Use repo variables instead of artifacts

.github/workflows/slack-notifier.yml

@@ -2,6 +2,9 @@ name: Post comments on slack, with rate limiting.
 on:
   workflow_call:
     secrets:
+      GITHUB_PAT:
+        description: 'The github token used to read the timeout variable.'
+        required: true
       SLACK_BOT_TOKEN:
         description: 'The slack API token, with `chat:write` permissions.'
         required: true
@@ -14,8 +17,8 @@ on:
         description: 'The message to send to slack.'
         required: true
         type: string
-      message-label:
-        description: 'A label identifying the message type. Used to rate limit messages.'
+      timeout-variable:
+        description: 'A repository variable used to store the last message timestamp.'
         required: true
         type: string
       timeout-minutes:
@@ -37,11 +40,41 @@ jobs:
     steps:
       - name: Check last message timestamp
         id: last-sent
-        uses: dawidd6/action-download-artifact@v6
-        with:
-          # Downloads the artifact from the most recent successful run
-          name: last-sent-${{ inputs.message-label }}.txt
-          if_no_artifact_found: ignore
+        run: |
+          set +e
+          gh api \
+            -H "Accept: application/vnd.github+json" \
+            -H "X-GitHub-Api-Version: 2022-11-28" \
+            /repos/$OWNER/$REPO/actions/variables/$VAR \
+            > read-variable.json
+          if [ $? -ne 0 ]
+          then
+            echo "Could not read the variable."
+            echo "missing=true" >> $GITHUB_OUTPUT
+          else
+            jq -r '.value' read-variable.json > last-sent.txt
+            echo "missing=false" >> $GITHUB_OUTPUT
+          fi
+        env:
+          GH_TOKEN: ${{ secrets.GITHUB_PAT }}
+          OWNER: ${{ github.repository_owner }}
+          REPO: ${{ github.event.repository.name }}
+          VAR: ${{ inputs.timeout-variable }}
+
+      - name: Create the timestamp variable if it's missing
+        if: ${{ steps.last-sent.outputs.missing == 'true' }}
+        run: |
+          gh api \
+            --method POST \
+            -H "Accept: application/vnd.github+json" \
+            -H "X-GitHub-Api-Version: 2022-11-28" \
+            /repos/$OWNER/$REPO/actions/variables \
+            -f "name=$VAR" -f "value=1990-01-01T00:00:00Z"
+        env:
+          GH_TOKEN: ${{ secrets.GITHUB_PAT }}
+          OWNER: ${{ github.repository_owner }}
+          REPO: ${{ github.event.repository.name }}
+          VAR: ${{ inputs.timeout-variable }}
 
       - name: Rate limit
         id: rate-limit
@@ -52,42 +85,52 @@ jobs:
           echo "\"$MESSAGE\""
           echo
 
-          if [ -f last-sent-${{ inputs.message-label }}.txt ]
+          if [ -f last-sent.txt ]
           then
-            LAST_SENT=$( cat last-sent-${{ inputs.message-label }}.txt )
+            LAST_SENT=$( cat last-sent.txt )
+            NOW=$( date +'%FT%TZ' )
             echo "Last sent: $LAST_SENT"
-            NOW=$( date +%s )
             echo "Now: $NOW"
+
+            DIFF_MINUTES=$(( ( $( date -d "$NOW" +%s ) - $( date -d "$LAST_SENT" +%s ) ) / 60 ))
             echo "Timeout: $TIMEOUT mins"
-            echo "Difference: $(( NOW - LAST_SENT ))"
+            echo "Difference: $DIFF_MINUTES mins"
 
-            if [ $(( NOW - LAST_SENT )) -lt $(( TIMEOUT * 60 )) ]
+            if [ $DIFF_MINUTES -lt $TIMEOUT ]
             then
-              echo "Rate limiting. Not sending the message."
+              echo "On timeout period. Not sending the message."
               echo "send=false" >> "$GITHUB_OUTPUT"
               exit 0
             fi
           else
-            echo "No last-sent file found."
+            echo "Last-sent variable was not set."
           fi
           echo "send=true" >> "$GITHUB_OUTPUT"
-          date +%s > last-sent-${{ inputs.message-label }}.txt
+          date +%s > last-sent.txt
         env:
           TIMEOUT: ${{ inputs.timeout-minutes }}
           MESSAGE: ${{ inputs.slack-message }}
 
       - name: Send notification
-        if: ${{ steps.rate-limit.outputs.send == 'true' }}
+        if: false && ${{ steps.rate-limit.outputs.send == 'true' }}
         uses: slackapi/[email protected]
         with:
           channel-id: ${{ inputs.channel-id }}
           slack-message: ${{ inputs.slack-message }}
         env:
           SLACK_BOT_TOKEN: ${{ secrets.SLACK_BOT_TOKEN }}
 
-      - name: Upload the new last-sent timestamp
+      - name: Modify the variable to save the new timestamp
         if: ${{ steps.rate-limit.outputs.send == 'true' }}
-        uses: actions/upload-artifact@v4
-        with:
-          name: last-sent-${{ inputs.message-label }}.txt
-          path: last-sent-${{ inputs.message-label }}.txt
+        run: |
+          gh api \
+            --method PATCH \
+            -H "Accept: application/vnd.github+json" \
+            -H "X-GitHub-Api-Version: 2022-11-28" \
+            /repos/$OWNER/$REPO/actions/variables/$VAR \
+            -f "name=$VAR" -f "value=$( date +'%FT%TZ' )"
+        env:
+          GH_TOKEN: ${{ secrets.GITHUB_PAT }}
+          OWNER: ${{ github.repository_owner }}
+          REPO: ${{ github.event.repository.name }}
+          VAR: ${{ inputs.timeout-variable }}

README.md

@@ -206,20 +206,20 @@ jobs:
         with:
             channel-id: "SOME CHANNEL ID"
             slack-message: "Hello 🌎!"
-            # An unique identifier for the message type, to use in rate limiting.
-            message-label: "hello"
             # A minimum time in minutes to wait before sending another message.
             timeout-minutes: 60
+            # A repository variable used to store the last message timestamp.
+            timeout-variable: "HELLO_MESSAGE_TIMESTAMP"
         secrets:
+            GITHUB_PAT: ${{ secrets.GITHUB_PAT }}
             SLACK_BOT_TOKEN: ${{ secrets.SLACK_BOT_TOKEN }}
 ```
 
 ### Inputs
 
 - `channel-id`: The ID of the channel to post the message to. (**required**)
 - `slack-message`: The message to post. (**required**)
-- `message-label`: An identifier for the message type, to use in rate limiting.
-  This label is tied to the workflow name. (**required**)
+- `timeout-variable`: A repository variable used to store the last message timestamp. (**required**)
 - `timeout-minutes`: A minimum time in minutes to wait before sending another message. Defaults to 24 hours.
 
 ### Outputs
@@ -234,3 +234,9 @@ channel. See the
 documentation for more information.
 If you are using a slack app, make sure to add it to the channel.
 See formatting options in the [Slack API documentation](https://api.slack.com/reference/surfaces/formatting).
+
+The fine-grained `GITHUB_PAT` secret must include the following permissions:
+
+| Permission | Access |
+| --- | --- |
+| Variables (repository) | Read and write |