karenc/concourse-slack-resource repository overview

⁠What is concourse-slack-resource?

A concourse resource to read and post messages to slack as a bot.

It reads messages from all the channels the bot is in (not tested but maximum 50 channels) and allows the bot to write to any of the channels.

⁠Prerequisites for using this resource

You'll need to create a slack app and a bot: https://api.slack.com/bot-users⁠

Once you set everything up, you should be able to find your app on https://api.slack.com/apps⁠

Under "OAuth & Permissions", you'll need the "OAuth Access Token" and "Bot User OAuth Access Token". They look something like xoxo-1234567890-abcdefghij and xoxo-1234567890-klmnopqrst.

The bot needs these scopes:

• channels:history (Access user's public channels)
• chat:write:bot (Send messages as bot)
• bot (Add a bot user with the username @bot)
• users:read (Access your workspaces's profile information)

You also need the bot user id (which is not the username and not the bot id), I found the user id by doing @<bot-username> in the slack web app and then copying the url, it looks something like this: https://openstax.slack.com/team/ABC123GHI⁠ and the user id is the last bit ABC123GHI.

These need to be stored in the vars.yml to be used with the example pipeline below, for example:

slack-user-access-token: xoxo-1234567890-abcdefghij
slack-bot-access-token: xoxo-1234567890-klmnopqrst
slack-bot-user-id: ABC123GHI

⁠Example concourse pipeline

You can find this in pipeline.yml⁠.

---
resource_types:
  - name: slack
    type: docker-image
    source:
      repository: karenc/concourse-slack-resource

resources:
  - name: bot
    type: slack
    source:
      user_access_token: ((slack-user-access-token))
      bot_access_token: ((slack-bot-access-token))
      bot_user_id: ((slack-bot-user-id))
      regexp: '<@((slack-bot-user-id))> (.*)'
    check_every: 10s

  - name: bot-write
    type: slack
    source:
      user_access_token: ((slack-user-access-token))
      bot_access_token: ((slack-user-bot-access-token))
      bot_user_id: ((slack-bot-user-id))

jobs:
  - name: test
    plan:
      - get: bot
        trigger: true
        version: every

      - put: bot-write
        params:
          text: '{{bot/message_text_0}} :tada:'
          channel: '{{bot/channel}}'

Note: The read and write resources need to be separate, otherwise there's an infinite loop after the put step when the implicit get triggers a new job :/

From https://concourse-ci.org/put-step.html⁠:

⁠Filtering and parsing incoming messages

regexp can be defined in the get resource, it is used to filter messages so only messages matching the regular expression are returned. It is also used to parse the messages so if you add groups, they will be available as different files.

In this example, if the message looks like <@ABC123GHI> hey!, the bot/ directory contains:

1. message_text: <@ABC123GHI> hey!
2. message_text_0: hey!
3. channel: CDEF7890
4. user: U0123456

⁠Sending messages

You need to provide at least two params text and channel. All the params can be found in https://api.slack.com/methods/chat.postMessage⁠, any params will be turned into arguments for chat.postMessage.

You can include content from files by doing something like: {{bot/message_text_0}} :tada:, following the example message above, this will be:

hey! :tada:

⁠Creating the pipeline on concourse

To create the example pipeline you can do:

fly -t example sp -p slack-bot -c pipeline.yml -l vars.yml

Unpause the pipeline:

fly -t example up -p slack-bot

And wait for the slack bot to respond. Remember to invite your bot to the channels you want.

⁠Debugging

If you're expecting the concourse pipeline to trigger but it's not happening, you can try:

fly -t example intercept -c slack-bot/bot

This gives you access to the container the resource is running in.

There should be a /tmp/body.json and /tmp/check_.log.

/tmp/body.json is what concourse is sending to /opt/resource/check or /opt/resource/in or /opt/resource/out.

It should look something like: (added line breaks for readability)

{
    "source": {
        "bot_access_token": "xoxo-1234567890-klmnopqrst",
        "bot_user_id": "ABC123GHI",
        "user_access_token": "xoxo-1234567890-abcdefghij"
    },
    "version": {
        "channel_id": "CDEF7890",
        "ts": "1570673298.005900"
    }
}

You can try running the check script yourself by doing:

cat /tmp/body.json | /opt/resource/check

There are some debugging output in stderr so hopefully you'll find the problem there.

For more information about concourse resources, see https://concourse-ci.org/implementing-resource-types.html⁠