MXS-1300: Make the MaxCtrl core a Node.js module

The core is now a module that is loaded by the command line client. This
allows the core library to be reused for testing.

maxctrl/maxctrl_core/lib/unlink.js

@@ -0,0 +1,49 @@
+/*
+ * Copyright (c) 2016 MariaDB Corporation Ab
+ *
+ * Use of this software is governed by the Business Source License included
+ * in the LICENSE.TXT file and at www.mariadb.com/bsl11.
+ *
+ * Change Date: 2020-01-01
+ *
+ * On the date above, in accordance with the Business Source License, use
+ * of this software will be governed by version 2 or later of the General
+ * Public License.
+ */
+require('../common.js')()
+
+function removeServer(argv, path, targets) {
+    maxctrl(argv, function(host) {
+        return doRequest(host, path, function(res) {
+            var servers =_.get(res, 'data.relationships.servers.data', [])
+
+            _.remove(servers, function(i) {
+                return targets.indexOf(i.id) != -1
+            })
+
+            // Update relationships and remove unnecessary parts
+            _.set(res, 'data.relationships.servers.data', servers)
+            delete res.data.attributes
+
+            return doAsyncRequest(host, path, null, {method: 'PATCH', body: res})
+        })
+    })
+}
+
+exports.command = 'unlink <command>'
+exports.desc = 'Unlink objects'
+exports.handler = function() {}
+exports.builder = function(yargs) {
+    yargs
+        .command('service <name> <server...>', 'Unlink servers from a service', {}, function(argv) {
+            removeServer(argv, 'services/' + argv.name, argv.server)
+        })
+        .command('monitor <name> <server...>', 'Unlink servers from a monitor', {}, function(argv) {
+            removeServer(argv, 'monitors/' + argv.name, argv.server)
+        })
+        .usage('Usage: unlink <command>')
+        .help()
+        .command('*', 'the default command', {}, () => {
+            logger.log('Unknown command. See output of `help unlink` for a list of commands.')
+        })
+}