Implemented forwarding of requests to the master

Implement the forwardTo function for requests to the master server.

client.js

@@ -358,6 +358,10 @@ class InstanceConnection extends link.Link {
 		}
 	}
 
+	async forwardRequestToMaster(message, request) {
+		return await request.send(this.slave, message.data);
+	}
+
 	async forwardEventToInstance(message, event) {
 		let instanceId = message.data.instance_id;
 		let instanceConnection = this.slave.instanceConnections.get(instanceId);

docs/writing-plugins.md

@@ -408,8 +408,8 @@ The following properties are recognized by the Request constructor:
     Target to forward request to.  Can be either `'master'` to indicate
     a slave should forward it to the master server when receiving it
     from an instance or `'instance'` to indicate it should be forwarded
-    to the instances specified by the `instance_id` event property.
-    This works by using a default handler for the event at the links
+    to the instances specified by the `instance_id` request property.
+    This works by using a default handler for the request at the links
     that forward it.
 
 **requestProperties**:

lib/link/messages.js

@@ -20,9 +20,9 @@ class Request {
 	 *     Links this request is valid on.  Takes an array of strings
 	 *     containing "<source>-<target>" specifications.
 	 * @param {?string} forwardTo -
-	 *     Optional target to forward this request to.  Only 'instance' is
-	 *     currently supported and adds instance_id into the
-	 *     requestProperties.
+	 *     Optional target to forward this request to.  'instance' add
+	 *     instance_id into the requestProperties and forward to the given
+	 *     instance.  'master' forwards it to the master server.
 	 * @param {Object<string, Object>} requestProperties -
 	 *     Mapping of property values to JSON schema specifications for the
 	 *     properties that are valid in the data payload of this requst.
@@ -46,7 +46,7 @@ class Request {
 				{"instance_id": { type: "integer" }}, requestProperties
 			);
 
-		} else if (forwardTo !== null) {
+		} else if (forwardTo !== "master" && forwardTo !== null) {
 			throw new Error(`Invalid forwardTo value ${forwardTo}`);
 		}
 
@@ -99,6 +99,9 @@ class Request {
 	 * If forwardTo was set to 'instance' the `forwardRequestToInstance`
 	 * method on the link is used as the default handler.
 	 *
+	 * If forwardTo was set to 'master' the `forwardRequesToMaster` method
+	 * on the link is used as the default handler.
+	 *
 	 * Does nothing if the link is neither a source nor a target for this
 	 * request.
 	 *
@@ -121,6 +124,8 @@ class Request {
 			if (!handler) {
 				if (this.forwardTo === 'instance') {
 					handler = link.forwardRequestToInstance;
+				} else if (this.forwardTo === "master") {
+					handler = link.forwardRequestToMaster;
 				}
 			}