CI: Generate Grafana version (and metadata) when the build binary is built (#54393)

* Add GenerateVersions as BeforeFunc

* Delete gen-version

* Fix lint

* Get build id from env var

pkg/build/config/version.go

@@ -16,6 +16,7 @@ type Metadata struct {
 	GrafanaVersion string      `json:"version,omitempty"`
 	ReleaseMode    ReleaseMode `json:"releaseMode,omitempty"`
 	GrabplVersion  string      `json:"grabplVersion,omitempty"`
+	CurrentCommit  string      `json:"currentCommit,omitempty"`
 }
 
 type ReleaseMode struct {
@@ -170,3 +171,11 @@ func CheckSemverSuffix() (ReleaseMode, error) {
 		return ReleaseMode{Mode: TagMode}, nil
 	}
 }
+
+func GetDroneCommit() (string, error) {
+	commit := strings.TrimSpace(os.Getenv("DRONE_COMMIT"))
+	if commit == "" {
+		return "", fmt.Errorf("the environment variable DRONE_COMMIT is missing")
+	}
+	return commit, nil
+}

pkg/build/config/version_mode.go

@@ -10,3 +10,15 @@ const (
 	PullRequestMode   VersionMode = "pull_request"
 	CustomMode        VersionMode = "custom"
 )
+
+const (
+	Tag         = "tag"
+	PullRequest = "pull_request"
+	Push        = "push"
+	Custom      = "custom"
+	Promote     = "promote"
+)
+
+const (
+	MainBranch = "main"
+)