CI: Add CI check for what's new link (#70046)

* Add whatsnewchecker

* Add whatsnewchecker_test

* Small fixes

* Add step in CI

* Fix lint

* Fix starlark

* t.Cleanup instead of separate func

* Skip check for test tags

pkg/build/cmd/main.go

@@ -82,6 +82,11 @@ func main() {
 				&buildIDFlag,
 			},
 		},
+		{
+			Name:   "whatsnew-checker",
+			Usage:  "Checks whatsNewUrl in package.json for differences between the tag and the docs version",
+			Action: WhatsNewChecker,
+		},
 		{
 			Name:   "build-docker",
 			Usage:  "Build Grafana Docker images",

pkg/build/cmd/whatsnewchecker.go

@@ -0,0 +1,71 @@
+package main
+
+import (
+	"encoding/json"
+	"fmt"
+	"os"
+	"path/filepath"
+	"regexp"
+	"strings"
+
+	"github.com/grafana/grafana/pkg/build/config"
+	"github.com/urfave/cli/v2"
+	"golang.org/x/mod/semver"
+)
+
+const GrafanaDir = "."
+
+var whatsNewRegex = regexp.MustCompile(`^.*whats-new-in-(v\d*-[\d+]*)`)
+
+type PackageJSON struct {
+	Grafana Grafana `json:"grafana"`
+	Version string  `json:"version"`
+}
+
+type Grafana struct {
+	WhatsNewUrl string `json:"whatsNewUrl"`
+}
+
+func WhatsNewChecker(c *cli.Context) error {
+	metadata, err := config.GenerateMetadata(c)
+	if err != nil {
+		return err
+	}
+
+	if metadata.ReleaseMode.IsTest {
+		fmt.Println("test mode, skipping check")
+		return nil
+	}
+	if metadata.ReleaseMode.Mode != config.TagMode {
+		return fmt.Errorf("non-tag pipeline, exiting")
+	}
+
+	tag := fmt.Sprintf("v%s", metadata.GrafanaVersion)
+
+	if !semver.IsValid(tag) {
+		return fmt.Errorf("non-semver compatible version %s, exiting", tag)
+	}
+
+	majorMinorDigits := strings.Replace(semver.MajorMinor(tag), ".", "-", 1)
+
+	pkgJSONPath := filepath.Join(GrafanaDir, "package.json")
+	//nolint:gosec
+	pkgJSONB, err := os.ReadFile(pkgJSONPath)
+	if err != nil {
+		return fmt.Errorf("failed to read %q: %w", pkgJSONPath, err)
+	}
+
+	var pkgObj PackageJSON
+	if err := json.Unmarshal(pkgJSONB, &pkgObj); err != nil {
+		return fmt.Errorf("failed decoding %q: %w", pkgJSONPath, err)
+	}
+
+	whatsNewSplit := whatsNewRegex.FindStringSubmatch(pkgObj.Grafana.WhatsNewUrl)
+	whatsNewVersion := whatsNewSplit[1]
+
+	if whatsNewVersion != majorMinorDigits {
+		return fmt.Errorf("whatsNewUrl in package.json needs to be updated to %s/", strings.Replace(whatsNewSplit[0], whatsNewVersion, majorMinorDigits, 1))
+	}
+
+	return nil
+}

pkg/build/cmd/whatsnewchecker_test.go

@@ -0,0 +1,83 @@
+package main
+
+import (
+	"encoding/json"
+	"flag"
+	"fmt"
+	"os"
+	"testing"
+
+	"github.com/grafana/grafana/pkg/build/config"
+	"github.com/stretchr/testify/require"
+	"github.com/urfave/cli/v2"
+)
+
+const (
+	DroneBuildEvent       = "DRONE_BUILD_EVENT"
+	DroneTag              = "DRONE_TAG"
+	DroneSemverPrerelease = "DRONE_SEMVER_PRERELEASE"
+)
+
+const whatsNewUrl = "https://grafana.com/docs/grafana/next/whatsnew/whats-new-in-"
+
+func TestWhatsNewChecker(t *testing.T) {
+	tests := []struct {
+		envMap             map[string]string
+		packageJsonVersion string
+		name               string
+		wantErr            bool
+		errMsg             string
+	}{
+		{envMap: map[string]string{DroneBuildEvent: config.PullRequest}, packageJsonVersion: "", name: "non-tag event", wantErr: true, errMsg: "non-tag pipeline, exiting"},
+		{envMap: map[string]string{DroneBuildEvent: config.Tag, DroneTag: "abcd123"}, packageJsonVersion: "", name: "non-semver compatible", wantErr: true, errMsg: "non-semver compatible version vabcd123, exiting"},
+		{envMap: map[string]string{DroneBuildEvent: config.Tag, DroneTag: "v0.0.0", DroneSemverPrerelease: "test"}, packageJsonVersion: "v10-0", name: "skip check for test tags", wantErr: false},
+		{envMap: map[string]string{DroneBuildEvent: config.Tag, DroneTag: "v10.0.0"}, packageJsonVersion: "v10-0", name: "package.json version matches tag", wantErr: false},
+		{envMap: map[string]string{DroneBuildEvent: config.Tag, DroneTag: "v10.0.0"}, packageJsonVersion: "v9-5", name: "package.json doesn't match tag", wantErr: true, errMsg: "whatsNewUrl in package.json needs to be updated to https://grafana.com/docs/grafana/next/whatsnew/whats-new-in-v10-0/"},
+	}
+	for _, tt := range tests {
+		app := cli.NewApp()
+		app.Version = "1.0.0"
+		context := cli.NewContext(app, &flag.FlagSet{}, nil)
+		t.Run(tt.name, func(t *testing.T) {
+			setUpEnv(t, tt.envMap)
+			err := createTempPackageJson(t, tt.packageJsonVersion)
+			require.NoError(t, err)
+
+			err = WhatsNewChecker(context)
+			if tt.wantErr {
+				require.Error(t, err)
+				require.Equal(t, tt.errMsg, err.Error())
+			} else {
+				require.NoError(t, err)
+			}
+		})
+	}
+}
+
+func setUpEnv(t *testing.T, envMap map[string]string) {
+	t.Helper()
+
+	os.Clearenv()
+	t.Setenv("DRONE_BUILD_NUMBER", "12345")
+	t.Setenv("DRONE_COMMIT", "abcd12345")
+	for k, v := range envMap {
+		t.Setenv(k, v)
+	}
+}
+
+func createTempPackageJson(t *testing.T, version string) error {
+	t.Helper()
+
+	grafanaData := Grafana{WhatsNewUrl: fmt.Sprintf("%s%s/", whatsNewUrl, version)}
+	data := PackageJSON{Grafana: grafanaData, Version: "1.2.3"}
+	file, _ := json.MarshalIndent(data, "", " ")
+
+	err := os.WriteFile("package.json", file, 0644)
+	require.NoError(t, err)
+
+	t.Cleanup(func() {
+		err := os.RemoveAll("package.json")
+		require.NoError(t, err)
+	})
+	return nil
+}