From a22b88ed89110125893ddcb76fa3d0eb437b8f9e Mon Sep 17 00:00:00 2001
From: Bryan Boreham <bjboreham@gmail.com>
Date: Fri, 27 Nov 2015 16:14:23 +0000
Subject: [PATCH] Track endpoints so we can register the right address with DNS

---
 plugin/driver.go  | 36 +++++++++++++++++++++++++++---------
 plugin/watcher.go | 43 +++++++++++++++----------------------------
 2 files changed, 42 insertions(+), 37 deletions(-)

diff --git a/plugin/driver.go b/plugin/driver.go
index 85cded7c..e5b1e413 100644
--- a/plugin/driver.go
+++ b/plugin/driver.go
@@ -2,6 +2,7 @@ package plugin
 
 import (
 	"fmt"
+	"sync"
 
 	"github.com/docker/libnetwork/drivers/remote/api"
 	"github.com/docker/libnetwork/types"
@@ -22,6 +23,8 @@ const (
 type driver struct {
 	version    string
 	nameserver string
+	sync.RWMutex
+	endpoints map[string]struct{}
 }
 
 func New(version string, nameserver string) (skel.Driver, error) {
@@ -30,15 +33,17 @@ func New(version string, nameserver string) (skel.Driver, error) {
 		return nil, errorf("could not connect to docker: %s", err)
 	}
 
-	_, err = NewWatcher(client)
+	driver := &driver{
+		nameserver: nameserver,
+		version:    version,
+		endpoints:  make(map[string]struct{}),
+	}
+
+	_, err = NewWatcher(client, driver)
 	if err != nil {
 		return nil, err
 	}
-
-	return &driver{
-		nameserver: nameserver,
-		version:    version,
-	}, nil
+	return driver, nil
 }
 
 func errorf(format string, a ...interface{}) error {
@@ -76,18 +81,31 @@ func (driver *driver) CreateEndpoint(create *api.CreateEndpointRequest) (*api.Cr
 	if create.Interface == nil {
 		return nil, fmt.Errorf("Not supported: creating an interface from within CreateEndpoint")
 	}
+	driver.Lock()
+	driver.endpoints[endID] = struct{}{}
+	driver.Unlock()
 	resp := &api.CreateEndpointResponse{}
 
 	Log.Infof("Create endpoint %s %+v", endID, resp)
 	return resp, nil
 }
 
-func (driver *driver) DeleteEndpoint(delete *api.DeleteEndpointRequest) error {
-	Log.Debugf("Delete endpoint request: %+v", delete)
-	Log.Infof("Delete endpoint %s", delete.EndpointID)
+func (driver *driver) DeleteEndpoint(deleteReq *api.DeleteEndpointRequest) error {
+	Log.Debugf("Delete endpoint request: %+v", deleteReq)
+	Log.Infof("Delete endpoint %s", deleteReq.EndpointID)
+	driver.Lock()
+	delete(driver.endpoints, deleteReq.EndpointID)
+	driver.Unlock()
 	return nil
 }
 
+func (driver *driver) HasEndpoint(endpointID string) bool {
+	driver.Lock()
+	_, found := driver.endpoints[endpointID]
+	driver.Unlock()
+	return found
+}
+
 func (driver *driver) EndpointInfo(req *api.EndpointInfoRequest) (*api.EndpointInfoResponse, error) {
 	Log.Debugf("Endpoint info request: %+v", req)
 	Log.Infof("Endpoint info %s", req.EndpointID)
diff --git a/plugin/watcher.go b/plugin/watcher.go
index c37b41e0..fbf43014 100644
--- a/plugin/watcher.go
+++ b/plugin/watcher.go
@@ -2,7 +2,6 @@ package plugin
 
 import (
 	"fmt"
-	"strings"
 
 	weaveapi "github.com/weaveworks/weave/api"
 	. "github.com/weaveworks/weave/common"
@@ -16,13 +15,14 @@ const (
 type watcher struct {
 	client *docker.Client
 	weave  *weaveapi.Client
+	driver *driver
 }
 
 type Watcher interface {
 }
 
-func NewWatcher(client *docker.Client) (Watcher, error) {
-	w := &watcher{client: client}
+func NewWatcher(client *docker.Client, driver *driver) (Watcher, error) {
+	w := &watcher{client: client, driver: driver}
 	err := client.AddObserver(w)
 	if err != nil {
 		return nil, err
@@ -50,34 +50,21 @@ func (w *watcher) ContainerStarted(id string) {
 		Log.Warningf("error inspecting container: %s", err)
 		return
 	}
-	// FIXME: check that it's on our network; but, the docker client lib doesn't know about .NetworkID
-	if isSubdomain(info.Config.Domainname, WeaveDomain) && w.haveWeaveClient() {
-		// one of ours
-		ip := info.NetworkSettings.IPAddress
-		fqdn := fmt.Sprintf("%s.%s", info.Config.Hostname, info.Config.Domainname)
-		if err := w.weave.RegisterWithDNS(id, fqdn, ip); err != nil {
-			Log.Warningf("unable to register with weaveDNS: %s", err)
+	if !w.haveWeaveClient() {
+		return
+	}
+	// check that it's on our network, via the endpointID
+	for _, net := range info.NetworkSettings.Networks {
+		if w.driver.HasEndpoint(net.EndpointID) {
+			fqdn := fmt.Sprintf("%s.%s", info.Config.Hostname, info.Config.Domainname)
+			if err := w.weave.RegisterWithDNS(id, fqdn, net.IPAddress); err != nil {
+				Log.Warningf("unable to register with weaveDNS: %s", err)
+			}
 		}
 	}
 }
 
 func (w *watcher) ContainerDied(id string) {
-	Log.Debugf("Container died %s", id)
-	info, err := w.client.InspectContainer(id)
-	if err != nil {
-		Log.Warningf("error inspecting container: %s", err)
-		return
-	}
-	if isSubdomain(info.Config.Domainname, WeaveDomain) && w.haveWeaveClient() {
-		ip := info.NetworkSettings.IPAddress
-		if err := w.weave.DeregisterWithDNS(id, ip); err != nil {
-			Log.Warningf("unable to deregister with weaveDNS: %s", err)
-		}
-	}
-}
-
-// Cheap and cheerful way to check x is, or is a subdomain, of
-// y. Neither are expected to start with a '.'.
-func isSubdomain(x string, y string) bool {
-	return x == y || strings.HasSuffix(x, "."+y)
+	// don't need to do this as WeaveDNS removes names on container died anyway
+	// (note by the time we get this event we can't see the EndpointID)
 }