[proxy] Mount /w from the host for weavewaited containers

We set it at container create. Had tried also setting it at start, but
it seems to cause weird behaviour, and there is no way to do it from the
CLI.

proxy/create_container_interceptor.go

@@ -53,10 +53,10 @@ func (i *createContainerInterceptor) InterceptRequest(r *http.Request) error {
 		if container.HostConfig == nil {
 			container.HostConfig = &docker.HostConfig{}
 		}
-		container.HostConfig.VolumesFrom = append(container.HostConfig.VolumesFrom, "weaveproxy:ro")
 		if container.Config == nil {
 			container.Config = &docker.Config{}
 		}
+		i.addWeaveWaitVolume(container.HostConfig)
 		if err := i.setWeaveWaitEntrypoint(container.Config); err != nil {
 			return err
 		}
@@ -75,6 +75,18 @@ func (i *createContainerInterceptor) InterceptRequest(r *http.Request) error {
 	return nil
 }
 
+func (i *createContainerInterceptor) addWeaveWaitVolume(hostConfig *docker.HostConfig) {
+	var binds []string
+	for _, bind := range hostConfig.Binds {
+		s := strings.Split(bind, ":")
+		if len(s) >= 2 && s[1] == "/w" {
+			continue
+		}
+		binds = append(binds, bind)
+	}
+	hostConfig.Binds = append(binds, fmt.Sprintf("%s:/w:ro", i.proxy.weaveWaitVolume))
+}
+
 func (i *createContainerInterceptor) setWeaveWaitEntrypoint(container *docker.Config) error {
 	if len(container.Entrypoint) == 0 {
 		image, err := i.proxy.client.InspectImage(container.Image)

proxy/proxy.go

@@ -3,6 +3,7 @@ package proxy
 import (
 	"crypto/tls"
 	"errors"
+	"fmt"
 	"net"
 	"net/http"
 	"net/url"
@@ -32,9 +33,10 @@ var (
 type Proxy struct {
 	Config
 
-	dial           func() (net.Conn, error)
-	client         *docker.Client
-	dockerBridgeIP string
+	dial            func() (net.Conn, error)
+	client          *docker.Client
+	dockerBridgeIP  string
+	weaveWaitVolume string
 }
 
 type Config struct {
@@ -85,9 +87,32 @@ func NewProxy(c Config) (*Proxy, error) {
 		return nil, err
 	}
 
+	if err = p.findWeaveWaitVolume(); err != nil {
+		return nil, err
+	}
+
 	return p, nil
 }
 
+func (proxy *Proxy) findWeaveWaitVolume() error {
+	container, err := proxy.client.InspectContainer("weaveproxy")
+	if err != nil {
+		return fmt.Errorf("Could not find the weavewait volume: %s", err)
+	}
+
+	if container.Volumes == nil {
+		return fmt.Errorf("Could not find the weavewait volume")
+	}
+
+	volume, ok := container.Volumes["/w"]
+	if !ok {
+		return fmt.Errorf("Could not find the weavewait volume")
+	}
+
+	proxy.weaveWaitVolume = volume
+	return nil
+}
+
 func (proxy *Proxy) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 	Info.Printf("%s %s", r.Method, r.URL)
 	path := r.URL.Path

test/610_proxy_wait_for_weave_test.sh

@@ -28,4 +28,9 @@ assert_raises "proxy docker_on $HOST1 exec c3 true"
 # Check we can't modify weavewait
 assert_raises "proxy docker_on $HOST1 run -e 'WEAVE_CIDR=10.2.1.2/24' $BASE_IMAGE touch /w/w" 1
 
+# Check only user-specified volumes and /w are mounted
+proxy docker_on $HOST1 create --name c4 -v /tmp/1:/srv1 -v /tmp/2:/srv2 -e 'WEAVE_CIDR=10.2.1.3/24' $BASE_IMAGE $CHECK_ETHWE_UP
+proxy docker_on $HOST1 start -ai c4
+assert "docker_on $HOST1 inspect --format='{{range \$k, \$v := .Volumes}}{{\$k}} {{end}}' c4" "/srv1 /srv2 /w "
+
 end_suite