diff --git a/client/client.go b/client/client.go index fa98e76135..9b0ba64666 100644 --- a/client/client.go +++ b/client/client.go @@ -86,9 +86,6 @@ import ( // [Go stdlib]: https://github.com/golang/go/blob/6244b1946bc2101b01955468f1be502dbadd6807/src/net/http/transport.go#L558-L569 const DummyHost = "api.moby.localhost" -// ErrRedirect is the error returned by checkRedirect when the request is non-GET. -var ErrRedirect = errors.New("unexpected redirect in response") - // Client is the API client that performs all operations // against a docker server. type Client struct { @@ -111,7 +108,7 @@ type Client struct { // header variables. When set to an empty string, the User-Agent header // is removed, and no header is sent. userAgent *string - // custom http headers configured by users. + // custom HTTP headers configured by users. customHTTPHeaders map[string]string // manualOverride is set to true when the version was set by users. manualOverride bool @@ -126,20 +123,25 @@ type Client struct { negotiated bool } -// CheckRedirect specifies the policy for dealing with redirect responses: -// If the request is non-GET return ErrRedirect, otherwise use the last response. +// ErrRedirect is the error returned by checkRedirect when the request is non-GET. +var ErrRedirect = errors.New("unexpected redirect in response") + +// CheckRedirect specifies the policy for dealing with redirect responses. It +// can be set on [http.Client.CheckRedirect] to prevent HTTP redirects for +// non-GET requests. It returns an [ErrRedirect] for non-GET request, otherwise +// returns a [http.ErrUseLastResponse], which is special-cased by http.Client +// to use the last response. // -// Go 1.8 changes behavior for HTTP redirects (specifically 301, 307, and 308) -// in the client. The Docker client (and by extension docker API client) can be -// made to send a request like POST /containers//start where what would normally -// be in the name section of the URL is empty. This triggers an HTTP 301 from -// the daemon. +// Go 1.8 changed behavior for HTTP redirects (specifically 301, 307, and 308) +// in the client. The client (and by extension API client) can be made to send +// a request like "POST /containers//start" where what would normally be in the +// name section of the URL is empty. This triggers an HTTP 301 from the daemon. // -// In go 1.8 this 301 will be converted to a GET request, and ends up getting +// In go 1.8 this 301 is converted to a GET request, and ends up getting // a 404 from the daemon. This behavior change manifests in the client in that // before, the 301 was not followed and the client did not generate an error, -// but now results in a message like Error response from daemon: page not found. -func CheckRedirect(req *http.Request, via []*http.Request) error { +// but now results in a message like "Error response from daemon: page not found". +func CheckRedirect(_ *http.Request, via []*http.Request) error { if via[0].Method == http.MethodGet { return http.ErrUseLastResponse } @@ -150,11 +152,11 @@ func CheckRedirect(req *http.Request, via []*http.Request) error { // default API host and version. It also initializes the custom HTTP headers to // add to each request. // -// It takes an optional list of Opt functional arguments, which are applied in +// It takes an optional list of [Opt] functional arguments, which are applied in // the order they're provided, which allows modifying the defaults when creating // the client. For example, the following initializes a client that configures -// itself with values from environment variables (client.FromEnv), and has -// automatic API version negotiation enabled (client.WithAPIVersionNegotiation()). +// itself with values from environment variables ([FromEnv]), and has automatic +// API version negotiation enabled ([WithAPIVersionNegotiation]). // // cli, err := client.NewClientWithOpts( // client.FromEnv, @@ -221,7 +223,7 @@ func (cli *Client) Close() error { return nil } -// getAPIPath returns the versioned request path to call the api. +// getAPIPath returns the versioned request path to call the API. // It appends the query parameters to the path if they are not empty. func (cli *Client) getAPIPath(ctx context.Context, p string, query url.Values) string { var apiPath string @@ -249,8 +251,8 @@ func (cli *Client) ClientVersion() string { // by the client, it uses the client's maximum version. // // If a manual override is in place, either through the "DOCKER_API_VERSION" -// (EnvOverrideAPIVersion) environment variable, or if the client is initialized -// with a fixed version (WithVersion(xx)), no negotiation is performed. +// ([EnvOverrideAPIVersion]) environment variable, or if the client is initialized +// with a fixed version ([WithVersion]), no negotiation is performed. // // If the API server's ping response does not contain an API version, or if the // client did not get a successful ping response, it assumes it is connected with @@ -270,8 +272,8 @@ func (cli *Client) NegotiateAPIVersion(ctx context.Context) { // version. // // If a manual override is in place, either through the "DOCKER_API_VERSION" -// (EnvOverrideAPIVersion) environment variable, or if the client is initialized -// with a fixed version (WithVersion(xx)), no negotiation is performed. +// ([EnvOverrideAPIVersion]) environment variable, or if the client is initialized +// with a fixed version ([WithVersion]), no negotiation is performed. // // If the API server's ping response does not contain an API version, we assume // we are connected with an old daemon without API version negotiation support, @@ -344,9 +346,10 @@ func ParseHostURL(host string) (*url.URL, error) { } // Dialer returns a dialer for a raw stream connection, with an HTTP/1.1 header, -// that can be used for proxying the daemon connection. +// that can be used for proxying the daemon connection. It is used by +// ["docker dial-stdio"]. // -// Used by `docker dial-stdio` (docker/cli#889). +// ["docker dial-stdio"]: https://github.com/docker/cli/pull/1014 func (cli *Client) Dialer() func(context.Context) (net.Conn, error) { return func(ctx context.Context) (net.Conn, error) { if transport, ok := cli.client.Transport.(*http.Transport); ok { diff --git a/client/options.go b/client/options.go index 10c9cbecfa..d258d0cfc0 100644 --- a/client/options.go +++ b/client/options.go @@ -13,23 +13,22 @@ import ( "github.com/pkg/errors" ) -// Opt is a configuration option to initialize a client +// Opt is a configuration option to initialize a [Client]. type Opt func(*Client) error -// FromEnv configures the client with values from environment variables. +// FromEnv configures the client with values from environment variables. It +// is the equivalent of using the [WithTLSClientConfigFromEnv], [WithHostFromEnv], +// and [WithVersionFromEnv] options. // // FromEnv uses the following environment variables: // -// DOCKER_HOST (EnvOverrideHost) to set the URL to the docker server. -// -// DOCKER_API_VERSION (EnvOverrideAPIVersion) to set the version of the API to -// use, leave empty for latest. -// -// DOCKER_CERT_PATH (EnvOverrideCertPath) to specify the directory from which to -// load the TLS certificates (ca.pem, cert.pem, key.pem). -// -// DOCKER_TLS_VERIFY (EnvTLSVerify) to enable or disable TLS verification (off by -// default). +// - DOCKER_HOST ([EnvOverrideHost]) to set the URL to the docker server. +// - DOCKER_API_VERSION ([EnvOverrideAPIVersion]) to set the version of the +// API to use, leave empty for latest. +// - DOCKER_CERT_PATH ([EnvOverrideCertPath]) to specify the directory from +// which to load the TLS certificates ("ca.pem", "cert.pem", "key.pem'). +// - DOCKER_TLS_VERIFY ([EnvTLSVerify]) to enable or disable TLS verification +// (off by default). func FromEnv(c *Client) error { ops := []Opt{ WithTLSClientConfigFromEnv(), @@ -45,7 +44,8 @@ func FromEnv(c *Client) error { } // WithDialContext applies the dialer to the client transport. This can be -// used to set the Timeout and KeepAlive settings of the client. +// used to set the Timeout and KeepAlive settings of the client. It returns +// an error if the client does not have a [http.Transport] configured. func WithDialContext(dialContext func(ctx context.Context, network, addr string) (net.Conn, error)) Opt { return func(c *Client) error { if transport, ok := c.client.Transport.(*http.Transport); ok { @@ -75,7 +75,7 @@ func WithHost(host string) Opt { } // WithHostFromEnv overrides the client host with the host specified in the -// DOCKER_HOST (EnvOverrideHost) environment variable. If DOCKER_HOST is not set, +// DOCKER_HOST ([EnvOverrideHost]) environment variable. If DOCKER_HOST is not set, // or set to an empty value, the host is not modified. func WithHostFromEnv() Opt { return func(c *Client) error { @@ -86,7 +86,7 @@ func WithHostFromEnv() Opt { } } -// WithHTTPClient overrides the client http client with the specified one +// WithHTTPClient overrides the client's HTTP client with the specified one. func WithHTTPClient(client *http.Client) Opt { return func(c *Client) error { if client != nil { @@ -96,7 +96,7 @@ func WithHTTPClient(client *http.Client) Opt { } } -// WithTimeout configures the time limit for requests made by the HTTP client +// WithTimeout configures the time limit for requests made by the HTTP client. func WithTimeout(timeout time.Duration) Opt { return func(c *Client) error { c.client.Timeout = timeout @@ -114,7 +114,9 @@ func WithUserAgent(ua string) Opt { } } -// WithHTTPHeaders overrides the client default http headers +// WithHTTPHeaders appends custom HTTP headers to the client's default headers. +// It does not allow for built-in headers (such as "User-Agent", if set) to +// be overridden. Also see [WithUserAgent]. func WithHTTPHeaders(headers map[string]string) Opt { return func(c *Client) error { c.customHTTPHeaders = headers @@ -122,7 +124,7 @@ func WithHTTPHeaders(headers map[string]string) Opt { } } -// WithScheme overrides the client scheme with the specified one +// WithScheme overrides the client scheme with the specified one. func WithScheme(scheme string) Opt { return func(c *Client) error { c.scheme = scheme @@ -130,7 +132,7 @@ func WithScheme(scheme string) Opt { } } -// WithTLSClientConfig applies a tls config to the client transport. +// WithTLSClientConfig applies a TLS config to the client transport. func WithTLSClientConfig(cacertPath, certPath, keyPath string) Opt { return func(c *Client) error { opts := tlsconfig.Options{ @@ -152,16 +154,16 @@ func WithTLSClientConfig(cacertPath, certPath, keyPath string) Opt { } // WithTLSClientConfigFromEnv configures the client's TLS settings with the -// settings in the DOCKER_CERT_PATH and DOCKER_TLS_VERIFY environment variables. -// If DOCKER_CERT_PATH is not set or empty, TLS configuration is not modified. +// settings in the DOCKER_CERT_PATH ([EnvOverrideCertPath]) and DOCKER_TLS_VERIFY +// ([EnvTLSVerify]) environment variables. If DOCKER_CERT_PATH is not set or empty, +// TLS configuration is not modified. // // WithTLSClientConfigFromEnv uses the following environment variables: // -// DOCKER_CERT_PATH (EnvOverrideCertPath) to specify the directory from which to -// load the TLS certificates (ca.pem, cert.pem, key.pem). -// -// DOCKER_TLS_VERIFY (EnvTLSVerify) to enable or disable TLS verification (off by -// default). +// - DOCKER_CERT_PATH ([EnvOverrideCertPath]) to specify the directory from +// which to load the TLS certificates ("ca.pem", "cert.pem", "key.pem"). +// - DOCKER_TLS_VERIFY ([EnvTLSVerify]) to enable or disable TLS verification +// (off by default). func WithTLSClientConfigFromEnv() Opt { return func(c *Client) error { dockerCertPath := os.Getenv(EnvOverrideCertPath) @@ -188,7 +190,8 @@ func WithTLSClientConfigFromEnv() Opt { } // WithVersion overrides the client version with the specified one. If an empty -// version is specified, the value will be ignored to allow version negotiation. +// version is provided, the value is ignored to allow version negotiation +// (see [WithAPIVersionNegotiation]). func WithVersion(version string) Opt { return func(c *Client) error { if version != "" { @@ -200,8 +203,9 @@ func WithVersion(version string) Opt { } // WithVersionFromEnv overrides the client version with the version specified in -// the DOCKER_API_VERSION environment variable. If DOCKER_API_VERSION is not set, -// the version is not modified. +// the DOCKER_API_VERSION ([EnvOverrideAPIVersion]) environment variable. +// If DOCKER_API_VERSION is not set, or set to an empty value, the version +// is not modified. func WithVersionFromEnv() Opt { return func(c *Client) error { return WithVersion(os.Getenv(EnvOverrideAPIVersion))(c) @@ -211,7 +215,7 @@ func WithVersionFromEnv() Opt { // WithAPIVersionNegotiation enables automatic API version negotiation for the client. // With this option enabled, the client automatically negotiates the API version // to use when making requests. API version negotiation is performed on the first -// request; subsequent requests will not re-negotiate. +// request; subsequent requests do not re-negotiate. func WithAPIVersionNegotiation() Opt { return func(c *Client) error { c.negotiateVersion = true