Be less aggressive about Docker and docs builds

Only trigger the Docker build workflow for ticket branches and tags.
Only trigger docs builds for ticket branches and the main branch,
and ignore commits that don't touch the documentation.

This should cut back on the useless Docker images and docuemntation
versions we push from dependency updates from dependabot and
neophile.

We'd like to preserve the behavior of only triggering Docker builds
if the tests pass, but unfortunately there isn't any way to do that
and also use different criteria for running the Docker workflow
without some very complicated machinations involving the REST API or
complex conditionals.  Live with spurious builds with failing tests
for now at least.

.github/workflows/ci.yaml

@@ -1,6 +1,6 @@
 name: CI
 
-on: [push]
+"on": [push]
 
 jobs:
   test:
@@ -89,69 +89,3 @@ jobs:
       - name: Run tox (PostgreSQL)
         run: tox -e docker
         if: matrix.database == 'PostgreSQL'
-
-  build:
-    runs-on: ubuntu-latest
-    needs: [test]
-
-    steps:
-      - uses: actions/checkout@v2
-
-      - name: Define the Docker tag
-        id: vars
-        run: echo ::set-output name=tag::$(echo ${GITHUB_REF} | sed -E 's,refs/(heads|tags)/,,' | sed -E 's,/,-,g')
-
-      - name: Print the tag
-        id: print
-        run: echo ${{steps.vars.outputs.tag}}
-
-      - name: Log into Docker Hub
-        run: echo ${{ secrets.DOCKER_TOKEN }} | docker login --username ${{ secrets.DOCKER_USERNAME }} --password-stdin
-
-      - name: Pull previous images
-        run: |
-          docker pull lsstsqre/gafaelfawr:deps-${{steps.vars.outputs.tag}} || true
-          docker pull lsstsqre/gafaelfawr:${{steps.vars.outputs.tag}} || true
-
-      - name: Build the dependencies Docker image
-        run: |
-          docker build --target dependencies-image \
-            --cache-from=lsstsqre/gafaelfawr:deps-${{steps.vars.outputs.tag}} \
-            --tag lsstsqre/gafaelfawr:deps-${{steps.vars.outputs.tag}} .
-
-      - name: Build the runtime Docker image
-        run: |
-          docker build --target runtime-image \
-            --cache-from=lsstsqre/gafaelfawr:${{steps.vars.outputs.tag}} \
-            --tag lsstsqre/gafaelfawr:${{steps.vars.outputs.tag}} .
-
-      - name: Push Docker images
-        run: |
-          docker push lsstsqre/gafaelfawr:deps-${{steps.vars.outputs.tag}}
-          docker push lsstsqre/gafaelfawr:${{steps.vars.outputs.tag}}
-
-  docs:
-    runs-on: ubuntu-latest
-
-    steps:
-      - uses: actions/checkout@v2
-
-      - name: Set up Python
-        uses: actions/setup-python@v2
-        with:
-          python-version: 3.8
-
-      - name: Install tox and LTD Conveyor
-        run: pip install tox ltd-conveyor
-
-      - name: Install graphviz and ImageMagick
-        run: sudo apt-get install graphviz imagemagick
-
-      - name: Run tox
-        run: tox -e docs
-
-      - name: Upload to LSST the Docs
-        env:
-          LTD_USERNAME: ${{ secrets.LTD_USERNAME }}
-          LTD_PASSWORD: ${{ secrets.LTD_PASSWORD }}
-        run: ltd upload --product gafaelfawr --gh --dir docs/_build/html

.github/workflows/docker.yaml

@@ -0,0 +1,48 @@
+name: Docker
+
+"on":
+  push:
+    branches:
+      - "tickets/**"
+    tags:
+      - "*"
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+
+    steps:
+      - uses: actions/checkout@v2
+
+      - name: Define the Docker tag
+        id: vars
+        run: echo ::set-output name=tag::$(echo ${GITHUB_REF} | sed -E 's,refs/(heads|tags)/,,' | sed -E 's,/,-,g')
+
+      - name: Print the tag
+        id: print
+        run: echo ${{steps.vars.outputs.tag}}
+
+      - name: Log into Docker Hub
+        run: echo ${{ secrets.DOCKER_TOKEN }} | docker login --username ${{ secrets.DOCKER_USERNAME }} --password-stdin
+
+      - name: Pull previous images
+        run: |
+          docker pull lsstsqre/gafaelfawr:deps-${{steps.vars.outputs.tag}} || true
+          docker pull lsstsqre/gafaelfawr:${{steps.vars.outputs.tag}} || true
+
+      - name: Build the dependencies Docker image
+        run: |
+          docker build --target dependencies-image \
+            --cache-from=lsstsqre/gafaelfawr:deps-${{steps.vars.outputs.tag}} \
+            --tag lsstsqre/gafaelfawr:deps-${{steps.vars.outputs.tag}} .
+
+      - name: Build the runtime Docker image
+        run: |
+          docker build --target runtime-image \
+            --cache-from=lsstsqre/gafaelfawr:${{steps.vars.outputs.tag}} \
+            --tag lsstsqre/gafaelfawr:${{steps.vars.outputs.tag}} .
+
+      - name: Push Docker images
+        run: |
+          docker push lsstsqre/gafaelfawr:deps-${{steps.vars.outputs.tag}}
+          docker push lsstsqre/gafaelfawr:${{steps.vars.outputs.tag}}

.github/workflows/docs.yaml

@@ -0,0 +1,38 @@
+name: Docs
+
+"on":
+  push:
+    branches:
+      - main
+      - master
+      - "tickets/**"
+    paths:
+      - "docs/**"
+      - "src/**.py"
+
+jobs:
+  docs:
+    runs-on: ubuntu-latest
+
+    steps:
+      - uses: actions/checkout@v2
+
+      - name: Set up Python
+        uses: actions/setup-python@v2
+        with:
+          python-version: 3.8
+
+      - name: Install tox and LTD Conveyor
+        run: pip install tox ltd-conveyor
+
+      - name: Install graphviz and ImageMagick
+        run: sudo apt-get install graphviz imagemagick
+
+      - name: Run tox
+        run: tox -e docs
+
+      - name: Upload to LSST the Docs
+        env:
+          LTD_USERNAME: ${{ secrets.LTD_USERNAME }}
+          LTD_PASSWORD: ${{ secrets.LTD_PASSWORD }}
+        run: ltd upload --product gafaelfawr --gh --dir docs/_build/html