Merge pull request #36 from simonpasquier/rework-status-api

Add `--metrics.status.endpoint` argument

Author: simonpasquier

api/metrics/v1/http.go

@@ -57,7 +57,6 @@ type handlerConfiguration struct {
 	statusMiddlewares      []func(http.Handler) http.Handler
 	writeMiddlewares       []func(http.Handler) http.Handler
 	alertmanagerMiddleware alertmanagerMiddleware
-	enableStatusEndpoints  bool
 }
 
 // HandlerOption modifies the handler's configuration.
@@ -165,13 +164,6 @@ func WithGlobalMiddleware(m ...func(http.Handler) http.Handler) HandlerOption {
 	}
 }
 
-// WithStatusEndpoints enables/disables the /status/* endpoints.
-func WithStatusEndpoints(enabled bool) HandlerOption {
-	return func(h *handlerConfiguration) {
-		h.enableStatusEndpoints = enabled
-	}
-}
-
 type handlerInstrumenter interface {
 	NewHandler(labels prometheus.Labels, handler http.Handler) http.HandlerFunc
 }
@@ -187,6 +179,7 @@ type Endpoints struct {
 	WriteEndpoint        *url.URL
 	RulesEndpoint        *url.URL
 	AlertmanagerEndpoint *url.URL
+	StatusEndpoint       *url.URL
 }
 
 // NewHandler creates the new metrics v1 handler.
@@ -352,25 +345,6 @@ func NewHandler(endpoints Endpoints, tlsOptions *tls.UpstreamOptions, opts ...Ha
 			)
 		})
 
-		if c.enableStatusEndpoints {
-			r.Group(func(r chi.Router) {
-				r.Use(func(handler http.Handler) http.Handler {
-					return server.InjectLabelsCtx(
-						prometheus.Labels{"group": "metricsv1", "handler": "status"},
-						handler,
-					)
-				})
-				r.Use(c.statusMiddlewares...)
-				r.Use(server.StripTenantPrefix("/api/metrics/v1"))
-				r.Handle(TSDBStatusRoute,
-					otelhttp.WithRouteTag(
-						c.spanRoutePrefix+TSDBStatusRoute,
-						proxyRead,
-					),
-				)
-			})
-		}
-
 		var uiProxy http.Handler
 		{
 			middlewares := proxy.Middlewares(
@@ -491,6 +465,40 @@ func NewHandler(endpoints Endpoints, tlsOptions *tls.UpstreamOptions, opts ...Ha
 		})
 	}
 
+	if endpoints.StatusEndpoint != nil {
+		middlewares := proxy.Middlewares(
+			proxy.MiddlewareSetUpstream(endpoints.ReadEndpoint),
+			proxy.MiddlewareSetPrefixHeader(),
+			proxy.MiddlewareLogger(c.logger),
+			proxy.MiddlewareMetrics(c.registry, prometheus.Labels{"proxy": "metricsv1-ui"}),
+		)
+
+		t := http.DefaultTransport.(*http.Transport)
+		t.TLSClientConfig = tlsOptions.NewClientConfig()
+
+		statusProxy := &httputil.ReverseProxy{
+			Director:  middlewares,
+			Transport: otelhttp.NewTransport(http.DefaultTransport),
+		}
+
+		r.Group(func(r chi.Router) {
+			r.Use(func(handler http.Handler) http.Handler {
+				return server.InjectLabelsCtx(
+					prometheus.Labels{"group": "metricsv1", "handler": "status"},
+					handler,
+				)
+			})
+			r.Use(c.statusMiddlewares...)
+			r.Use(server.StripTenantPrefix("/api/metrics/v1"))
+			r.Handle(TSDBStatusRoute,
+				otelhttp.WithRouteTag(
+					c.spanRoutePrefix+TSDBStatusRoute,
+					statusProxy,
+				),
+			)
+		})
+	}
+
 	if endpoints.AlertmanagerEndpoint != nil {
 		var proxyAlertmanager http.Handler
 		{

main.go

@@ -146,16 +146,16 @@ type metricsConfig struct {
 	writeEndpoint        *url.URL
 	rulesEndpoint        *url.URL
 	alertmanagerEndpoint *url.URL
+	statusEndpoint       *url.URL
 	upstreamWriteTimeout time.Duration
 	upstreamCAFile       string
 	upstreamCertFile     string
 	upstreamKeyFile      string
 	tenantHeader         string
 	tenantLabel          string
 	// enable metrics if at least one {read|write}Endpoint} is provided.
-	enabled               bool
-	enableCertWatcher     bool
-	enableStatusEndpoints bool
+	enabled           bool
+	enableCertWatcher bool
 }
 
 type logsConfig struct {
@@ -646,6 +646,7 @@ func main() {
 					WriteEndpoint:        cfg.metrics.writeEndpoint,
 					RulesEndpoint:        cfg.metrics.rulesEndpoint,
 					AlertmanagerEndpoint: cfg.metrics.alertmanagerEndpoint,
+					StatusEndpoint:       cfg.metrics.statusEndpoint,
 				}
 
 				rateLimitMiddleware := ratelimit.WithLocalRateLimiter(rateLimits...)
@@ -734,7 +735,6 @@ func main() {
 					}
 
 					const matchParamName = "match[]"
-					level.Info(logger).Log("msg", "status API", "enabled", cfg.metrics.enableStatusEndpoints)
 					r.Mount("/api/metrics/v1/{tenant}", metricsv1.NewHandler(
 						eps,
 						metricsUpstreamClientOptions,
@@ -751,7 +751,6 @@ func main() {
 						metricsv1.WithReadMiddleware(authorization.WithAuthorizers(authorizers, rbac.Read, "metrics")),
 						metricsv1.WithReadMiddleware(metricsv1.WithEnforceTenancyOnQuery(cfg.metrics.tenantLabel, matchParamName)),
 						metricsv1.WithReadMiddleware(metricsv1.WithEnforceAuthorizationLabels()),
-						metricsv1.WithStatusEndpoints(cfg.metrics.enableStatusEndpoints),
 						metricsv1.WithStatusMiddleware(authorization.WithAuthorizers(authorizers, rbac.Read, "metrics")),
 						metricsv1.WithUIMiddleware(authorization.WithAuthorizers(authorizers, rbac.Read, "metrics")),
 						metricsv1.WithAlertmanagerAlertsReadMiddleware(
@@ -1113,6 +1112,7 @@ func parseFlags() (config, error) {
 		rawMetricsWriteEndpoint        string
 		rawMetricsRulesEndpoint        string
 		rawMetricsAlertmanagerEndpoint string
+		rawMetricsStatusEndpoint       string
 		rawLogsReadEndpoint            string
 		rawLogsRulesEndpoint           string
 		rawLogsTailEndpoint            string
@@ -1191,14 +1191,14 @@ func parseFlags() (config, error) {
 		"Comma-separated list of stream selectors that should be extracted from queries and sent to OPA during authorization.")
 	flag.StringVar(&rawMetricsReadEndpoint, "metrics.read.endpoint", "",
 		"The endpoint against which to send read requests for metrics. It used as a fallback to 'query.endpoint' and 'query-range.endpoint'.")
-	flag.BoolVar(&cfg.metrics.enableStatusEndpoints, "metrics.read.enable-status-endpoints", false,
-		"Enable the metric status endpoints")
 	flag.StringVar(&rawMetricsWriteEndpoint, "metrics.write.endpoint", "",
 		"The endpoint against which to make write requests for metrics.")
 	flag.StringVar(&rawMetricsRulesEndpoint, "metrics.rules.endpoint", "",
 		"The endpoint against which to make get requests for listing recording/alerting rules and put requests for creating/updating recording/alerting rules.")
 	flag.StringVar(&rawMetricsAlertmanagerEndpoint, "metrics.alertmanager.endpoint", "",
 		"The endpoint against which to make requests for alerts and silences")
+	flag.StringVar(&rawMetricsStatusEndpoint, "metrics.status.endpoint", "",
+		"The endpoint against which to make requests for status information about metrics (e.g. '/api/v1/status/tsdb').")
 	flag.DurationVar(&cfg.metrics.upstreamWriteTimeout, "metrics.write-timeout", metricsMiddlewareTimeout,
 		"The HTTP write timeout for proxied requests to the metrics endpoint.")
 	flag.StringVar(&cfg.metrics.upstreamCAFile, "metrics.tls.ca-file", "",
@@ -1345,6 +1345,17 @@ func parseFlags() (config, error) {
 		cfg.metrics.alertmanagerEndpoint = alertmanagerEndpoint
 	}
 
+	if rawMetricsStatusEndpoint != "" {
+		cfg.metrics.enabled = true
+
+		statusEndpoint, err := url.ParseRequestURI(rawMetricsStatusEndpoint)
+		if err != nil {
+			return cfg, fmt.Errorf("--metrics.status.endpoint %q is invalid: %w", rawMetricsStatusEndpoint, err)
+		}
+
+		cfg.metrics.statusEndpoint = statusEndpoint
+	}
+
 	if rawLogsReadEndpoint != "" {
 		cfg.logs.enabled = true