Also allow docker in containers spawned by an authorized app

src/docker.js

@@ -14,6 +14,7 @@ exports = module.exports = {
     deleteContainers: deleteContainers,
     createSubcontainer: createSubcontainer,
     getContainerIdByIp: getContainerIdByIp,
+    getAppIdByContainerIp: getAppIdByContainerIp,
     inspect: inspect,
     inspectByName: inspect,
     execContainer: execContainer
@@ -384,6 +385,24 @@ function getContainerIdByIp(ip, callback) {
     });
 }
 
+function getAppIdByContainerIp(ip, callback) {
+    assert.strictEqual(typeof ip, 'string');
+    assert.strictEqual(typeof callback, 'function');
+
+    getContainerIdByIp(ip, function (error, containerId) {
+        if (error) return callback(error);
+
+        inspect(containerId, function (error, result) {
+            if (error) return callback(error);
+
+            var appId = result.Config.Labels.appId;
+            if (!appId) return callback(new Error('No app associated with this ip'));
+
+            callback(null, appId);
+        });
+    });
+}
+
 function inspect(containerId, callback) {
     assert.strictEqual(typeof containerId, 'string');
     assert.strictEqual(typeof callback, 'function');