Support fetching observability from ctx. (#2610)

* add option to load observability config from ctx

Signed-off-by: Kenny Leung <kleung@chainguard.dev>

* comments and tests

Signed-off-by: Kenny Leung <kleung@chainguard.dev>

* undo

Signed-off-by: Kenny Leung <kleung@chainguard.dev>

* move observability setup logic into function to match logger

Signed-off-by: Kenny Leung <kleung@chainguard.dev>

* fix arg

Signed-off-by: Kenny Leung <kleung@chainguard.dev>

Signed-off-by: Kenny Leung <kleung@chainguard.dev>

injection/sharedmain/main.go

@@ -104,6 +104,25 @@ func GetLeaderElectionConfig(ctx context.Context) (*leaderelection.Config, error
 	return leaderelection.NewConfigFromConfigMap(leaderElectionConfigMap)
 }
 
+// GetObservabilityConfig gets the observability config from the (in order):
+// 1. provided context,
+// 2. reading from the API server,
+// 3. defaults (if not found).
+func GetObservabilityConfig(ctx context.Context) (*metrics.ObservabilityConfig, error) {
+	if cfg := metrics.GetObservabilityConfig(ctx); cfg != nil {
+		return cfg, nil
+	}
+
+	observabilityConfigMap, err := kubeclient.Get(ctx).CoreV1().ConfigMaps(system.Namespace()).Get(ctx, metrics.ConfigMapName(), metav1.GetOptions{})
+	if apierrors.IsNotFound(err) {
+		return metrics.NewObservabilityConfigFromConfigMap(nil)
+	}
+	if err != nil {
+		return nil, err
+	}
+	return metrics.NewObservabilityConfigFromConfigMap(observabilityConfigMap)
+}
+
 // EnableInjectionOrDie enables Knative Injection and starts the informers.
 // Both Context and Config are optional.
 // Deprecated: use injection.EnableInjectionOrDie
@@ -249,6 +268,8 @@ func MainWithConfig(ctx context.Context, component string, cfg *rest.Config, cto
 			leaderElectionConfig.GetComponentConfig(component))
 	}
 
+	SetupObservabilityOrDie(ctx, component, logger, profilingHandler)
+
 	controllers, webhooks := ControllersAndWebhooksFromCtors(ctx, cmw, ctors...)
 	WatchLoggingConfigOrDie(ctx, cmw, logger, atomicLevel, component)
 	WatchObservabilityConfigOrDie(ctx, cmw, profilingHandler, logger, component)
@@ -327,6 +348,18 @@ func SetupLoggerOrDie(ctx context.Context, component string) (*zap.SugaredLogger
 	return l, level
 }
 
+// SetupObservabilityOrDie sets up the observability using the config from the given context
+// or dies by calling log.Fatalf.
+func SetupObservabilityOrDie(ctx context.Context, component string, logger *zap.SugaredLogger, profilingHandler *profiling.Handler) {
+	observabilityConfig, err := GetObservabilityConfig(ctx)
+	if err != nil {
+		logger.Fatal("Error loading observability configuration: ", err)
+	}
+	observabilityConfigMap := observabilityConfig.GetConfigMap()
+	metrics.ConfigMapWatcher(ctx, component, SecretFetcher(ctx), logger)(&observabilityConfigMap)
+	profilingHandler.UpdateFromConfigMap(&observabilityConfigMap)
+}
+
 // CheckK8sClientMinimumVersionOrDie checks that the hosting Kubernetes cluster
 // is at least the minimum allowable version or dies by calling log.Fatalw.
 func CheckK8sClientMinimumVersionOrDie(ctx context.Context, logger *zap.SugaredLogger) {

injection/sharedmain/main_test.go

@@ -26,6 +26,7 @@ import (
 	"knative.dev/pkg/injection"
 	"knative.dev/pkg/leaderelection"
 	"knative.dev/pkg/logging"
+	"knative.dev/pkg/metrics"
 )
 
 func TestEnabledControllers(t *testing.T) {
@@ -103,3 +104,25 @@ func TestWithLeaderElectionConfig(t *testing.T) {
 		t.Errorf("(-got, +want) = %s", diff)
 	}
 }
+
+func TextWithObservabilityConfig(t *testing.T) {
+	want := &metrics.ObservabilityConfig{
+		EnableVarLogCollection:  false,
+		LoggingURLTemplate:      "url-template",
+		RequestLogTemplate:      "log-template",
+		EnableProbeRequestLog:   true,
+		RequestMetricsBackend:   "prometheus",
+		EnableProfiling:         true,
+		EnableRequestLog:        false,
+		MetricsCollectorAddress: "localhost:9090",
+	}
+	ctx := metrics.WithConfig(context.Background(), want)
+
+	got, err := GetObservabilityConfig(ctx)
+	if err != nil {
+		t.Fatalf("GetObservabilityConfig() = %v", err)
+	}
+	if diff := cmp.Diff(got, want); diff != "" {
+		t.Errorf("(-got, +want) = %s", diff)
+	}
+}

metrics/config_observability.go

@@ -17,8 +17,10 @@ limitations under the License.
 package metrics
 
 import (
+	"context"
 	"fmt"
 	"os"
+	"strconv"
 	texttemplate "text/template"
 
 	corev1 "k8s.io/api/core/v1"
@@ -81,6 +83,22 @@ type ObservabilityConfig struct {
 	MetricsCollectorAddress string
 }
 
+type ocfg struct{}
+
+// WithConfig associates a observability configuration with the context.
+func WithConfig(ctx context.Context, cfg *ObservabilityConfig) context.Context {
+	return context.WithValue(ctx, ocfg{}, cfg)
+}
+
+// GetObservability gets the observability config from the provided context.
+func GetObservabilityConfig(ctx context.Context) *ObservabilityConfig {
+	untyped := ctx.Value(ocfg{})
+	if untyped == nil {
+		return nil
+	}
+	return untyped.(*ObservabilityConfig)
+}
+
 func defaultConfig() *ObservabilityConfig {
 	return &ObservabilityConfig{
 		LoggingURLTemplate:    DefaultLogURLTemplate,
@@ -120,6 +138,21 @@ func NewObservabilityConfigFromConfigMap(configMap *corev1.ConfigMap) (*Observab
 	return oc, nil
 }
 
+func (oc *ObservabilityConfig) GetConfigMap() corev1.ConfigMap {
+	return corev1.ConfigMap{
+		Data: map[string]string{
+			"logging.enable-var-log-collection":           strconv.FormatBool(oc.EnableVarLogCollection),
+			"logging.revision-url-template":               oc.LoggingURLTemplate,
+			ReqLogTemplateKey:                             oc.RequestLogTemplate,
+			EnableReqLogKey:                               strconv.FormatBool(oc.EnableRequestLog),
+			EnableProbeReqLogKey:                          strconv.FormatBool(oc.EnableProbeRequestLog),
+			"metrics.request-metrics-backend-destination": oc.RequestMetricsBackend,
+			"profiling.enable":                            strconv.FormatBool(oc.EnableProfiling),
+			"metrics.opencensus-address":                  oc.MetricsCollectorAddress,
+		},
+	}
+}
+
 // ConfigMapName gets the name of the metrics ConfigMap
 func ConfigMapName() string {
 	if cm := os.Getenv(configMapNameEnv); cm != "" {

metrics/config_observability_test.go

@@ -154,3 +154,55 @@ func TestConfigMapName(t *testing.T) {
 		t.Errorf("ConfigMapName = %q, want: %q", got, want)
 	}
 }
+
+func TestObservabilityConfigMap(t *testing.T) {
+	observabilityConfigMapTests := []struct {
+		name              string
+		config            *ObservabilityConfig
+		wantConfigMapData map[string]string
+	}{{
+		name: "observability configuration with all inputs",
+		config: &ObservabilityConfig{
+			EnableProbeRequestLog:  true,
+			EnableProfiling:        true,
+			EnableVarLogCollection: true,
+			EnableRequestLog:       true,
+			LoggingURLTemplate:     "https://logging.io",
+			RequestLogTemplate:     `{"requestMethod": "{{.Request.Method}}"}`,
+			RequestMetricsBackend:  "opencensus",
+		},
+		wantConfigMapData: map[string]string{
+			EnableProbeReqLogKey:                          "true",
+			"logging.enable-var-log-collection":           "true",
+			ReqLogTemplateKey:                             `{"requestMethod": "{{.Request.Method}}"}`,
+			"logging.revision-url-template":               "https://logging.io",
+			EnableReqLogKey:                               "true",
+			"metrics.request-metrics-backend-destination": "opencensus",
+			"profiling.enable":                            "true",
+			"metrics.opencensus-address":                  "",
+		},
+	}, {
+		name:   "observability configuration default config",
+		config: defaultConfig(),
+		wantConfigMapData: map[string]string{
+			EnableProbeReqLogKey:                          "false",
+			"logging.enable-var-log-collection":           "false",
+			ReqLogTemplateKey:                             `{"httpRequest": {"requestMethod": "{{.Request.Method}}", "requestUrl": "{{js .Request.RequestURI}}", "requestSize": "{{.Request.ContentLength}}", "status": {{.Response.Code}}, "responseSize": "{{.Response.Size}}", "userAgent": "{{js .Request.UserAgent}}", "remoteIp": "{{js .Request.RemoteAddr}}", "serverIp": "{{.Revision.PodIP}}", "referer": "{{js .Request.Referer}}", "latency": "{{.Response.Latency}}s", "protocol": "{{.Request.Proto}}"}, "traceId": "{{index .Request.Header "X-B3-Traceid"}}"}`,
+			"logging.revision-url-template":               "",
+			EnableReqLogKey:                               "false",
+			"metrics.request-metrics-backend-destination": "prometheus",
+			"profiling.enable":                            "false",
+			"metrics.opencensus-address":                  "",
+		},
+	}}
+
+	for _, tt := range observabilityConfigMapTests {
+		t.Run(tt.name, func(t *testing.T) {
+			cm := tt.config.GetConfigMap()
+
+			if got, want := cm.Data, tt.wantConfigMapData; !cmp.Equal(got, want) {
+				t.Errorf("Got = %v, want: %v, diff(-want,+got)\n%s", got, want, cmp.Diff(want, got))
+			}
+		})
+	}
+}