Add Run Scheduled Action To Commit Regular Updates as a GitHub Actions TIL

README.md

@@ -10,7 +10,7 @@ working across different projects via [VisualMode](https://www.visualmode.dev/).
 
 For a steady stream of TILs, [sign up for my newsletter](https://visualmode.kit.com/newsletter).
 
-_1844 TILs and counting..._
+_1845 TILs and counting..._
 
 See some of the other learning resources I work on:
 
@@ -486,6 +486,7 @@ If you've learned something here, support my efforts writing daily TILs by
 - [Capture An Output Value For Use In A Later Step](github-actions/capture-an-output-value-for-use-in-a-later-step.md)
 - [Disable A Workflow With The gh CLI](github-actions/disable-a-workflow-with-the-gh-cli.md)
 - [Reference An Encrypted Secret In An Action](github-actions/reference-an-encrypted-secret-in-an-action.md)
+- [Run Schedule Action To Commit Regular Updates](github-actions/run-scheduled-action-to-commit-regular-updates.md)
 - [Trigger A Workflow Via An API Call](github-actions/trigger-a-workflow-via-an-api-call.md)
 - [Use Labels To Block PR Merge](github-actions/use-labels-to-block-pr-merge.md)
 

github-actions/run-scheduled-action-to-commit-regular-updates.md

@@ -0,0 +1,58 @@
+# Run Scheduled Action To Commit Regular Updates
+
+The quintessential example of what GitHub Actions are used for is running CI
+tasks like the test suite, type checker, linter, etc. Each CI step runs to
+completion and either passes or fails and you see the results in the GitHub PR
+interface. That's a great use case, but far from the only one. GitHub Actions
+are a much more general-purpose execution environment that can be used for much
+more.
+
+Here is a recent example that expanded my mind a bit on what is possible with
+GitHub actions. Imagine a GitHub Action that is scheduled to run once a day, it
+executes a script that might make changes to the repo itself (e.g. the
+`README.md`), and then commits those changes (self-updating the repo).
+
+Here is a minimal version of a workflow that does that:
+
+```yaml
+on:
+  schedule:
+    - cron: '17 11 * * *' # daily at 11:17 UTC (06:17 CT)
+  workflow_dispatch:
+
+permissions:
+  contents: write
+
+jobs:
+  update:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4 # get the repo + push credentials
+
+      - run: ./bin/regenerate_readme.sh # apply updates to README
+
+      - run: |
+          git config user.name  "github-actions[bot]"
+          git config user.email "github-actions[bot]@users.noreply.github.com"
+          git add -A README.md
+          git diff --staged --quiet || {
+            git commit -m "chore: regenerate README with latest updates"
+            git push
+          } # commit updates to README if there are any, otherwise no-op
+```
+
+Once a day at 11:17 UTC, GitHub Actions will run this workflow which is made up
+of a single job with permissions to write to the repo.
+
+- First, it checks out the repo in the job container which includes push
+credentials.
+- Then it runs a script that might update the README (e.g. maybe based on other
+things that have since been committed to the repo).
+- Last, it attempts to stage any changes the script made to the README. If there
+are any, then it will commit them with that generic commit message. Finally it
+will push that commit to the main branch.
+
+If this all sounds a bit untethered from a real-world example, then take a look
+at how I use this exact pattern to [apply daily updates to my GitHub Profile
+README](https://github.com/jbranchaud/jbranchaud/blob/main/.github/workflows/update-tils.yml)
+based on the latest [TILs](https://github.com/jbranchaud/til) I have written.