Pulsar-Cat

A versatile command-line tool for Apache Pulsar

Overview

Pulsar-Cat is a command-line utility for Apache Pulsar that lets you produce, consume, and inspect topics easily. It's designed to be simple yet powerful, making it ideal for Pulsar administrators, developers, and for debugging Pulsar deployments.

Think of it as a "netcat for Pulsar" - a swiss-army knife for interacting with your Pulsar deployment.

Features

• Producer mode: Send messages to Pulsar topics from stdin or files
• Consumer mode: Read messages from Pulsar topics and print to stdout
• List mode: View information about clusters, brokers, topics, and partitions
• Format control: Customize output format for messages
• Support for compression: Control message compression
• Authentication support: Connect to secured Pulsar clusters

Installation

Building from source

git clone https://github.com/user/pulsar-cat.git
cd pulsar-cat
./build.sh

Usage

Pulsar-Cat operates in one of three modes:

• produce or P: Producer mode
• consume or C: Consumer mode
• list or L: List mode (metadata)

Basic Usage

pulsar-cat --broker <BROKER_URL> <COMMAND> [OPTIONS]

The broker URL is always required:

pulsar-cat --broker pulsar://localhost:6650 <COMMAND> [OPTIONS]

Producer Mode

Send messages to a topic:

pulsar-cat --broker pulsar://localhost:6650 produce --topic my-topic
message1
message2
message3

Send messages with a specific partition:

pulsar-cat --broker pulsar://localhost:6650 produce --topic my-topic --partition 0

Send messages with keys:

pulsar-cat --broker pulsar://localhost:6650 produce --topic my-topic --key ":"
key1:message1
key2:message2

Enforce keys for all messages:

pulsar-cat --broker pulsar://localhost:6650 produce --topic my-topic --key ":" --enforce-key

Use compression:

pulsar-cat --broker pulsar://localhost:6650 produce --topic my-topic --compression zstd

Consumer Mode

Read messages from a topic:

pulsar-cat --broker pulsar://localhost:6650 consume --topic my-topic

Format output:

pulsar-cat --broker pulsar://localhost:6650 consume --topic my-topic --format 'Key: %k, Value: %s'

List Mode

List topics in a namespace:

pulsar-cat --broker pulsar://localhost:6650 list --namespace tenant/namespace

View information about a specific topic:

pulsar-cat --broker pulsar://localhost:6650 list --topic tenant/namespace/topic

Authentication

Connect to a secured Pulsar cluster:

pulsar-cat --broker pulsar+ssl://localhost:6651 consume --topic my-topic --auth_token "your-token"

Format String Options

When using the --format option in consumer mode, the following placeholders are available:

• %t: Topic name
• %p: Partition
• %o: Message offset
• %k: Message key
• %s: Message payload (string)
• %S: Message payload size in bytes
• %h: Message headers
• %T: Message timestamp

Compression Options

Available compression algorithms:

• none: No compression (default)
• lz4: LZ4 compression
• zlib: ZLIB compression
• zstd: ZSTD compression
• snappy: Snappy compression

Examples

Consume messages from a topic

pulsar-cat --broker pulsar://localhost:6650 consume --topic my-topic

Produce messages with a key

pulsar-cat --broker pulsar://localhost:6650 produce --topic my-topic --key ":"
user1:{"name":"Alice","action":"login"}
user2:{"name":"Bob","action":"search"}

Display formatted messages

pulsar-cat --broker pulsar://localhost:6650 consume --topic my-topic \
  --format "Offset: %o, Key: %k, Value: %s, Time: %T"

List topics in a namespace

pulsar-cat --broker pulsar://localhost:6650 list --namespace my-tenant/my-namespace

License

Pulsar-Cat is licensed under the Apache License 2.0 - see LICENSE file for details.