Added pprof tool (#2512)

CHANGELOG.md

@@ -56,6 +56,7 @@ be deprecated eventually.
 - [#2339](https://github.com/influxdata/telegraf/pull/2339): Increment gather_errors for all errors emitted by inputs.
 - [#2071](https://github.com/influxdata/telegraf/issues/2071): Use official docker SDK.
 - [#1678](https://github.com/influxdata/telegraf/pull/1678): Add AMQP consumer input plugin
+- [#2512](https://github.com/influxdata/telegraf/pull/2512): Added pprof tool.
 - [#2501](https://github.com/influxdata/telegraf/pull/2501): Support DEAD(X) state in system input plugin.
 - [#2522](https://github.com/influxdata/telegraf/pull/2522): Add support for mongodb client certificates.
 - [#1948](https://github.com/influxdata/telegraf/pull/1948): Support adding SNMP table indexes as tags.

cmd/telegraf/telegraf.go

@@ -4,6 +4,8 @@ import (
 	"flag"
 	"fmt"
 	"log"
+	"net/http"
+	_ "net/http/pprof" // Comment this line to disable pprof endpoint.
 	"os"
 	"os/signal"
 	"runtime"
@@ -24,6 +26,8 @@ import (
 
 var fDebug = flag.Bool("debug", false,
 	"turn on debug logging")
+var pprofAddr = flag.String("pprof-addr", "",
+	"pprof address to listen on, not activate pprof if empty")
 var fQuiet = flag.Bool("quiet", false,
 	"run in quiet mode")
 var fTest = flag.Bool("test", false, "gather metrics, print them out, and exit")
@@ -87,6 +91,7 @@ The commands & flags are:
   --output-filter     filter the output plugins to enable, separator is :
   --usage             print usage for a plugin, ie, 'telegraf --usage mysql'
   --debug             print metrics as they're generated to stdout
+  --pprof-addr        pprof address to listen on, format: localhost:6060 or :6060
   --quiet             run in quiet mode
 
 Examples:
@@ -105,6 +110,9 @@ Examples:
 
   # run telegraf, enabling the cpu & memory input, and influxdb output plugins
   telegraf --config telegraf.conf --input-filter cpu:mem --output-filter influxdb
+
+  # run telegraf with pprof
+  telegraf --config telegraf.conf --pprof-addr localhost:6060
 `
 
 var stop chan struct{}
@@ -267,6 +275,23 @@ func main() {
 		processorFilters = strings.Split(":"+strings.TrimSpace(*fProcessorFilters)+":", ":")
 	}
 
+	if *pprofAddr != "" {
+		go func() {
+			pprofHostPort := *pprofAddr
+			parts := strings.Split(pprofHostPort, ":")
+			if len(parts) == 2 && parts[0] == "" {
+				pprofHostPort = fmt.Sprintf("localhost:%s", parts[1])
+			}
+			pprofHostPort = "http://" + pprofHostPort + "/debug/pprof"
+
+			log.Printf("I! Starting pprof HTTP server at: %s", pprofHostPort)
+
+			if err := http.ListenAndServe(*pprofAddr, nil); err != nil {
+				log.Fatal("E! " + err.Error())
+			}
+		}()
+	}
+
 	if len(args) > 0 {
 		switch args[0] {
 		case "version":

docs/PROFILING.md

+# Telegraf profiling
+
+Telegraf uses the standard package `net/http/pprof`. This package serves via its HTTP server runtime profiling data in the format expected by the pprof visualization tool.
+
+By default, the profiling is turned off.
+
+To enable profiling you need to specify address to config parameter `pprof-addr`, for example:
+
+```
+telegraf --config telegraf.conf --pprof-addr localhost:6060
+```
+
+There are several paths to get different profiling information:
+
+To look at the heap profile:
+
+`go tool pprof http://localhost:6060/debug/pprof/heap`
+
+or to look at a 30-second CPU profile:
+
+`go tool pprof http://localhost:6060/debug/pprof/profile?seconds=30`
+
+To view all available profiles, open `http://localhost:6060/debug/pprof/` in your browser.
+