add AzureHttpTriggerPlugin

README.md

@@ -94,6 +94,27 @@ Library | Underlying Plugin Name
 | [`request-promise`](https://github.com/request/request-promise) | `http` / `https` |
 | [`koa`](https://github.com/koajs/koa) | `http` / `https` |
 
+## Experimental Azure Functions Support
+
+The plugin `AzureHttpTriggerPlugin` provides a wrapper function for an Azure Functions Javascript HttpTrigger endpoint. This is an http server endpoint and it must be instrumented manually currently. So far all other plugins tested work within the HttpTrigger and so a trace can pass through the Function and on to other endpoints called by the function. How much sense it makes to instrument an Azure Function which already lives in the cloud and has robust monitoring incorporated is a good question, but at the least this plugin will allow those endpoints to show up in a Skywalking trace.
+
+### Usage:
+
+```javascript
+const {default: agent, AzureHttpTriggerPlugin} = require('skywalking-backend-js');
+
+agent.start({ ... });
+
+module.exports = AzureHttpTriggerPlugin.wrap(async function (context, req) {
+
+  /* contents of http trigger function */
+
+});
+```
+
+All that needs to be done is the actual trigger function needs to be wrapped with `azureHttpTriggerPlugin.wrap()`, whether that function is a default export or an explicitly named `entryPoint` or `run` or `index`.
+
+
 ## Contact Us
 * Submit [an issue](https://github.com/apache/skywalking/issues/new) by using [Nodejs] as title prefix.
 * Mail list: **[email protected]**. Mail to `[email protected]`, follow the reply to subscribe the mail list.

src/core/PluginInstaller.ts

@@ -49,7 +49,7 @@ export default class PluginInstaller {
 
   private checkModuleVersion = (plugin: SwPlugin): { version: string; isSupported: boolean } => {
     try {
-      if (this.isBuiltIn(plugin.module)) {
+      if (plugin.versions === '!' || this.isBuiltIn(plugin.module)) {
         return {
           version: '*',
           isSupported: true,
@@ -101,7 +101,11 @@ export default class PluginInstaller {
           return;
         }
 
-        logger.info(`Installing plugin ${plugin.module} ${plugin.versions}`);
+        if (plugin.versions === '!') {
+          logger.info(`Explicit instrumentation plugin ${plugin.module} available`);
+        } else {
+          logger.info(`Installing plugin ${plugin.module} ${plugin.versions}`);
+        }
 
         plugin.install(this);
       } catch (e) {

src/index.ts

@@ -53,3 +53,4 @@ class Agent {
 
 export default new Agent();
 export { default as ContextManager } from './trace/context/ContextManager';
+export { default as AzureHttpTriggerPlugin } from './plugins/AzureHttpTriggerPlugin';

src/plugins/AzureHttpTriggerPlugin.ts

@@ -0,0 +1,139 @@
+/*!
+ *
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You 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.
+ *
+ */
+
+import SwPlugin from '../core/SwPlugin';
+import { URL } from 'url';
+import ContextManager from '../trace/context/ContextManager';
+import { Component } from '../trace/Component';
+import Tag from '../Tag';
+import { SpanLayer } from '../proto/language-agent/Tracing_pb';
+import { ContextCarrier } from '../trace/context/ContextCarrier';
+import DummySpan from '../trace/span/DummySpan';
+import { ignoreHttpMethodCheck } from '../config/AgentConfig';
+
+class AzureHttpTriggerPlugin implements SwPlugin {
+  readonly module = 'azureHttpTrigger';
+  readonly versions = '!';
+
+  install(): void {}
+
+  wrap(func: any) {
+    return function(this: any, context: any) {
+      let outRet = true;
+      let outName: any;
+
+      for (const def of context.bindingDefinitions || []) {
+        if (def.type === 'http' && def.directioun === 'out') {
+          outName = def.name;
+          outRet = outName === '$return'
+        }
+      }
+
+      const req = context.req;
+      const url = new URL(req.url);
+      const operation = url.pathname.replace(/\?.*$/g, '');
+      const carrier = ContextCarrier.from(req.headers);
+
+      const span: any = ignoreHttpMethodCheck(req.method)
+        ? DummySpan.create()
+        : ContextManager.current.newEntrySpan(operation, carrier);
+
+      span.layer = SpanLayer.HTTP;
+      span.component = Component.HTTP_SERVER;
+      span.peer = (req.headers['x-forwarded-for'] || '???').split(',').shift();
+
+      span.tag(Tag.httpMethod(req.method));
+      span.tag(Tag.httpURL(url.origin + url.pathname));
+
+      span.start();
+
+      let stop = (ret?: any) => {
+        stop = (v: any) => v;
+
+        let res = outRet ? ret : context.bindings[outName] || context.res;
+        const status = span.errored ? 500 : !res ? 0 : res.status || 200;
+
+        if (status) {
+          span.tag(Tag.httpStatusCode(status));
+
+          if (status >= 400)
+            span.errored = true;
+        }
+
+        span.stop();
+
+        return ret;
+      };
+
+      const done = context.done;
+      let did = false;
+
+      context.done = function(err: any, _ret: any) {
+        if (!did) {
+          if (err)
+            span.error(err);
+
+          if (arguments.length >= 2)
+            arguments[1] = stop(_ret);
+          else
+            stop();
+
+          did = true;
+        }
+
+        return done.apply(this, arguments);
+      };
+
+      let ret;
+
+      try {
+        ret = func.apply(this, arguments);
+
+      } catch (err) {
+        span.error(err);
+        stop();
+
+        throw err;
+      }
+
+      if (ret && typeof ret.then === 'function') {  // generic Promise check
+        ret = ret.then(
+          (_ret: any) => {
+
+            return stop(_ret);
+          },
+
+          (err: any) => {
+            span.error(err);
+            stop();
+
+            return Promise.reject(err);
+          }
+        );
+      }
+
+      span.async();
+
+      return ret;
+    };
+  }
+}
+
+// noinspection JSUnusedGlobalSymbols
+export default new AzureHttpTriggerPlugin();