Return nice client-side message for docker logs

Signed-off-by: Alexander Morozov <lk4d4@docker.com>

api/client/logs.go

@@ -2,6 +2,7 @@ package client
 
 import (
 	"encoding/json"
+	"fmt"
 	"net/url"
 	"time"
 
@@ -11,6 +12,11 @@ import (
 	"github.com/docker/docker/pkg/timeutils"
 )
 
+var validDrivers = map[string]bool{
+	"json-file": true,
+	"journald":  true,
+}
+
 // CmdLogs fetches the logs of a given container.
 //
 // docker logs [OPTIONS] CONTAINER
@@ -36,6 +42,10 @@ func (cli *DockerCli) CmdLogs(args ...string) error {
 		return err
 	}
 
+	if !validDrivers[c.HostConfig.LogConfig.Type] {
+		return fmt.Errorf("\"logs\" command is supported only for \"json-file\" and \"journald\" logging drivers (got: %s)", c.HostConfig.LogConfig.Type)
+	}
+
 	v := url.Values{}
 	v.Set("stdout", "1")
 	v.Set("stderr", "1")

integration-cli/docker_cli_daemon_test.go

@@ -1242,10 +1242,10 @@ func (s *DockerDaemonSuite) TestDaemonLoggingDriverNoneLogsError(c *check.C) {
 	}
 	id := strings.TrimSpace(out)
 	out, err = s.d.Cmd("logs", id)
-	if err != nil {
+	if err == nil {
-		c.Fatalf("Logs request should be sent and then fail with \"none\" driver")
+		c.Fatalf("Logs should fail with 'none' driver")
 	}
-	if !strings.Contains(out, `Error running logs job: Failed to get logging factory: logger: no log driver named 'none' is registered`) {
+	if !strings.Contains(out, `"logs" command is supported only for "json-file" and "journald" logging drivers (got: none)`) {
 		c.Fatalf("There should be an error about none not being a recognized log driver, got: %s", out)
 	}
 }