Implement pprof support

Instead of having pprof support hardcoded into just the writer, allow
the port to be specified via the configuration.

README.md

@@ -139,6 +139,10 @@ nats_subject_monitor = "influx-spout-monitor"
 # The listener will serve Kubernetes liveness and readiness probes on this port
 # at /healthz and /readyz. Set to 0 (the default) to disable probes support.
 probe_port = 0
+
+# The listener will serve Go pprof requests at this port. Set to 0 (the
+default) to disable pprof support.
+pprof_port = 0
 ```
 
 ### HTTP Listener
@@ -187,6 +191,10 @@ nats_subject_monitor = "influx-spout-monitor"
 # The HTTP listener will serve Kubernetes liveness and readiness probes on this
 # port at /healthz and /readyz. Set to 0 (the default) to disable probes support.
 probe_port = 0
+
+# The HTTP listener will serve Go pprof requests at this port. Set to 0 (the
+default) to disable pprof support.
+pprof_port = 0
 ```
 
 ### Filter
@@ -228,6 +236,10 @@ workers = 8
 # /healthz and /readyz. Set to 0 (the default) to disable probes support.
 probe_port = 0
 
+# The filter will serve Go pprof requests at this port. Set to 0 (the default)
+# to disable pprof support.
+pprof_port = 0
+
 # Incoming metrics with timestamps ± this value from the current time will be
 # rejected. Metrics with timestamps that are significantly different from previously
 # written timestamps negatively impact InfluxDB performance.
@@ -340,6 +352,10 @@ nats_subject_monitor = "influx-spout-monitor"
 # The writer will serve Kubernetes liveness and readiness probes on this port at
 # /healthz and /readyz. Set to 0 (the default) to disable probes support.
 probe_port = 0
+
+# The writer will serve Go pprof requests at this port. Set to 0 (the default)
+# to disable pprof support.
+pprof_port = 0
 ```
 
 A writer will batch up messages until one of the limits defined by the
@@ -376,6 +392,10 @@ port = 9331
 # The monitor will serve Kubernetes liveness and readiness probes on this port
 # at /healthz and /readyz. Set to 0 (the default) to disable probes support.
 probe_port = 0
+
+# The monitor will serve Go pprof requests at this port. Set to 0 (the default)
+# to disable pprof support.
+pprof_port = 0
 ```
 
 ## Running tests

cmd/run.go

@@ -16,8 +16,13 @@ package cmd
 
 import (
 	"fmt"
+	"log"
+	"net/http"
 	"runtime"
 
+	// Profiling support
+	_ "net/http/pprof"
+
 	"github.com/jumptrading/influx-spout/config"
 	"github.com/jumptrading/influx-spout/filter"
 	"github.com/jumptrading/influx-spout/listener"
@@ -38,6 +43,16 @@ func Run(configFile string) (out Stoppable, err error) {
 		return nil, fmt.Errorf("Error while loading config file: %v", err)
 	}
 
+	if c.PprofPort > 0 {
+		go func() {
+			log.Printf("starting pprof listener on port %d", c.PprofPort)
+			err := http.ListenAndServe(fmt.Sprintf(":%d", c.PprofPort), nil)
+			if err != nil {
+				log.Printf("pprof listener exited: %v", err)
+			}
+		}()
+	}
+
 	switch c.Mode {
 	case "listener":
 		out, err = listener.StartListener(c)

config/config.go

@@ -52,6 +52,7 @@ type Config struct {
 	Rule                []Rule   `toml:"rule"`
 	MaxTimeDeltaSecs    int      `toml:"max_time_delta_secs"`
 	ProbePort           int      `toml:"probe_port"`
+	PprofPort           int      `toml:"pprof_port"`
 	Debug               bool     `toml:"debug"`
 }
 
@@ -81,6 +82,7 @@ func newDefaultConfig() *Config {
 		ListenerBatchBytes:  1024 * 1024,
 		MaxTimeDeltaSecs:    600,
 		ProbePort:           0,
+		PprofPort:           0,
 	}
 }
 

config/config_small_test.go

@@ -57,6 +57,7 @@ listener_batch_bytes = 4096
 max_time_delta_secs = 789
 
 probe_port = 6789
+pprof_port = 5432
 `
 	conf, err := parseConfig(validConfigSample)
 	require.NoError(t, err, "Couldn't parse a valid config: %v\n", err)
@@ -83,6 +84,7 @@ probe_port = 6789
 	assert.Equal(t, "nats://localhost:4222", conf.NATSAddress, "Address must match")
 
 	assert.Equal(t, 6789, conf.ProbePort)
+	assert.Equal(t, 5432, conf.PprofPort)
 }
 
 func TestAllDefaults(t *testing.T) {
@@ -109,6 +111,7 @@ func TestAllDefaults(t *testing.T) {
 	assert.Equal(t, 1048576, conf.ListenerBatchBytes)
 	assert.Equal(t, 600, conf.MaxTimeDeltaSecs)
 	assert.Equal(t, 0, conf.ProbePort)
+	assert.Equal(t, 0, conf.PprofPort)
 	assert.Equal(t, false, conf.Debug)
 	assert.Len(t, conf.Rule, 0)
 }

writer/writer.go

@@ -27,7 +27,6 @@ import (
 	"time"
 
 	"net/http"
-	_ "net/http/pprof" // for profiling a nasty memleak
 
 	"github.com/nats-io/go-nats"
 
@@ -77,8 +76,6 @@ func StartWriter(c *config.Config) (_ *Writer, err error) {
 		}
 	}()
 
-	go http.ListenAndServe(":8080", nil) // for pprof profiling
-
 	w.rules, err = filter.RuleSetFromConfig(c)
 	if err != nil {
 		return nil, err