Lib.rs

krs

krs is a simple Kafka command-line tool written in Rust, inspired by kt.

Dual-licensed under MIT or the UNLICENSE.

Features

• Easy to type
• Fast startup
• Hopefully intuitive to use
• Diagnostic output to stderr, main output to stdout, which allows below feature
• JSON output for easy consumption with jq
• Change some context variables (e.g. Kafka brokers or Zookeeper host) via environment variables, .env files, or pass it directly through the CLI.

Walkthrough

First and foremost, always consult -h or help (or let me know if some stuff is unclear).

krs -h
krs help
# All subcommands also have `help`, thanks to the amazing `clap` library.
krs env help

krs collects Kafka brokers and Zookeeper hosts from environment variables, .env file, and the CLI arguments as its context. To show context variables:

$ krs env show # or just `krs env`

If in doubt, you can always ask the tool which environment you're currently working on:

$ cat .env
KRS_ZOOKEEPER=localhost:2181
$ export KRS_BROKERS=localhost:9092
$ krs env show
Environment:
  brokers: localhost:2181 (from env var (KRS_BROKERS))
  zookeeper: localhost:9092 (from .env file (KRS_ZOOKEEPER))

There's a small helper to set the context variables (or you can just put the environment variables KRS_BROKERS/KRS_ZOOKEEPER in your .env file directly):

$ krs env set -b localhost:9092 -z localhost:2181

Once you've set context variables, you can list Kafka topics:

krs topics list # or just `krs topics`
# You should pipe the output to `jq` to make it look much better.
krs topics | jq

Describe a Kafka topic:

krs topics describe -b localhost:9092 -z localhost:2181 -t topic-name

Produce and consume from topics:

krs topics create -t my-topic
krs producer -t my-topic
Starting console producer. Press Ctrl+C to exit.
> hello
Sent: (0, 1)

Compatibility

MSRV is Rust 1.39.0 (mostly because I built the tool with that version and haven't tested it with previous ones).

Mostly tested with Kafka 2.1.1-cp1 (Commit:9aa84c2aaa91e392).

Upcoming Features

Note: There will be no guarantees as to when these features are going to be implemented, but feel free to submit a PR.

• Consume from specified offset (earliest, latest, etc.)
• Describe configs for other Kafka resources (consumer groups, etc.)
• Port more management commands
• Bit more fine-grained control for producer (handle keys, send to partitions)
• More colors on the stderr output.

Why?

• Typing kafka-console-consumer --broker-list localhost:9092 --topic test is a mouthful.
• In cases you forgot the arguments to kafka-topics --create, the tool will bombard you with its complete list of options, burying the most important error message that tells you what arguments you're missing.
• JVM startup is annoyingly slow for simple CLI tools.
• RIIR, but in good spirit! I think the tool where the inspiration came from was already a fantastic idea.
• But most importantly, I just needed a project to learn Rust! :)