Concourse Slack Resource

Resource for sending and updating in Slack from Concourse. There's a few other resources available but as far as I'm aware this is the only one that supports sending blocks.

Configuration

Source

channel - required - the channel id to send the message to - either this or params.channel must be provided

bot_token - required - the OAUTH token for the Slack bot to use

debug - optional - include verbose status messages - do not use in production, this will leak credentials.

Params

blocks - required - the blocks to send to slack - see the example below

blocks_file - required - a file containing the blocks to send to slack - required if not setting the blocks option

timestamp - optional - the timestamp of a previous message to update

thread_ts - optional - the timestamp of a previous message to start a thread under

text - optional - text to send, if provided with blocks then this will be used as fallback text (for example, in notifications where blocks can't be rendered)

channel - optional - the channel id to send the message to - will override source.channel if provided

A note on channels

The Slack APIs for posting messages and updating messages are slightly different. When posting a message you can use the name of the channel, whereas when updating a message with the chat.update API you must provide the channel ID. It's recommended that you just specify the channel ID in the source configuration for this resource since that works everywhere.

Environment variable interpolation

Concourse provides a few environment variables to put steps that contain metadata about the build. This resource will interpolate environment variables given they're in the {{ $ENV_VAR }} format.

For example,

- put: slack-general
  params:
  blocks: |
    [
      {
        "type": "section",
        "text": {
            "type": "mrkdwn",
            "text": "Concourse available at {{ $ATC_EXTERNAL_URL }}"
        }
      }
    ]

No Get

Since v7.9.0, Concourse has supported an option called no_get in put steps. This skips the implicit get step right after doing a put. You can use no_get with this resource as long as you don't need the message timestamp later on.

An example

jobs:
  - name: slack
    plan:
      # Send a message
      - put: slack-general
        params:
          text: Fallback text displaed when blocks can't be rendered in notifications!
          blocks: |
            [
              {
                "type": "section",
                "text": {
                  "type": "mrkdwn",
                  "text": "Hello from <{{ $ATC_EXTERNAL_URL }}|Concourse>!"
                }
              }
            ]

      - load_var: timestamp
        file: slack-general/ts

      - task: wait
        config:
          platform: linux
          image_resource:
            type: registry-image
            source: {repository: alpine}
          outputs:
            - name: msg
          run:
            path: sh
            args:
              - -exc
              - |
                sleep 5

                echo -n '[
                  {
                    "type": "section",
                    "text": {
                      "type": "mrkdwn",
                      "text": "Updated"
                    }
                  }
                ]' > msg/blocks
      
      # Update the message from earlier using the contents of a file
      - put: slack-general
        inputs:
          - msg
        params:
          timestamp: ((.:timestamp))
          blocks_file: msg/blocks
      
      # Send a thread
      - put: slack-general
        inputs: []
        params:
          thread_ts: ((.:timestamp))
          blocks: |
            [
              {
                "type": "section",
                "text": {
                  "type": "mrkdwn",
                  "text": "I'm a thread message!"
                }
              }
            ]

resources:
  - name: slack-general
    check_every: never
    type: slack
    source:
      channel: "((secret/slack/channel))"
      bot_token: "((secret/slack))"

resource_types:
  - name: slack
    type: registry-image
    source:
      repository: ca5ey32/concourse-slack-resource
      tag: 0.1.1