PodInfo should indicate when a pod is not found

Client should react.  Also, dial down the chattiness of errors for
pods which do not exist and stop processing NotFound earlier in
the podinfo chain

pkg/client/podinfo.go

@@ -18,6 +18,7 @@ package client
 
 import (
 	"encoding/json"
+	"errors"
 	"fmt"
 	"io/ioutil"
 	"net"
@@ -27,6 +28,9 @@ import (
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/api"
 )
 
+// ErrPodInfoNotAvailable may be returned when the requested pod info is not available
+var ErrPodInfoNotAvailable = errors.New("no pod info available")
+
 // PodInfoGetter is an interface for things that can get information about a pod's containers.
 // Injectable for easy testing.
 type PodInfoGetter interface {
@@ -58,6 +62,9 @@ func (c *HTTPPodInfoGetter) GetPodInfo(host, podID string) (api.PodInfo, error)
 		return nil, err
 	}
 	defer response.Body.Close()
+	if response.StatusCode == http.StatusNotFound {
+		return nil, ErrPodInfoNotAvailable
+	}
 	body, err := ioutil.ReadAll(response.Body)
 	if err != nil {
 		return nil, err

pkg/client/podinfo_test.go

@@ -67,3 +67,31 @@ func TestHTTPPodInfoGetter(t *testing.T) {
 		t.Errorf("Unexpected response.  Expected: %#v, received %#v", expectObj, gotObj)
 	}
 }
+
+func TestHTTPPodInfoGetterNotFound(t *testing.T) {
+	expectObj := api.PodInfo{
+		"myID": docker.Container{ID: "myID"},
+	}
+	_, err := json.Marshal(expectObj)
+	expectNoError(t, err)
+	fakeHandler := util.FakeHandler{
+		StatusCode:   404,
+		ResponseBody: "Pod not found",
+	}
+	testServer := httptest.NewServer(&fakeHandler)
+
+	hostURL, err := url.Parse(testServer.URL)
+	expectNoError(t, err)
+	parts := strings.Split(hostURL.Host, ":")
+
+	port, err := strconv.Atoi(parts[1])
+	expectNoError(t, err)
+	podInfoGetter := &HTTPPodInfoGetter{
+		Client: http.DefaultClient,
+		Port:   uint(port),
+	}
+	_, err = podInfoGetter.GetPodInfo(parts[0], "foo")
+	if err != ErrPodInfoNotAvailable {
+		t.Errorf("Expected %#v, Got %#v", ErrPodInfoNotAvailable, err)
+	}
+}

pkg/kubelet/docker.go

@@ -17,6 +17,7 @@ limitations under the License.
 package kubelet
 
 import (
+	"errors"
 	"fmt"
 	"math/rand"
 	"strings"
@@ -115,6 +116,9 @@ func getKubeletDockerContainers(client DockerInterface) (DockerContainers, error
 	return result, nil
 }
 
+// ErrNoContainersInPod is returned when there are no running containers for a given pod
+var ErrNoContainersInPod = errors.New("no containers exist for this pod")
+
 // GetDockerPodInfo returns docker info for all containers in the pod/manifest.
 func getDockerPodInfo(client DockerInterface, manifestID string) (api.PodInfo, error) {
 	info := api.PodInfo{}
@@ -140,6 +144,10 @@ func getDockerPodInfo(client DockerInterface, manifestID string) (api.PodInfo, e
 			info[dockerContainerName] = *inspectResult
 		}
 	}
+	if len(info) == 0 {
+		return nil, ErrNoContainersInPod
+	}
+
 	return info, nil
 }
 

pkg/kubelet/server.go

@@ -54,7 +54,12 @@ func (s *Server) error(w http.ResponseWriter, err error) {
 }
 
 func (s *Server) ServeHTTP(w http.ResponseWriter, req *http.Request) {
-	defer httplog.MakeLogged(req, &w).Log()
+	defer httplog.MakeLogged(req, &w).StacktraceWhen(
+		httplog.StatusIsNot(
+			http.StatusOK,
+			http.StatusNotFound,
+		),
+	).Log()
 
 	u, err := url.ParseRequestURI(req.RequestURI)
 	if err != nil {
@@ -95,6 +100,10 @@ func (s *Server) ServeHTTP(w http.ResponseWriter, req *http.Request) {
 			return
 		}
 		info, err := s.Kubelet.GetPodInfo(podID)
+		if err == ErrNoContainersInPod {
+			http.Error(w, "Pod does not exist", http.StatusNotFound)
+			return
+		}
 		if err != nil {
 			s.error(w, err)
 			return

pkg/master/pod_cache.go

@@ -17,7 +17,6 @@ limitations under the License.
 package master
 
 import (
-	"errors"
 	"sync"
 	"time"
 
@@ -57,7 +56,7 @@ func (p *PodCache) GetPodInfo(host, podID string) (api.PodInfo, error) {
 	defer p.podLock.Unlock()
 	value, ok := p.podInfo[podID]
 	if !ok {
-		return nil, errors.New("no cached pod info")
+		return nil, client.ErrPodInfoNotAvailable
 	}
 	return value, nil
 }
@@ -82,7 +81,7 @@ func (p *PodCache) UpdateAllContainers() {
 	}
 	for _, pod := range pods {
 		err := p.updatePodInfo(pod.CurrentState.Host, pod.ID)
-		if err != nil {
+		if err != nil && err != client.ErrPodInfoNotAvailable {
 			glog.Errorf("Error synchronizing container: %#v", err)
 		}
 	}

pkg/registry/pod_registry.go

@@ -86,12 +86,16 @@ func (storage *PodRegistryStorage) fillPodInfo(pod *api.Pod) {
 	if storage.podCache != nil {
 		info, err := storage.podCache.GetPodInfo(pod.CurrentState.Host, pod.ID)
 		if err != nil {
+			if err != client.ErrPodInfoNotAvailable {
 				glog.Errorf("Error getting container info from cache: %#v", err)
+			}
 			if storage.podInfoGetter != nil {
 				info, err = storage.podInfoGetter.GetPodInfo(pod.CurrentState.Host, pod.ID)
 			}
 			if err != nil {
+				if err != client.ErrPodInfoNotAvailable {
 					glog.Errorf("Error getting fresh container info: %#v", err)
+				}
 				return
 			}
 		}
@@ -104,7 +108,7 @@ func (storage *PodRegistryStorage) fillPodInfo(pod *api.Pod) {
 				glog.Warningf("No network settings: %#v", netContainerInfo)
 			}
 		} else {
-			glog.Warningf("Couldn't find network container in %v", info)
+			glog.Warningf("Couldn't find network container for %s in %v", pod.ID, info)
 		}
 	}
 }