Disable crashing pugins (#4440)

* Disable crashing pugins

When one of the plugins subscriptions fails, disable the whole plugin.

* pr feedback

* fix logging

* lint

packages/dd-trace/src/plugins/plugin.js

@@ -3,6 +3,7 @@
 // TODO: move anything related to tracing to TracingPlugin instead
 
 const dc = require('dc-polyfill')
+const logger = require('../log')
 const { storage } = require('../../../datadog-core')
 
 class Subscription {
@@ -72,7 +73,17 @@ module.exports = class Plugin {
   }
 
   addSub (channelName, handler) {
-    this._subscriptions.push(new Subscription(channelName, handler))
+    const plugin = this
+    const wrappedHandler = function () {
+      try {
+        return handler.apply(this, arguments)
+      } catch (e) {
+        logger.error('Error in plugin handler:', e)
+        logger.info('Disabling plugin:', plugin.id)
+        plugin.configure(false)
+      }
+    }
+    this._subscriptions.push(new Subscription(channelName, wrappedHandler))
   }
 
   addBind (channelName, transform) {

packages/dd-trace/test/plugins/plugin.spec.js

@@ -0,0 +1,69 @@
+'use strict'
+
+require('../setup/tap')
+
+const Plugin = require('../../src/plugins/plugin')
+const plugins = require('../../src/plugins')
+const { channel } = require('dc-polyfill')
+
+describe('Plugin', () => {
+  class BadPlugin extends Plugin {
+    static get id () { return 'badPlugin' }
+
+    constructor () {
+      super()
+      this.addSub('apm:badPlugin:start', this.start)
+    }
+
+    start () {
+      throw new Error('this is one bad plugin')
+    }
+  }
+
+  class GoodPlugin extends Plugin {
+    static get id () { return 'goodPlugin' }
+
+    constructor () {
+      super()
+      this.addSub('apm:goodPlugin:start', this.start)
+    }
+
+    start () {
+      //
+    }
+  }
+
+  const testPlugins = { badPlugin: BadPlugin, goodPlugin: GoodPlugin }
+  const loadChannel = channel('dd-trace:instrumentation:load')
+
+  before(() => {
+    for (const [name, cls] of Object.entries(testPlugins)) {
+      plugins[name] = cls
+      loadChannel.publish({ name })
+    }
+  })
+
+  after(() => { Object.keys(testPlugins).forEach(name => delete plugins[name]) })
+
+  it('should disable upon error', () => {
+    const plugin = new BadPlugin()
+    plugin.configure({ enabled: true })
+
+    expect(plugin._enabled).to.be.true
+
+    channel('apm:badPlugin:start').publish({ foo: 'bar' })
+
+    expect(plugin._enabled).to.be.false
+  })
+
+  it('should not disable with no error', () => {
+    const plugin = new GoodPlugin()
+    plugin.configure({ enabled: true })
+
+    expect(plugin._enabled).to.be.true
+
+    channel('apm:goodPlugin:start').publish({ foo: 'bar' })
+
+    expect(plugin._enabled).to.be.true
+  })
+})