Add Pulsar collector

.dockerignore

@@ -55,6 +55,7 @@
 !zipkin-collector/kafka/src/main/**
 !zipkin-collector/rabbitmq/src/main/**
 !zipkin-collector/scribe/src/main/**
+!zipkin-collector/pulsar/src/main/**
 !zipkin-junit5/src/main/**
 !zipkin-storage/src/main/**
 !zipkin-storage/cassandra/src/main/**

.github/workflows/test.yml

@@ -69,6 +69,7 @@ jobs:
           - name: zipkin-collector-activemq
           - name: zipkin-collector-kafka
           - name: zipkin-collector-rabbitmq
+          - name: zipkin-collector-pulsar
           - name: zipkin-storage-cassandra
           - name: zipkin-storage-elasticsearch
           - name: zipkin-storage-mysql-v1

README.md

@@ -24,7 +24,7 @@ aggregate behavior including error paths or calls to deprecated services.
 Application’s need to be “instrumented” to report trace data to Zipkin. This
 usually means configuration of a [tracer or instrumentation library](https://zipkin.io/pages/tracers_instrumentation.html). The most
 popular ways to report data to Zipkin are via http or Kafka, though many other
-options exist, such as Apache ActiveMQ, gRPC and RabbitMQ. The data served to
+options exist, such as Apache ActiveMQ, gRPC, RabbitMQ and Apache Pulsar. The data served to
 the UI is stored in-memory, or persistently with a supported backend such as
 Apache Cassandra or Elasticsearch.
 

docker/examples/README.md

@@ -118,6 +118,18 @@ $ docker compose -f docker-compose-rabbitmq.yml up
 Then configure the [RabbitMQ sender](https://github.com/openzipkin/zipkin-reporter-java/blob/master/amqp-client/src/main/java/zipkin2/reporter/amqp/RabbitMQSender.java)
 using a `host` value of `localhost` or a non-local hostname if in docker.
 
+
+## Pulsar
+
+You can collect traces from [Pulsar](../test-images/zipkin-pulsar/README.md) in addition to HTTP, using the
+`docker-compose-pulsar.yml` file. This configuration starts `zipkin` and `zipkin-pulsar` in their
+own containers.
+
+To add Pulsar configuration, run:
+```bash
+$ docker compose -f docker-compose-pulsar.yml up
+```
+
 ## Eureka
 
 You can register Zipkin for service discovery in [Eureka](../test-images/zipkin-eureka/README.md)

docker/examples/docker-compose-pulsar.yml

@@ -0,0 +1,32 @@
+#
+# Copyright The OpenZipkin Authors
+# SPDX-License-Identifier: Apache-2.0
+#
+
+# This file uses the version 2 docker compose file format, described here:
+# https://docs.docker.com/compose/compose-file/#version-2
+#
+# It extends the default configuration from docker-compose.yml to add a test
+# pulsar server, which is used as a span transport.
+
+version: '2.4'
+
+services:
+  pulsar:
+    image: ghcr.io/openzipkin/zipkin-pulsar:${TAG:-latest}
+    container_name: pulsar
+    ports: # expose the pulsar port so apps can publish spans.
+      - "6650:6650"
+      # - "8080:8080" # uncomment to expose the pulsar http port.
+
+  zipkin:
+    extends:
+      file: docker-compose.yml
+      service: zipkin
+    # slim doesn't include Pulsar support, so switch to the larger image
+    image: ghcr.io/openzipkin/zipkin:${TAG:-latest}
+    environment:
+      - PULSAR_SERVICE_URL=pulsar://pulsar:6650
+    depends_on:
+      pulsar:
+        condition: service_healthy

zipkin-collector/pom.xml

@@ -29,6 +29,7 @@
     <module>kafka</module>
     <module>rabbitmq</module>
     <module>scribe</module>
+    <module>pulsar</module>
   </modules>
 
   <dependencies>

zipkin-collector/pulsar/README.md

@@ -0,0 +1,57 @@
+# collector-pulsar
+
+## PulsarCollector
+
+This collector is implemented as a Pulsar consumer supporting Pulsar brokers running
+version 4.x or later, and the default subscription type is `Shared`, in Shared subscription type, 
+multiple consumers can attach to the same subscription and messages are delivered 
+in a round-robin distribution across consumers.
+
+This collector is implemented as a Pulsar consumer supporting Pulsar brokers running version 4.x or later. 
+The default `subscriptionType` is `Shared`, which allows multiple consumers to attach to the same subscription, 
+with messages delivered in a round-robin distribution across consumers, the default `subscriptionInitialPosition`
+is `Earliest`, you can modify the consumer settings as needed through the `consumerProps` parameter.
+Also, the client settings can also be modified through the `clientProps` parameter.
+
+For information about running this collector as a module in Zipkin server, see
+the [Zipkin Server README](../../zipkin-server/README.md#pulsar-collector).
+
+When using this collector as a library outside of Zipkin server,
+[zipkin2.collector.pulsar.PulsarCollector.Builder](src/main/java/zipkin2/collector/pulsar/PulsarCollector.java)
+includes defaults that will operate against a Pulsar topic name `zipkin`.
+
+## Encoding spans into Pulsar messages
+
+The message's binary data includes a list of spans. Supported encodings
+are the same as the http [POST /spans](https://zipkin.io/zipkin-api/#/paths/%252Fspans) body.
+
+### Json
+
+The message's binary data is a list of spans in json. The first character must be '[' (decimal 91).
+
+`Codec.JSON.writeSpans(spans)` performs the correct json encoding.
+
+### Thrift
+
+The message's binary data includes a list header followed by N spans serialized in TBinaryProtocol
+
+`Codec.THRIFT.writeSpans(spans)` encodes spans in the following fashion:
+
+```
+write_byte(12) // type of the list elements: 12 == struct
+write_i32(count) // count of spans that will follow
+for (int i = 0; i < count; i++) {
+  writeTBinaryProtocol(spans(i))
+}
+```
+
+### Legacy encoding
+
+Older versions of zipkin accepted a single span per message, as opposed
+to a list per message. This practice is deprecated, but still supported.
+
+## Logging
+
+Zipkin by default suppresses all logging output from Pulsar client operations as they can get quite verbose. Start
+Zipkin
+with `--logging.level.org.apache.pulsar=INFO` or similar to override this during troubleshooting for example.

zipkin-collector/pulsar/pom.xml

@@ -0,0 +1,39 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--
+
+    Copyright The OpenZipkin Authors
+    SPDX-License-Identifier: Apache-2.0
+
+-->
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+  <modelVersion>4.0.0</modelVersion>
+
+  <parent>
+    <groupId>io.zipkin.zipkin2</groupId>
+    <artifactId>zipkin-collector-parent</artifactId>
+    <version>3.4.5-SNAPSHOT</version>
+  </parent>
+
+  <artifactId>zipkin-collector-pulsar</artifactId>
+  <name>Collector: Pulsar</name>
+
+  <properties>
+    <main.basedir>${project.basedir}/../..</main.basedir>
+    <pulsar-client.version>4.0.2</pulsar-client.version>
+  </properties>
+
+  <dependencies>
+    <dependency>
+      <groupId>${project.groupId}</groupId>
+      <artifactId>zipkin-collector</artifactId>
+      <version>${project.version}</version>
+    </dependency>
+
+    <dependency>
+      <groupId>org.apache.pulsar</groupId>
+      <artifactId>pulsar-client</artifactId>
+      <version>${pulsar-client.version}</version>
+    </dependency>
+  </dependencies>
+</project>

zipkin-collector/pulsar/src/main/java/zipkin2/collector/pulsar/LazyPulsarInit.java

@@ -0,0 +1,80 @@
+/*
+ * Copyright The OpenZipkin Authors
+ * SPDX-License-Identifier: Apache-2.0
+ */
+package zipkin2.collector.pulsar;
+
+import org.apache.pulsar.client.api.PulsarClient;
+import org.apache.pulsar.client.api.PulsarClientException;
+import zipkin2.CheckResult;
+import zipkin2.collector.Collector;
+import zipkin2.collector.CollectorMetrics;
+
+import java.util.Map;
+import java.util.concurrent.atomic.AtomicReference;
+
+class LazyPulsarInit {
+
+  private final Collector collector;
+  private final CollectorMetrics metrics;
+  private final String topic;
+  private final int concurrency;
+  private final Map<String, Object> clientProps, consumerProps;
+  public volatile PulsarClient result;
+  final AtomicReference<CheckResult> failure = new AtomicReference<>();
+
+  LazyPulsarInit(PulsarCollector.Builder builder) {
+    this.collector = builder.delegate.build();
+    this.metrics = builder.metrics;
+    this.topic = builder.topic;
+    this.concurrency = builder.concurrency;
+    this.clientProps = builder.clientProps;
+    this.consumerProps = builder.consumerProps;
+  }
+
+  void init() {
+    if (result == null) {
+      synchronized (this) {
+        if (result == null) {
+          result = subscribe();
+        }
+      }
+    }
+  }
+
+  private PulsarClient subscribe() {
+    PulsarClient client;
+    try {
+      client = PulsarClient.builder()
+          .loadConf(clientProps)
+          .build();
+    } catch (Exception e) {
+      failure.set(CheckResult.failed(e));
+      throw new RuntimeException("Pulsar client creation failed. " + e.getMessage(), e);
+    }
+
+    try {
+      for (int i = 0; i < concurrency; i++) {
+        PulsarSpanConsumer consumer = new PulsarSpanConsumer(topic, consumerProps, client, collector, metrics);
+        consumer.startConsumer();
+      }
+      return client;
+    } catch (Exception e) {
+      try {
+        client.close();
+      } catch (PulsarClientException ex) {
+        // Nobody cares me.
+      }
+      failure.set(CheckResult.failed(e));
+      throw new RuntimeException("Pulsar Client is unable to subscribe to the topic(" + topic + "), please check the service.", e);
+    }
+  }
+
+  void close() throws PulsarClientException {
+    PulsarClient maybe = result;
+    if (maybe != null) {
+      result.close();
+      result = null;
+    }
+  }
+}