package client // import "github.com/docker/docker/client" import ( "bytes" "context" "encoding/json" "fmt" "io" "io/ioutil" "net" "net/http" "net/url" "os" "strings" "github.com/docker/docker/api/types" "github.com/docker/docker/api/types/versions" "github.com/docker/docker/errdefs" "github.com/pkg/errors" ) // serverResponse is a wrapper for http API responses. type serverResponse struct { body io.ReadCloser header http.Header statusCode int reqURL *url.URL } // head sends an http request to the docker API using the method HEAD. func (cli *Client) head(ctx context.Context, path string, query url.Values, headers map[string][]string) (serverResponse, error) { return cli.sendRequest(ctx, http.MethodHead, path, query, nil, headers) } // get sends an http request to the docker API using the method GET with a specific Go context. func (cli *Client) get(ctx context.Context, path string, query url.Values, headers map[string][]string) (serverResponse, error) { return cli.sendRequest(ctx, http.MethodGet, path, query, nil, headers) } // post sends an http request to the docker API using the method POST with a specific Go context. func (cli *Client) post(ctx context.Context, path string, query url.Values, obj interface{}, headers map[string][]string) (serverResponse, error) { body, headers, err := encodeBody(obj, headers) if err != nil { return serverResponse{}, err } return cli.sendRequest(ctx, http.MethodPost, path, query, body, headers) } func (cli *Client) postRaw(ctx context.Context, path string, query url.Values, body io.Reader, headers map[string][]string) (serverResponse, error) { return cli.sendRequest(ctx, http.MethodPost, path, query, body, headers) } // putRaw sends an http request to the docker API using the method PUT. func (cli *Client) putRaw(ctx context.Context, path string, query url.Values, body io.Reader, headers map[string][]string) (serverResponse, error) { return cli.sendRequest(ctx, http.MethodPut, path, query, body, headers) } // delete sends an http request to the docker API using the method DELETE. func (cli *Client) delete(ctx context.Context, path string, query url.Values, headers map[string][]string) (serverResponse, error) { return cli.sendRequest(ctx, http.MethodDelete, path, query, nil, headers) } type headers map[string][]string func encodeBody(obj interface{}, headers headers) (io.Reader, headers, error) { if obj == nil { return nil, headers, nil } body, err := encodeData(obj) if err != nil { return nil, headers, err } if headers == nil { headers = make(map[string][]string) } headers["Content-Type"] = []string{"application/json"} return body, headers, nil } func (cli *Client) buildRequest(method, path string, body io.Reader, headers headers) (*http.Request, error) { expectedPayload := (method == http.MethodPost || method == http.MethodPut) if expectedPayload && body == nil { body = bytes.NewReader([]byte{}) } req, err := http.NewRequest(method, path, body) if err != nil { return nil, err } req = cli.addHeaders(req, headers) if cli.proto == "unix" || cli.proto == "npipe" { // For local communications, it doesn't matter what the host is. We just // need a valid and meaningful host name. (See #189) req.Host = "docker" } req.URL.Host = cli.addr req.URL.Scheme = cli.scheme if expectedPayload && req.Header.Get("Content-Type") == "" { req.Header.Set("Content-Type", "text/plain") } return req, nil } func (cli *Client) sendRequest(ctx context.Context, method, path string, query url.Values, body io.Reader, headers headers) (serverResponse, error) { req, err := cli.buildRequest(method, cli.getAPIPath(ctx, path, query), body, headers) if err != nil { return serverResponse{}, err } resp, err := cli.doRequest(ctx, req) if err != nil { return resp, errdefs.FromStatusCode(err, resp.statusCode) } err = cli.checkResponseErr(resp) return resp, errdefs.FromStatusCode(err, resp.statusCode) } func (cli *Client) doRequest(ctx context.Context, req *http.Request) (serverResponse, error) { serverResp := serverResponse{statusCode: -1, reqURL: req.URL} req = req.WithContext(ctx) resp, err := cli.client.Do(req) if err != nil { if cli.scheme != "https" && strings.Contains(err.Error(), "malformed HTTP response") { return serverResp, fmt.Errorf("%v.\n* Are you trying to connect to a TLS-enabled daemon without TLS?", err) } if cli.scheme == "https" && strings.Contains(err.Error(), "bad certificate") { return serverResp, errors.Wrap(err, "The server probably has client authentication (--tlsverify) enabled. Please check your TLS client certification settings") } // Don't decorate context sentinel errors; users may be comparing to // them directly. if errors.Is(err, context.Canceled) || errors.Is(err, context.DeadlineExceeded) { return serverResp, err } if nErr, ok := err.(*url.Error); ok { if nErr, ok := nErr.Err.(*net.OpError); ok { if os.IsPermission(nErr.Err) { return serverResp, errors.Wrapf(err, "Got permission denied while trying to connect to the Docker daemon socket at %v", cli.host) } } } if err, ok := err.(net.Error); ok { if err.Timeout() { return serverResp, ErrorConnectionFailed(cli.host) } if strings.Contains(err.Error(), "connection refused") || strings.Contains(err.Error(), "dial unix") { return serverResp, ErrorConnectionFailed(cli.host) } } // Although there's not a strongly typed error for this in go-winio, // lots of people are using the default configuration for the docker // daemon on Windows where the daemon is listening on a named pipe // `//./pipe/docker_engine, and the client must be running elevated. // Give users a clue rather than the not-overly useful message // such as `error during connect: Get http://%2F%2F.%2Fpipe%2Fdocker_engine/v1.26/info: // open //./pipe/docker_engine: The system cannot find the file specified.`. // Note we can't string compare "The system cannot find the file specified" as // this is localised - for example in French the error would be // `open //./pipe/docker_engine: Le fichier spécifié est introuvable.` if strings.Contains(err.Error(), `open //./pipe/docker_engine`) { // Checks if client is running with elevated privileges if f, elevatedErr := os.Open("\\\\.\\PHYSICALDRIVE0"); elevatedErr == nil { err = errors.Wrap(err, "In the default daemon configuration on Windows, the docker client must be run with elevated privileges to connect.") } else { f.Close() err = errors.Wrap(err, "This error may indicate that the docker daemon is not running.") } } return serverResp, errors.Wrap(err, "error during connect") } if resp != nil { serverResp.statusCode = resp.StatusCode serverResp.body = resp.Body serverResp.header = resp.Header } return serverResp, nil } func (cli *Client) checkResponseErr(serverResp serverResponse) error { if serverResp.statusCode >= 200 && serverResp.statusCode < 400 { return nil } var body []byte var err error if serverResp.body != nil { bodyMax := 1 * 1024 * 1024 // 1 MiB bodyR := &io.LimitedReader{ R: serverResp.body, N: int64(bodyMax), } body, err = ioutil.ReadAll(bodyR) if err != nil { return err } if bodyR.N == 0 { return fmt.Errorf("request returned %s with a message (> %d bytes) for API route and version %s, check if the server supports the requested API version", http.StatusText(serverResp.statusCode), bodyMax, serverResp.reqURL) } } if len(body) == 0 { return fmt.Errorf("request returned %s for API route and version %s, check if the server supports the requested API version", http.StatusText(serverResp.statusCode), serverResp.reqURL) } var ct string if serverResp.header != nil { ct = serverResp.header.Get("Content-Type") } var errorMessage string if (cli.version == "" || versions.GreaterThan(cli.version, "1.23")) && ct == "application/json" { var errorResponse types.ErrorResponse if err := json.Unmarshal(body, &errorResponse); err != nil { return errors.Wrap(err, "Error reading JSON") } errorMessage = strings.TrimSpace(errorResponse.Message) } else { errorMessage = strings.TrimSpace(string(body)) } return errors.Wrap(errors.New(errorMessage), "Error response from daemon") } func (cli *Client) addHeaders(req *http.Request, headers headers) *http.Request { // Add CLI Config's HTTP Headers BEFORE we set the Docker headers // then the user can't change OUR headers for k, v := range cli.customHTTPHeaders { if versions.LessThan(cli.version, "1.25") && k == "User-Agent" { continue } req.Header.Set(k, v) } for k, v := range headers { req.Header[k] = v } return req } func encodeData(data interface{}) (*bytes.Buffer, error) { params := bytes.NewBuffer(nil) if data != nil { if err := json.NewEncoder(params).Encode(data); err != nil { return nil, err } } return params, nil } func ensureReaderClosed(response serverResponse) { if response.body != nil { // Drain up to 512 bytes and close the body to let the Transport reuse the connection io.CopyN(ioutil.Discard, response.body, 512) response.body.Close() } }