moby/client/ping.go
Sebastiaan van Stijn 38e6d474af
client: return rich / errdefs errors
this patch makes the client return errors matching
the errdefs interface.

Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
2019-03-16 00:40:39 +01:00

64 lines
2 KiB
Go

package client // import "github.com/docker/docker/client"
import (
"context"
"net/http"
"path"
"github.com/docker/docker/api/server/httputils"
"github.com/docker/docker/api/types"
)
// 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.
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("HEAD", path.Join(cli.basePath, "/_ping"), nil, nil)
if err != nil {
return ping, err
}
serverResp, err := cli.doRequest(ctx, req)
if err == nil {
defer ensureReaderClosed(serverResp)
switch serverResp.statusCode {
case http.StatusOK, http.StatusInternalServerError:
// Server handled the request, so parse the response
return parsePingResponse(cli, serverResp)
}
}
req, err = cli.buildRequest("GET", path.Join(cli.basePath, "/_ping"), nil, nil)
if err != nil {
return ping, err
}
serverResp, err = cli.doRequest(ctx, req)
if err != nil {
return ping, err
}
defer ensureReaderClosed(serverResp)
return parsePingResponse(cli, serverResp)
}
func parsePingResponse(cli *Client, resp serverResponse) (types.Ping, error) {
var ping types.Ping
if resp.header == nil {
err := cli.checkResponseErr(resp)
return ping, httputils.FromStatusCode(err, resp.statusCode)
}
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 = types.BuilderVersion(bv)
}
err := cli.checkResponseErr(resp)
return ping, httputils.FromStatusCode(err, resp.statusCode)
}