Add API version to `docker version`

Docker-DCO-1.1-Signed-off-by: Guillaume J. Charmes <guillaume@charmes.net> (github: creack)

api/client/commands.go

@@ -357,6 +357,7 @@ func (cli *DockerCli) CmdVersion(args ...string) error {
 	if dockerversion.VERSION != "" {
 		fmt.Fprintf(cli.out, "Client version: %s\n", dockerversion.VERSION)
 	}
+	fmt.Fprintf(cli.out, "Client API version: %s\n", api.APIVERSION)
 	fmt.Fprintf(cli.out, "Go version (client): %s\n", goruntime.Version())
 	if dockerversion.GITCOMMIT != "" {
 		fmt.Fprintf(cli.out, "Git commit (client): %s\n", dockerversion.GITCOMMIT)
@@ -379,6 +380,9 @@ func (cli *DockerCli) CmdVersion(args ...string) error {
 	}
 	out.Close()
 	fmt.Fprintf(cli.out, "Server version: %s\n", remoteVersion.Get("Version"))
+	if apiVersion := remoteVersion.Get("ApiVersion"); apiVersion != "" {
+		fmt.Fprintf(cli.out, "Server API version: %s\n", apiVersion)
+	}
 	fmt.Fprintf(cli.out, "Git commit (server): %s\n", remoteVersion.Get("GitCommit"))
 	fmt.Fprintf(cli.out, "Go version (server): %s\n", remoteVersion.Get("GoVersion"))
 	release := utils.GetReleaseVersion()

integration-cli/docker_cli_version_test.go

@@ -17,7 +17,17 @@ func TestVersionEnsureSucceeds(t *testing.T) {
 		t.Fatal("failed to execute docker version")
 	}
 
-	stringsToCheck := []string{"Client version:", "Go version (client):", "Git commit (client):", "Server version:", "Git commit (server):", "Go version (server):", "Last stable version:"}
+	stringsToCheck := []string{
+		"Client version:",
+		"Client API version:",
+		"Go version (client):",
+		"Git commit (client):",
+		"Server version:",
+		"Server API version:",
+		"Git commit (server):",
+		"Go version (server):",
+		"Last stable version:",
+	}
 
 	for _, linePrefix := range stringsToCheck {
 		if !strings.Contains(out, linePrefix) {

server/server.go

@@ -3,6 +3,7 @@ package server
 import (
 	"encoding/json"
 	"fmt"
+	"github.com/dotcloud/docker/api"
 	"github.com/dotcloud/docker/archive"
 	"github.com/dotcloud/docker/daemonconfig"
 	"github.com/dotcloud/docker/dockerversion"
@@ -823,6 +824,7 @@ func (srv *Server) DockerInfo(job *engine.Job) engine.Status {
 func (srv *Server) DockerVersion(job *engine.Job) engine.Status {
 	v := &engine.Env{}
 	v.Set("Version", dockerversion.VERSION)
+	v.Set("ApiVersion", api.APIVERSION)
 	v.Set("GitCommit", dockerversion.GITCOMMIT)
 	v.Set("GoVersion", goruntime.Version())
 	v.Set("Os", goruntime.GOOS)