ci(.github): add a golang integration check (#4888)

A new GitHub Actions workflow is added to verify Golang integration.

The workflow installs necessary Go tools and the librarian CLI, checks
out the google-cloud-go repository, runs `librarian generate`, and
executes vet checks.
It also includes a step to automatically create an issue on failure when
running on the main branch.

This ensures that changes to the librarian CLI do not break the
generation process for the Go client libraries.

Author: JoeWang1127

.github/workflows/golang.yaml

@@ -0,0 +1,62 @@
+# Copyright 2026 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+name: Golang
+on: [push, pull_request, merge_group]
+permissions:
+  contents: read
+  issues: write
+jobs:
+  integration:
+    runs-on: ubuntu-24.04
+    if: github.event_name == 'push' && github.ref == 'refs/heads/main'
+    steps:
+      - uses: actions/checkout@v6
+      - uses: actions/setup-go@v6
+        with:
+          go-version-file: "go.mod"
+      - name: Install go tools
+        run: |
+          go install tool
+          # TODO(https://github.com/googleapis/librarian/issues/4894), Use golangci-lint
+          # for static checkers and linters.
+          # we need to install golint and staticcheck because
+          # the vet check uses this tool.
+          go install golang.org/x/lint/golint@latest
+          go install honnef.co/go/tools/cmd/staticcheck@latest
+      - uses: ./.github/actions/install-protoc
+      - name: Install librarian
+        run: go install ./cmd/librarian
+      - name: Checkout google-cloud-go
+        uses: actions/checkout@v6
+        with:
+          repository: googleapis/google-cloud-go
+          path: google-cloud-go
+      - name: Run librarian generate
+        working-directory: google-cloud-go
+        run: librarian generate --all
+        # TODO(https://github.com/googleapis/librarian/issues/4895): Standardize static analysi
+        # tool across librarian and google-cloud-go.
+        # The vet.sh script is a comprehensive CI/CD utility in google-cloud-go that enforces code
+        # quality by running static analysis tools. We use this check to validate code generated
+        # by librarian.
+      - name: Run vet check
+        working-directory: google-cloud-go
+        run: ./.github/workflows/vet.sh
+  create-issue-on-failure:
+    needs: [integration]
+    if: ${{ always() && contains(needs.*.result, 'failure') && github.event_name == 'push' && github.ref == 'refs/heads/main' }}
+    uses: ./.github/workflows/create-issue-on-failure.yaml
+    with:
+      language: Go
+      repository: google-cloud-go