proxy needs to add weavewait to execs as well

Bug came up in a test where we are restarting and doing an exec checking
a network interface right away. weavewait is only added if the container
has a WEAVE_CIDR var set, the same as at container creation.

proxy/common.go

@@ -1,13 +1,24 @@
 package proxy
 
 import (
+	"bytes"
+	"encoding/json"
+	"fmt"
+	"io/ioutil"
+	"net/http"
 	"os/exec"
+	"regexp"
 	"strings"
 
 	"github.com/fsouza/go-dockerclient"
 	. "github.com/weaveworks/weave/common"
 )
 
+var (
+	containerIDRegexp   = regexp.MustCompile("^/v[0-9\\.]*/containers/([^/]*)/.*")
+	weaveWaitEntrypoint = []string{"/home/weavewait/weavewait"}
+)
+
 func callWeave(args ...string) ([]byte, error) {
 	args = append([]string{"--local"}, args...)
 	Debug.Print("Calling weave", args)
@@ -26,3 +37,29 @@ func weaveCIDRsFromConfig(config *docker.Config) ([]string, bool) {
 	}
 	return nil, false
 }
+
+func marshalRequestBody(r *http.Request, body interface{}) error {
+	newBody, err := json.Marshal(body)
+	if err != nil {
+		return err
+	}
+	r.Body = ioutil.NopCloser(bytes.NewReader(newBody))
+	r.ContentLength = int64(len(newBody))
+	return nil
+}
+
+func inspectContainerInPath(client *docker.Client, path string) (*docker.Container, error) {
+	subs := containerIDRegexp.FindStringSubmatch(path)
+	if subs == nil {
+		err := fmt.Errorf("No container id found in request with path %s", path)
+		Warning.Println(err)
+		return nil, err
+	}
+	containerID := subs[1]
+
+	container, err := client.InspectContainer(containerID)
+	if err != nil {
+		Warning.Printf("Error inspecting container %s: %v", containerID, err)
+	}
+	return container, err
+}

proxy/create_container_interceptor.go

@@ -75,7 +75,7 @@ func (i *createContainerInterceptor) setWeaveWaitEntrypoint(container *docker.Co
 		command = image.Cmd
 	}
 
-	container.Entrypoint = []string{"/home/weavewait/weavewait"}
+	container.Entrypoint = weaveWaitEntrypoint
 	container.Cmd = append(entry, command...)
 	return nil
 }

proxy/create_exec_interceptor.go

@@ -0,0 +1,51 @@
+package proxy
+
+import (
+	"encoding/json"
+	"io/ioutil"
+	"net/http"
+
+	"github.com/fsouza/go-dockerclient"
+)
+
+type createExecInterceptor struct {
+	client *docker.Client
+}
+
+type createExecRequestBody struct {
+	*docker.Config
+	HostConfig *docker.HostConfig `json:"HostConfig,omitempty" yaml:"HostConfig,omitempty"`
+	MacAddress string             `json:"MacAddress,omitempty" yaml:"MacAddress,omitempty"`
+}
+
+func (i *createExecInterceptor) InterceptRequest(r *http.Request) error {
+	body, err := ioutil.ReadAll(r.Body)
+	if err != nil {
+		return err
+	}
+	r.Body.Close()
+
+	options := docker.CreateExecOptions{}
+	if err := json.Unmarshal(body, &options); err != nil {
+		return err
+	}
+
+	container, err := inspectContainerInPath(i.client, r.URL.Path)
+	if err != nil {
+		return err
+	}
+
+	if _, ok := weaveCIDRsFromConfig(container.Config); ok {
+		options.Cmd = append(weaveWaitEntrypoint, options.Cmd...)
+	}
+
+	if err := marshalRequestBody(r, options); err != nil {
+		return err
+	}
+
+	return nil
+}
+
+func (i *createExecInterceptor) InterceptResponse(r *http.Response) error {
+	return nil
+}

proxy/proxy.go

@@ -14,6 +14,7 @@ import (
 var (
 	containerCreateRegexp = regexp.MustCompile("/v[0-9\\.]*/containers/create")
 	containerStartRegexp  = regexp.MustCompile("^/v[0-9\\.]*/containers/[^/]*/(re)?start$")
+	execCreateRegexp      = regexp.MustCompile("^/v[0-9\\.]*/containers/[^/]*/exec$")
 )
 
 type Proxy struct {
@@ -68,6 +69,8 @@ func (proxy *Proxy) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 		proxy.serveWithInterceptor(&createContainerInterceptor{proxy.client, proxy.withDNS, proxy.dockerBridgeIP}, w, r)
 	case containerStartRegexp.MatchString(path):
 		proxy.serveWithInterceptor(&startContainerInterceptor{proxy.client, proxy.withDNS}, w, r)
+	case execCreateRegexp.MatchString(path):
+		proxy.serveWithInterceptor(&createExecInterceptor{proxy.client}, w, r)
 	case strings.HasPrefix(path, "/weave"):
 		w.WriteHeader(http.StatusOK)
 	default:

proxy/start_container_interceptor.go

@@ -2,15 +2,12 @@ package proxy
 
 import (
 	"net/http"
-	"regexp"
 	"strings"
 
 	"github.com/fsouza/go-dockerclient"
 	. "github.com/weaveworks/weave/common"
 )
 
-var containerIDRegexp = regexp.MustCompile("^/v[0-9\\.]*/containers/([^/]*)/.*")
-
 type startContainerInterceptor struct {
 	client  *docker.Client
 	withDNS bool
@@ -21,17 +18,9 @@ func (i *startContainerInterceptor) InterceptRequest(r *http.Request) error {
 }
 
 func (i *startContainerInterceptor) InterceptResponse(r *http.Response) error {
-	subs := containerIDRegexp.FindStringSubmatch(r.Request.URL.Path)
-	if subs == nil {
-		Warning.Printf("No container id found in request with path %s", r.Request.URL.Path)
-		return nil
-	}
-	containerID := subs[1]
-
-	container, err := i.client.InspectContainer(containerID)
+	container, err := inspectContainerInPath(i.client, r.Request.URL.Path)
 	if err != nil {
-		Warning.Printf("Error inspecting container %s: %v", containerID, err)
-		return nil
+		return err
 	}
 
 	cidrs, ok := weaveCIDRsFromConfig(container.Config)
@@ -39,12 +28,12 @@ func (i *startContainerInterceptor) InterceptResponse(r *http.Response) error {
 		Debug.Print("No Weave CIDR, ignoring")
 		return nil
 	}
-	Info.Printf("Container %s was started with CIDR \"%s\"", containerID, strings.Join(cidrs, " "))
+	Info.Printf("Container %s was started with CIDR \"%s\"", container.ID, strings.Join(cidrs, " "))
 	args := []string{"attach"}
 	args = append(args, cidrs...)
-	args = append(args, containerID)
+	args = append(args, container.ID)
 	if _, err := callWeave(args...); err != nil {
-		Warning.Printf("Attaching container %s to weave failed: %v", containerID, err)
+		Warning.Printf("Attaching container %s to weave failed: %v", container.ID, err)
 		return nil
 	}
 	return nil

test/640_proxy_restart_reattaches_test.sh

@@ -14,7 +14,7 @@ docker_proxy_on $HOST1 run -e WEAVE_CIDR=$C2/24 -dt --name=c2 -h $NAME gliderlab
 docker_proxy_on $HOST1 run -e WEAVE_CIDR=$C1/24 -dt --name=c1 aanand/docker-dnsutils /bin/sh
 
 docker_proxy_on $HOST1 restart c2
-assert_raises "exec_on $HOST1 c2 ip link show ethwe | grep 'state UP'"
+assert_raises "proxy_exec_on $HOST1 c2 ip link show ethwe | grep 'state \\(UP\\|UNKNOWN\\)'"
 assert_dns_record $HOST1 c1 $NAME $C2
 
 end_suite

test/config.sh

@@ -97,6 +97,14 @@ exec_on() {
     docker -H tcp://$host:2375 exec $container "$@"
 }
 
+proxy_exec_on() {
+    host=$1
+    container=$2
+    shift 2
+    docker -H tcp://$host:12375 exec $container "$@"
+}
+
+
 start_container() {
     host=$1
     shift 1