cmd/revid-cli: add profiling support

cmd/revid-cli/main.go

@@ -25,12 +25,15 @@ LICENSE
   You should have received a copy of the GNU General Public License
   along with revid in gpl.txt. If not, see http://www.gnu.org/licenses.
 */
+
 package main
 
 import (
 	"flag"
 	"fmt"
+	"log"
 	"os"
+	"runtime/pprof"
 	"strconv"
 	"time"
 	"unicode"
@@ -82,6 +85,9 @@ const (
 	revidStopTime      = 5 * time.Second
 )
 
+// canProfile is set to false with revid-cli is built with "-tags profile".
+var canProfile = true
+
 // Globals
 var (
 	rv     *revid.Revid
@@ -89,6 +95,8 @@ var (
 )
 
 func main() {
+	cpuprofile := flag.String("cpuprofile", "", "write cpu profile to `file`")
+
 	flagNames := [noOfConfigFlags]struct{ name, description string }{
 		{"Input", "The input type"},
 		{"InputCodec", "The codec of the input"},
@@ -126,6 +134,21 @@ func main() {
 
 	flag.Parse()
 
+	if *cpuprofile != "" {
+		if canProfile {
+			f, err := os.Create(*cpuprofile)
+			if err != nil {
+				log.Fatal("could not create CPU profile: ", err)
+			}
+			if err := pprof.StartCPUProfile(f); err != nil {
+				log.Fatal("could not start CPU profile: ", err)
+			}
+			defer pprof.StopCPUProfile()
+		} else {
+			fmt.Fprintln(os.Stderr, "Ignoring cpuprofile flag - http/pprof built in.")
+		}
+	}
+
 	switch *configFlags[inputPtr] {
 	case "Raspivid":
 		config.Input = revid.Raspivid

cmd/revid-cli/profile.go

@@ -0,0 +1,36 @@
+/*
+NAME
+  revid-cli - command line interface for Revid.
+
+DESCRIPTION
+  See Readme.md
+
+AUTHORS
+  Dan Kortschak <dan@ausocean.org>
+
+LICENSE
+  revid-cli is Copyright (C) 2017-2018 the Australian Ocean Lab (AusOcean)
+
+  It is free software: you can redistribute it and/or modify them
+  under the terms of the GNU General Public License as published by the
+  Free Software Foundation, either version 3 of the License, or (at your
+  option) any later version.
+
+  It is distributed in the hope that it will be useful, but WITHOUT
+  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+  FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
+  for more details.
+
+  You should have received a copy of the GNU General Public License
+  along with revid in gpl.txt. If not, see http://www.gnu.org/licenses.
+*/
+
+// +build profile
+
+package main
+
+import _ "net/http/pprof"
+
+func init() {
+	canProfile = false
+}