kt - a Kafka tool that likes JSON.

Some reasons why you might be interested:

Consume messages on specific partitions between specific offsets.
Display topic information (e.g., with partition offset and leader info)
Modify consumer group offsets (e.g., resetting or manually setting offsets per topic and per partition)
JSON output for easy consumption with tools like kp or jq.
JSON input to facilitate automation via tools like jsonify.
Configure brokers and topic via environment variables for a shell session
Fast start up time.
No buffering of output.
Binary keys and payloads can be passed and presented in base64 or hex encoding

Examples

Read details about topics that match the regex output

$ kt topic -filter news -partitions
{
  "name": "actor-news",
  "partitions": [
    {
      "id": 0,
      "oldest": 0,
      "newest": 0
    }
  ]
}

Produce messages:

$ echo 'Alice wins Oscar' | kt produce -topic actor-news -literal
{
  "count": 1,
  "partition": 0,
  "startOffset": 0
}
$ for i in {6..9} ; do echo Bourne sequel $i in production. | kt produce -topic actor-news -literal ;done
{
  "count": 1,
  "partition": 0,
  "startOffset": 1
}
{
  "count": 1,
  "partition": 0,
  "startOffset": 2
}
{
  "count": 1,
  "partition": 0,
  "startOffset": 3
}
{
  "count": 1,
  "partition": 0,
  "startOffset": 4
}

Or pass in JSON object to control key, value and partition:

$ echo '{"value": "Terminator terminated", "key": "Arni", "partition": 0}' | kt produce -topic actor-news
{
  "count": 1,
  "partition": 0,
  "startOffset": 5
}

Read messages at specific offsets on specific partitions:

$ kt consume -topic actor-news -offsets 0=1:2
{
  "partition": 0,
  "offset": 1,
  "key": "",
  "value": "Bourne sequel 6 in production.",
  "timestamp": "1970-01-01T00:59:59.999+01:00"
}
{
  "partition": 0,
  "offset": 2,
  "key": "",
  "value": "Bourne sequel 7 in production.",
  "timestamp": "1970-01-01T00:59:59.999+01:00"
}

Follow a topic, starting relative to newest offset:

$ kt consume -topic actor-news -offsets all=newest-1:
{
  "partition": 0,
  "offset": 4,
  "key": "",
  "value": "Bourne sequel 9 in production.",
  "timestamp": "1970-01-01T00:59:59.999+01:00"
}
{
  "partition": 0,
  "offset": 5,
  "key": "Arni",
  "value": "Terminator terminated",
  "timestamp": "1970-01-01T00:59:59.999+01:00"
}
^Creceived interrupt - shutting down
shutting down partition consumer for partition 0

View offsets for a given consumer group:

$ kt group -group enews -topic actor-news -partitions 0
found 1 groups
found 1 topics
{
  "name": "enews",
  "topic": "actor-news",
  "offsets": [
    {
      "partition": 0,
      "offset": 6,
      "lag": 0
    }
  ]
}

Change consumer group offset:

$ kt group -group enews -topic actor-news -partitions 0 -reset 1
found 1 groups
found 1 topics
{
  "name": "enews",
  "topic": "actor-news",
  "offsets": [
    {
      "partition": 0,
      "offset": 1,
      "lag": 5
    }
  ]
}
$ kt group -group enews -topic actor-news -partitions 0
found 1 groups
found 1 topics
{
  "name": "enews",
  "topic": "actor-news",
  "offsets": [
    {
      "partition": 0,
      "offset": 1,
      "lag": 5
    }
  ]
}

Installation

You can download kt via the Releases section.

Alternatively, the usual way via the go tool, for example:

$ go get -u github.com/fgeller/kt

Docker

@Paxa maintains an image to run kt in a Docker environment - thanks!

For more information: https://github.com/Paxa/kt

Usage:

$ kt -help
kt is a tool for Kafka.

Usage:

        kt command [arguments]

The commands are:

        consume        consume messages.
        produce        produce messages.
        topic          topic information.
        group          consumer group information and modification.

Use "kt [command] -help" for for information about the command.

michaelritsema/kt

kt - a Kafka tool that likes JSON.

Examples

Installation

Docker

Usage: