From 68096b0437f2afe52b29452f9e6122ead1b11eea Mon Sep 17 00:00:00 2001
From: Bryan Boreham <bjboreham@gmail.com>
Date: Wed, 1 Apr 2015 16:47:55 +0100
Subject: [PATCH] Generalize updater.go

---
 {nameserver => common/updater}/updater.go | 15 +++++++++------
 nameserver/zone.go                        |  5 +++++
 weavedns/main.go                          |  3 ++-
 3 files changed, 16 insertions(+), 7 deletions(-)
 rename {nameserver => common/updater}/updater.go (69%)

diff --git a/nameserver/updater.go b/common/updater/updater.go
similarity index 69%
rename from nameserver/updater.go
rename to common/updater/updater.go
index 45725395..f46944cb 100644
--- a/nameserver/updater.go
+++ b/common/updater/updater.go
@@ -1,10 +1,14 @@
-package nameserver
+package updater
 
 import (
 	"github.com/fsouza/go-dockerclient"
 	. "github.com/zettio/weave/common"
 )
 
+type ContainerObserver interface {
+	ContainerDied(ident string) error
+}
+
 func checkError(err error, apiPath string) {
 	if err != nil {
 		Error.Fatalf("[updater] Unable to connect to Docker API on %s: %s",
@@ -12,7 +16,7 @@ func checkError(err error, apiPath string) {
 	}
 }
 
-func StartUpdater(apiPath string, zone Zone) error {
+func Start(apiPath string, ob ContainerObserver) error {
 	client, err := docker.NewClient(apiPath)
 	checkError(err, apiPath)
 
@@ -27,18 +31,17 @@ func StartUpdater(apiPath string, zone Zone) error {
 
 	go func() {
 		for event := range events {
-			handleEvent(zone, event, client)
+			handleEvent(ob, event, client)
 		}
 	}()
 	return nil
 }
 
-func handleEvent(zone Zone, event *docker.APIEvents, client *docker.Client) error {
+func handleEvent(ob ContainerObserver, event *docker.APIEvents, client *docker.Client) error {
 	switch event.Status {
 	case "die":
 		id := event.ID
-		Info.Printf("[updater] Container %s down. Removing records", id)
-		zone.DeleteRecordsFor(id)
+		ob.ContainerDied(id)
 	}
 	return nil
 }
diff --git a/nameserver/zone.go b/nameserver/zone.go
index c63fe7b4..27b9ea47 100644
--- a/nameserver/zone.go
+++ b/nameserver/zone.go
@@ -139,3 +139,8 @@ func (zone *ZoneDb) DeleteRecordsFor(ident string) error {
 	zone.recs = zone.recs[:w]
 	return nil
 }
+
+func (zone *ZoneDb) ContainerDied(ident string) error {
+	Info.Printf("[zonedb] Container %s down. Removing records", ident)
+	return zone.DeleteRecordsFor(ident)
+}
diff --git a/weavedns/main.go b/weavedns/main.go
index 66b68021..7c239e0c 100644
--- a/weavedns/main.go
+++ b/weavedns/main.go
@@ -4,6 +4,7 @@ import (
 	"flag"
 	"fmt"
 	. "github.com/zettio/weave/common"
+	"github.com/zettio/weave/common/updater"
 	weavedns "github.com/zettio/weave/nameserver"
 	weavenet "github.com/zettio/weave/net"
 	"io"
@@ -57,7 +58,7 @@ func main() {
 	var zone = new(weavedns.ZoneDb)
 
 	if watch {
-		err := weavedns.StartUpdater(apiPath, zone)
+		err := updater.Start(apiPath, zone)
 		if err != nil {
 			Error.Fatal("Unable to start watcher", err)
 		}