Consolidate Docker verification for CI workflows

.github/actions/verify-docker/action.yml

@@ -0,0 +1,20 @@
+name: 'Verify Docker'
+description: 'Verify that the runner Docker daemon is available and emit Docker/buildx version diagnostics. No-op on non-Linux runners.'
+runs:
+  using: "composite"
+  steps:
+    - name: Verify Docker daemon and emit diagnostics
+      # Aspire CI only relies on Docker on Linux runners; the macOS and Windows
+      # GitHub-hosted runners don't have a working Docker daemon. Skip there so
+      # callers don't need to repeat `if: runner.os == 'Linux'` at every call site.
+      if: runner.os == 'Linux'
+      shell: bash
+      run: |
+        # Run docker info first as the gating check, but never let it short-circuit
+        # the diagnostics that follow — those are most useful when the daemon is
+        # broken. Re-raise its exit code at the end so the step still fails.
+        rc=0
+        docker info || rc=$?
+        docker version || echo "::warning::docker version failed with exit code $?"
+        docker buildx version || echo "::warning::docker buildx version failed with exit code $?"
+        exit $rc

.github/workflows/build-cli-e2e-image.yml

@@ -38,7 +38,7 @@ jobs:
         uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
 
       - name: Verify Docker is running
-        run: docker info
+        uses: ./.github/actions/verify-docker
 
       - name: Export GitHub Actions cache runtime
         uses: actions/github-script@60a0d83039c74a4aee543508d2ffcb1c3799cdea # v7.0.1
@@ -75,32 +75,29 @@ jobs:
               echo "Building $display_name with the default Ubuntu apt sources"
             fi
 
-            docker buildx build \
-              --load \
-              --cache-from "type=gha,scope=$cache_scope" \
-              --cache-to "type=gha,scope=$cache_scope,mode=max,ignore-error=true" \
-              "${build_args[@]}" \
-              -f "$dockerfile" \
-              -t "$tag" \
-              .
-          }
-
-          build_java_image() {
-            local mirror="$1"
-            local -a build_args=()
-
-            if [[ -n "$mirror" ]]; then
-              echo "Building Java polyglot image with Ubuntu apt mirror: $mirror"
-              build_args+=(--build-arg "UBUNTU_APT_MIRROR=$mirror")
+            if [[ -n "$cache_scope" ]]; then
+              # Cached path: use the buildx docker-container builder so we can read/write
+              # BuildKit layers from the GitHub Actions cache.
+              docker buildx build \
+                --load \
+                --cache-from "type=gha,scope=$cache_scope" \
+                --cache-to "type=gha,scope=$cache_scope,mode=max,ignore-error=true" \
+                "${build_args[@]}" \
+                -f "$dockerfile" \
+                -t "$tag" \
+                .
             else
-              echo "Building Java polyglot image with the default Ubuntu apt sources"
+              # Uncached path: build through the default docker daemon driver so the
+              # image can reference other locally-loaded images via FROM (e.g. the
+              # polyglot base built earlier in this step). The docker-container buildx
+              # driver does not have access to the daemon's image store and would try
+              # to pull such references from a registry.
+              DOCKER_BUILDKIT=1 docker build \
+                "${build_args[@]}" \
+                -f "$dockerfile" \
+                -t "$tag" \
+                .
             fi
-
-            DOCKER_BUILDKIT=1 docker build \
-              "${build_args[@]}" \
-              -f tests/Shared/Docker/Dockerfile.e2e-polyglot-java \
-              -t "$CLI_E2E_POLYGLOT_JAVA_IMAGE_TAG" \
-              .
           }
 
           build_with_mirror_retry() {
@@ -121,10 +118,11 @@ jobs:
             build_with_mirror_retry "polyglot base image" "tests/Shared/Docker/Dockerfile.e2e-polyglot-base" "$CLI_E2E_POLYGLOT_BASE_IMAGE_TAG" "$CLI_E2E_POLYGLOT_BASE_IMAGE_CACHE_SCOPE"
             docker tag "$CLI_E2E_POLYGLOT_BASE_IMAGE_TAG" "$CLI_E2E_POLYGLOT_IMAGE_TAG"
 
-            if ! build_java_image "http://azure.archive.ubuntu.com/ubuntu/"; then
-              echo "Java polyglot image build failed with the Azure Ubuntu apt mirror; retrying with default Ubuntu apt sources"
-              build_java_image ""
-            fi
+            # The Java polyglot image extends the polyglot base via `FROM
+            # aspire-e2e-polyglot-base`, which only exists in the local docker daemon.
+            # Pass an empty cache scope so build_image uses the daemon-backed
+            # `docker build` path instead of the docker-container buildx driver.
+            build_with_mirror_retry "Java polyglot image" "tests/Shared/Docker/Dockerfile.e2e-polyglot-java" "$CLI_E2E_POLYGLOT_JAVA_IMAGE_TAG" ""
           fi
 
       - name: Save CLI E2E Docker image tarballs

.github/workflows/deployment-tests.yml

@@ -245,11 +245,7 @@ jobs:
           echo "✅ Azure authentication successful"
 
       - name: Verify Docker is running
-        run: |
-          echo "Verifying Docker daemon..."
-          docker version
-          docker info | head -20
-          echo "✅ Docker is available"
+        uses: ./.github/actions/verify-docker
 
       - name: Run deployment test (${{ matrix.shortname }})
         id: run_tests

.github/workflows/reproduce-flaky-tests.yml

@@ -177,9 +177,8 @@ jobs:
         env:
           WSL_INTEROP: ""
 
-      - name: Verify Docker is running (Linux)
-        if: runner.os == 'Linux'
-        run: docker info
+      - name: Verify Docker is running
+        uses: ./.github/actions/verify-docker
 
       - name: Download prebuilt CLI E2E Docker image
         if: ${{ needs.setup.outputs.is_cli_e2e == 'true' && runner.os == 'Linux' }}

.github/workflows/run-tests.yml

@@ -114,9 +114,7 @@ jobs:
           WSL_INTEROP: ""
 
       - name: Verify Docker is running
-        # nested docker containers not supported on windows
-        if: runner.os == 'Linux'
-        run: docker info
+        uses: ./.github/actions/verify-docker
 
       - name: Download prebuilt CLI E2E Docker image
         if: ${{ fromJson(inputs.properties).requiresCliArchive == true && runner.os == 'Linux' }}

.github/workflows/tests-daily-smoke.yml

@@ -53,7 +53,7 @@ jobs:
         run: ./restore.sh
 
       - name: Verify Docker is running
-        run: docker info
+        uses: ./.github/actions/verify-docker
 
       - name: Download prebuilt CLI E2E Docker image
         uses: actions/download-artifact@3e5f45b2cfb9172054b4087a40e8e0b5a5461e7c # v8.0.1

.github/workflows/tests.yml

@@ -86,7 +86,6 @@ jobs:
     name: Build CLI E2E Docker image
     uses: ./.github/workflows/build-cli-e2e-image.yml
     needs: setup_for_tests
-    if: ${{ fromJson(needs.setup_for_tests.outputs.tests_matrix_requires_cli_archive).include[0] != null }}
 
   tests_no_nugets:
     name: ${{ matrix.shortname }}

docs/ci/verify-docker.md

@@ -0,0 +1,7 @@
+# Verify Docker action
+
+Workflows that need Docker should use `.github/actions/verify-docker` instead of running `docker info` directly. The action checks that the Docker daemon is reachable with `docker info` and always emits `docker version` and `docker buildx version` so logs are useful when the daemon is broken.
+
+The action is a no-op on non-Linux runners, so callers can use it unconditionally even from cross-OS jobs — there's no need to gate the step with `if: runner.os == 'Linux'`.
+
+Extend this action when CI needs a stronger Docker runner contract.