String topicPath, String consumer, + boolean commit, boolean ownOffsets) throws Exception { + Handler handler = new Handler(commit, ownOffsets, EXPECTED); + // [BEGIN topic_handler_settings] + ReadEventHandlersSettings handlers = ReadEventHandlersSettings.newBuilder() + .setEventHandler(handler).build(); + // [END topic_handler_settings] + // [BEGIN topic_async_reader] + AsyncReader reader = topicClient.createAsyncReader(readerSettings(topicPath, consumer), handlers); + reader.init().get(30, TimeUnit.SECONDS); + // [END topic_async_reader] + try { + handler.awaitMessages(); + } finally { + reader.shutdown().get(30, TimeUnit.SECONDS); + } + } + + private static void readSelectors(TopicClient topicClient, String topicPath) throws Exception { + String anotherTopic = topicPath + "_another"; + topicClient.createTopic(anotherTopic, CreateTopicSettings.newBuilder() + .addConsumer(Consumer.newBuilder().setName("selectors").build()).build()) + .get(30, TimeUnit.SECONDS).expectSuccess(); + // [BEGIN topic_reader_selectors] + ReaderSettings settings = ReaderSettings.newBuilder().setConsumerName("selectors") + .addTopic(TopicReadSettings.newBuilder().setPath(topicPath).build()) + .addTopic(TopicReadSettings.newBuilder().setPath(anotherTopic) + .setReadFrom(Instant.EPOCH).setMaxLag(Duration.ofHours(1)).build()).build(); + // [END topic_reader_selectors] + SyncReader reader = topicClient.createSyncReader(settings); + try { + // [BEGIN topic_sync_reader_background] + reader.init(); + // [END topic_sync_reader_background] + checkMessage(reader.receive(30, TimeUnit.SECONDS)); + } finally { + reader.shutdown(); + topicClient.dropTopic(anotherTopic).get(30, TimeUnit.SECONDS).expectSuccess(); + } + } + + private static void readWithoutConsumer(TopicClient topicClient, String topicPath) throws Exception { + Handler handler = new Handler(false, true, EXPECTED) { + // [BEGIN topic_no_consumer_offset] + @Override + public void onStartPartitionSession(StartPartitionSessionEvent event) { + event.confirm(StartPartitionSessionSettings.newBuilder().setReadOffset(0L).build()); + } + // [END topic_no_consumer_offset] + }; + // [BEGIN topic_no_consumer] + ReaderSettings settings = ReaderSettings.newBuilder().withoutConsumer() + .addTopic(TopicReadSettings.newBuilder().setPath(topicPath) + .setPartitionIds(Arrays.asList(0L, 1L, 2L)).build()) + .setErrorsHandler((status, error) -> handler.fail(error != null ? error + : new IllegalStateException("Reader failed: " + status))).build(); + // [END topic_no_consumer] + AsyncReader reader = topicClient.createAsyncReader(settings, + ReadEventHandlersSettings.newBuilder().setEventHandler(handler).build()); + try { + reader.init().get(30, TimeUnit.SECONDS); + handler.awaitMessages(); + } finally { + reader.shutdown().get(30, TimeUnit.SECONDS); + } + } + + private static void commitOutside(TopicClient topicClient, String topicPath) throws Exception { + SyncReader reader = topicClient.createSyncReader(readerSettings(topicPath, "outside")); + try { + reader.initAndWait(); + tech.ydb.topic.read.Message message = reader.receive(30, TimeUnit.SECONDS); + checkMessage(message); + // [BEGIN topic_commit_outside] + topicClient.commitOffset(topicPath, CommitOffsetSettings.newBuilder() + .setReadSessionId(reader.getSessionId()).setPartitionId(0) + .setConsumer("outside").setOffset(message.getOffset() + 1).build()) + .get(30, TimeUnit.SECONDS).expectSuccess(); + // [END topic_commit_outside] + } finally { + reader.shutdown(); + } + } + + private static void transactions(TopicClient topicClient, TableClient tableClient, String topicPath) + throws Exception { + topicClient.createTopic(topicPath, CreateTopicSettings.newBuilder() + .addConsumer(Consumer.newBuilder().setName("sync").build()) + .addConsumer(Consumer.newBuilder().setName("async").build()).build()) + .get(30, TimeUnit.SECONDS).expectSuccess(); + try { + SyncWriter writer = topicClient.createSyncWriter(writerSettings(topicPath, "ydb-tech-tx-sync")); + try (Session session = tableClient.createSession(Duration.ofSeconds(30)).get(30, TimeUnit.SECONDS).getValue()) { + writer.init(); + // [BEGIN topic_write_tx_sync] + TableTransaction transaction = session.createNewTransaction(TxMode.SERIALIZABLE_RW); + transaction.executeDataQuery("SELECT 1").get(30, TimeUnit.SECONDS).getValue(); + writer.send(Message.of(bytes("tx-sync")), SendSettings.newBuilder().setTransaction(transaction).build()); + writer.flush(); + transaction.commit().get(30, TimeUnit.SECONDS).expectSuccess(); + // [END topic_write_tx_sync] + } finally { + writer.shutdown(30, TimeUnit.SECONDS); + } + + AsyncWriter asyncWriter = topicClient.createAsyncWriter(writerSettings(topicPath, "ydb-tech-tx-async")); + try (Session session = tableClient.createSession(Duration.ofSeconds(30)).get(30, TimeUnit.SECONDS).getValue()) { + asyncWriter.init().get(30, TimeUnit.SECONDS); + // [BEGIN topic_write_tx_async] + TableTransaction transaction = session.createNewTransaction(TxMode.SERIALIZABLE_RW); + transaction.executeDataQuery("SELECT 1").get(30, TimeUnit.SECONDS).getValue(); + asyncWriter.send(Message.of(bytes("tx-async")), SendSettings.newBuilder().setTransaction(transaction).build()) + .get(30, TimeUnit.SECONDS); + transaction.commit().get(30, TimeUnit.SECONDS).expectSuccess(); + // [END topic_write_tx_async] + } finally { + asyncWriter.shutdown().get(30, TimeUnit.SECONDS); + } + + SyncReader reader = topicClient.createSyncReader(readerSettings(topicPath, "sync")); + Set received = new HashSet<>(); + try { + reader.initAndWait(); + for (int index = 0; index < 2; index++) { + try (Session session = tableClient.createSession(Duration.ofSeconds(30)).get(30, TimeUnit.SECONDS).getValue()) { + TableTransaction transaction = session.createNewTransaction(TxMode.SERIALIZABLE_RW); + transaction.executeDataQuery("SELECT 1").get(30, TimeUnit.SECONDS).getValue(); + // [BEGIN topic_read_tx_sync] + tech.ydb.topic.read.Message message = reader.receive(ReceiveSettings.newBuilder() + .setTransaction(transaction).setTimeout(30, TimeUnit.SECONDS).build()); + received.add(new String(message.getData(), StandardCharsets.UTF_8)); + transaction.commit().get(30, TimeUnit.SECONDS).expectSuccess(); + // [END topic_read_tx_sync] + } + } + require(received.equals(new HashSet<>(Arrays.asList("tx-sync", "tx-async"))), "Unexpected transactional messages"); + } finally { + reader.shutdown(); + } + + TransactionHandler handler = new TransactionHandler(tableClient); + AsyncReader asyncReader = topicClient.createAsyncReader(readerSettings(topicPath, "async"), + ReadEventHandlersSettings.newBuilder().setEventHandler(handler).build()); + handler.reader = asyncReader; + try { + asyncReader.init().get(30, TimeUnit.SECONDS); + require(handler.done.await(30, TimeUnit.SECONDS), "Timed out waiting for transactional messages"); + if (handler.failure.get() != null) { + throw new IllegalStateException("Transactional handler failed", handler.failure.get()); + } + } finally { + asyncReader.shutdown().get(30, TimeUnit.SECONDS); + } + } finally { + topicClient.dropTopic(topicPath).get(30, TimeUnit.SECONDS).expectSuccess(); + } + } + + private static String checkMessage(tech.ydb.topic.read.Message message) { + require(message != null, "Timed out waiting for a message"); + String payload = new String(message.getData(), StandardCharsets.UTF_8); + require(EXPECTED.contains(payload), "Unexpected payload: " + payload); + if (payload.startsWith("metadata")) { + // [BEGIN topic_read_metadata] + for (MetadataItem item : message.getMetadataItems()) { + System.out.println(item.getKey() + ": " + new String(item.getValue(), StandardCharsets.UTF_8)); + } + // [END topic_read_metadata] + require(message.getMetadataItems().stream().anyMatch(item -> item.getKey().equals("meta-key") + && Arrays.equals(item.getValue(), bytes("meta-value"))), "Unexpected metadata"); + } + return payload; + } + + private static byte[] bytes(String value) { + return value.getBytes(StandardCharsets.UTF_8); + } + + private static void require(boolean condition, String message) { + if (!condition) { + throw new IllegalStateException(message); + } + } + + private static class Handler extends AbstractReadEventHandler { + private final boolean commit; + private final boolean ownOffsets; + private final Set expected; + private final Set received = ConcurrentHashMap.newKeySet(); + private final ConcurrentMap offsets = new ConcurrentHashMap<>(); + private final AtomicReference failure = new AtomicReference<>(); + private final CountDownLatch done; + + private Handler(boolean commit, boolean ownOffsets, Set expected) { + this.commit = commit; + this.ownOffsets = ownOffsets; + this.expected = expected; + this.done = new CountDownLatch(expected.size()); + } + + // [BEGIN topic_read_batch] + @Override + public void onMessages(DataReceivedEvent event) { + try { + for (tech.ydb.topic.read.Message message : event.getMessages()) { + String payload = checkMessage(message); + offsets.put(event.getPartitionSession().getPartitionId(), message.getOffset() + 1); + received.add(payload); + if (!commit) { + done.countDown(); + } + } + if (commit) { + commitBatch(event); + } + } catch (Exception error) { + failure.set(error); + while (done.getCount() > 0) { + done.countDown(); + } + } + } + // [END topic_read_batch] + + // [BEGIN topic_read_batch_commit] + private void commitBatch(DataReceivedEvent event) throws Exception { + event.commit().get(30, TimeUnit.SECONDS); + for (int index = 0; index < event.getMessages().size(); index++) { + done.countDown(); + } + } + // [END topic_read_batch_commit] + + // [BEGIN topic_client_offset] + @Override + public void onStartPartitionSession(StartPartitionSessionEvent event) { + if (ownOffsets) { + long offset = offsets.getOrDefault(event.getPartitionSession().getPartitionId(), 0L); + event.confirm(StartPartitionSessionSettings.newBuilder() + .setReadOffset(offset).setCommitOffset(offset).build()); + } else { + event.confirm(); + } + } + // [END topic_client_offset] + + // [BEGIN topic_soft_stop] + @Override + public void onStopPartitionSession(StopPartitionSessionEvent event) { + System.out.println("Stopped partition session: " + event.getPartitionSessionId()); + event.confirm(); + } + // [END topic_soft_stop] + + // [BEGIN topic_hard_stop] + @Override + public void onPartitionSessionClosed(PartitionSessionClosedEvent event) { + System.out.println("Closed partition: " + event.getPartitionSession().getPartitionId()); + } + // [END topic_hard_stop] + + private void awaitMessages() throws Exception { + require(done.await(30, TimeUnit.SECONDS), "Timed out waiting for asynchronous messages"); + if (failure.get() != null) { + throw new IllegalStateException("Reader handler failed", failure.get()); + } + require(received.equals(expected), "Unexpected asynchronous payloads"); + } + + private void fail(Throwable error) { + failure.set(error); + while (done.getCount() > 0) { + done.countDown(); + } + } + } + + private static final class TransactionHandler extends AbstractReadEventHandler { + private final TableClient tableClient; + private final CountDownLatch done = new CountDownLatch(2); + private final AtomicReference failure = new AtomicReference<>(); + private AsyncReader reader; + + private TransactionHandler(TableClient tableClient) { + this.tableClient = tableClient; + } + + // [BEGIN topic_read_tx_async] + @Override + public void onMessages(DataReceivedEvent event) { + try { + for (tech.ydb.topic.read.Message message : event.getMessages()) { + try (Session session = tableClient.createSession(Duration.ofSeconds(30)) + .get(30, TimeUnit.SECONDS).getValue()) { + TableTransaction transaction = session.createNewTransaction(TxMode.SERIALIZABLE_RW); + transaction.executeDataQuery("SELECT 1").get(30, TimeUnit.SECONDS).getValue(); + reader.updateOffsetsInTransaction(transaction, message.getPartitionOffsets(), + UpdateOffsetsInTransactionSettings.newBuilder().build()) + .get(30, TimeUnit.SECONDS).expectSuccess(); + transaction.commit().get(30, TimeUnit.SECONDS).expectSuccess(); + require(new String(message.getData(), StandardCharsets.UTF_8).startsWith("tx-"), + "Unexpected transactional payload"); + done.countDown(); + } + } + } catch (Exception error) { + failure.set(error); + while (done.getCount() > 0) { + done.countDown(); + } + } + } + // [END topic_read_tx_async] + } +}