api: generalize version information to any platform component

This change adds a Platform struct with a Name field and a general
Components field to the Version API type. This will allow API
consumers to show version information for the whole platform and
it will allow API providers to set the versions for the various
components of the platform.

All changes here are backwards compatible.

Signed-off-by: Tibor Vass <tibor@docker.com>
Upstream-commit: 9152e63290e4a4e586b811cce39082efc649b912
Component: engine

components/engine/api/server/router/system/system_routes.go

@@ -6,7 +6,6 @@ import (
 	"net/http"
 	"time"
 
-	"github.com/docker/docker/api"
 	"github.com/docker/docker/api/server/httputils"
 	"github.com/docker/docker/api/types"
 	"github.com/docker/docker/api/types/events"
@@ -65,7 +64,6 @@ func (s *systemRouter) getInfo(ctx context.Context, w http.ResponseWriter, r *ht
 
 func (s *systemRouter) getVersion(ctx context.Context, w http.ResponseWriter, r *http.Request, vars map[string]string) error {
 	info := s.backend.SystemVersion()
-	info.APIVersion = api.DefaultVersion
 
 	return httputils.WriteJSON(w, http.StatusOK, info)
 }

components/engine/api/types/types.go

@@ -107,9 +107,21 @@ type Ping struct {
 	Experimental bool
 }
 
+// ComponentVersion describes the version information for a specific component.
+type ComponentVersion struct {
+	Name    string
+	Version string
+	Details map[string]string `json:",omitempty"`
+}
+
 // Version contains response of Engine API:
 // GET "/version"
 type Version struct {
+	Platform   struct{ Name string } `json:",omitempty"`
+	Components []ComponentVersion    `json:",omitempty"`
+
+	// The following fields are deprecated, they relate to the Engine component and are kept for backwards compatibility
+
 	Version       string
 	APIVersion    string `json:"ApiVersion"`
 	MinAPIVersion string `json:"MinAPIVersion,omitempty"`