Merge current v1.7 into master

docs/configuration/backends/kubernetes.md

@@ -108,7 +108,7 @@ The endpoint may be specified to override the environment variable values inside
 
 When the environment variables are not found, Traefik will try to connect to the Kubernetes API server with an external-cluster client.
 In this case, the endpoint is required.
-Specifically, it may be set to the URL used by `kubectl proxy` to connect to a Kubernetes cluster using the granted autentication and authorization of the associated kubeconfig.
+Specifically, it may be set to the URL used by `kubectl proxy` to connect to a Kubernetes cluster using the granted authentication and authorization of the associated kubeconfig.
 
 ### `labelselector`
 

docs/configuration/tracing.md

@@ -1,6 +1,6 @@
 # Tracing
 
-Tracing system allows developers to visualize call flows in there infrastructures.
+The tracing system allows developers to visualize call flows in their infrastructure.
 
 We use [OpenTracing](http://opentracing.io). It is an open standard designed for distributed tracing.
 

docs/index.md

@@ -138,7 +138,7 @@ IP: 172.27.0.3
 Run more instances of your `whoami` service with the following command:
 
 ```shell
-docker-compose up -d --scale whoami=2
+docker-compose scale whoami=2
 ```
 
 Go back to your browser ([http://localhost:8080](http://localhost:8080)) and see that Træfik has automatically detected the new instance of the container.

docs/user-guide/docker-and-lets-encrypt.md

@@ -232,7 +232,7 @@ Finally but not unimportantly, we tell Træfik to route **to** port `9000`, sinc
 `Service labels` allow managing many routes for the same container.
 
 When both `container labels` and `service labels` are defined, `container labels` are just used as default values for missing `service labels` but no frontend/backend are going to be defined only with these labels.
-Obviously, labels `traefik.frontend.rule` and `traefik.port` described above, will only be used to complete information set in `service labels` during the container frontends/bakends creation.
+Obviously, labels `traefik.frontend.rule` and `traefik.port` described above, will only be used to complete information set in `service labels` during the container frontends/backends creation.
 
 In the example, two service names are defined : `basic` and `admin`.
 They allow creating two frontends and two backends.

metrics/prometheus.go

@@ -7,6 +7,7 @@ import (
 	"sync"
 
 	"github.com/containous/mux"
+	"github.com/containous/traefik/log"
 	"github.com/containous/traefik/safe"
 	"github.com/containous/traefik/types"
 	"github.com/go-kit/kit/metrics"
@@ -15,25 +16,31 @@ import (
 )
 
 const (
-	metricNamePrefix = "traefik_"
+	// MetricNamePrefix prefix of all metric names
+	MetricNamePrefix = "traefik_"
 
 	// server meta information
-	configReloadsTotalName         = metricNamePrefix + "config_reloads_total"
-	configReloadsFailuresTotalName = metricNamePrefix + "config_reloads_failure_total"
-	configLastReloadSuccessName    = metricNamePrefix + "config_last_reload_success"
-	configLastReloadFailureName    = metricNamePrefix + "config_last_reload_failure"
+	metricConfigPrefix             = MetricNamePrefix + "config_"
+	configReloadsTotalName         = metricConfigPrefix + "reloads_total"
+	configReloadsFailuresTotalName = metricConfigPrefix + "reloads_failure_total"
+	configLastReloadSuccessName    = metricConfigPrefix + "last_reload_success"
+	configLastReloadFailureName    = metricConfigPrefix + "last_reload_failure"
 
 	// entrypoint
-	entrypointReqsTotalName   = metricNamePrefix + "entrypoint_requests_total"
-	entrypointReqDurationName = metricNamePrefix + "entrypoint_request_duration_seconds"
-	entrypointOpenConnsName   = metricNamePrefix + "entrypoint_open_connections"
+	metricEntryPointPrefix    = MetricNamePrefix + "entrypoint_"
+	entrypointReqsTotalName   = metricEntryPointPrefix + "requests_total"
+	entrypointReqDurationName = metricEntryPointPrefix + "request_duration_seconds"
+	entrypointOpenConnsName   = metricEntryPointPrefix + "open_connections"
 
-	// backend level
-	backendReqsTotalName    = metricNamePrefix + "backend_requests_total"
-	backendReqDurationName  = metricNamePrefix + "backend_request_duration_seconds"
-	backendOpenConnsName    = metricNamePrefix + "backend_open_connections"
-	backendRetriesTotalName = metricNamePrefix + "backend_retries_total"
-	backendServerUpName     = metricNamePrefix + "backend_server_up"
+	// backend level.
+
+	// MetricBackendPrefix prefix of all backend metric names
+	MetricBackendPrefix     = MetricNamePrefix + "backend_"
+	backendReqsTotalName    = MetricBackendPrefix + "requests_total"
+	backendReqDurationName  = MetricBackendPrefix + "request_duration_seconds"
+	backendOpenConnsName    = MetricBackendPrefix + "open_connections"
+	backendRetriesTotalName = MetricBackendPrefix + "retries_total"
+	backendServerUpName     = MetricBackendPrefix + "server_up"
 )
 
 // promState holds all metric state internally and acts as the only Collector we register for Prometheus.
@@ -61,6 +68,16 @@ func (h PrometheusHandler) AddRoutes(router *mux.Router) {
 // RegisterPrometheus registers all Prometheus metrics.
 // It must be called only once and failing to register the metrics will lead to a panic.
 func RegisterPrometheus(config *types.Prometheus) Registry {
+	standardRegistry := initStandardRegistry(config)
+
+	if !registerPromState() {
+		return nil
+	}
+
+	return standardRegistry
+}
+
+func initStandardRegistry(config *types.Prometheus) Registry {
 	buckets := []float64{0.1, 0.3, 1.2, 5.0}
 	if config.Buckets != nil {
 		buckets = config.Buckets
@@ -137,7 +154,6 @@ func RegisterPrometheus(config *types.Prometheus) Registry {
 		backendRetries.cv.Describe,
 		backendServerUp.gv.Describe,
 	}
-	stdprometheus.MustRegister(promState)
 
 	return &standardRegistry{
 		enabled:                        true,
@@ -156,6 +172,17 @@ func RegisterPrometheus(config *types.Prometheus) Registry {
 	}
 }
 
+func registerPromState() bool {
+	if err := stdprometheus.Register(promState); err != nil {
+		if _, ok := err.(stdprometheus.AlreadyRegisteredError); !ok {
+			log.Errorf("Unable to register Traefik to Prometheus: %v", err)
+			return false
+		}
+		log.Debug("Prometheus collector already registered.")
+	}
+	return true
+}
+
 // OnConfigurationUpdate receives the current configuration from Traefik.
 // It then converts the configuration to the optimized package internal format
 // and sets it to the promState.

metrics/prometheus_test.go

@@ -11,8 +11,82 @@ import (
 	"github.com/containous/traefik/types"
 	"github.com/prometheus/client_golang/prometheus"
 	dto "github.com/prometheus/client_model/go"
+	"github.com/stretchr/testify/assert"
 )
 
+func TestRegisterPromState(t *testing.T) {
+	// Reset state of global promState.
+	defer promState.reset()
+
+	testCases := []struct {
+		desc                 string
+		prometheusSlice      []*types.Prometheus
+		initPromState        bool
+		unregisterPromState  bool
+		expectedNbRegistries int
+	}{
+		{
+			desc:                 "Register once",
+			prometheusSlice:      []*types.Prometheus{{}},
+			expectedNbRegistries: 1,
+			initPromState:        true,
+		},
+		{
+			desc:                 "Register once with no promState init",
+			prometheusSlice:      []*types.Prometheus{{}},
+			expectedNbRegistries: 0,
+		},
+		{
+			desc:                 "Register twice",
+			prometheusSlice:      []*types.Prometheus{{}, {}},
+			expectedNbRegistries: 2,
+			initPromState:        true,
+		},
+		{
+			desc:                 "Register twice with no promstate init",
+			prometheusSlice:      []*types.Prometheus{{}, {}},
+			expectedNbRegistries: 0,
+		},
+		{
+			desc:                 "Register twice with unregister",
+			prometheusSlice:      []*types.Prometheus{{}, {}},
+			unregisterPromState:  true,
+			expectedNbRegistries: 2,
+			initPromState:        true,
+		},
+		{
+			desc:                 "Register twice with unregister but no promstate init",
+			prometheusSlice:      []*types.Prometheus{{}, {}},
+			unregisterPromState:  true,
+			expectedNbRegistries: 0,
+		},
+	}
+
+	for _, test := range testCases {
+		actualNbRegistries := 0
+		for _, prom := range test.prometheusSlice {
+			if test.initPromState {
+				initStandardRegistry(prom)
+			}
+
+			promReg := registerPromState()
+			if promReg != false {
+				actualNbRegistries++
+			}
+
+			if test.unregisterPromState {
+				prometheus.Unregister(promState)
+			}
+
+			promState.reset()
+		}
+
+		prometheus.Unregister(promState)
+
+		assert.Equal(t, test.expectedNbRegistries, actualNbRegistries)
+	}
+}
+
 // reset is a utility method for unit testing. It should be called after each
 // test run that changes promState internally in order to avoid dependencies
 // between unit tests.

requirements.txt

@@ -1,4 +1,4 @@
-mkdocs>=0.17.3
-pymdown-extensions>=1.4
-mkdocs-bootswatch>=0.4.0
-mkdocs-material>=2.2.6
+mkdocs==0.17.5
+pymdown-extensions==4.12
+mkdocs-bootswatch==0.5.0
+mkdocs-material==2.9.4

server/server.go

@@ -633,8 +633,11 @@ func registerMetricClients(metricsConfig *types.Metrics) metrics.Registry {
 
 	var registries []metrics.Registry
 	if metricsConfig.Prometheus != nil {
-		registries = append(registries, metrics.RegisterPrometheus(metricsConfig.Prometheus))
-		log.Debug("Configured Prometheus metrics")
+		prometheusRegister := metrics.RegisterPrometheus(metricsConfig.Prometheus)
+		if prometheusRegister != nil {
+			registries = append(registries, prometheusRegister)
+			log.Debug("Configured Prometheus metrics")
+		}
 	}
 	if metricsConfig.Datadog != nil {
 		registries = append(registries, metrics.RegisterDatadog(metricsConfig.Datadog))