web/api: enable running API legacy and v1 in parallel

main.go

@@ -41,7 +41,8 @@ import (
 	"github.com/prometheus/prometheus/storage/remote/influxdb"
 	"github.com/prometheus/prometheus/storage/remote/opentsdb"
 	"github.com/prometheus/prometheus/web"
-	"github.com/prometheus/prometheus/web/api"
+	"github.com/prometheus/prometheus/web/api/legacy"
+	"github.com/prometheus/prometheus/web/api/v1"
 )
 
 const deletionBatchSize = 100
@@ -184,16 +185,22 @@ func NewPrometheus() *prometheus {
 		PathPrefix: *pathPrefix,
 	}
 
-	metricsService := &api.MetricsService{
+	apiLegacy := &legacy.API{
 		Now:         clientmodel.Now,
 		Storage:     memStorage,
 		QueryEngine: queryEngine,
 	}
 
+	apiv1 := &v1.API{
+		Storage:     memStorage,
+		QueryEngine: queryEngine,
+	}
+
 	webService := web.NewWebService(&web.WebServiceOptions{
 		PathPrefix:      *pathPrefix,
 		StatusHandler:   prometheusStatus,
-		MetricsHandler:  metricsService,
+		APILegacy:       apiLegacy,
+		APIv1:           apiv1,
 		ConsolesHandler: consolesHandler,
 		AlertsHandler:   alertsHandler,
 		GraphsHandler:   graphsHandler,

web/api/legacy/api.go

@@ -11,7 +11,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-package api
+package legacy
 
 import (
 	"net/http"
@@ -26,18 +26,18 @@ import (
 	"github.com/prometheus/prometheus/util/route"
 )
 
-// MetricsService manages the /api HTTP endpoint.
+// API manages the /api HTTP endpoint.
-type MetricsService struct {
+type API struct {
 	Now         func() clientmodel.Timestamp
 	Storage     local.Storage
 	QueryEngine *promql.Engine
 }
 
 // RegisterHandler registers the handler for the various endpoints below /api.
-func (msrv *MetricsService) RegisterHandler(router *route.Router) {
+func (api *API) Register(router *route.Router) {
-	router.Get("/query", handle("query", msrv.Query))
+	router.Get("/query", handle("query", api.Query))
-	router.Get("/query_range", handle("query_range", msrv.QueryRange))
+	router.Get("/query_range", handle("query_range", api.QueryRange))
-	router.Get("/metrics", handle("metrics", msrv.Metrics))
+	router.Get("/metrics", handle("metrics", api.Metrics))
 }
 
 func handle(name string, f http.HandlerFunc) http.HandlerFunc {

web/api/legacy/api_test.go

@@ -11,7 +11,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-package api
+package legacy
 
 import (
 	"io/ioutil"
@@ -93,13 +93,13 @@ func TestQuery(t *testing.T) {
 	})
 	storage.WaitForIndexing()
 
-	api := MetricsService{
+	api := &API{
 		Now:         testNow,
 		Storage:     storage,
 		QueryEngine: promql.NewEngine(storage),
 	}
 	rtr := route.New()
-	api.RegisterHandler(rtr.WithPrefix("/api"))
+	api.Register(rtr.WithPrefix("/api"))
 
 	server := httptest.NewServer(rtr)
 	defer server.Close()

web/api/legacy/query.go

@@ -11,7 +11,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-package api
+package legacy
 
 import (
 	"encoding/json"
@@ -63,20 +63,20 @@ func parseDuration(d string) (time.Duration, error) {
 }
 
 // Query handles the /api/query endpoint.
-func (serv MetricsService) Query(w http.ResponseWriter, r *http.Request) {
+func (api *API) Query(w http.ResponseWriter, r *http.Request) {
 	setAccessControlHeaders(w)
 	w.Header().Set("Content-Type", "application/json")
 
 	params := httputil.GetQueryParams(r)
 	expr := params.Get("expr")
 
-	timestamp, err := parseTimestampOrNow(params.Get("timestamp"), serv.Now())
+	timestamp, err := parseTimestampOrNow(params.Get("timestamp"), api.Now())
 	if err != nil {
 		httpJSONError(w, fmt.Errorf("invalid query timestamp %s", err), http.StatusBadRequest)
 		return
 	}
 
-	query, err := serv.QueryEngine.NewInstantQuery(expr, timestamp)
+	query, err := api.QueryEngine.NewInstantQuery(expr, timestamp)
 	if err != nil {
 		httpJSONError(w, err, http.StatusOK)
 		return
@@ -92,7 +92,7 @@ func (serv MetricsService) Query(w http.ResponseWriter, r *http.Request) {
 }
 
 // QueryRange handles the /api/query_range endpoint.
-func (serv MetricsService) QueryRange(w http.ResponseWriter, r *http.Request) {
+func (api *API) QueryRange(w http.ResponseWriter, r *http.Request) {
 	setAccessControlHeaders(w)
 	w.Header().Set("Content-Type", "application/json")
 
@@ -111,7 +111,7 @@ func (serv MetricsService) QueryRange(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
-	end, err := parseTimestampOrNow(params.Get("end"), serv.Now())
+	end, err := parseTimestampOrNow(params.Get("end"), api.Now())
 	if err != nil {
 		httpJSONError(w, fmt.Errorf("invalid query timestamp: %s", err), http.StatusBadRequest)
 		return
@@ -121,7 +121,7 @@ func (serv MetricsService) QueryRange(w http.ResponseWriter, r *http.Request) {
 	// the current time as the end time. Instead, the "end" parameter should
 	// simply be omitted or set to an empty string for that case.
 	if end == 0 {
-		end = serv.Now()
+		end = api.Now()
 	}
 
 	// For safety, limit the number of returned points per timeseries.
@@ -136,7 +136,7 @@ func (serv MetricsService) QueryRange(w http.ResponseWriter, r *http.Request) {
 	end = end.Add(-time.Duration(end.UnixNano() % int64(step)))
 	start := end.Add(-duration)
 
-	query, err := serv.QueryEngine.NewRangeQuery(expr, start, end, step)
+	query, err := api.QueryEngine.NewRangeQuery(expr, start, end, step)
 	if err != nil {
 		httpJSONError(w, err, http.StatusOK)
 		return
@@ -152,11 +152,11 @@ func (serv MetricsService) QueryRange(w http.ResponseWriter, r *http.Request) {
 }
 
 // Metrics handles the /api/metrics endpoint.
-func (serv MetricsService) Metrics(w http.ResponseWriter, r *http.Request) {
+func (api *API) Metrics(w http.ResponseWriter, r *http.Request) {
 	setAccessControlHeaders(w)
 	w.Header().Set("Content-Type", "application/json")
 
-	metricNames := serv.Storage.LabelValuesForLabelName(clientmodel.MetricNameLabel)
+	metricNames := api.Storage.LabelValuesForLabelName(clientmodel.MetricNameLabel)
 	sort.Sort(metricNames)
 	resultBytes, err := json.Marshal(metricNames)
 	if err != nil {

web/api/legacy/query_test.go

@@ -11,7 +11,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-package api
+package legacy
 
 import (
 	"testing"

web/web.go

@@ -26,13 +26,14 @@ import (
 
 	pprof_runtime "runtime/pprof"
 
+	clientmodel "github.com/prometheus/client_golang/model"
 	"github.com/prometheus/client_golang/prometheus"
 	"github.com/prometheus/log"
+
+	"github.com/prometheus/prometheus/web/api/legacy"
+	"github.com/prometheus/prometheus/web/api/v1"
+
 	"github.com/prometheus/prometheus/util/route"
-
-	clientmodel "github.com/prometheus/client_golang/model"
-
-	"github.com/prometheus/prometheus/web/api"
 	"github.com/prometheus/prometheus/web/blob"
 )
 
@@ -57,7 +58,8 @@ type WebService struct {
 type WebServiceOptions struct {
 	PathPrefix      string
 	StatusHandler   *PrometheusStatusHandler
-	MetricsHandler  *api.MetricsService
+	APILegacy       *legacy.API
+	APIv1           *v1.API
 	AlertsHandler   *AlertsHandler
 	ConsolesHandler *ConsolesHandler
 	GraphsHandler   *GraphsHandler
@@ -75,7 +77,7 @@ func NewWebService(o *WebServiceOptions) *WebService {
 	if o.PathPrefix != "" {
 		// If the prefix is missing for the root path, append it.
 		router.Get("/", func(w http.ResponseWriter, r *http.Request) {
-			http.Redirect(w, r, o.PathPrefix, 301)
+			http.Redirect(w, r, o.PathPrefix, 302)
 		})
 		router = router.WithPrefix(o.PathPrefix)
 	}
@@ -89,7 +91,9 @@ func NewWebService(o *WebServiceOptions) *WebService {
 
 	router.Get(*metricsPath, prometheus.Handler().ServeHTTP)
 
-	o.MetricsHandler.RegisterHandler(router.WithPrefix("/api"))
+	o.APILegacy.Register(router.WithPrefix("/api"))
+
+	o.APIv1.Register(router.WithPrefix("/api/v1"))
 
 	router.Get("/consoles/*filepath", instr("consoles", o.ConsolesHandler))