From 20afb0ee047bc81c5d16adda6cbd3efb935272ea Mon Sep 17 00:00:00 2001
From: Chris Moultrie <tebriel@github.com>
Date: Thu, 25 Jun 2020 16:51:03 -0400
Subject: [PATCH] Support emitting distribution metrics alongside or instead of
 histograms

---
 README.md         |  2 +-
 lib/index.js      | 11 +++++++++--
 lib/index.test.js | 23 ++++++++++++++++++++---
 3 files changed, 30 insertions(+), 6 deletions(-)

diff --git a/README.md b/README.md
index dfb6486..db61efc 100644
--- a/README.md
+++ b/README.md
@@ -23,8 +23,8 @@ All options are optional.
 * `protocol` *boolean* include protocol tag. `default = false`
 * `response_code` *boolean* include http response codes. `default = false`
 * `delim` *string* char to replace pipe char with in the route `default = '-'`
+* `timing_type` *string* the type of metric to emit `histogram`, `distribution`, or `both`. `default = 'histogram'`
 
 ## License
 
 View the [LICENSE](https://github.com/AppPress/node-connect-datadog/blob/master/LICENSE) file.
-
diff --git a/lib/index.js b/lib/index.js
index e5b2699..ea58d38 100644
--- a/lib/index.js
+++ b/lib/index.js
@@ -10,6 +10,7 @@ module.exports = function (options) {
 	let protocol = options.protocol || false;
 	let response_code = options.response_code || false;
 	let DELIM = options.delim || '-';
+	let timing_type = options.timing_type || 'histogram';
 	let REGEX_PIPE = /\|/g;
 
 	/**
@@ -44,7 +45,7 @@ module.exports = function (options) {
 			res.end(chunk, encoding);
 
 			let statTags = [...tags];
-			
+
 			const route = getRoute(req, base_url);
 			if (route.length > 0) {
 				statTags.push(`route:${route}`);
@@ -68,7 +69,13 @@ module.exports = function (options) {
 				datadog.increment(`${stat}.response_code.all`, 1, statTags);
 			}
 
-			datadog.histogram(`${stat}.response_time`, new Date() - req._startTime, 1, statTags);
+			if (['histogram', 'both'].includes(timing_type)) {
+				datadog.histogram(`${stat}.response_time`, new Date() - req._startTime, 1, statTags);
+      }
+
+			if (['distribution', 'both'].includes(timing_type)) {
+				datadog.distribution(`${stat}.dist.response_time`, new Date() - req._startTime, 1, statTags);
+			}
 		};
 
 		next();
diff --git a/lib/index.test.js b/lib/index.test.js
index 11cbb9e..f9cf51d 100644
--- a/lib/index.test.js
+++ b/lib/index.test.js
@@ -2,6 +2,7 @@ const connectDatadog = require("./index");
 
 const mockStatsDImplementation = {
   histogram: jest.fn(),
+  distribution: jest.fn(),
   increment: jest.fn(),
 }
 
@@ -35,6 +36,7 @@ describe('connectDatadog', () => {
 
   afterEach(() => {
     mockStatsDImplementation.histogram.mockReset()
+    mockStatsDImplementation.distribution.mockReset()
     mockStatsDImplementation.increment.mockReset()
   })
 
@@ -101,7 +103,10 @@ describe('connectDatadog', () => {
       let dogstatsd
 
       beforeEach(() => {
-        dogstatsd = { histogram: jest.fn() }
+        dogstatsd = {
+          histogram: jest.fn(),
+          distribution: jest.fn(),
+        }
       })
 
       it('gets a value for the dogstatsd option', async () => {
@@ -109,6 +114,18 @@ describe('connectDatadog', () => {
         expect(dogstatsd.histogram).toHaveBeenCalled()
       })
 
+      it('uses distribution when specified', async () => {
+        await asyncConnectDatadogAndCallMiddleware({ dogstatsd, timing_type: 'distribution' });
+        expect(dogstatsd.histogram).not.toHaveBeenCalled();
+        expect(dogstatsd.distribution).toHaveBeenCalled();
+      })
+
+      it('uses both timing types when specified', async () => {
+        await asyncConnectDatadogAndCallMiddleware({ dogstatsd, timing_type: 'both' });
+        expect(dogstatsd.histogram).toHaveBeenCalled();
+        expect(dogstatsd.distribution).toHaveBeenCalled();
+      })
+
       it('uses the default value for the dogstatsd option if not passed', async () => {
         await asyncConnectDatadogAndCallMiddleware({})
         expect(mockStatsDImplementation.histogram).toHaveBeenCalled()
@@ -213,7 +230,7 @@ describe('connectDatadog', () => {
               `route:${req.baseUrl}`,
               `response_code:${res.statusCode}`,
             ]
-    
+
             await asyncConnectDatadogAndCallMiddleware({ base_url: true, response_code: true })
             expectConnectedToDatadog(stat, statTags, false)
             expect(next).toHaveBeenCalled()
@@ -227,7 +244,7 @@ describe('connectDatadog', () => {
             const statTags = [
               `response_code:${res.statusCode}`,
             ]
-    
+
             await asyncConnectDatadogAndCallMiddleware({ response_code: true })
             expectConnectedToDatadog(stat, statTags, false)
             expect(next).toHaveBeenCalled()