make the GraphiteClient reconnect on error

gostatsd/gostatsd.go

@@ -2,9 +2,10 @@ package main
 
 import (
 	"flag"
-	"github.com/kisielk/gostatsd/statsd"
 	"log"
 	"time"
+
+	"git.autistici.org/ale/gostatsd/statsd"
 )
 
 const (

statsd/graphite.go

@@ -5,6 +5,7 @@ import (
 	"fmt"
 	"net"
 	"regexp"
+	"sync"
 	"time"
 )
 
@@ -24,19 +25,38 @@ func normalizeBucketName(name string) string {
 
 // GraphiteClient is an object that is used to send messages to a Graphite server's UDP interface
 type GraphiteClient struct {
-	conn *net.Conn
+	addr string
+	conn net.Conn
+	lock sync.Mutex
 }
 
 // SendMetrics sends the metrics in a MetricsMap to the Graphite server
 func (client *GraphiteClient) SendMetrics(metrics MetricMap) (err error) {
+	// Connect opportunistically.
+	client.lock.Lock()
+	if client.conn == nil {
+		client.conn, err = net.Dial("tcp", client.addr)
+	}
+	conn := client.conn
+	client.lock.Unlock()
+	if err != nil {
+		return err
+	}
+
 	buf := new(bytes.Buffer)
 	now := time.Now().Unix()
 	for k, v := range metrics {
 		nk := normalizeBucketName(k)
 		fmt.Fprintf(buf, "%s %f %d\n", nk, v, now)
 	}
-	_, err = buf.WriteTo(*client.conn)
+	_, err = buf.WriteTo(conn)
 	if err != nil {
+		conn.Close()
+		client.lock.Lock()
+		if client.conn == conn {
+			client.conn = nil
+		}
+		client.lock.Unlock()
 		return err
 	}
 	return nil
@@ -44,7 +64,6 @@ func (client *GraphiteClient) SendMetrics(metrics MetricMap) (err error) {
 
 // NewGraphiteClient constructs a GraphiteClient object by connecting to an address
 func NewGraphiteClient(addr string) (client GraphiteClient, err error) {
-	conn, err := net.Dial("tcp", addr)
-	client = GraphiteClient{&conn}
+	client = GraphiteClient{addr: addr}
 	return
 }