Files
moby/internal/test/request/request.go
Sebastiaan van Stijn 7e7e100be0 Add HEAD support for /_ping endpoint
Monitoring systems and load balancers are usually configured to use HEAD
requests for health monitoring. The /_ping endpoint currently does not
support this type of request, which means that those systems have fallback
to GET requests.

This patch adds support for HEAD requests on the /_ping endpoint.

Although optional, this patch also returns `Content-Type` and `Content-Length`
headers in case of a HEAD request; Refering to RFC 7231, section 4.3.2:

    The HEAD method is identical to GET except that the server MUST NOT
    send a message body in the response (i.e., the response terminates at
    the end of the header section).  The server SHOULD send the same
    header fields in response to a HEAD request as it would have sent if
    the request had been a GET, except that the payload header fields
    (Section 3.3) MAY be omitted.  This method can be used for obtaining
    metadata about the selected representation without transferring the
    representation data and is often used for testing hypertext links for
    validity, accessibility, and recent modification.

    A payload within a HEAD request message has no defined semantics;
    sending a payload body on a HEAD request might cause some existing
    implementations to reject the request.

    The response to a HEAD request is cacheable; a cache MAY use it to
    satisfy subsequent HEAD requests unless otherwise indicated by the
    Cache-Control header field (Section 5.2 of [RFC7234]).  A HEAD
    response might also have an effect on previously cached responses to
    GET; see Section 4.3.5 of [RFC7234].

With this patch applied, either `GET` or `HEAD` requests work; the only
difference is that the body is empty in case of a `HEAD` request;

    curl -i --unix-socket /var/run/docker.sock http://localhost/_ping
    HTTP/1.1 200 OK
    Api-Version: 1.40
    Cache-Control: no-cache, no-store, must-revalidate
    Docker-Experimental: false
    Ostype: linux
    Pragma: no-cache
    Server: Docker/dev (linux)
    Date: Mon, 14 Jan 2019 12:35:16 GMT
    Content-Length: 2
    Content-Type: text/plain; charset=utf-8

    OK

    curl --head -i --unix-socket /var/run/docker.sock http://localhost/_ping
    HTTP/1.1 200 OK
    Api-Version: 1.40
    Cache-Control: no-cache, no-store, must-revalidate
    Content-Length: 0
    Content-Type: text/plain; charset=utf-8
    Docker-Experimental: false
    Ostype: linux
    Pragma: no-cache
    Server: Docker/dev (linux)
    Date: Mon, 14 Jan 2019 12:34:15 GMT

The client is also updated to use `HEAD` by default, but fallback to `GET`
if the daemon does not support this method.

Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
2019-01-31 18:18:24 +01:00

224 lines
6.8 KiB
Go

package request // import "github.com/docker/docker/internal/test/request"
import (
"context"
"crypto/tls"
"fmt"
"io"
"io/ioutil"
"net"
"net/http"
"net/url"
"os"
"path/filepath"
"time"
"github.com/docker/docker/client"
"github.com/docker/docker/internal/test"
"github.com/docker/docker/internal/test/environment"
"github.com/docker/docker/opts"
"github.com/docker/docker/pkg/ioutils"
"github.com/docker/go-connections/sockets"
"github.com/docker/go-connections/tlsconfig"
"github.com/pkg/errors"
"gotest.tools/assert"
)
// NewAPIClient returns a docker API client configured from environment variables
func NewAPIClient(t assert.TestingT, ops ...func(*client.Client) error) client.APIClient {
if ht, ok := t.(test.HelperT); ok {
ht.Helper()
}
ops = append([]func(*client.Client) error{client.FromEnv}, ops...)
clt, err := client.NewClientWithOpts(ops...)
assert.NilError(t, err)
return clt
}
// DaemonTime provides the current time on the daemon host
func DaemonTime(ctx context.Context, t assert.TestingT, client client.APIClient, testEnv *environment.Execution) time.Time {
if ht, ok := t.(test.HelperT); ok {
ht.Helper()
}
if testEnv.IsLocalDaemon() {
return time.Now()
}
info, err := client.Info(ctx)
assert.NilError(t, err)
dt, err := time.Parse(time.RFC3339Nano, info.SystemTime)
assert.NilError(t, err, "invalid time format in GET /info response")
return dt
}
// DaemonUnixTime returns the current time on the daemon host with nanoseconds precision.
// It return the time formatted how the client sends timestamps to the server.
func DaemonUnixTime(ctx context.Context, t assert.TestingT, client client.APIClient, testEnv *environment.Execution) string {
if ht, ok := t.(test.HelperT); ok {
ht.Helper()
}
dt := DaemonTime(ctx, t, client, testEnv)
return fmt.Sprintf("%d.%09d", dt.Unix(), int64(dt.Nanosecond()))
}
// Post creates and execute a POST request on the specified host and endpoint, with the specified request modifiers
func Post(endpoint string, modifiers ...func(*Options)) (*http.Response, io.ReadCloser, error) {
return Do(endpoint, append(modifiers, Method(http.MethodPost))...)
}
// Delete creates and execute a DELETE request on the specified host and endpoint, with the specified request modifiers
func Delete(endpoint string, modifiers ...func(*Options)) (*http.Response, io.ReadCloser, error) {
return Do(endpoint, append(modifiers, Method(http.MethodDelete))...)
}
// Get creates and execute a GET request on the specified host and endpoint, with the specified request modifiers
func Get(endpoint string, modifiers ...func(*Options)) (*http.Response, io.ReadCloser, error) {
return Do(endpoint, modifiers...)
}
// Head creates and execute a HEAD request on the specified host and endpoint, with the specified request modifiers
func Head(endpoint string, modifiers ...func(*Options)) (*http.Response, io.ReadCloser, error) {
return Do(endpoint, append(modifiers, Method(http.MethodHead))...)
}
// Do creates and execute a request on the specified endpoint, with the specified request modifiers
func Do(endpoint string, modifiers ...func(*Options)) (*http.Response, io.ReadCloser, error) {
opts := &Options{
host: DaemonHost(),
}
for _, mod := range modifiers {
mod(opts)
}
req, err := newRequest(endpoint, opts)
if err != nil {
return nil, nil, err
}
client, err := newHTTPClient(opts.host)
if err != nil {
return nil, nil, err
}
resp, err := client.Do(req)
var body io.ReadCloser
if resp != nil {
body = ioutils.NewReadCloserWrapper(resp.Body, func() error {
defer resp.Body.Close()
return nil
})
}
return resp, body, err
}
// ReadBody read the specified ReadCloser content and returns it
func ReadBody(b io.ReadCloser) ([]byte, error) {
defer b.Close()
return ioutil.ReadAll(b)
}
// newRequest creates a new http Request to the specified host and endpoint, with the specified request modifiers
func newRequest(endpoint string, opts *Options) (*http.Request, error) {
hostURL, err := client.ParseHostURL(opts.host)
if err != nil {
return nil, errors.Wrapf(err, "failed parsing url %q", opts.host)
}
req, err := http.NewRequest("GET", endpoint, nil)
if err != nil {
return nil, errors.Wrap(err, "failed to create request")
}
if os.Getenv("DOCKER_TLS_VERIFY") != "" {
req.URL.Scheme = "https"
} else {
req.URL.Scheme = "http"
}
req.URL.Host = hostURL.Host
for _, config := range opts.requestModifiers {
if err := config(req); err != nil {
return nil, err
}
}
return req, nil
}
// newHTTPClient creates an http client for the specific host
// TODO: Share more code with client.defaultHTTPClient
func newHTTPClient(host string) (*http.Client, error) {
// FIXME(vdemeester) 10*time.Second timeout of SockRequest… ?
hostURL, err := client.ParseHostURL(host)
if err != nil {
return nil, err
}
transport := new(http.Transport)
if hostURL.Scheme == "tcp" && os.Getenv("DOCKER_TLS_VERIFY") != "" {
// Setup the socket TLS configuration.
tlsConfig, err := getTLSConfig()
if err != nil {
return nil, err
}
transport = &http.Transport{TLSClientConfig: tlsConfig}
}
transport.DisableKeepAlives = true
err = sockets.ConfigureTransport(transport, hostURL.Scheme, hostURL.Host)
return &http.Client{Transport: transport}, err
}
func getTLSConfig() (*tls.Config, error) {
dockerCertPath := os.Getenv("DOCKER_CERT_PATH")
if dockerCertPath == "" {
return nil, errors.New("DOCKER_TLS_VERIFY specified, but no DOCKER_CERT_PATH environment variable")
}
option := &tlsconfig.Options{
CAFile: filepath.Join(dockerCertPath, "ca.pem"),
CertFile: filepath.Join(dockerCertPath, "cert.pem"),
KeyFile: filepath.Join(dockerCertPath, "key.pem"),
}
tlsConfig, err := tlsconfig.Client(*option)
if err != nil {
return nil, err
}
return tlsConfig, nil
}
// DaemonHost return the daemon host string for this test execution
func DaemonHost() string {
daemonURLStr := "unix://" + opts.DefaultUnixSocket
if daemonHostVar := os.Getenv("DOCKER_HOST"); daemonHostVar != "" {
daemonURLStr = daemonHostVar
}
return daemonURLStr
}
// SockConn opens a connection on the specified socket
func SockConn(timeout time.Duration, daemon string) (net.Conn, error) {
daemonURL, err := url.Parse(daemon)
if err != nil {
return nil, errors.Wrapf(err, "could not parse url %q", daemon)
}
var c net.Conn
switch daemonURL.Scheme {
case "npipe":
return npipeDial(daemonURL.Path, timeout)
case "unix":
return net.DialTimeout(daemonURL.Scheme, daemonURL.Path, timeout)
case "tcp":
if os.Getenv("DOCKER_TLS_VERIFY") != "" {
// Setup the socket TLS configuration.
tlsConfig, err := getTLSConfig()
if err != nil {
return nil, err
}
dialer := &net.Dialer{Timeout: timeout}
return tls.DialWithDialer(dialer, daemonURL.Scheme, daemonURL.Host, tlsConfig)
}
return net.DialTimeout(daemonURL.Scheme, daemonURL.Host, timeout)
default:
return c, errors.Errorf("unknown scheme %v (%s)", daemonURL.Scheme, daemon)
}
}