Capture action plugin metrics (#971)

Just like how we capture metrics relating to performance of classic integrations, this patch now enables capturing of metrics related to action destinations as well.

.changeset/metal-drinks-repeat.md

@@ -0,0 +1,5 @@
+---
+'@segment/analytics-next': minor
+---
+
+Capture action plugin metrics

packages/browser/package.json

@@ -44,7 +44,7 @@
   "size-limit": [
     {
       "path": "dist/umd/index.js",
-      "limit": "28.9 KB"
+      "limit": "29 KB"
     }
   ],
   "dependencies": {

packages/browser/src/plugins/remote-loader/__tests__/action-destination.test.ts

@@ -0,0 +1,72 @@
+import unfetch from 'unfetch'
+import { PluginFactory } from '..'
+
+import { AnalyticsBrowser } from '../../../browser'
+import { createSuccess } from '../../../test-helpers/factories'
+
+jest.mock('unfetch')
+jest.mocked(unfetch).mockImplementation(() =>
+  createSuccess({
+    integrations: {},
+    remotePlugins: [
+      {
+        name: 'testDestination',
+        libraryName: 'testDestination',
+        settings: {
+          subscriptions: [
+            {
+              name: 'Track Calls',
+              enabled: true,
+              partnerAction: 'trackEvent',
+              subscribe: 'type = "track"',
+            },
+          ],
+        },
+      },
+    ],
+  })
+)
+
+const testDestination: PluginFactory = () => {
+  return {
+    name: 'testDestination',
+    version: '1.0.0',
+    type: 'destination',
+    isLoaded: () => true,
+    load: () => Promise.resolve(),
+    track: (ctx) => Promise.resolve(ctx),
+  }
+}
+
+testDestination.pluginName = 'testDestination'
+
+describe('ActionDestination', () => {
+  it('captures essential metrics when invoking methods on an action plugin', async () => {
+    const ajs = AnalyticsBrowser.load({
+      writeKey: 'abc',
+      plugins: [testDestination],
+    })
+
+    await ajs.ready()
+
+    expect(ajs.ctx?.stats.metrics[0]).toMatchObject(
+      expect.objectContaining({
+        metric: 'analytics_js.action_plugin.invoke',
+        tags: ['method:load', 'action_plugin_name:testDestination'],
+      })
+    )
+
+    const trackCtx = await ajs.track('test')
+
+    const actionInvokeMetric = trackCtx.stats.metrics.find(
+      (m) => m.metric === 'analytics_js.action_plugin.invoke'
+    )
+
+    expect(actionInvokeMetric).toMatchObject(
+      expect.objectContaining({
+        metric: 'analytics_js.action_plugin.invoke',
+        tags: ['method:track', 'action_plugin_name:testDestination'],
+      })
+    )
+  })
+})

packages/browser/src/plugins/remote-loader/index.ts

@@ -79,7 +79,21 @@ export class ActionDestination implements DestinationPlugin {
         transformedContext = await this.transform(ctx)
       }
 
-      await this.action[methodName]!(transformedContext)
+      try {
+        ctx.stats.increment('analytics_js.action_plugin.invoke', 1, [
+          `method:${methodName}`,
+          `action_plugin_name:${this.action.name}`,
+        ])
+
+        await this.action[methodName]!(transformedContext)
+      } catch (error) {
+        ctx.stats.increment('analytics_js.action_plugin.invoke.error', 1, [
+          `method:${methodName}`,
+          `action_plugin_name:${this.action.name}`,
+        ])
+
+        throw error
+      }
 
       return ctx
     }
@@ -101,8 +115,22 @@ export class ActionDestination implements DestinationPlugin {
     return this.action.ready ? this.action.ready() : Promise.resolve()
   }
 
-  load(ctx: Context, analytics: Analytics): Promise<unknown> {
-    return this.action.load(ctx, analytics)
+  async load(ctx: Context, analytics: Analytics): Promise<unknown> {
+    try {
+      ctx.stats.increment('analytics_js.action_plugin.invoke', 1, [
+        `method:load`,
+        `action_plugin_name:${this.action.name}`,
+      ])
+
+      return await this.action.load(ctx, analytics)
+    } catch (error) {
+      ctx.stats.increment('analytics_js.action_plugin.invoke.error', 1, [
+        `method:load`,
+        `action_plugin_name:${this.action.name}`,
+      ])
+
+      throw error
+    }
   }
 
   unload(ctx: Context, analytics: Analytics): Promise<unknown> | unknown {