add a client to get container info from kubelet

pkg/client/containerinfo.go

@@ -0,0 +1,91 @@
+/*
+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 (
+	"bytes"
+	"encoding/json"
+	"fmt"
+	"io"
+	"net"
+	"net/http"
+	"strconv"
+
+	"github.com/google/cadvisor/info"
+)
+
+type ContainerInfoGetter interface {
+	GetContainerInfo(host, podID, containerID string, req *info.ContainerInfoRequest) (*info.ContainerInfo, error)
+	GetMachineInfo(host string, req *info.ContainerInfoRequest) (*info.ContainerInfo, error)
+}
+
+type HTTPContainerInfoGetter struct {
+	Client *http.Client
+	Port   int
+}
+
+func (self *HTTPContainerInfoGetter) getContainerInfo(host, path string, req *info.ContainerInfoRequest) (*info.ContainerInfo, error) {
+	var body io.Reader
+	if req != nil {
+		content, err := json.Marshal(req)
+		if err != nil {
+			return nil, err
+		}
+		body = bytes.NewBuffer(content)
+	}
+
+	request, err := http.NewRequest(
+		"GET",
+		fmt.Sprintf("http://%v/stats/%v",
+			net.JoinHostPort(host, strconv.Itoa(self.Port)),
+			path,
+		),
+		body,
+	)
+	if err != nil {
+		return nil, err
+	}
+
+	response, err := self.Client.Do(request)
+	if err != nil {
+		return nil, err
+	}
+	defer response.Body.Close()
+	if response.StatusCode != http.StatusOK {
+		return nil, fmt.Errorf("trying to get info for %v from %v; received status %v",
+			path, host, response.Status)
+	}
+	decoder := json.NewDecoder(response.Body)
+	var cinfo info.ContainerInfo
+	err = decoder.Decode(&cinfo)
+	if err != nil {
+		return nil, err
+	}
+	return &cinfo, nil
+}
+
+func (self *HTTPContainerInfoGetter) GetContainerInfo(host, podID, containerID string, req *info.ContainerInfoRequest) (*info.ContainerInfo, error) {
+	return self.getContainerInfo(
+		host,
+		fmt.Sprintf("%v/%v", podID, containerID),
+		req,
+	)
+}
+
+func (self *HTTPContainerInfoGetter) GetMachineInfo(host string, req *info.ContainerInfoRequest) (*info.ContainerInfo, error) {
+	return self.getContainerInfo(host, "", req)
+}