add a client to get container info from kubelet

pkg/client/containerinfo_test.go

@@ -0,0 +1,171 @@
+/*
+Copyright 2014 Google Inc. All rights reserved.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package client
+
+import (
+	"encoding/json"
+	"net/http"
+	"net/http/httptest"
+	"net/url"
+	"path"
+	"reflect"
+	"strconv"
+	"strings"
+	"testing"
+	"time"
+
+	"github.com/google/cadvisor/info"
+	itest "github.com/google/cadvisor/info/test"
+)
+
+func testHTTPContainerInfoGetter(
+	req *info.ContainerInfoRequest,
+	cinfo *info.ContainerInfo,
+	podID string,
+	containerID string,
+	status int,
+	t *testing.T,
+) {
+	expectedPath := "/stats"
+	if len(podID) > 0 && len(containerID) > 0 {
+		expectedPath = path.Join(expectedPath, podID, containerID)
+	}
+	ts := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		if status != 0 {
+			w.WriteHeader(status)
+		}
+		if strings.TrimRight(r.URL.Path, "/") != strings.TrimRight(expectedPath, "/") {
+			t.Fatalf("Received request to an invalid path. Should be %v. got %v",
+				expectedPath, r.URL.Path)
+		}
+
+		decoder := json.NewDecoder(r.Body)
+		var receivedReq info.ContainerInfoRequest
+		err := decoder.Decode(&receivedReq)
+		if err != nil {
+			t.Fatal(err)
+		}
+		// Note: This will not make a deep copy of req.
+		// So changing req after Get*Info would be a race.
+		expectedReq := req
+		// Fill any empty fields with default value
+		expectedReq = expectedReq.FillDefaults()
+		if !reflect.DeepEqual(expectedReq, &receivedReq) {
+			t.Errorf("received wrong request")
+		}
+		encoder := json.NewEncoder(w)
+		err = encoder.Encode(cinfo)
+		if err != nil {
+			t.Fatal(err)
+		}
+	}))
+	hostURL, err := url.Parse(ts.URL)
+	if err != nil {
+		t.Fatal(err)
+	}
+	parts := strings.Split(hostURL.Host, ":")
+
+	port, err := strconv.Atoi(parts[1])
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	containerInfoGetter := &HTTPContainerInfoGetter{
+		Client: http.DefaultClient,
+		Port:   port,
+	}
+
+	var receivedContainerInfo *info.ContainerInfo
+	if len(podID) > 0 && len(containerID) > 0 {
+		receivedContainerInfo, err = containerInfoGetter.GetContainerInfo(parts[0], podID, containerID, req)
+	} else {
+		receivedContainerInfo, err = containerInfoGetter.GetMachineInfo(parts[0], req)
+	}
+	if status == 0 || status == http.StatusOK {
+		if err != nil {
+			t.Errorf("received unexpected error: %v", err)
+		}
+
+		if !receivedContainerInfo.Eq(cinfo) {
+			t.Error("received unexpected container info")
+		}
+	} else {
+		if err == nil {
+			t.Error("did not receive expected error.")
+		}
+	}
+}
+
+func TestHTTPContainerInfoGetterGetContainerInfoSuccessfully(t *testing.T) {
+	req := &info.ContainerInfoRequest{
+		NumStats:   10,
+		NumSamples: 10,
+	}
+	req = req.FillDefaults()
+	cinfo := itest.GenerateRandomContainerInfo(
+		"dockerIDWhichWillNotBeChecked", // docker ID
+		2, // Number of cores
+		req,
+		1*time.Second,
+	)
+	testHTTPContainerInfoGetter(req, cinfo, "somePodID", "containerNameInK8S", 0, t)
+}
+
+func TestHTTPContainerInfoGetterGetMachineInfoSuccessfully(t *testing.T) {
+	req := &info.ContainerInfoRequest{
+		NumStats:   10,
+		NumSamples: 10,
+	}
+	req = req.FillDefaults()
+	cinfo := itest.GenerateRandomContainerInfo(
+		"dockerIDWhichWillNotBeChecked", // docker ID
+		2, // Number of cores
+		req,
+		1*time.Second,
+	)
+	testHTTPContainerInfoGetter(req, cinfo, "", "", 0, t)
+}
+
+func TestHTTPContainerInfoGetterGetContainerInfoWithError(t *testing.T) {
+	req := &info.ContainerInfoRequest{
+		NumStats:   10,
+		NumSamples: 10,
+	}
+	req = req.FillDefaults()
+	cinfo := itest.GenerateRandomContainerInfo(
+		"dockerIDWhichWillNotBeChecked", // docker ID
+		2, // Number of cores
+		req,
+		1*time.Second,
+	)
+	testHTTPContainerInfoGetter(req, cinfo, "somePodID", "containerNameInK8S", http.StatusNotFound, t)
+}
+
+func TestHTTPContainerInfoGetterGetMachineInfoWithError(t *testing.T) {
+	req := &info.ContainerInfoRequest{
+		NumStats:   10,
+		NumSamples: 10,
+	}
+	req = req.FillDefaults()
+	cinfo := itest.GenerateRandomContainerInfo(
+		"dockerIDWhichWillNotBeChecked", // docker ID
+		2, // Number of cores
+		req,
+		1*time.Second,
+	)
+	testHTTPContainerInfoGetter(req, cinfo, "", "", http.StatusNotFound, t)
+}