feat(github): dump request stats per-repo

Closes #1516

lib/platform/github/gh-got-wrapper.js

@@ -5,6 +5,7 @@ const parseLinkHeader = require('parse-link-header');
 const endpoints = require('../../util/endpoints');
 
 let cache = {};
+let stats = {};
 
 async function get(path, options, retries = 5) {
   const { host } = URL.parse(path);
@@ -19,6 +20,7 @@ async function get(path, options, retries = 5) {
     return cache[path];
   }
   logger.debug(`${method.toUpperCase()} ${path}`);
+  stats.requestCount = (stats.requestCount || 0) + 1;
   try {
     if (appMode) {
       const appAccept = 'application/vnd.github.machine-man-preview+json';
@@ -37,6 +39,10 @@ async function get(path, options, retries = 5) {
       }
     }
     const res = await ghGot(path, opts);
+    if (res && res.headers) {
+      stats.rateLimit = res.headers['x-ratelimit-limit'];
+      stats.rateLimitRemaining = res.headers['x-ratelimit-remaining'];
+    }
     if (opts.paginate) {
       // Check if result is paginated
       const pageLimit = opts.pageLimit || 10;
@@ -181,6 +187,11 @@ get.setAppMode = function setAppMode(val) {
 get.reset = function reset() {
   cache = null;
   cache = {};
+  // istanbul ignore if
+  if (stats.requestCount) {
+    logger.info({ stats }, 'Request stats');
+  }
+  stats = {};
 };
 
 module.exports = get;