Move plugin client creation to the extension point

Signed-off-by: Brian Goff <cpuguy83@gmail.com>
Upstream-commit: f51a96c0165fdcbbe11f62b66b582b7e202f211b
Component: engine

components/engine/api/swagger.yaml

@@ -1859,6 +1859,13 @@ definitions:
                 type: "string"
                 x-nullable: false
                 example: "plugins.sock"
+              ProtocolScheme:
+                type: "string"
+                example: "some.protocol/v1.0"
+                description: "Protocol to use for clients connecting to the plugin."
+                enum:
+                  - ""
+                  - "moby.plugins.http/v1"
           Entrypoint:
             type: "array"
             items:

components/engine/api/types/plugin.go

@@ -121,6 +121,9 @@ type PluginConfigArgs struct {
 // swagger:model PluginConfigInterface
 type PluginConfigInterface struct {
 
+	// Protocol to use for clients connecting to the plugin.
+	ProtocolScheme string `json:"ProtocolScheme,omitempty"`
+
 	// socket
 	// Required: true
 	Socket string `json:"Socket"`