Refactor Docker CI workflows

Split previous docker test CI into one for PRs and one for triggering
the main buildx workflow that deploys new images to Docker Hub.

Note that this needs to be further refactored soon to use reusable
workflows. The main portion of docker/docker-compose tests is duplicated
between the new main + test workflows.

.github/workflows/buildx.yml

@@ -2,7 +2,7 @@ name: buildx
 
 on:
   workflow_run:
-    workflows: ["docker_tests"]
+    workflows: ["docker_main"]
     branches: [main]
     types:
       - completed

.github/workflows/docker_main.yml

@@ -0,0 +1,27 @@
+name: docker_main
+
+on:
+  workflow_run:
+    workflows: ["tests"]
+    branches: [main]
+    types:
+      - completed
+
+# TODO: Needs refactoring to use reusable workflows and share w/ docker_tests
+jobs:
+  on-success:
+    runs-on: ubuntu-latest
+    steps:
+    - name: checkout code
+      uses: actions/checkout@v2
+    - name: build and test (docker)
+      run: |
+        docker build --tag whoogle-search:test .
+        docker run --publish 5000:5000 --detach --name whoogle-search whoogle-search:test
+        sleep 15
+        docker exec whoogle-search curl -f http://localhost:5000/healthz || exit 1
+    - name: build and test (docker-compose)
+      run: |
+        docker-compose up --detach
+        sleep 15
+        docker exec whoogle-search curl -f http://localhost:5000/healthz || exit 1

.github/workflows/docker_tests.yml

@@ -1,21 +1,25 @@
 name: docker_tests
 
 on:
-  workflow_run:
-    workflows: ["tests"]
-    branches: [main]
-    types:
-      - completed
+  push:
+    branches: main
+  pull_request:
+    branches: main
 
 jobs:
-  on-success:
+  docker:
     runs-on: ubuntu-latest
     steps:
     - name: checkout code
       uses: actions/checkout@v2
-    - name: build and test
+    - name: build and test (docker)
       run: |
         docker build --tag whoogle-search:test .
-        docker run --publish 5000:5000 --detach --name whoogle-search whoogle-search:test
+        docker run --publish 5000:5000 --detach --name whoogle-search-nocompose whoogle-search:test
+        sleep 15
+        docker exec whoogle-search-nocompose curl -f http://localhost:5000/healthz || exit 1
+    - name: build and test (docker-compose)
+      run: |
+        docker-compose up --detach
         sleep 15
         docker exec whoogle-search curl -f http://localhost:5000/healthz || exit 1