Slack notification action that just works
This is the continuation of adamkdean/simple-slack-notify.
We've attempted to use a few of the Slack notification actions that are currently available, but they all seem to have limitations or be quite verbose, so we set out to create a simple yet effective action that just does what you need and nothing else. In the examples below, we'll show a few different variations of how the action could be used.
The main features are:
- Status based messages meaning one step handles job successes, failures, and cancellations
- JavaScript strings for embedding environment variables or custom logic into notification strings
- Easy to add fields based on standard Slack JSON inputs
Be sure that you set the SLACK_WEBHOOK_URL environment variable, either in the job or in the step like this:
- uses: edge/simple-slack-notify@master
env:
SLACK_WEBHOOK_URL: ${{ secrets.SLACK_WEBHOOK_URL }}The simplest use would consist of relying on the webhook's defaults and simply providing some text.
- name: Simple notification
uses: edge/simple-slack-notify@master
with:
text: 'This is the simplest notification'
Overriding the channel is sometimes needed, such as to separate out builds, deployments, and alerts perhaps.
- name: Channel specific notification
uses: edge/simple-slack-notify@master
with:
channel: '#alerts'
text: 'Something is happening and someone should probably panic'
The above works well, but what would really make someone panic is if we make the alert red, right?
You can use danger, warning, good, or a hex code such as #d90000.
- name: Panic inducing notification
uses: edge/simple-slack-notify@master
with:
channel: '#alerts'
text: 'Something is happening and someone should probably panic'
color: 'danger'
Perhaps you also want to change the username?
- name: Panic Bot notification
uses: edge/simple-slack-notify@master
with:
channel: '#alerts'
username: 'Panic Bot'
text: 'Something is happening and someone should probably panic'
color: 'danger'
The action also supports fields, but due to the limitations of GitHub actions only passing in inputs as strings, we can't use yaml arrays. So, this is how you'd specify a field:
- name: Specifying what to panic about notification
uses: edge/simple-slack-notify@master
with:
channel: '#alerts'
username: 'Panic Bot'
text: 'Something is happening and someone should probably panic'
color: 'danger'
fields: |
[{ "title": "Reason to panic", "value": "Deployed failed halfway through" }]
If there were multiple reasons to panic, you'd add more objects to the fields array:
- name: Specifying what to panic about notification
uses: edge/simple-slack-notify@master
with:
channel: '#alerts'
username: 'Panic Bot'
text: 'Something is happening and someone should probably panic'
color: 'danger'
fields: |
[{ "title": "Reason to panic", "value": "Deployed failed halfway through", "short": true },
{ "title": "Timestamp", "value": "${Date.now()}", "short": true }]
Did you notice that some JavaScript snook in? Input strings are evaluated as a JavaScript strings, which means you can put environment variables into your messages, such as the GITHUB_WORKFLOW variable or GITHUB_RUN_NUMBER etc. The environment is stored within the env variable so to access environment variables in your strings, you simply use ${env.GITHUB_REPOSITORY} etc. Here's an example:
- name: Environment variable notification
uses: edge/simple-slack-notify@master
with:
channel: '#example'
text: '${env.GITHUB_WORKFLOW} (${env.GITHUB_RUN_NUMBER}) has finished'
fields: |
[{ "title": "Repository", "value": "${env.GITHUB_REPOSITORY}", "short": true },
{ "title": "Branch", "value": "${env.BRANCH}", "short": true }]
Now, each job has a status, which can be success, failed, or cancelled. Most other notification plugins use multiple blocks with if: success() and if: failed() etc but we don't need to do that. We can simply pass in the status and set status specific text. We use if: always() so that it runs regardless of whether the job is successful or not.
- name: Build notification
if: always()
uses: edge/simple-slack-notify@master
with:
channel: '#builds'
status: ${{ job.status }}
success_text: '${env.GITHUB_WORKFLOW} (${env.GITHUB_RUN_NUMBER}) build completed successfully'
failure_text: '${env.GITHUB_WORKFLOW} (${env.GITHUB_RUN_NUMBER}) build failed'
cancelled_text: '${env.GITHUB_WORKFLOW} (${env.GITHUB_RUN_NUMBER}) build was cancelled'
fields: |
[{ "title": "Repository", "value": "${env.GITHUB_REPOSITORY}", "short": true },
{ "title": "Branch", "value": "${env.BRANCH}", "short": true }]
There are likely other ways you can use this action, so please submit a pull request if you want to add your useful example to this list. I hope this is as useful for you as it is for me.
Note: the BRANCH variable isn't standard. To get that, use the following:
- name: Extract branch name
shell: bash
run: echo "::set-env name=BRANCH::$(echo ${GITHUB_REF#refs/heads/} | sed 's/\//_/g')"
This won't work for actions initiated by a pull request though.
If you want to link to the run, that's super easy. Just add the following string either to a field or to the message.
${env.GITHUB_SERVER_URL}/${env.GITHUB_REPOSITORY}/actions/runs/${env.GITHUB_RUN_ID}
So for a field you'd have:
{ "title": "Action URL", "value": "${env.GITHUB_SERVER_URL}/${env.GITHUB_REPOSITORY}/actions/runs/${env.GITHUB_RUN_ID}"}
| Input | Details | Example/possible values |
|---|---|---|
| cancelled_text | The message to send if status is cancelled | |
| channel | The channel you want to send to | #general |
| color | The color you want to use | "good", "danger", "warning" or a hex code |
| disable_eval | Disable JS string evaluation. False by default | false |
| failure_text | The message to send if status is failure | |
| fields | JSON string containing an array of fields to attach to the notification | |
| status | Pass the job status through and omit color for status based color | |
| success_text | The message to send if status is success | |
| text | The message that you want to send regardless of status | |
| username | Used to override the default username |
MIT License
Copyright (c) 2020 Adam K Dean <[email protected]>
Edge Network Technologies Ltd <[email protected]>
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