From 7df16e9233d6b5402d4343f3cefb02461945c1de Mon Sep 17 00:00:00 2001
From: Delyan Raychev <delyan.raychev@microsoft.com>
Date: Tue, 27 Oct 2020 09:14:25 -0700
Subject: [PATCH] debugger: Expose all feature flags via /debug/feature-flags
 endpoint (#1926)

---
 pkg/debugger/feature_flags.go | 19 +++++++++++++++++++
 pkg/debugger/server.go        | 14 ++++++++------
 2 files changed, 27 insertions(+), 6 deletions(-)
 create mode 100644 pkg/debugger/feature_flags.go

diff --git a/pkg/debugger/feature_flags.go b/pkg/debugger/feature_flags.go
new file mode 100644
index 0000000000..d51f3c39a1
--- /dev/null
+++ b/pkg/debugger/feature_flags.go
@@ -0,0 +1,19 @@
+package debugger
+
+import (
+	"encoding/json"
+	"fmt"
+	"net/http"
+
+	"github.com/openservicemesh/osm/pkg/featureflags"
+)
+
+func (ds debugServer) getFeatureFlags() http.Handler {
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		if featureFlagsJSON, err := json.Marshal(featureflags.Features); err != nil {
+			log.Error().Err(err).Msgf("Error marshaling feature flags struct: %+v", featureflags.Features)
+		} else {
+			_, _ = fmt.Fprint(w, string(featureFlagsJSON))
+		}
+	})
+}
diff --git a/pkg/debugger/server.go b/pkg/debugger/server.go
index 48e41afc31..77aa9ef2be 100644
--- a/pkg/debugger/server.go
+++ b/pkg/debugger/server.go
@@ -14,12 +14,14 @@ import (
 // GetHandlers implements DebugServer interface and returns the rest of URLs and the handling functions.
 func (ds debugServer) GetHandlers() map[string]http.Handler {
 	handlers := map[string]http.Handler{
-		"/debug/certs":      ds.getCertHandler(),
-		"/debug/xds":        ds.getXDSHandler(),
-		"/debug/proxy":      ds.getProxies(),
-		"/debug/policies":   ds.getSMIPoliciesHandler(),
-		"/debug/config":     ds.getOSMConfigHandler(),
-		"/debug/namespaces": ds.getMonitoredNamespacesHandler(),
+		"/debug/certs":         ds.getCertHandler(),
+		"/debug/xds":           ds.getXDSHandler(),
+		"/debug/proxy":         ds.getProxies(),
+		"/debug/policies":      ds.getSMIPoliciesHandler(),
+		"/debug/config":        ds.getOSMConfigHandler(),
+		"/debug/namespaces":    ds.getMonitoredNamespacesHandler(),
+		"/debug/feature-flags": ds.getFeatureFlags(),
+
 		// Pprof handlers
 		"/debug/pprof/":        http.HandlerFunc(pprof.Index),
 		"/debug/pprof/cmdline": http.HandlerFunc(pprof.Cmdline),