kubernetes · lavalamp · Jul 21, 2014 · Jul 15, 2014 · Jul 21, 2014 · lavalamp
diff --git a/pkg/apiserver/apiserver.go b/pkg/apiserver/apiserver.go
@@ -17,15 +17,21 @@ limitations under the License.
 package apiserver
 
 import (
+	"bytes"
 	"encoding/json"
 	"fmt"
 	"io/ioutil"
+	"net"
 	"net/http"
+	"net/http/httputil"
+	"net/url"
 	"path"
 	"runtime/debug"
 	"strings"
 	"time"
 
+	"code.google.com/p/go.net/html"
+	"code.google.com/p/go.net/html/atom"
 	"code.google.com/p/go.net/websocket"
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/api"
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/healthz"
@@ -153,6 +159,8 @@ func New(storage map[string]RESTStorage, prefix string) *APIServer {
 
 	s.mux.HandleFunc("/", s.notFound)
 
+	s.mux.HandleFunc("/proxy/minion/", s.handleMinionReq)
+
 	return s
 }
 
@@ -171,6 +179,120 @@ func (server *APIServer) handleIndex(w http.ResponseWriter, req *http.Request) {
 	fmt.Fprint(w, data)
 }
 
+func (server *APIServer) handleMinionReq(w http.ResponseWriter, req *http.Request) {
+	minionPrefix := "/proxy/minion/"
+	if !strings.HasPrefix(req.URL.Path, minionPrefix) {
+		server.notFound(w, req)
+		return
+	}
+
+	path := req.URL.Path[len(minionPrefix):]
+	rawQuery := req.URL.RawQuery
+
+	// Expect path as: ${minion}/${query_to_minion}
+	// and query_to_minion can be any query that kubelet will accept.
+	//
+	// For example:
+	// To query stats of a minion or a pod or a container,
+	// path string can be ${minion}/stats/<podid>/<containerName> or
+	// ${minion}/podInfo?podID=<podid>
+	//
+	// To query logs on a minion, path string can be:
+	// ${minion}/logs/
+	idx := strings.Index(path, "/")
+	minionHost := path[:idx]
+	_, port, _ := net.SplitHostPort(minionHost)
+	if port == "" {
+		// Couldn't retrieve port information
+		// TODO: Retrieve port info from a common object
+		minionHost += ":10250"
+	}
+	minionPath := path[idx:]
+
+	minionURL := &url.URL{
+		Scheme: "http",
+		Host:   minionHost,
+	}
+	newReq, err := http.NewRequest("GET", minionPath+"?"+rawQuery, nil)
+	if err != nil {
+		glog.Errorf("Failed to create request: %s", err)
+	}
+
+	proxy := httputil.NewSingleHostReverseProxy(minionURL)
+	proxy.Transport = &minionTransport{}
+	proxy.ServeHTTP(w, newReq)
+}
+
+type minionTransport struct{}
+
+func (t *minionTransport) RoundTrip(req *http.Request) (*http.Response, error) {
+	resp, err := http.DefaultTransport.RoundTrip(req)
+
+	if strings.Contains(resp.Header.Get("Content-Type"), "text/plain") {
+		// Do nothing, simply pass through
+		return resp, err
+	}
+
+	resp, err = t.ProcessResponse(req, resp)
+	return resp, err
+}
+
+func (t *minionTransport) ProcessResponse(req *http.Request, resp *http.Response) (*http.Response, error) {
+	body, err := ioutil.ReadAll(resp.Body)
+	if err != nil {
+		// copying the response body did not work
+		return nil, err
+	}
+
+	bodyNode := &html.Node{
+		Type:     html.ElementNode,
+		Data:     "body",
+		DataAtom: atom.Body,
+	}
+	nodes, err := html.ParseFragment(bytes.NewBuffer(body), bodyNode)
+	if err != nil {
+		glog.Errorf("Failed to found <body> node: %v", err)
+		return resp, err
+	}
+
+	// Define the method to traverse the doc tree and update href node to
+	// point to correct minion
+	var updateHRef func(*html.Node)
+	updateHRef = func(n *html.Node) {
+		if n.Type == html.ElementNode && n.Data == "a" {
+			for i, attr := range n.Attr {
+				if attr.Key == "href" {
+					Url := &url.URL{
+						Path: "/proxy/minion/" + req.URL.Host + req.URL.Path + attr.Val,
+					}
+					n.Attr[i].Val = Url.String()
+					break
+				}
+			}
+		}
+		for c := n.FirstChild; c != nil; c = c.NextSibling {
+			updateHRef(c)
+		}
+	}
+
+	newContent := &bytes.Buffer{}
+	for _, n := range nodes {
+		updateHRef(n)
+		err = html.Render(newContent, n)
+		if err != nil {
+			glog.Errorf("Failed to render: %v", err)
+		}
+	}
+
+	resp.Body = ioutil.NopCloser(newContent)
+	// Update header node with new content-length
+	// TODO: Remove any hash/signature headers here?
+	resp.Header.Del("Content-Length")
+	resp.ContentLength = int64(newContent.Len())
+
+	return resp, err
+}
+
 // HTTP Handler interface
 func (server *APIServer) ServeHTTP(w http.ResponseWriter, req *http.Request) {
 	defer func() {

diff --git a/pkg/apiserver/apiserver_test.go b/pkg/apiserver/apiserver_test.go
@@ -25,6 +25,7 @@ import (
 	"net/http/httptest"
 	"net/url"
 	"reflect"
+	"strings"
 	"sync"
 	"testing"
 	"time"
@@ -666,3 +667,52 @@ func TestWatchHTTP(t *testing.T) {
 		t.Errorf("Unexpected non-error")
 	}
 }
+
+func TestMinionTransport(t *testing.T) {
+	content := string(`<pre><a href="kubelet.log">kubelet.log</a><a href="google.log">google.log</a></pre>`)
+	transport := &minionTransport{}
+
+	// Test /logs/
+	request := &http.Request{
+		Method: "GET",
+		URL: &url.URL{
+			Scheme: "http",
+			Host:   "minion1:10250",
+			Path:   "/logs/",
+		},
+	}
+	response := &http.Response{
+		Status:     "200 OK",
+		StatusCode: http.StatusOK,
+		Body:       ioutil.NopCloser(strings.NewReader(content)),
+		Close:      true,
+	}
+	updated_resp, _ := transport.ProcessResponse(request, response)
+	body, _ := ioutil.ReadAll(updated_resp.Body)
+	expected := string(`<pre><a href="/proxy/minion/minion1:10250/logs/kubelet.log">kubelet.log</a><a href="/proxy/minion/minion1:10250/logs/google.log">google.log</a></pre>`)
+	if !strings.Contains(string(body), expected) {
+		t.Errorf("Received wrong content: %s", string(body))
+	}
+
+	// Test subdir under /logs/
+	request = &http.Request{
+		Method: "GET",
+		URL: &url.URL{
+			Scheme: "http",
+			Host:   "minion1:8080",
+			Path:   "/whatever/apt/",
+		},
+	}
+	response = &http.Response{
+		Status:     "200 OK",
+		StatusCode: http.StatusOK,
+		Body:       ioutil.NopCloser(strings.NewReader(content)),
+		Close:      true,
+	}
+	updated_resp, _ = transport.ProcessResponse(request, response)
+	body, _ = ioutil.ReadAll(updated_resp.Body)
+	expected = string(`<pre><a href="/proxy/minion/minion1:8080/whatever/apt/kubelet.log">kubelet.log</a><a href="/proxy/minion/minion1:8080/whatever/apt/google.log">google.log</a></pre>`)
+	if !strings.Contains(string(body), expected) {
+		t.Errorf("Received wrong content: %s", string(body))
+	}
+}
diff --git a/pkg/kubelet/kubelet.go b/pkg/kubelet/kubelet.go
@@ -59,6 +59,8 @@ type CadvisorInterface interface {
 }
 
 // New creates a new Kubelet.
+// TODO: currently it is only called by test code.
+// Need cleanup.
 func New() *Kubelet {
 	return &Kubelet{}
 }
@@ -77,6 +79,7 @@ type Kubelet struct {
 	HTTPCheckFrequency time.Duration
 	pullLock           sync.Mutex
 	HealthChecker      health.HealthChecker
+	LogServer          http.Handler
 }
 
 type manifestUpdate struct {
@@ -94,6 +97,9 @@ const (
 // RunKubelet starts background goroutines. If config_path, manifest_url, or address are empty,
 // they are not watched. Never returns.
 func (kl *Kubelet) RunKubelet(dockerEndpoint, configPath, manifestURL string, etcdServers []string, address string, port uint) {
+	if kl.LogServer == nil {
+		kl.LogServer = http.StripPrefix("/logs/", http.FileServer(http.Dir("/var/log/")))
+	}
 	if kl.CadvisorClient == nil {
 		var err error
 		kl.CadvisorClient, err = cadvisor.NewClient("http://127.0.0.1:5000")
@@ -812,3 +818,9 @@ func (kl *Kubelet) healthy(container api.Container, dockerContainer *docker.APIC
 	}
 	return kl.HealthChecker.HealthCheck(container)
 }
+
+// Returns logs of current machine.
+func (kl *Kubelet) ServeLogs(w http.ResponseWriter, req *http.Request) {
+	// TODO: whitelist logs we are willing to serve
+	kl.LogServer.ServeHTTP(w, req)
+}
diff --git a/pkg/kubelet/server.go b/pkg/kubelet/server.go
@@ -47,6 +47,7 @@ type kubeletInterface interface {
 	GetRootInfo(req *info.ContainerInfoRequest) (*info.ContainerInfo, error)
 	GetMachineInfo() (*info.MachineInfo, error)
 	GetPodInfo(name string) (api.PodInfo, error)
+	ServeLogs(w http.ResponseWriter, req *http.Request)
 }
 
 func (s *Server) error(w http.ResponseWriter, err error) {
@@ -131,6 +132,8 @@ func (s *Server) ServeHTTP(w http.ResponseWriter, req *http.Request) {
 		}
 		w.Header().Add("Content-type", "application/json")
 		w.Write(data)
+	case strings.HasPrefix(u.Path, "/logs/"):
+		s.Kubelet.ServeLogs(w, req)
 	default:
 		s.DelegateHandler.ServeHTTP(w, req)
 	}

diff --git a/pkg/kubelet/server_test.go b/pkg/kubelet/server_test.go
@@ -23,7 +23,9 @@ import (
 	"io/ioutil"
 	"net/http"
 	"net/http/httptest"
+	"net/http/httputil"
 	"reflect"
+	"strings"
 	"testing"
 
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/api"
@@ -37,6 +39,7 @@ type fakeKubelet struct {
 	containerInfoFunc func(podID, containerName string, req *info.ContainerInfoRequest) (*info.ContainerInfo, error)
 	rootInfoFunc      func(query *info.ContainerInfoRequest) (*info.ContainerInfo, error)
 	machineInfoFunc   func() (*info.MachineInfo, error)
+	logFunc           func(w http.ResponseWriter, req *http.Request)
 }
 
 func (fk *fakeKubelet) GetPodInfo(name string) (api.PodInfo, error) {
@@ -55,6 +58,10 @@ func (fk *fakeKubelet) GetMachineInfo() (*info.MachineInfo, error) {
 	return fk.machineInfoFunc()
 }
 
+func (fk *fakeKubelet) ServeLogs(w http.ResponseWriter, req *http.Request) {
+	fk.logFunc(w, req)
+}
+
 type serverTestFramework struct {
 	updateChan      chan manifestUpdate
 	updateReader    *channelReader
@@ -253,3 +260,31 @@ func TestMachineInfo(t *testing.T) {
 		t.Errorf("received wrong data: %#v", receivedInfo)
 	}
 }
+
+func TestServeLogs(t *testing.T) {
+	fw := makeServerTest()
+
+	content := string(`<pre><a href="kubelet.log">kubelet.log</a><a href="google.log">google.log</a></pre>`)
+
+	fw.fakeKubelet.logFunc = func(w http.ResponseWriter, req *http.Request) {
+		w.WriteHeader(http.StatusOK)
+		w.Header().Add("Content-Type", "text/html")
+		w.Write([]byte(content))
+	}
+
+	resp, err := http.Get(fw.testHTTPServer.URL + "/logs/")
+	if err != nil {
+		t.Fatalf("Got error GETing: %v", err)
+	}
+	defer resp.Body.Close()
+
+	body, err := httputil.DumpResponse(resp, true)
+	if err != nil {
+		// copying the response body did not work
+		t.Errorf("Cannot copy resp: %#v", err)
+	}
+	result := string(body)
+	if !strings.Contains(result, "kubelet.log") || !strings.Contains(result, "google.log") {
+		t.Errorf("Received wrong data: %s", result)
+	}
+}
diff --git a/third_party/deps.sh b/third_party/deps.sh
@@ -13,6 +13,7 @@ DEP_PACKAGES="
   gopkg.in/v1/yaml
   bitbucket.org/kardianos/osext
   code.google.com/p/google-api-go-client/googleapi
+  code.google.com/p/go.net/html
   github.com/coreos/go-log/log
   github.com/coreos/go-systemd/journal
   code.google.com/p/go.net/websocket