github.com/adityamillind98/moby@v23.0.0-rc.4+incompatible/client/ping.go (about)

     1  package client // import "github.com/docker/docker/client"
     2  
     3  import (
     4  	"context"
     5  	"net/http"
     6  	"path"
     7  	"strings"
     8  
     9  	"github.com/docker/docker/api/types"
    10  	"github.com/docker/docker/api/types/swarm"
    11  	"github.com/docker/docker/errdefs"
    12  )
    13  
    14  // Ping pings the server and returns the value of the "Docker-Experimental",
    15  // "Builder-Version", "OS-Type" & "API-Version" headers. It attempts to use
    16  // a HEAD request on the endpoint, but falls back to GET if HEAD is not supported
    17  // by the daemon.
    18  func (cli *Client) Ping(ctx context.Context) (types.Ping, error) {
    19  	var ping types.Ping
    20  
    21  	// Using cli.buildRequest() + cli.doRequest() instead of cli.sendRequest()
    22  	// because ping requests are used during API version negotiation, so we want
    23  	// to hit the non-versioned /_ping endpoint, not /v1.xx/_ping
    24  	req, err := cli.buildRequest(http.MethodHead, path.Join(cli.basePath, "/_ping"), nil, nil)
    25  	if err != nil {
    26  		return ping, err
    27  	}
    28  	serverResp, err := cli.doRequest(ctx, req)
    29  	if err == nil {
    30  		defer ensureReaderClosed(serverResp)
    31  		switch serverResp.statusCode {
    32  		case http.StatusOK, http.StatusInternalServerError:
    33  			// Server handled the request, so parse the response
    34  			return parsePingResponse(cli, serverResp)
    35  		}
    36  	} else if IsErrConnectionFailed(err) {
    37  		return ping, err
    38  	}
    39  
    40  	req, err = cli.buildRequest(http.MethodGet, path.Join(cli.basePath, "/_ping"), nil, nil)
    41  	if err != nil {
    42  		return ping, err
    43  	}
    44  	serverResp, err = cli.doRequest(ctx, req)
    45  	defer ensureReaderClosed(serverResp)
    46  	if err != nil {
    47  		return ping, err
    48  	}
    49  	return parsePingResponse(cli, serverResp)
    50  }
    51  
    52  func parsePingResponse(cli *Client, resp serverResponse) (types.Ping, error) {
    53  	var ping types.Ping
    54  	if resp.header == nil {
    55  		err := cli.checkResponseErr(resp)
    56  		return ping, errdefs.FromStatusCode(err, resp.statusCode)
    57  	}
    58  	ping.APIVersion = resp.header.Get("API-Version")
    59  	ping.OSType = resp.header.Get("OSType")
    60  	if resp.header.Get("Docker-Experimental") == "true" {
    61  		ping.Experimental = true
    62  	}
    63  	if bv := resp.header.Get("Builder-Version"); bv != "" {
    64  		ping.BuilderVersion = types.BuilderVersion(bv)
    65  	}
    66  	if si := resp.header.Get("Swarm"); si != "" {
    67  		parts := strings.SplitN(si, "/", 2)
    68  		ping.SwarmStatus = &swarm.Status{
    69  			NodeState:        swarm.LocalNodeState(parts[0]),
    70  			ControlAvailable: len(parts) == 2 && parts[1] == "manager",
    71  		}
    72  	}
    73  	err := cli.checkResponseErr(resp)
    74  	return ping, errdefs.FromStatusCode(err, resp.statusCode)
    75  }