CI: Track backend code coverage (#100856)

* CI: Track backend code coverage

This is a super rudimentary way to track this coverage. The important bit for me is the ability to extract the coverage
files.

* CI: Allow tests to fail

* Codeowners: Assign ownership of coverage tracking

* CI: Join coverage info in the job

* CI: Attempt to parallellise tests

* CI: Upload despite failures

* CI: Pattern is not regex

* CI: Set up repository and Go before merging

* CI: Generate go before checking coverage

* CI: Multi-line string

* CI: Backticks execute commands; avoid them

* CI: Make the output a bit prettier

Tabs are absurdly large.

* CI: Remove comment on retention

.github/CODEOWNERS

@@ -760,6 +760,7 @@ embed.go @grafana/grafana-as-code
 /.github/workflows/auto-milestone.yml @grafana/grafana-developer-enablement-squad
 /.github/workflows/backport.yml @grafana/grafana-developer-enablement-squad
 /.github/workflows/bump-version.yml @grafana/grafana-developer-enablement-squad
+/.github/workflows/backend-coverage.yml @Proximyst
 /.github/workflows/close-milestone.yml @grafana/grafana-developer-enablement-squad
 /.github/workflows/release-pr.yml @grafana/grafana-developer-enablement-squad
 /.github/workflows/release-comms.yml @grafana/grafana-developer-enablement-squad

.github/workflows/backend-coverage.yml

@@ -0,0 +1,96 @@
+name: Backend Coverage (OSS)
+on:
+  push:
+    paths:
+      - pkg/**
+      - .github/workflows/backend-coverage.yml
+      - go.*
+    branches:
+      - main
+  pull_request:
+
+jobs:
+  unit-tests:
+    name: Run unit tests (OSS)
+    runs-on: ubuntu-latest
+    if: github.repository == 'grafana/grafana'
+    steps:
+      - name: Check out repository
+        uses: actions/checkout@v4.2.2
+      - name: Setup Go environment
+        uses: actions/setup-go@v5.3.0
+        with:
+          go-version-file: go.work
+      - name: Run tests
+        run: make gen-go test-go-unit
+      - name: Upload coverage file
+        uses: actions/upload-artifact@v4
+        if: success() || failure()
+        with:
+          name: unit-cov
+          path: unit.cov
+          retention-days: 1
+          compression-level: 9 # this is raw text, and includes a _lot_ of repetition. compressing it should yield pretty good results.
+  integration-tests:
+    name: Run integration tests (OSS)
+    runs-on: ubuntu-latest
+    if: github.repository == 'grafana/grafana'
+    steps:
+      - name: Check out repository
+        uses: actions/checkout@v4.2.2
+      - name: Setup Go environment
+        uses: actions/setup-go@v5.3.0
+        with:
+          go-version-file: go.work
+      - name: Run tests
+        run: make gen-go test-go-integration
+      - name: Upload coverage file
+        uses: actions/upload-artifact@v4
+        if: success() || failure()
+        with:
+          name: integration-cov
+          path: integration.cov
+          retention-days: 1
+          compression-level: 9 # this is raw text, and includes a _lot_ of repetition. compressing it should yield pretty good results.
+  report-coverage:
+    name: Report coverage from unit and integration tests (OSS)
+    needs: [unit-tests, integration-tests]
+    runs-on: ubuntu-latest
+    # we don't do always() so as to not run even if the workflow is cancelled
+    if: github.repository == 'grafana/grafana' && (success() || failure())
+    steps:
+      - name: Check out repository
+        uses: actions/checkout@v4.2.2
+      - name: Setup Go environment
+        uses: actions/setup-go@v5.3.0
+        with:
+          go-version-file: go.work
+      - name: Generate Go
+        run: make gen-go
+      - uses: actions/download-artifact@v4
+        with:
+          pattern: '*-cov'
+          path: .
+          merge-multiple: true
+      - name: Join coverage outputs
+        run: |
+          cp unit.cov backend.cov
+          tail -n+2 integration.cov >> backend.cov
+      - name: Convert coverage info to per-func stats
+        run: go tool cover -func backend.cov > backend-funcs.log
+      - name: Upload coverage file
+        uses: actions/upload-artifact@v4
+        with:
+          name: backend-cov
+          path: |
+            backend.cov
+            backend-funcs.log
+          retention-days: 30
+          compression-level: 9 # this is raw text, and includes a _lot_ of repetition. compressing it should yield pretty good results.
+      - name: Set summary to total coverage
+        # We use single quotes here to disable the bash backtick behaviour of executing commands.
+        run: |
+          echo '# Coverage' >> $GITHUB_STEP_SUMMARY
+          echo '```' >> $GITHUB_STEP_SUMMARY
+          grep 'total:' backend-funcs.log | tr '\t' ' ' >> $GITHUB_STEP_SUMMARY
+          echo '```' >> $GITHUB_STEP_SUMMARY

.gitignore

@@ -16,6 +16,7 @@ vendor/
 /requests
 tsconfig.tsbuildinfo
 __debug_bin*
+*.cov
 
 # yarn
 .yarn/cache

Makefile

@@ -248,8 +248,7 @@ test-go: test-go-unit test-go-integration
 .PHONY: test-go-unit
 test-go-unit: ## Run unit tests for backend with flags.
 	@echo "test backend unit tests"
-	printf '$(GO_TEST_FILES)' | xargs \
-	$(GO) test $(GO_RACE_FLAG) -short -covermode=atomic -timeout=30m
+	$(GO) test $(GO_RACE_FLAG) -short -covermode=atomic -coverprofile=unit.cov -timeout=30m $(GO_TEST_FILES)
 
 .PHONY: test-go-unit-pretty
 test-go-unit-pretty: check-tparse
@@ -262,7 +261,7 @@ test-go-unit-pretty: check-tparse
 .PHONY: test-go-integration
 test-go-integration: ## Run integration tests for backend with flags.
 	@echo "test backend integration tests"
-	$(GO) test $(GO_RACE_FLAG) -count=1 -run "^TestIntegration" -covermode=atomic -timeout=5m $(GO_INTEGRATION_TESTS)
+	$(GO) test $(GO_RACE_FLAG) -count=1 -run "^TestIntegration" -covermode=atomic -coverprofile=integration.cov -timeout=5m $(GO_INTEGRATION_TESTS)
 
 .PHONY: test-go-integration-alertmanager
 test-go-integration-alertmanager: ## Run integration tests for the remote alertmanager (config taken from the mimir_backend block).