1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
|
package client
import (
"context"
"net/http"
"path"
"strings"
"github.com/docker/docker/api/types"
"github.com/docker/docker/api/types/build"
"github.com/docker/docker/api/types/swarm"
)
// Ping pings the server and returns the value of the "Docker-Experimental",
// "Builder-Version", "OS-Type" & "API-Version" headers. It attempts to use
// a HEAD request on the endpoint, but falls back to GET if HEAD is not supported
// by the daemon. It ignores internal server errors returned by the API, which
// may be returned if the daemon is in an unhealthy state, but returns errors
// for other non-success status codes, failing to connect to the API, or failing
// to parse the API response.
func (cli *Client) Ping(ctx context.Context) (types.Ping, error) {
var ping types.Ping
// Using cli.buildRequest() + cli.doRequest() instead of cli.sendRequest()
// because ping requests are used during API version negotiation, so we want
// to hit the non-versioned /_ping endpoint, not /v1.xx/_ping
req, err := cli.buildRequest(ctx, http.MethodHead, path.Join(cli.basePath, "/_ping"), nil, nil)
if err != nil {
return ping, err
}
resp, err := cli.doRequest(req)
if err != nil {
if IsErrConnectionFailed(err) {
return ping, err
}
// We managed to connect, but got some error; continue and try GET request.
} else {
defer ensureReaderClosed(resp)
switch resp.StatusCode {
case http.StatusOK, http.StatusInternalServerError:
// Server handled the request, so parse the response
return parsePingResponse(cli, resp)
}
}
// HEAD failed; fallback to GET.
req.Method = http.MethodGet
resp, err = cli.doRequest(req)
defer ensureReaderClosed(resp)
if err != nil {
return ping, err
}
return parsePingResponse(cli, resp)
}
func parsePingResponse(cli *Client, resp *http.Response) (types.Ping, error) {
if resp == nil {
return types.Ping{}, nil
}
var ping types.Ping
if resp.Header == nil {
return ping, cli.checkResponseErr(resp)
}
ping.APIVersion = resp.Header.Get("Api-Version")
ping.OSType = resp.Header.Get("Ostype")
if resp.Header.Get("Docker-Experimental") == "true" {
ping.Experimental = true
}
if bv := resp.Header.Get("Builder-Version"); bv != "" {
ping.BuilderVersion = build.BuilderVersion(bv)
}
if si := resp.Header.Get("Swarm"); si != "" {
state, role, _ := strings.Cut(si, "/")
ping.SwarmStatus = &swarm.Status{
NodeState: swarm.LocalNodeState(state),
ControlAvailable: role == "manager",
}
}
return ping, cli.checkResponseErr(resp)
}
|
