add endpoint for prometheus

hashicorp · Sep 10, 2017 · 7fbaa64 · 7fbaa64
1 parent db261cd
commit 7fbaa64
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Showing 3 changed files with 40 additions and 7 deletions.
diff --git a/command/agent/command.go b/command/agent/command.go
@@ -18,6 +18,7 @@ import (
 	metrics "github.com/armon/go-metrics"
 	"github.com/armon/go-metrics/circonus"
 	"github.com/armon/go-metrics/datadog"
+	"github.com/armon/go-metrics/prometheus"
 	"github.com/hashicorp/consul/lib"
 	checkpoint "github.com/hashicorp/go-checkpoint"
 	gsyslog "github.com/hashicorp/go-syslog"
@@ -661,6 +662,12 @@ func (c *Command) setupTelemetry(config *Config) (*metrics.InmemSink, error) {
 		fanout = append(fanout, sink)
 	}
 
+	// Configure the prometheus sink
+	promSink, err := prometheus.NewPrometheusSink()
+	if err != nil {
+		fanout = append(fanout, promSink)
+	}
+
 	// Configure the datadog sink
 	if telConfig.DataDogAddr != "" {
 		sink, err := datadog.NewDogStatsdSink(telConfig.DataDogAddr, config.NodeName)

diff --git a/command/agent/http.go b/command/agent/http.go
@@ -15,6 +15,8 @@ import (
 	"github.com/NYTimes/gziphandler"
 	"github.com/hashicorp/nomad/helper/tlsutil"
 	"github.com/hashicorp/nomad/nomad/structs"
+	"github.com/prometheus/client_golang/prometheus"
+	"github.com/prometheus/client_golang/prometheus/promhttp"
 	"github.com/ugorji/go/codec"
 )
 
@@ -80,8 +82,15 @@ func NewHTTPServer(agent *Agent, config *Config) (*HTTPServer, error) {
 	}
 	srv.registerHandlers(config.EnableDebug)
 
-	// Start the server
+	// Handle requests with gzip compression
 	go http.Serve(ln, gziphandler.GzipHandler(mux))
+
+	// Register Prometheus separately as this requires uncompressed responses
+	srv.registerPrometheusHandler()
+
+	// Handle requests without gzip compression
+	go http.Serve(ln, mux)
+
 	return srv, nil
 }
 
@@ -101,8 +110,15 @@ func newScadaHttp(agent *Agent, list net.Listener) *HTTPServer {
 	}
 	srv.registerHandlers(false) // Never allow debug for SCADA
 
-	// Start the server
+	// Handle requests with gzip compression
 	go http.Serve(list, gziphandler.GzipHandler(mux))
+
+	// Register Prometheus separately as this requires uncompressed responses
+	srv.registerPrometheusHandler()
+
+	// Handle requests without gzip compression
+	go http.Serve(list, mux)
+
 	return srv
 }
 
@@ -131,6 +147,19 @@ func (s *HTTPServer) Shutdown() {
 	}
 }
 
+// Create a prometheus handler and register it separately, as other requests
+// use gzip compression
+func (s *HTTPServer) registerPrometheusHandler() {
+	handlerOptions := promhttp.HandlerOpts{
+		ErrorLog:           s.logger,
+		ErrorHandling:      promhttp.ContinueOnError,
+		DisableCompression: true,
+	}
+
+	handler := promhttp.HandlerFor(prometheus.DefaultGatherer, handlerOptions)
+	s.mux.Handle("/metrics", handler)
+}
+
 // registerHandlers is used to attach our handlers to the mux
 func (s *HTTPServer) registerHandlers(enableDebug bool) {
 	s.mux.HandleFunc("/v1/jobs", s.wrap(s.JobsRequest))

diff --git a/command/agent/metrics_endpoint.go b/command/agent/metrics_endpoint.go
@@ -4,13 +4,10 @@ import (
 	"net/http"
 )
 
+// MetricsRequest returns metrics in JSON format
 func (s *HTTPServer) MetricsRequest(resp http.ResponseWriter, req *http.Request) (interface{}, error) {
 	if req.Method == "GET" {
-		return s.newMetricsRequest(resp, req)
+		return s.agent.InmemSink.DisplayMetrics(resp, req)
 	}
 	return nil, CodedError(405, ErrInvalidMethod)
 }
-
-func (s *HTTPServer) newMetricsRequest(resp http.ResponseWriter, req *http.Request) (interface{}, error) {
-	return s.agent.InmemSink.DisplayMetrics(resp, req)
-}