chore: release 0.29.0.rc0 (#1600)

pkg/httphandler/version.go

@@ -0,0 +1,45 @@
+package httphandler
+
+import (
+	"encoding/json"
+	"fmt"
+	"net/http"
+
+	"github.com/prometheus/common/version"
+)
+
+type VersionHandler struct{}
+
+// Same struct prometheus uses for their /version endpoint.
+// Separate copy to avoid pulling all of prometheus as a dependency.
+type prometheusVersion struct {
+	Version   string `json:"version"`
+	Revision  string `json:"revision"`
+	Branch    string `json:"branch"`
+	BuildUser string `json:"buildUser"`
+	BuildDate string `json:"buildDate"`
+	GoVersion string `json:"goVersion"`
+}
+
+// Interface guard.
+var _ http.Handler = (*VersionHandler)(nil)
+
+func NewVersionHandler() VersionHandler {
+	return VersionHandler{}
+}
+
+func (h VersionHandler) ServeHTTP(w http.ResponseWriter, _ *http.Request) {
+	// we can't use "version" directly as it is a package, and not an object that
+	// can be serialized.
+	err := json.NewEncoder(w).Encode(prometheusVersion{
+		Version:   version.Version,
+		Revision:  version.Revision,
+		Branch:    version.Branch,
+		BuildUser: version.BuildUser,
+		BuildDate: version.BuildDate,
+		GoVersion: version.GoVersion,
+	})
+	if err != nil {
+		http.Error(w, fmt.Sprintf("error encoding JSON: %s", err), http.StatusInternalServerError)
+	}
+}