Merge pull request #5527 from ipfs/feat/pprof-lock

pprof: create HTTP endpoint for setting MutexProfileFraction

cmd/ipfs/daemon.go

@@ -448,6 +448,7 @@ func serveHTTPApi(req *cmds.Request, cctx *oldcmds.Context) (<-chan error, error
 		corehttp.VersionOption(),
 		defaultMux("/debug/vars"),
 		defaultMux("/debug/pprof/"),
+		corehttp.MutexFractionOption("/debug/pprof-mutex/"),
 		corehttp.MetricsScrapingOption("/debug/metrics/prometheus"),
 		corehttp.LogOption(),
 	}

core/corehttp/mutex_profile.go

+package corehttp
+
+import (
+	"net"
+	"net/http"
+	"runtime"
+	"strconv"
+
+	core "github.com/ipfs/go-ipfs/core"
+)
+
+// MutexFractionOption allows to set runtime.SetMutexProfileFraction via HTTP
+// using POST request with parameter 'fraction'.
+func MutexFractionOption(path string) ServeOption {
+	return func(_ *core.IpfsNode, _ net.Listener, mux *http.ServeMux) (*http.ServeMux, error) {
+		mux.HandleFunc(path, func(w http.ResponseWriter, r *http.Request) {
+			if r.Method != http.MethodPost {
+				w.WriteHeader(http.StatusMethodNotAllowed)
+				return
+			}
+			if err := r.ParseForm(); err != nil {
+				w.WriteHeader(http.StatusBadRequest)
+				w.Write([]byte(err.Error()))
+				return
+			}
+
+			asfr := r.Form.Get("fraction")
+			if len(asfr) == 0 {
+				w.WriteHeader(http.StatusBadRequest)
+				return
+			}
+
+			fr, err := strconv.Atoi(asfr)
+			if err != nil {
+				w.WriteHeader(http.StatusBadRequest)
+				w.Write([]byte(err.Error()))
+				return
+			}
+			log.Infof("Setting MutexProfileFraction to %d", fr)
+			runtime.SetMutexProfileFraction(fr)
+		})
+
+		return mux, nil
+	}
+}

test/sharness/t0110-gateway.sh

@@ -106,6 +106,21 @@ test_expect_success "output only has one transfer encoding header" '
   test_cmp tecount_out tecount_exp
 '
 
+curl_pprofmutex() {
+  curl -f -X POST "http://127.0.0.1:$apiport/debug/pprof-mutex/?fraction=$1"
+}
+
+test_expect_success "set mutex fraction for pprof (negative so it doesn't enable)" '
+  curl_pprofmutex -1
+'
+
+test_expect_success "test failure conditions of mutex pprof endpoint" '
+  test_must_fail curl_pprofmutex &&
+    test_must_fail curl_pprofmutex that_is_string &&
+    test_must_fail curl -f -X GET "http://127.0.0.1:$apiport/debug/pprof-mutex/?fraction=-1"
+'
+
+
 test_expect_success "setup index hash" '
   mkdir index &&
   echo "<p></p>" > index/index.html &&