Move exec and events components to util module

The exec and events components are common components that
are used by both runtime and registry. It makes sense to
move them into the util package.

This also adds some docs to the registry module

packages/node_modules/@node-red/util/index.js

@@ -17,6 +17,8 @@
 const log = require("./lib/log");
 const i18n = require("./lib/i18n");
 const util = require("./lib/util");
+const events = require("./lib/events");
+const exec = require("./lib/exec");
 
 /**
  * This module provides common utilities for the Node-RED runtime and editor
@@ -54,4 +56,18 @@ module.exports = {
     * @memberof @node-red/util
     */
     util: util,
+
+    /**
+    * Runtime events
+    * @mixes @node-red/util_event
+    * @memberof @node-red/util
+    */
+    events: events,
+
+    /**
+    * Run system commands with event-log integration
+    * @mixes @node-red/util_exec
+    * @memberof @node-red/util
+    */
+    exec: exec
 }

packages/node_modules/@node-red/util/lib/events.js

@@ -0,0 +1,73 @@
+/*!
+ * Copyright JS Foundation and other contributors, http://js.foundation
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ **/
+
+ /**
+  * Runtime events
+  * @mixin @node-red/util_events
+  */
+
+const events = new (require("events")).EventEmitter();
+
+
+const deprecatedEvents = {
+    "nodes-stopped": "flows:stopped",
+    "nodes-started": "flows:started"
+}
+
+function wrapEventFunction(obj,func) {
+    events["_"+func] = events[func];
+    return function(eventName, listener) {
+        if (deprecatedEvents.hasOwnProperty(eventName)) {
+            const log = require("@node-red/util").log;
+            const stack = (new Error().stack).split("\n")[2].split("(")[1].slice(0,-1);
+            log.warn(`[RED.events] Deprecated use of "${eventName}" event from "${stack}". Use "${deprecatedEvents[eventName]}" instead.`)
+        }
+        return events["_"+func].call(events,eventName,listener)
+    }
+}
+
+
+events.on = wrapEventFunction(events,"on");
+events.once = wrapEventFunction(events,"once");
+events.addListener = events.on;
+
+
+
+module.exports = events;
+
+/**
+ * Runtime events emitter
+ * @mixin @node-red/util_events
+ */
+
+/**
+ * Register an event listener for a runtime event
+ * @name on
+ * @function
+ * @memberof @node-red/util_events
+ * @param {String} eventName - the name of the event to listen to
+ * @param {Function} listener - the callback function for the event
+ */
+
+ /**
+  * Emit an event to all of its registered listeners
+  * @name emit
+  * @function
+  * @memberof @node-red/util_events
+  * @param {String} eventName - the name of the event to emit
+  * @param {any} ...args - the arguments to pass in the event
+  * @return {Boolean} - whether the event had listeners or not
+  */

packages/node_modules/@node-red/util/lib/exec.js

@@ -0,0 +1,91 @@
+/*!
+ * Copyright JS Foundation and other contributors, http://js.foundation
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ **/
+
+/**
+ * Run system commands with event-log integration
+ * @mixin @node-red/util_exec
+ */
+
+const child_process = require('child_process');
+const events = require("./events");
+const util = require('./util');
+
+function logLines(id,type,data) {
+    events.emit("event-log", {id:id,payload:{ts: Date.now(),data:data,type:type}});
+}
+
+module.exports = {
+    /**
+     * Run a system command with stdout/err being emitted as 'event-log' events
+     * on the @node-red/util/events handler.
+     *
+     * The main arguments to this function are the same as passed to `child_process.spawn`
+     *
+     * @param {String} command - the command to run
+     * @param {Array}  args - arguments for the command
+     * @param {Object} options - options to pass child_process.spawn
+     * @param {Boolean} emit - whether to emit events to the event-log for each line of stdout/err
+     * @return {Promise} A promise that resolves (rc=0) or rejects (rc!=0) when the command completes. The value
+     *                   of the promise is an object of the form:
+     *
+     *       {
+     *           code: <exit code>,
+     *           stdout: <standard output from the command>,
+     *           stderr: <standard error from the command>
+     *       }
+
+     * @memberof @node-red/util_exec
+     */
+    run: function(command,args,options,emit) {
+        var invocationId = util.generateId();
+
+        emit && events.emit("event-log", {ts: Date.now(),id:invocationId,payload:{ts: Date.now(),data:command+" "+args.join(" ")}});
+
+        return new Promise((resolve, reject) => {
+            let stdout = "";
+            let stderr = "";
+            const child = child_process.spawn(command,args,options);
+            child.stdout.on('data', (data) => {
+                const str = ""+data;
+                stdout += str;
+                emit && logLines(invocationId,"out",str);
+            });
+            child.stderr.on('data', (data) => {
+                const str = ""+data;
+                stderr += str;
+                emit && logLines(invocationId,"err",str);
+            });
+            child.on('error', function(err) {
+                stderr = err.toString();
+                emit && logLines(invocationId,"err",stderr);
+            })
+            child.on('close', (code) => {
+                let result = {
+                    code: code,
+                    stdout: stdout,
+                    stderr: stderr
+                }
+                emit && events.emit("event-log", {id:invocationId,payload:{ts: Date.now(),data:"rc="+code}});
+
+                if (code === 0) {
+                    resolve(result)
+                } else {
+                    reject(result);
+                }
+            });
+        })
+    }
+}

packages/node_modules/@node-red/util/lib/log.js

@@ -1,4 +1,4 @@
-/**
+/*!
  * Copyright JS Foundation and other contributors, http://js.foundation
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
@@ -12,7 +12,6 @@
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
- * @ignore
  **/
 
 /**
@@ -91,7 +90,7 @@ var consoleLogger = function(msg) {
             } catch(e){
                 message = 'Exception trying to log: '+util.inspect(message);
             }
-            
+
             util.log("["+levelNames[msg.level]+"] "+(msg.type?"["+msg.type+":"+(msg.name||msg.id)+"] ":"")+message);
         }
     }