pulsar – apache

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Pulsar is a distributed pub-sub messaging platform with a very
flexible messaging model and an intuitive client API.

Learn more about Pulsar at https://pulsar.apache.org

Main features

• Horizontally scalable (Millions of independent topics and millions

of messages published per second)

• Strong ordering and consistency guarantees
• Low latency durable storage
• Topic and queue semantics
• Load balancer
• Designed for being deployed as a hosted service:
• Multi-tenant
• Authentication
• Authorization
• Quotas
• Support mixing very different workloads
• Optional hardware isolation
• Keeps track of consumer cursor position
• REST API for provisioning, admin and stats
• Geo replication
• Transparent handling of partitioned topics
• Transparent batching of messages

Repositories

This repository is the main repository of Apache Pulsar. Pulsar PMC also maintains other repositories for
components in the Pulsar ecosystem, including connectors, adapters, and other language clients.

• Pulsar Core

Helm Chart

• Pulsar Helm Chart

Ecosystem

• Pulsar Adapters

Clients

• .NET/C# Client
• C++ Client
• Go Client
• NodeJS Client
• Python Client
• Reactive Java Client

Dashboard & Management Tools

• Dekaf UI
• Pulsar Manager

Website

• Pulsar Site

CI/CD

• Pulsar CI

Archived/Halted

• Pulsar Connectors (bundled as pulsar-io)
• Pulsar Translation
• Ruby Client

Pulsar Runtime Java Version Recommendation

> Note*:
>
> When using Java versions, it is recommended to
> use a recent version of a particular Java release (17 or 21)
> with the most recent bug fixes and security patches.
> For example, the JVM bug JDK-8351933 can cause stability issues in
> Pulsar.
> JDK-8351933 was fixed in Java 17.0.17+ and Java 21.0.8+.
> Pulsar Docker images come with the most recent Java version at the time of release.

When using the Pulsar Java client, it is recommended to set specific system properties and JVM options to allow optimal performance.

pulsar ver >= 4.1 and master branch

Docker image Java runtime: 21

3.3 <= pulsar ver <= 4.0

Docker image Java runtime: 21

2.10 <= pulsar ver <= 3.0

Docker image Java runtime: 17

2.8 <= pulsar ver <= 2.10

pulsar ver < 2.8

Build Pulsar

The quick start below covers the essentials; see <code class="ra0-md-code">CONTRIBUTING.md</code> → Building
for the full build and lint commands, and <code class="ra0-md-code">ARCHITECTURE.md</code> → Build infrastructure
for the Gradle build infrastructure and how to change build files.

Requirements

• JDK

• zip

There is also a guide for setting up the tooling for building Pulsar.

> Note*:
>
> This project includes a Gradle Wrapper so no separate Gradle installation is needed.
> Use ./gradlew on Linux/macOS and gradlew.bat on Windows.
>
> For a better developer experience, install Gradle command-line completion (gradle-completion installation) for bash and zsh shells.

Build

./gradlew assemble                                                       # compile and assemble
./gradlew :pulsar-client-original:test --tests "ConsumerBuilderImplTest" # run a single test
bin/pulsar standalone                                                    # run a standalone service
./gradlew quickCheck                                                     # license headers + checkstyle, no compile
./gradlew sanityCheck                                                    # quickCheck + compile main/test (pre-PR)

For the full build, lint, test, and PR workflow — test groups, integration tests, Personal CI, and PR
conventions — see <code class="ra0-md-code">CONTRIBUTING.md</code>. For the module map and the Gradle build
infrastructure see <code class="ra0-md-code">ARCHITECTURE.md</code>, and for coding conventions see
<code class="ra0-md-code">CODING.md</code>. AI coding agents should start from <code class="ra0-md-code">AGENTS.md</code>.

Check https://pulsar.apache.org for documentation and examples.

Build custom docker images

The commands used in the Apache Pulsar release process can be found in the release process documentation.

Here are some general instructions for building custom docker images:

• Java 21 is the recommended JDK version since branch-4.0.

The following command builds the docker image apachepulsar/pulsar:latest:

./gradlew docker

After the image is built, it can be tagged and pushed to your custom repository. Here's an example of a bash script that tags the docker image with the current version and git revision and pushes it to localhost:32000/apachepulsar.

image_repo_and_project=localhost:32000/apachepulsar
pulsar_version=$(src/get-pulsar-version.sh)
gitrev=$(git rev-parse HEAD | colrm 10)
tag="${pulsar_version}-${gitrev}"
echo "Using tag $tag"
docker tag apachepulsar/pulsar:latest ${image_repo_and_project}/pulsar:$tag
docker push ${image_repo_and_project}/pulsar:$tag

Setting up your IDE

Read https://pulsar.apache.org/contribute/setup-ide for setting up IntelliJ IDEA or Eclipse for developing Pulsar.

Documentation

> Note*:
>
> For how to make contributions to Pulsar documentation, see Pulsar Documentation Contribution Guide.

Contact

Mailing lists

• The mailing lists are the primary contact for the Apache Pulsar project.
• Your email to the mailing list might be placed in a moderation queue if you haven't joined the mailing list by subscribing before posting.

> Note*
>
> Please note that security-related issues or concerns should not be reported in public channels.
> Follow the instructions in the Security Policy to contact the ASF Security Team and the Apache Pulsar PMC directly.

Slack

Pulsar slack channel at https://apache-pulsar.slack.com/

You can self-register at https://communityinviter.com/apps/apache-pulsar/apache-pulsar

Security Policy

See the Pulsar security policy for the full policy. In short: never disclose a suspected vulnerability publicly* (issue, PR, or discussion) before a fix is released, and a human must verify and take responsibility for a report — autonomous agents must not file security reports on their own.

Reporting a security vulnerability

Report privately by email to the Apache Security Team at security@apache.org; you may also copy the Apache Pulsar PMC's private list, private@pulsar.apache.org. See the Pulsar security policy for more detail.

Checking exposure to an already-public CVE

An already-public CVE is not* a private disclosure. Search PRs and issues by the CVE id at <https://github.com/apache/pulsar/pulls> (including closed ones), then ask via a GitHub issue or the dev@pulsar.apache.org mailing list if needed. Pulsar's supported versions are listed at <https://pulsar.apache.org/contribute/release-policy/>; upgrade to a supported version to receive security updates. See the Pulsar security policy.

License

Licensed under the Apache License, Version 2.0: http://www.apache.org/licenses/LICENSE-2.0

Crypto Notice

This distribution includes cryptographic software. The country in which you currently reside may have restrictions on the import, possession, use, and/or re-export to another country, of encryption software. BEFORE using any encryption software, please check your country's laws, regulations and policies concerning the import, possession, or use, and re-export of encryption software, to see if this is permitted. See The Wassenaar Arrangement for more information.

The U.S. Government Department of Commerce, Bureau of Industry and Security (BIS), has classified this software as Export Commodity Control Number (ECCN) 5D002.C.1, which includes information security software using or performing cryptographic functions with asymmetric algorithms. The form and manner of this Apache Software Foundation distribution makes it eligible for export under the License Exception ENC Technology Software Unrestricted (TSU) exception (see the BIS Export Administration Regulations, Section 740.13) for both object code and source code.

The following provides more details on the included cryptographic software: Pulsar uses the SSL library from Bouncy Castle written by http://www.bouncycastle.org.