Refactoring API version handling.
This should make it easier to add future API versions and makes it a bit simpler to look through the API.
This commit is contained in:
parent
48c994e5be
commit
77283196f6
201
api/handler.go
201
api/handler.go
@ -21,6 +21,8 @@ import (
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"io"
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"net/http"
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"path"
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"regexp"
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"sort"
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"strings"
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"time"
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@ -30,26 +32,18 @@ import (
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)
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const (
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apiResource = "/api/"
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containersApi = "containers"
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subcontainersApi = "subcontainers"
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machineApi = "machine"
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dockerApi = "docker"
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version1_0 = "v1.0"
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version1_1 = "v1.1"
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version1_2 = "v1.2"
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apiResource = "/api/"
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)
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var supportedApiVersions map[string]struct{} = map[string]struct{}{
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version1_0: {},
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version1_1: {},
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version1_2: {},
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}
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func RegisterHandlers(m manager.Manager) error {
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apiVersions := getApiVersions()
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supportedApiVersions := make(map[string]ApiVersion, len(apiVersions))
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for _, v := range apiVersions {
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supportedApiVersions[v.Version()] = v
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}
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http.HandleFunc(apiResource, func(w http.ResponseWriter, r *http.Request) {
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err := handleRequest(m, w, r)
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err := handleRequest(supportedApiVersions, m, w, r)
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if err != nil {
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http.Error(w, err.Error(), 500)
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}
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@ -58,145 +52,68 @@ func RegisterHandlers(m manager.Manager) error {
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return nil
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}
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func handleRequest(m manager.Manager, w http.ResponseWriter, r *http.Request) error {
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// Captures the API version, requestType [optional], and remaining request [optional].
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var apiRegexp = regexp.MustCompile("/api/([^/]+)/?([^/]+)?(.*)")
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const (
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apiVersion = iota + 1
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apiRequestType
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apiRequestArgs
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)
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func handleRequest(supportedApiVersions map[string]ApiVersion, m manager.Manager, w http.ResponseWriter, r *http.Request) error {
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start := time.Now()
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defer glog.V(2).Infof("Request took %s", time.Since(start))
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defer func() {
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glog.V(2).Infof("Request took %s", time.Since(start))
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}()
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request := r.URL.Path
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requestElements := strings.Split(r.URL.Path, "/")
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// Verify that we have all the elements we expect:
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// <empty>/api/<version>/<request type>[/<args...>]
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// [0] [1] [2] [3] [4...]
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if len(requestElements) < 4 {
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const apiPrefix = "/api"
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if !strings.HasPrefix(request, apiPrefix) {
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return fmt.Errorf("incomplete API request %q", request)
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}
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// Get all the element parts.
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emptyElement := requestElements[0]
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apiElement := requestElements[1]
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version := requestElements[2]
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requestType := requestElements[3]
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requestArgs := []string{}
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if len(requestElements) > 4 {
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requestArgs = requestElements[4:]
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// If the request doesn't have an API version, list those.
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if request == apiPrefix || request == apiResource {
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versions := make([]string, 0, len(supportedApiVersions))
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for v := range supportedApiVersions {
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versions = append(versions, v)
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}
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sort.Strings(versions)
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fmt.Fprintf(w, "Supported API versions: %s", strings.Join(versions, ","))
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return nil
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}
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// The container name is the path after the requestType.
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containerName := path.Join("/", strings.Join(requestArgs, "/"))
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// Verify that we have all the elements we expect:
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// /<version>/<request type>[/<args...>]
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requestElements := apiRegexp.FindStringSubmatch(request)
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if len(requestElements) == 0 {
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return fmt.Errorf("malformed request %q", request)
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}
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version := requestElements[apiVersion]
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requestType := requestElements[apiRequestType]
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requestArgs := strings.Split(requestElements[apiRequestArgs], "/")
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// Check elements.
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if len(emptyElement) != 0 {
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return fmt.Errorf("unexpected API request format %q", request)
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}
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if apiElement != "api" {
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return fmt.Errorf("invalid API request format %q", request)
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}
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if _, ok := supportedApiVersions[version]; !ok {
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// Check supported versions.
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versionHandler, ok := supportedApiVersions[version]
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if !ok {
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return fmt.Errorf("unsupported API version %q", version)
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}
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switch {
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case requestType == machineApi:
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glog.V(2).Infof("Api - Machine")
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// Get the MachineInfo
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machineInfo, err := m.GetMachineInfo()
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if err != nil {
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return err
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}
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err = writeResult(machineInfo, w)
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if err != nil {
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return err
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}
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case requestType == containersApi:
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glog.V(2).Infof("Api - Container(%s)", containerName)
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// Get the query request.
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query, err := getContainerInfoRequest(r.Body)
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if err != nil {
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return err
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}
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// Get the container.
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cont, err := m.GetContainerInfo(containerName, query)
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if err != nil {
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return fmt.Errorf("failed to get container %q with error: %s", containerName, err)
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}
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// Only output the container as JSON.
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err = writeResult(cont, w)
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if err != nil {
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return err
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}
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case requestType == subcontainersApi:
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if version == version1_0 {
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return fmt.Errorf("request type of %q not supported in API version %q", requestType, version)
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}
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glog.V(2).Infof("Api - Subcontainers(%s)", containerName)
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// Get the query request.
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query, err := getContainerInfoRequest(r.Body)
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if err != nil {
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return err
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}
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// Get the subcontainers.
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containers, err := m.SubcontainersInfo(containerName, query)
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if err != nil {
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return fmt.Errorf("failed to get subcontainers for container %q with error: %s", containerName, err)
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}
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// Only output the containers as JSON.
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err = writeResult(containers, w)
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if err != nil {
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return err
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}
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case requestType == dockerApi:
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if version == version1_0 || version == version1_1 {
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return fmt.Errorf("request type of %q not supported in API version %q", requestType, version)
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}
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containerName = strings.TrimLeft(containerName, "/")
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glog.V(2).Infof("Api - Docker(%s)", containerName)
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// Get the query request.
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query, err := getContainerInfoRequest(r.Body)
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if err != nil {
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return err
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}
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var containers map[string]info.ContainerInfo
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if containerName == "" {
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// Get all Docker containers.
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containers, err = m.AllDockerContainers(query)
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if err != nil {
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return fmt.Errorf("failed to get all Docker containers with error: %v", err)
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}
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} else {
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// Get one Docker container.
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var cont info.ContainerInfo
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cont, err = m.DockerContainer(containerName, query)
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if err != nil {
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return fmt.Errorf("failed to get Docker container %q with error: %v", containerName, err)
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}
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containers = map[string]info.ContainerInfo{
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cont.Name: cont,
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}
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}
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// Only output the containers as JSON.
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err = writeResult(containers, w)
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if err != nil {
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return err
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}
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default:
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return fmt.Errorf("unknown API request type %q", requestType)
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// If no request type, list possible request types.
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if requestType == "" {
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requestTypes := versionHandler.SupportedRequestTypes()
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sort.Strings(requestTypes)
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fmt.Fprintf(w, "Supported request types: %q", strings.Join(requestTypes, ","))
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return nil
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}
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return nil
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// Trim the first empty element from the request.
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if len(requestArgs) > 0 && requestArgs[0] == "" {
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requestArgs = requestArgs[1:]
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}
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return versionHandler.HandleRequest(requestType, requestArgs, m, w, r)
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}
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func writeResult(res interface{}, w http.ResponseWriter) error {
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@ -224,3 +141,7 @@ func getContainerInfoRequest(body io.ReadCloser) (*info.ContainerInfoRequest, er
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return &query, nil
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}
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func getContainerName(request []string) string {
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return path.Join("/", strings.Join(request, "/"))
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}
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221
api/versions.go
Normal file
221
api/versions.go
Normal file
@ -0,0 +1,221 @@
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// Copyright 2015 Google Inc. All Rights Reserved.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package api
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import (
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"fmt"
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"net/http"
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"github.com/golang/glog"
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"github.com/google/cadvisor/info"
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"github.com/google/cadvisor/manager"
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)
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const (
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containersApi = "containers"
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subcontainersApi = "subcontainers"
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machineApi = "machine"
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dockerApi = "docker"
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)
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// Interface for a cAdvisor API version
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type ApiVersion interface {
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// Returns the version string.
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Version() string
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// List of supported API endpoints.
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SupportedRequestTypes() []string
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// Handles a request. The second argument is the parameters after /api/<version>/<endpoint>
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HandleRequest(requestType string, request []string, m manager.Manager, w http.ResponseWriter, r *http.Request) error
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}
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// Gets all supported API versions.
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func getApiVersions() []ApiVersion {
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v1_0 := &version1_0{}
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v1_1 := newVersion1_1(v1_0)
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v1_2 := newVersion1_2(v1_1)
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return []ApiVersion{v1_0, v1_1, v1_2}
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}
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// API v1.0
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type version1_0 struct {
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}
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func (self *version1_0) Version() string {
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return "v1.0"
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}
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func (self *version1_0) SupportedRequestTypes() []string {
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return []string{containersApi, machineApi}
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}
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func (self *version1_0) HandleRequest(requestType string, request []string, m manager.Manager, w http.ResponseWriter, r *http.Request) error {
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switch {
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case requestType == machineApi:
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glog.V(2).Infof("Api - Machine")
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// Get the MachineInfo
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machineInfo, err := m.GetMachineInfo()
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if err != nil {
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return err
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}
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err = writeResult(machineInfo, w)
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if err != nil {
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return err
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}
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case requestType == containersApi:
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containerName := getContainerName(request)
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glog.V(2).Infof("Api - Container(%s)", containerName)
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// Get the query request.
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query, err := getContainerInfoRequest(r.Body)
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if err != nil {
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return err
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}
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// Get the container.
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cont, err := m.GetContainerInfo(containerName, query)
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if err != nil {
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return fmt.Errorf("failed to get container %q with error: %s", containerName, err)
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}
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// Only output the container as JSON.
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err = writeResult(cont, w)
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if err != nil {
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return err
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}
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default:
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return fmt.Errorf("unknown request type %q", requestType)
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}
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return nil
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}
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// API v1.1
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type version1_1 struct {
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baseVersion *version1_0
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}
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// v1.1 builds on v1.0.
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func newVersion1_1(v *version1_0) *version1_1 {
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return &version1_1{
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baseVersion: v,
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}
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}
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func (self *version1_1) Version() string {
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return "v1.1"
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}
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func (self *version1_1) SupportedRequestTypes() []string {
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return append(self.baseVersion.SupportedRequestTypes(), subcontainersApi)
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}
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func (self *version1_1) HandleRequest(requestType string, request []string, m manager.Manager, w http.ResponseWriter, r *http.Request) error {
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switch {
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case requestType == subcontainersApi:
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containerName := getContainerName(request)
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glog.V(2).Infof("Api - Subcontainers(%s)", containerName)
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// Get the query request.
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query, err := getContainerInfoRequest(r.Body)
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if err != nil {
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return err
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}
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// Get the subcontainers.
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containers, err := m.SubcontainersInfo(containerName, query)
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if err != nil {
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return fmt.Errorf("failed to get subcontainers for container %q with error: %s", containerName, err)
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}
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// Only output the containers as JSON.
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err = writeResult(containers, w)
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if err != nil {
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return err
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}
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return nil
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default:
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return self.baseVersion.HandleRequest(requestType, request, m, w, r)
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}
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}
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// API v1.2
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type version1_2 struct {
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baseVersion *version1_1
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}
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// v1.2 builds on v1.1.
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func newVersion1_2(v *version1_1) *version1_2 {
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return &version1_2{
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baseVersion: v,
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}
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}
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func (self *version1_2) Version() string {
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return "v1.2"
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}
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func (self *version1_2) SupportedRequestTypes() []string {
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return append(self.baseVersion.SupportedRequestTypes(), dockerApi)
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}
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func (self *version1_2) HandleRequest(requestType string, request []string, m manager.Manager, w http.ResponseWriter, r *http.Request) error {
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switch {
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case requestType == dockerApi:
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glog.V(2).Infof("Api - Docker(%v)", request)
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// Get the query request.
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query, err := getContainerInfoRequest(r.Body)
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if err != nil {
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return err
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}
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var containers map[string]info.ContainerInfo
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switch len(request) {
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case 0:
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// Get all Docker containers.
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containers, err = m.AllDockerContainers(query)
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if err != nil {
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return fmt.Errorf("failed to get all Docker containers with error: %v", err)
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}
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case 1:
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// Get one Docker container.
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var cont info.ContainerInfo
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cont, err = m.DockerContainer(request[0], query)
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if err != nil {
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return fmt.Errorf("failed to get Docker container %q with error: %v", request[0], err)
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}
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containers = map[string]info.ContainerInfo{
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cont.Name: cont,
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}
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default:
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return fmt.Errorf("unknown request for Docker container %v", request)
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}
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// Only output the containers as JSON.
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err = writeResult(containers, w)
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if err != nil {
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return err
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}
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return nil
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default:
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return self.baseVersion.HandleRequest(requestType, request, m, w, r)
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}
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}
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