kafka PageViewTypedDemo 源码
kafka PageViewTypedDemo 代码
文件路径：/streams/examples/src/main/java/org/apache/kafka/streams/examples/pageview/PageViewTypedDemo.java
/*
* 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.kafka.streams.examples.pageview;
import com.fasterxml.jackson.annotation.JsonSubTypes;
import com.fasterxml.jackson.annotation.JsonTypeInfo;
import com.fasterxml.jackson.databind.ObjectMapper;
import org.apache.kafka.clients.consumer.ConsumerConfig;
import org.apache.kafka.common.errors.SerializationException;
import org.apache.kafka.common.serialization.Deserializer;
import org.apache.kafka.common.serialization.Serde;
import org.apache.kafka.common.serialization.Serdes;
import org.apache.kafka.common.serialization.Serializer;
import org.apache.kafka.streams.KafkaStreams;
import org.apache.kafka.streams.KeyValue;
import org.apache.kafka.streams.StreamsBuilder;
import org.apache.kafka.streams.StreamsConfig;
import org.apache.kafka.streams.kstream.Consumed;
import org.apache.kafka.streams.kstream.Produced;
import org.apache.kafka.streams.kstream.Grouped;
import org.apache.kafka.streams.kstream.KStream;
import org.apache.kafka.streams.kstream.KTable;
import org.apache.kafka.streams.kstream.TimeWindows;
import java.io.IOException;
import java.time.Duration;
import java.util.Map;
import java.util.Properties;
import java.util.concurrent.CountDownLatch;
/**
* Demonstrates how to perform a join between a KStream and a KTable, i.e. an example of a stateful computation,
* using specific data types (here: JSON POJO; but can also be Avro specific bindings, etc.) for serdes
* in Kafka Streams.
*
* In this example, we join a stream of pageviews (aka clickstreams) that reads from a topic named "streams-pageview-input"
* with a user profile table that reads from a topic named "streams-userprofile-input", where the data format
* is JSON string representing a record in the stream or table, to compute the number of pageviews per user region.
*
* Before running this example you must create the input topics and the output topic (e.g. via
* bin/kafka-topics --create ...), and write some data to the input topics (e.g. via
* bin/kafka-console-producer). Otherwise you won't see any data arriving in the output topic.
*
* The inputs for this example are:
* - Topic: streams-pageview-input
* Key Format: (String) USER_ID
* Value Format: (JSON) {"_t": "pv", "user": (String USER_ID), "page": (String PAGE_ID), "timestamp": (long ms TIMESTAMP)}
*
* - Topic: streams-userprofile-input
* Key Format: (String) USER_ID
* Value Format: (JSON) {"_t": "up", "region": (String REGION), "timestamp": (long ms TIMESTAMP)}
*
* To observe the results, read the output topic (e.g., via bin/kafka-console-consumer)
* - Topic: streams-pageviewstats-typed-output
* Key Format: (JSON) {"_t": "wpvbr", "windowStart": (long ms WINDOW_TIMESTAMP), "region": (String REGION)}
* Value Format: (JSON) {"_t": "rc", "count": (long REGION_COUNT), "region": (String REGION)}
*
* Note, the "_t" field is necessary to help Jackson identify the correct class for deserialization in the
* generic {@link JSONSerde}. If you instead specify a specific serde per class, you won't need the extra "_t" field.
*/
@SuppressWarnings({"WeakerAccess", "unused"})
public class PageViewTypedDemo {
/**
* A serde for any class that implements {@link JSONSerdeCompatible}. Note that the classes also need to
* be registered in the {@code @JsonSubTypes} annotation on {@link JSONSerdeCompatible}.
*
* @param <T> The concrete type of the class that gets de/serialized
*/
public static class JSONSerde<T extends JSONSerdeCompatible> implements Serializer<T>, Deserializer<T>, Serde<T> {
private static final ObjectMapper OBJECT_MAPPER = new ObjectMapper();
@Override
public void configure(final Map<String, ?> configs, final boolean isKey) {}
@SuppressWarnings("unchecked")
@Override
public T deserialize(final String topic, final byte[] data) {
if (data == null) {
return null;
}
try {
return (T) OBJECT_MAPPER.readValue(data, JSONSerdeCompatible.class);
} catch (final IOException e) {
throw new SerializationException(e);
}
}
@Override
public byte[] serialize(final String topic, final T data) {
if (data == null) {
return null;
}
try {
return OBJECT_MAPPER.writeValueAsBytes(data);
} catch (final Exception e) {
throw new SerializationException("Error serializing JSON message", e);
}
}
@Override
public void close() {}
@Override
public Serializer<T> serializer() {
return this;
}
@Override
public Deserializer<T> deserializer() {
return this;
}
}
/**
* An interface for registering types that can be de/serialized with {@link JSONSerde}.
*/
@SuppressWarnings("DefaultAnnotationParam") // being explicit for the example
@JsonTypeInfo(use = JsonTypeInfo.Id.NAME, include = JsonTypeInfo.As.PROPERTY, property = "_t")
@JsonSubTypes({
@JsonSubTypes.Type(value = PageView.class, name = "pv"),
@JsonSubTypes.Type(value = UserProfile.class, name = "up"),
@JsonSubTypes.Type(value = PageViewByRegion.class, name = "pvbr"),
@JsonSubTypes.Type(value = WindowedPageViewByRegion.class, name = "wpvbr"),
@JsonSubTypes.Type(value = RegionCount.class, name = "rc")
})
public interface JSONSerdeCompatible {
}
// POJO classes
static public class PageView implements JSONSerdeCompatible {
public String user;
public String page;
public Long timestamp;
}
static public class UserProfile implements JSONSerdeCompatible {
public String region;
public Long timestamp;
}
static public class PageViewByRegion implements JSONSerdeCompatible {
public String user;
public String page;
public String region;
}
static public class WindowedPageViewByRegion implements JSONSerdeCompatible {
public long windowStart;
public String region;
}
static public class RegionCount implements JSONSerdeCompatible {
public long count;
public String region;
}
public static void main(final String[] args) {
final Properties props = new Properties();
props.put(StreamsConfig.APPLICATION_ID_CONFIG, "streams-pageview-typed");
props.put(StreamsConfig.BOOTSTRAP_SERVERS_CONFIG, "localhost:9092");
props.put(StreamsConfig.DEFAULT_TIMESTAMP_EXTRACTOR_CLASS_CONFIG, JsonTimestampExtractor.class);
props.put(StreamsConfig.DEFAULT_KEY_SERDE_CLASS_CONFIG, JSONSerde.class);
props.put(StreamsConfig.DEFAULT_VALUE_SERDE_CLASS_CONFIG, JSONSerde.class);
props.put(StreamsConfig.CACHE_MAX_BYTES_BUFFERING_CONFIG, 0);
props.put(StreamsConfig.COMMIT_INTERVAL_MS_CONFIG, 1000L);
// setting offset reset to earliest so that we can re-run the demo code with the same pre-loaded data
props.put(ConsumerConfig.AUTO_OFFSET_RESET_CONFIG, "earliest");
final StreamsBuilder builder = new StreamsBuilder();
final KStream<String, PageView> views = builder.stream("streams-pageview-input", Consumed.with(Serdes.String(), new JSONSerde<>()));
final KTable<String, UserProfile> users = builder.table("streams-userprofile-input", Consumed.with(Serdes.String(), new JSONSerde<>()));
final Duration duration24Hours = Duration.ofHours(24);
final KStream<WindowedPageViewByRegion, RegionCount> regionCount = views
.leftJoin(users, (view, profile) -> {
final PageViewByRegion viewByRegion = new PageViewByRegion();
viewByRegion.user = view.user;
viewByRegion.page = view.page;
if (profile != null) {
viewByRegion.region = profile.region;
} else {
viewByRegion.region = "UNKNOWN";
}
return viewByRegion;
})
.map((user, viewRegion) -> new KeyValue<>(viewRegion.region, viewRegion))
.groupByKey(Grouped.with(Serdes.String(), new JSONSerde<>()))
.windowedBy(TimeWindows.ofSizeAndGrace(Duration.ofDays(7), duration24Hours).advanceBy(Duration.ofSeconds(1)))
.count()
.toStream()
.map((key, value) -> {
final WindowedPageViewByRegion wViewByRegion = new WindowedPageViewByRegion();
wViewByRegion.windowStart = key.window().start();
wViewByRegion.region = key.key();
final RegionCount rCount = new RegionCount();
rCount.region = key.key();
rCount.count = value;
return new KeyValue<>(wViewByRegion, rCount);
});
// write to the result topic
regionCount.to("streams-pageviewstats-typed-output", Produced.with(new JSONSerde<>(), new JSONSerde<>()));
final KafkaStreams streams = new KafkaStreams(builder.build(), props);
final CountDownLatch latch = new CountDownLatch(1);
// attach shutdown handler to catch control-c
Runtime.getRuntime().addShutdownHook(new Thread("streams-pipe-shutdown-hook") {
@Override
public void run() {
streams.close();
latch.countDown();
}
});
try {
streams.start();
latch.await();
} catch (final Throwable e) {
e.printStackTrace();
System.exit(1);
}
System.exit(0);
}
}
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