Merge pull request #156 from pelias/rate-limit

feat: Add a rate limit feature

README.md

@@ -16,7 +16,7 @@ maximum were achieved. The weighting of individual parts of the test can be adju
 **Note:** fuzzy-tester requires NPM version 2 or greater. The NPM team
 [recommends](http://blog.npmjs.org/post/85484771375/how-to-install-npm) you update NPM using NPM
 itself with `sudo npm install -g npm`.
-## Usage
+## Example Usage
 
 ```
 // in the root directory of the repo containing the tests
@@ -26,6 +26,16 @@ fuzzy-tester -e prod
 fuzzy-tester -t dev
 ```
 
+
+## Command Line Parameters
+
+* `--help` show help :)
+* `-e` Select an envronment from `pelias.json` to run tests against. A list of valid environments will be printed if an invalid value or no value is passed
+* `-o` Select an output mode. Valid values are `terminal` (default), `csv`, `json`, and `autocomplete` (see below)
+* `-q` Enable quiet mode. Only test failures (not successes) are printed
+* `-t` Select a test 'type' to filter on. This is a free-text value that can be added to each test, to allow running a subset of tests
+* `-r` Set a limit of the number of requests that can be sent per second when running tests. This is useful to avoid overloading a small Pelias server
+
 ## Test Case Files
 Test-cases are expected to live in `test_cases/`, and are split into test
 *suites* in individual JSON files. Each file must contain the following

bin/fuzzy-tester

@@ -27,7 +27,7 @@ var analyze_results = require( '../lib/analyze_results' );
   var urls = gather_test_urls(config, testSuites);
 
   // request all urls
-  request_urls(urls, function processResponses(responses) {
+  request_urls(config, urls, function processResponses(responses) {
     // responses is a simple object where the keys are urls, and the value is the
     // entire response from fetching that url
     // test cases can have many URLs (in autocomplete mode), and the same url

lib/processArguments.js

@@ -47,6 +47,11 @@ function setUpCommander() {
     endpointHelp,
     'prod'
   )
+  .option(
+    '-r, --rate <int>',
+    'The maxium number of requests per second (RPS) to allow',
+    100
+  )
   .option(
     '-o, --output <type>',
     outputGeneratorHelp,
@@ -113,6 +118,7 @@ function getConfig() {
       url: apiUrl,
       name: commander.endpoint
     },
+    rate: commander.rate,
     outputGenerator: outputGenerator,
     testType: commander.testType,
     testSuites: testSuites,

lib/request_urls.js

@@ -26,13 +26,14 @@ function shouldRetryRequest(res) {
   return false;
 }
 
-function request_urls(urls, callback) {
+function request_urls(config, urls, callback) {
   var total_length = urls.length;
   var responses = {};
   var httpAgent = new http.Agent({keepAlive: true, maxSockets: 1});
   var httpsAgent = new https.Agent({keepAlive: true, maxSockets: 1});
   var intervalId;
-  var test_interval = new ExponentialBackoff(1, 5, 1, 20000);
+  const interval = 1000 / config.rate; // the number of miliseconds to delay between requests
+  var test_interval = new ExponentialBackoff(interval, 5, interval, 20000);
   var delay = test_interval.getBackoff();
 
   var getOneUrl = function (){