moby/client/ping_test.go

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package client // import "github.com/docker/docker/client"
import (
"context"
"errors"
"io/ioutil"
"net/http"
"strings"
"testing"
"gotest.tools/assert"
is "gotest.tools/assert/cmp"
)
// TestPingFail tests that when a server sends a non-successful response that we
// can still grab API details, when set.
// Some of this is just exercising the code paths to make sure there are no
// panics.
func TestPingFail(t *testing.T) {
var withHeader bool
client := &Client{
client: newMockClient(func(req *http.Request) (*http.Response, error) {
resp := &http.Response{StatusCode: http.StatusInternalServerError}
if withHeader {
resp.Header = http.Header{}
resp.Header.Set("API-Version", "awesome")
resp.Header.Set("Docker-Experimental", "true")
}
resp.Body = ioutil.NopCloser(strings.NewReader("some error with the server"))
return resp, nil
}),
}
ping, err := client.Ping(context.Background())
assert.ErrorContains(t, err, "some error with the server")
assert.Check(t, is.Equal(false, ping.Experimental))
assert.Check(t, is.Equal("", ping.APIVersion))
withHeader = true
ping2, err := client.Ping(context.Background())
assert.ErrorContains(t, err, "some error with the server")
assert.Check(t, is.Equal(true, ping2.Experimental))
assert.Check(t, is.Equal("awesome", ping2.APIVersion))
}
// TestPingWithError tests the case where there is a protocol error in the ping.
// This test is mostly just testing that there are no panics in this code path.
func TestPingWithError(t *testing.T) {
client := &Client{
client: newMockClient(func(req *http.Request) (*http.Response, error) {
resp := &http.Response{StatusCode: http.StatusInternalServerError}
resp.Header = http.Header{}
resp.Header.Set("API-Version", "awesome")
resp.Header.Set("Docker-Experimental", "true")
resp.Body = ioutil.NopCloser(strings.NewReader("some error with the server"))
return resp, errors.New("some error")
}),
}
ping, err := client.Ping(context.Background())
assert.ErrorContains(t, err, "some error")
assert.Check(t, is.Equal(false, ping.Experimental))
assert.Check(t, is.Equal("", ping.APIVersion))
}
// TestPingSuccess tests that we are able to get the expected API headers/ping
// details on success.
func TestPingSuccess(t *testing.T) {
client := &Client{
client: newMockClient(func(req *http.Request) (*http.Response, error) {
resp := &http.Response{StatusCode: http.StatusOK}
resp.Header = http.Header{}
resp.Header.Set("API-Version", "awesome")
resp.Header.Set("Docker-Experimental", "true")
resp.Body = ioutil.NopCloser(strings.NewReader("OK"))
return resp, nil
}),
}
ping, err := client.Ping(context.Background())
assert.NilError(t, err)
assert.Check(t, is.Equal(true, ping.Experimental))
assert.Check(t, is.Equal("awesome", ping.APIVersion))
}
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>
2019-01-14 17:08:49 +00:00
// TestPingHeadFallback tests that the client falls back to GET if HEAD fails.
func TestPingHeadFallback(t *testing.T) {
tests := []struct {
status int
expected string
}{
{
status: http.StatusOK,
expected: "HEAD",
},
{
status: http.StatusInternalServerError,
expected: "HEAD",
},
{
status: http.StatusNotFound,
expected: "HEAD, GET",
},
{
status: http.StatusMethodNotAllowed,
expected: "HEAD, GET",
},
}
for _, tc := range tests {
tc := tc
t.Run(http.StatusText(tc.status), func(t *testing.T) {
var reqs []string
client := &Client{
client: newMockClient(func(req *http.Request) (*http.Response, error) {
reqs = append(reqs, req.Method)
resp := &http.Response{StatusCode: http.StatusOK}
if req.Method == http.MethodHead {
resp.StatusCode = tc.status
}
resp.Header = http.Header{}
resp.Header.Add("API-Version", strings.Join(reqs, ", "))
return resp, nil
}),
}
ping, _ := client.Ping(context.Background())
assert.Check(t, is.Equal(ping.APIVersion, tc.expected))
})
}
}