Add toggle to inject the tenant ID to generated metrics (#3638)

CHANGELOG.md

@@ -7,6 +7,7 @@
 
 * [CHANGE] Update Alpine image version to 3.20 [#3710](https://github.com/grafana/tempo/pull/3710) (@joe-elliott)
 * [ENHANCEMENT] TraceQL - Add support for trace:id and span:id [#3670](https://github.com/grafana/tempo/pull/3670) (@ie-pham)
+* [ENHANCEMENT] Add toggle to inject the tenant ID to generated metrics [#3638](https://github.com/grafana/tempo/pull/3638) (@kvrhdn)
 * [BUGFIX] Fix TraceQL queries involving non boolean operations between statics and attributes. [#3698](https://github.com/grafana/tempo/pull/3698) (@joe-elliott)
 
 ## v2.5.0-rc.0

docs/sources/tempo/configuration/_index.md

@@ -384,6 +384,9 @@ metrics_generator:
         # A list of labels that will be added to all generated metrics.
         [external_labels: <map>]
 
+        # If set, the tenant ID will added as label with the given label name to all generated metrics.
+        [inject_tenant_id_as: <string>]
+
         # The maximum length of label names. Label names exceeding this limit will be truncated.
         [max_label_name_length: <int> | default = 1024]
 

modules/generator/registry/config.go

@@ -18,6 +18,8 @@ type Config struct {
 	// ExternalLabels are added to any time series generated by this instance.
 	ExternalLabels map[string]string `yaml:"external_labels,omitempty"`
 
+	InjectTenantIDAs string `yaml:"inject_tenant_id_as,omitempty"`
+
 	// MaxLabelNameLength configures the maximum length of label names. Label names exceeding
 	// this limit will be truncated.
 	MaxLabelNameLength int `yaml:"max_label_name_length"`

modules/generator/registry/registry.go

@@ -101,6 +101,10 @@ func New(cfg *Config, overrides Overrides, tenant string, appendable storage.App
 	hostname, _ := os.Hostname()
 	externalLabels["__metrics_gen_instance"] = hostname
 
+	if cfg.InjectTenantIDAs != "" {
+		externalLabels[cfg.InjectTenantIDAs] = tenant
+	}
+
 	r := &ManagedRegistry{
 		onShutdown: cancel,
 

modules/generator/registry/registry_test.go

@@ -153,6 +153,25 @@ func TestManagedRegistry_externalLabels(t *testing.T) {
 	collectRegistryMetricsAndAssert(t, registry, appender, expectedSamples)
 }
 
+func TestManagedRegistry_injectTenantIDAs(t *testing.T) {
+	appender := &capturingAppender{}
+
+	cfg := &Config{
+		InjectTenantIDAs: "__tempo_tenant",
+	}
+	registry := New(cfg, &mockOverrides{}, "test", appender, log.NewNopLogger())
+	defer registry.Close()
+
+	counter := registry.NewCounter("my_counter")
+	counter.Inc(nil, 1.0)
+
+	expectedSamples := []sample{
+		newSample(map[string]string{"__name__": "my_counter", "__metrics_gen_instance": mustGetHostname(), "__tempo_tenant": "test"}, 0, 0),
+		newSample(map[string]string{"__name__": "my_counter", "__metrics_gen_instance": mustGetHostname(), "__tempo_tenant": "test"}, 0, 1),
+	}
+	collectRegistryMetricsAndAssert(t, registry, appender, expectedSamples)
+}
+
 func TestManagedRegistry_maxSeries(t *testing.T) {
 	appender := &capturingAppender{}