Node v4.2.0 - Clamp bufferLength, better dev mode debugging, and flush queue on process exit (#284)

* feat(node): cap the buffer length at 100 logs

* feat(node): ensure buffer length is between 1 and 30 and flush queue on process exit

Author: Ilias Tsangaris

packages/node/README.md

@@ -60,7 +60,7 @@ app.use(readme.metrics('<<apiKey>>', req => ({
 | Option       | Use                                                                                                                                                                                                                                                                                                                     |
 | :----------- | :---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
 | development  | **default: false** If true, the log will be separate from normal production logs. This is great for separating staging or test data from data coming from customers.                                                                                                                                                    |
-| bufferLength | **default: 10** By default, we only send logs to ReadMe after 10 requests are made. Depending on the usage of your API it make make sense to send logs more or less frequently.                                                                                                                                         |
+| bufferLength | **default: 1** By default, we perform a buffer flush to ReadMe after a single request is made. Depending on the usage of your API it make make sense to do this more or less frequently. The buffer will always flush after 30 logs are made, so any number that is larger will be ignored. Also keep in mind that any request over 1mb will receive a 413 response.                                                                     |
 | denylist     | **optional** An array of keys from your API requests, responses headers, and request bodies that you wish to not be sent to ReadMe.<br /><br />If you configure a `denylist`, it will override any `allowlist` configuration.                                                                                           |
 | allowlist    | **optional** An array of keys from your API requests and responses headers and bodies that you only wish to send to ReadMe.                                                                                                                                                                                             |
 | baseLogUrl   | **optional** This is the base URL for your ReadMe project. Normally this would be `https://projectName.readme.io` or `https://docs.yourdomain.com`, however if this value is not supplied, a request to the ReadMe API will be made once a day to retrieve it. This data is cached into `node_modules/.cache/readmeio`. |

packages/node/index.js

@@ -5,10 +5,15 @@ const crypto = require('crypto');
 const config = require('./config');
 const flatCache = require('flat-cache');
 const findCacheDir = require('find-cache-dir');
+const clamp = require('lodash/clamp');
 const pkg = require('./package.json');
 
 const constructPayload = require('./lib/construct-payload');
 
+// Make sure we flush the queue if the process is exited
+let doSend = () => {};
+process.on('exit', doSend);
+
 // We're doing this to buffer up the response body
 // so we can send it off to the metrics server
 // It's unfortunate that this isn't accessible
@@ -96,7 +101,8 @@ module.exports.metrics = (apiKey, group, options = {}) => {
   if (!apiKey) throw new Error('You must provide your ReadMe API key');
   if (!group) throw new Error('You must provide a grouping function');
 
-  const bufferLength = options.bufferLength || config.bufferLength;
+  // Ensures the buffer length is between 1 and 30
+  const bufferLength = clamp(options.bufferLength || config.bufferLength, 1, 30);
   const requestTimeout = config.timeout;
   const encodedApiKey = Buffer.from(`${apiKey}:`).toString('base64');
   let baseLogUrl = options.baseLogUrl || undefined;
@@ -116,48 +122,51 @@ module.exports.metrics = (apiKey, group, options = {}) => {
 
     patchResponse(res);
 
-    function send() {
+    doSend = () => {
+      const json = queue.slice();
+      queue = [];
+
+      const signal = timeoutSignal(requestTimeout);
+
+      fetch(`${config.host}/v1/request`, {
+        method: 'post',
+        body: JSON.stringify(json),
+        headers: {
+          Authorization: `Basic ${encodedApiKey}`,
+          'Content-Type': 'application/json',
+          'User-Agent': `${pkg.name}/${pkg.version}`,
+        },
+        signal,
+      })
+        .then(() => {})
+        .catch(e => {
+          // Silently discard errors and timeouts.
+          if (options.development) throw e;
+        })
+        .finally(() => {
+          timeoutSignal.clear(signal);
+        });
+    };
+
+    function startSend() {
       // This should in future become more sophisticated,
       // with flush timeouts and more error checking but
       // this is fine for now
       const payload = constructPayload(req, res, group, options, { logId, startedDateTime });
       queue.push(payload);
-      if (queue.length >= bufferLength) {
-        const json = queue.slice();
-        queue = [];
-
-        const signal = timeoutSignal(requestTimeout);
-
-        fetch(`${config.host}/v1/request`, {
-          method: 'post',
-          body: JSON.stringify(json),
-          headers: {
-            Authorization: `Basic ${encodedApiKey}`,
-            'Content-Type': 'application/json',
-            'User-Agent': `${pkg.name}/${pkg.version}`,
-          },
-          signal,
-        })
-          .then(() => {})
-          .catch(() => {
-            // Silently discard errors and timeouts.
-          })
-          .finally(() => {
-            timeoutSignal.clear(signal);
-          });
-      }
+      if (queue.length >= bufferLength) doSend();
 
       cleanup(); // eslint-disable-line no-use-before-define
     }
 
     function cleanup() {
-      res.removeListener('finish', send);
+      res.removeListener('finish', startSend);
       res.removeListener('error', cleanup);
       res.removeListener('close', cleanup);
     }
 
     // Add response listeners
-    res.once('finish', send);
+    res.once('finish', startSend);
     res.once('error', cleanup);
     res.once('close', cleanup);
 

packages/node/package-lock.json

@@ -1,7 +1,7 @@
 {
   "name": "readmeio",
   "description": "Track your API metrics within ReadMe.",
-  "version": "4.1.0",
+  "version": "4.2.0",
   "license": "ISC",
   "homepage": "https://readme.com/metrics",
   "bugs": {