add config flag to disable 1.9 metrics backwards compatibility. Add warnings on start and reload on default value

agent/agent.go

@@ -592,6 +592,12 @@ func (a *Agent) Start(ctx context.Context) error {
 		go a.retryJoinWAN()
 	}
 
+	// DEPRECATED: Warn users if they're emitting deprecated metrics. Remove this warning and the flagged metrics in a
+	// future release of Consul.
+	if !a.config.Telemetry.DisableCompatOneNine {
+		a.logger.Warn("DEPRECATED Backwards compatibility with pre-1.9 metrics enabled. These metrics will be removed in a future version of Consul. Set `telemetry { disable_compat_1.9 = true }` to disable them.")
+	}
+
 	return nil
 }
 
@@ -3489,6 +3495,12 @@ func (a *Agent) ReloadConfig() error {
 	// breaking some existing behavior.
 	newCfg.NodeID = a.config.NodeID
 
+	// DEPRECATED: Warn users on reload if they're emitting deprecated metrics. Remove this warning and the flagged
+	// metrics in a future release of Consul.
+	if !a.config.Telemetry.DisableCompatOneNine {
+		a.logger.Warn("DEPRECATED Backwards compatibility with pre-1.9 metrics enabled. These metrics will be removed in a future version of Consul. Set `telemetry { disable_compat_1.9 = true }` to disable them.")
+	}
+
 	return a.reloadConfigInternal(newCfg)
 }
 

agent/config/builder.go

@@ -936,6 +936,7 @@ func (b *Builder) Build() (rt RuntimeConfig, err error) {
 			CirconusCheckTags:                  b.stringVal(c.Telemetry.CirconusCheckTags),
 			CirconusSubmissionInterval:         b.stringVal(c.Telemetry.CirconusSubmissionInterval),
 			CirconusSubmissionURL:              b.stringVal(c.Telemetry.CirconusSubmissionURL),
+			DisableCompatOneNine:               b.boolVal(c.Telemetry.DisableCompatOneNine),
 			DisableHostname:                    b.boolVal(c.Telemetry.DisableHostname),
 			DogstatsdAddr:                      b.stringVal(c.Telemetry.DogstatsdAddr),
 			DogstatsdTags:                      c.Telemetry.DogstatsdTags,

agent/config/config.go

@@ -628,6 +628,7 @@ type Telemetry struct {
 	CirconusCheckTags                  *string  `json:"circonus_check_tags,omitempty" hcl:"circonus_check_tags" mapstructure:"circonus_check_tags"`
 	CirconusSubmissionInterval         *string  `json:"circonus_submission_interval,omitempty" hcl:"circonus_submission_interval" mapstructure:"circonus_submission_interval"`
 	CirconusSubmissionURL              *string  `json:"circonus_submission_url,omitempty" hcl:"circonus_submission_url" mapstructure:"circonus_submission_url"`
+	DisableCompatOneNine               *bool    `json:"disable_compat_1.9,omitempty" hcl:"disable_compat_1.9" mapstructure:"disable_compat_1.9"`
 	DisableHostname                    *bool    `json:"disable_hostname,omitempty" hcl:"disable_hostname" mapstructure:"disable_hostname"`
 	DogstatsdAddr                      *string  `json:"dogstatsd_addr,omitempty" hcl:"dogstatsd_addr" mapstructure:"dogstatsd_addr"`
 	DogstatsdTags                      []string `json:"dogstatsd_tags,omitempty" hcl:"dogstatsd_tags" mapstructure:"dogstatsd_tags"`

agent/config/runtime_test.go

@@ -5227,7 +5227,8 @@ func TestFullConfig(t *testing.T) {
 				"metrics_prefix": "ftO6DySn",
 				"prometheus_retention_time": "15s",
 				"statsd_address": "drce87cy",
-				"statsite_address": "HpFwKB8R"
+				"statsite_address": "HpFwKB8R",
+				"disable_compat_1.9": true
 			},
 			"tls_cipher_suites": "TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA,TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA256",
 			"tls_min_version": "pAOWafkR",
@@ -5911,6 +5912,7 @@ func TestFullConfig(t *testing.T) {
 				prometheus_retention_time = "15s"
 				statsd_address = "drce87cy"
 				statsite_address = "HpFwKB8R"
+				disable_compat_1.9 = true
 			}
 			tls_cipher_suites = "TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA,TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA256"
 			tls_min_version = "pAOWafkR"
@@ -6681,6 +6683,7 @@ func TestFullConfig(t *testing.T) {
 			CirconusCheckTags:                  "prvO4uBl",
 			CirconusSubmissionInterval:         "DolzaflP",
 			CirconusSubmissionURL:              "gTcbS93G",
+			DisableCompatOneNine:               true,
 			DisableHostname:                    true,
 			DogstatsdAddr:                      "0wSndumK",
 			DogstatsdTags:                      []string{"3N81zSUB", "Xtj8AnXZ"},
@@ -7379,6 +7382,7 @@ func TestSanitize(t *testing.T) {
 			"CirconusSubmissionInterval": "",
 			"CirconusSubmissionURL": "",
 			"Disable": false,
+			"DisableCompatOneNine": false,
 			"DisableHostname": false,
 			"DogstatsdAddr": "",
 			"DogstatsdTags": [],

agent/http.go

@@ -195,14 +195,15 @@ func (s *HTTPHandlers) handler(enableDebug bool) http.Handler {
 			start := time.Now()
 			handler(resp, req)
 
-			// This new metric is disabled by default with the prefix_filter option.
-			// It will be enabled by default in a future version.
 			labels := []metrics.Label{{Name: "method", Value: req.Method}, {Name: "path", Value: path_label}}
 			metrics.MeasureSinceWithLabels([]string{"api", "http"}, start, labels)
 
-			// Duplicated information. Kept for backward compatibility.
-			key := append([]string{"http", req.Method}, parts...)
-			metrics.MeasureSince(key, start)
+			// DEPRECATED Emit pre-1.9 metric as `consul.http...` to maintain backwards compatibility. Enabled by
+			// default. Users may set `telemetry { disable_compat_1.9 = true }`
+			if !s.agent.config.Telemetry.DisableCompatOneNine {
+				key := append([]string{"http", req.Method}, parts...)
+				metrics.MeasureSince(key, start)
+			}
 		}
 
 		var gzipHandler http.Handler

lib/telemetry.go

@@ -132,6 +132,11 @@ type TelemetryConfig struct {
 	// hcl: telemetry { circonus_submission_url = string }
 	CirconusSubmissionURL string `json:"circonus_submission_url,omitempty" mapstructure:"circonus_submission_url"`
 
+	// DisableCompatOneNine is a flag to stop emitting metrics that have been deprecated in version 1.9.
+	//
+	// hcl: telemetry { disable_compat_1.9 = (true|false) }
+	DisableCompatOneNine bool `json:"disable_compat_1.9,omitempty" mapstructure:"disable_compat_1.9"`
+
 	// DisableHostname will disable hostname prefixing for all metrics.
 	//
 	// hcl: telemetry { disable_hostname = (true|false)