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.