Added metrics argument to headless inorder to export metrics

Summary:
This diff makes headless flipper accept `metrics` argument. Once this is passed. The headless flipper will terminate to export the metrics of the plugins, the type of the export looks like the following.

```
export type MetricType = {[metricName: string]: number};
type MetricPluginType = {[pluginID: string]: MetricType};
export type ExportMetricType = {[clientID: string]: MetricPluginType};

```

This diff, uses the store to export the metrics. I will modify the logic to accept the data which gets exported through `exportData`

Reviewed By: passy

Differential Revision: D14933499

fbshipit-source-id: dade5b7bc59ea4beb6d16c5ef471737e8597358a

android/sample/src/main/java/com/facebook/flipper/sample/ExampleActions.java

@@ -46,8 +46,7 @@ public final class ExampleActions {
   }
 
   public static void sendGetRequest() {
-    final Request request =
-        new Request.Builder().url("https://api.github.com/repos/facebook/yoga").get().build();
+    final Request request = new Request.Builder().url("https://api.github.com/repos/facebook/yoga").get().build();
     FlipperSampleApplication.sOkHttpClient
         .newCall(request)
         .enqueue(

headless/index.js

@@ -14,6 +14,8 @@ import dispatcher from '../src/dispatcher/index.js';
 import {init as initLogger} from '../src/fb-stubs/Logger.js';
 import reducers from '../src/reducers/index.js';
 import {exportStore} from '../src/utils/exportData.js';
+import exportMetrics from '../src/utils/exportMetrics.js';
+
 // $FlowFixMe this file exist, trust me, flow!
 import setup from '../static/setup.js';
 
@@ -50,6 +52,12 @@ yargs
         describe: 'Enable verbose logging',
         type: 'boolean',
       });
+      yargs.option('metrics', {
+        alias: 'metrics',
+        default: false,
+        describe: 'Will export metrics instead of data when flipper terminates',
+        type: 'boolean',
+      });
     },
     startFlipper,
   )
@@ -59,6 +67,7 @@ yargs
 function startFlipper({
   dev,
   verbose,
+  metrics,
   exit,
   'insecure-port': insecurePort,
   'secure-port': securePort,
@@ -100,12 +109,21 @@ function startFlipper({
       // TODO(T42325892): Investigate why the export stalls without exiting the
       // current eventloop task here.
       setTimeout(() => {
-        exportStore(store)
-          .then(({serializedString}) => {
-            originalConsole.log(serializedString);
-            process.exit();
-          })
-          .catch(console.error);
+        if (metrics) {
+          exportMetrics(store)
+            .then(payload => {
+              originalConsole.log(payload);
+              process.exit();
+            })
+            .catch(console.error);
+        } else {
+          exportStore(store)
+            .then(({serializedString}) => {
+              originalConsole.log(serializedString);
+              process.exit();
+            })
+            .catch(console.error);
+        }
       }, 10);
     }
     return next(action);
@@ -122,9 +140,14 @@ function startFlipper({
   if (exit == 'sigint') {
     process.on('SIGINT', async () => {
       try {
-        const {serializedString, errorArray} = await exportStore(store);
-        errorArray.forEach(console.error);
-        originalConsole.log(serializedString);
+        if (metrics) {
+          const payload = await exportMetrics(store);
+          originalConsole.log(payload);
+        } else {
+          const {serializedString, errorArray} = await exportStore(store);
+          errorArray.forEach(console.error);
+          originalConsole.log(serializedString);
+        }
       } catch (e) {
         console.error(e);
       }

src/plugin.js

@@ -83,6 +83,9 @@ export class FlipperBasePlugin<
     method: string,
     data: Object,
   ) => $Shape<PersistedState>;
+  static exportMetrics: ?(
+    persistedState: PersistedState,
+  ) => Promise<Map<string, number | string>>;
   static exportPersistedState: ?(
     callClient: (string, ?Object) => Promise<Object>,
     persistedState: ?PersistedState,

src/plugins/network/index.js

@@ -107,6 +107,19 @@ export default class extends FlipperPlugin<State, *, PersistedState> {
     responses: {},
   };
 
+  static exportMetrics = (
+    persistedState: PersistedState,
+  ): Promise<Map<string, number | string>> => {
+    const failures = Object.keys(persistedState.responses).reduce(function(
+      previous,
+      key,
+    ) {
+      return previous + (persistedState.responses[key].status >= 400);
+    },
+    0);
+    return Promise.resolve(new Map([['NUMBER_NETWORK_FAILURES', failures]]));
+  };
+
   static persistedStateReducer = (
     persistedState: PersistedState,
     method: string,

src/utils/exportMetrics.js

@@ -0,0 +1,52 @@
+/**
+ * Copyright 2018-present Facebook.
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ * @format
+ */
+import type {MiddlewareAPI} from '../reducers';
+import {serialize} from './serialization.js';
+import type {FlipperPlugin, FlipperDevicePlugin} from 'flipper';
+
+type MetricType = Map<string, Map<string, string | number>>;
+
+export type ExportMetricType = Map<string, MetricType>;
+
+export default async function exportMetrics(
+  store: MiddlewareAPI,
+): Promise<string> {
+  const state = store.getState();
+  let metrics: ExportMetricType = new Map();
+  for (let key in state.pluginStates) {
+    const pluginStateData = state.pluginStates[key];
+    const arr = key.split('#');
+    const pluginName = arr.pop();
+    const clientID = arr.join('#');
+    const pluginsMap: Map<
+      string,
+      Class<FlipperDevicePlugin<> | FlipperPlugin<>>,
+    > = new Map([]);
+    state.plugins.clientPlugins.forEach((val, key) => {
+      pluginsMap.set(key, val);
+    });
+    state.plugins.devicePlugins.forEach((val, key) => {
+      pluginsMap.set(key, val);
+    });
+    const exportMetrics1: ?(
+      persistedState: any,
+    ) => Promise<Map<string, string | number>> = pluginsMap.get(pluginName)
+      ?.exportMetrics;
+    if (pluginsMap.has(pluginName) && exportMetrics1) {
+      const metricMap = await exportMetrics1(pluginStateData);
+      const pluginMap = new Map([[pluginName, metricMap]]);
+      if (!metrics.get(clientID)) {
+        metrics.set(clientID, pluginMap);
+        continue;
+      }
+      const prevMetricMap = metrics.get(clientID);
+      // $FlowFixMe: prevMetricMap cannot be null, because clientID is added only when the pluingMetricMap is available
+      metrics.set(clientID, new Map([...prevMetricMap, ...pluginMap]));
+    }
+  }
+  return Promise.resolve(serialize(metrics));
+}