Ability to deploy demos of branches

* Ability to deploy additional branch demos, closes #1442
* Only run tests before deploy on main branch
* Documentation for continuous deployment

.github/workflows/deploy-latest.yml

@@ -29,6 +29,7 @@ jobs:
         python -m pip install -e .[docs]
         python -m pip install sphinx-to-sqlite==0.1a1
     - name: Run tests
+      if: ${{ github.ref == 'refs/heads/main' }}
       run: |
         pytest -n auto -m "not serial"
         pytest -m "serial"
@@ -50,6 +51,8 @@ jobs:
       run: |-
         gcloud config set run/region us-central1
         gcloud config set project datasette-222320
+        export SUFFIX="-${GITHUB_REF#refs/heads/}"
+        export SUFFIX=${SUFFIX#-main}
         datasette publish cloudrun fixtures.db extra_database.db \
             -m fixtures.json \
             --plugins-dir=plugins \
@@ -57,7 +60,10 @@ jobs:
             --version-note=$GITHUB_SHA \
             --extra-options="--setting template_debug 1 --setting trace_debug 1 --crossdb" \
             --install=pysqlite3-binary \
-            --service=datasette-latest
+            --service "datasette-latest$SUFFIX"
+    - name: Deploy to docs as well (only for main)
+      if: ${{ github.ref == 'refs/heads/main' }}
+      run: |-
         # Deploy docs.db to a different service
         datasette publish cloudrun docs.db \
             --branch=$GITHUB_SHA \

docs/contributing.rst

@@ -202,6 +202,17 @@ For added productivity, you can use use `sphinx-autobuild <https://pypi.org/proj
 
 Now browse to ``http://localhost:8000/`` to view the documentation. Any edits you make should be instantly reflected in your browser.
 
+.. _contributing_continuous_deployment:
+
+Continuously deployed demo instances
+------------------------------------
+
+The demo instance at `latest.datasette.io <https://latest.datasette.io/>`__ is re-deployed automatically to Google Cloud Run for every push to ``main`` that passes the test suite. This is implemented by the GitHub Actions workflow at `.github/workflows/deploy-latest.yml <https://github.com/simonw/datasette/blob/main/.github/workflows/deploy-latest.yml>`__.
+
+Specific branches can also be set to automatically deploy by adding them to the ``on: push: branches`` block at the top of the workflow YAML file. Branches configured in this way will be deployed to a new Cloud Run service whether or not their tests pass.
+
+The Cloud Run URL for a branch demo can be found in the GitHub Actions logs.
+
 .. _contributing_release:
 
 Release process