Add go pprof support across fission components (#2112)

Signed-off-by: Sanket Sudake <sanketsudake@gmail.com>

pkg/utils/profile/profile.go

@@ -0,0 +1,74 @@
+/*
+Copyright 2021 The Fission Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+// To use profile in a go program over http
+// import this package and call ProfileIfEnabled()
+// in your main function.
+// Please set the environment variable PPROF_ENABLE=true to enable/disable it runtime.
+// To customize host and port you can set PPROF_HOST and PPROF_PORT environment variables.
+//	$ PPROF_ENABLE=true PPROF_HOST=localhost PPROF_PORT=6060 go run myprogram.go
+
+package profile
+
+import (
+	"fmt"
+	"log"
+	"net/http"
+	_ "net/http/pprof"
+	"os"
+
+	"go.uber.org/zap"
+	"go.uber.org/zap/zapcore"
+)
+
+func getPprofAddr() string {
+	pprofHost := os.Getenv("PPROF_HOST")
+	if pprofHost == "" {
+		pprofHost = "localhost"
+	}
+	pprofPort := os.Getenv("PPROF_PORT")
+	if pprofPort == "" {
+		pprofPort = "6060"
+	}
+	return fmt.Sprintf("%s:%s", pprofHost, pprofPort)
+}
+
+func ProfileIfEnabled() {
+	enablePprof := os.Getenv("PPROF_ENABLED")
+	if enablePprof != "true" {
+		return
+	}
+
+	pprofMux := http.DefaultServeMux
+	http.DefaultServeMux = http.NewServeMux()
+
+	config := zap.NewProductionConfig()
+	config.EncoderConfig.EncodeTime = zapcore.ISO8601TimeEncoder
+	logger, err := config.Build()
+	if err != nil {
+		log.Fatalf("can't initialize zap logger: %v", err)
+	}
+	defer logger.Sync()
+
+	addr := getPprofAddr()
+	logger.Info("Running pprof server", zap.String("addr", addr))
+	go func() {
+		err = http.ListenAndServe(addr, pprofMux)
+		if err != nil {
+			logger.Fatal("pprof http server failed", zap.Error(err))
+		}
+	}()
+}