From 0f90115cba6c2ea5ae0d51649795ac16d25ce6b9 Mon Sep 17 00:00:00 2001
From: piotr-yuxuan <piotr-yuxuan@users.noreply.github.com>
Date: Thu, 28 Sep 2023 11:17:43 +0100
Subject: [PATCH] Simplistic load testing

---
 README.md                                     | 15 +++++++++-
 pom.xml                                       | 16 ++++++++++
 .../api/ApiControllerLoadSimulationTest.java  | 29 +++++++++++++++++++
 3 files changed, 59 insertions(+), 1 deletion(-)
 create mode 100644 src/test/java/com/github/piotryuxuan/springbootplayground/api/ApiControllerLoadSimulationTest.java

diff --git a/README.md b/README.md
index d9093fe..59a3262 100644
--- a/README.md
+++ b/README.md
@@ -47,7 +47,20 @@ Grafana dashboards:
 - https://grafana.com/grafana/dashboards/6756-spring-boot-statistics/
 - Ideally there would be a standard dashboard for endpoints and another for database connections.
 
-### Reference Documentation
+# Load Simulation
+
+A load simulation is described using the Java DSL. You can run it with Gatling:
+
+``` zsh
+mvn gatling:test
+```
+
+Of course it doesn't have a lot of meaning to run such simulation a local computer with a lot of different possible perturbation. An isolated, network-optimised environment in AWS is more repeatable. Still, it can give a rough, uneducated hint at the performance. Keep in mind that your local machine may have a limitation on the number of open file descriptors (`ulimit`), which further degrades the ability to simulate high load.
+
+A note on AWS resources: instances should be in the same availability zone (ha ha), and Elastic Fabric Adapter network interface should help make the CPU and memory the limiting factors, not the network IO.
+
+# Reference Documentation
+
 For further reference, please consider the following sections:
 
 * [Official Apache Maven documentation](https://maven.apache.org/guides/index.html)
diff --git a/pom.xml b/pom.xml
index e684ec9..ed50144 100644
--- a/pom.xml
+++ b/pom.xml
@@ -57,6 +57,13 @@
 			<artifactId>springdoc-openapi-starter-webmvc-api</artifactId>
 			<version>2.2.0</version>
 		</dependency>
+
+		<dependency>
+			<groupId>io.gatling.highcharts</groupId>
+			<artifactId>gatling-charts-highcharts</artifactId>
+			<version>3.9.5</version>
+			<scope>test</scope>
+		</dependency>
 	</dependencies>
 
 	<build>
@@ -73,6 +80,15 @@
 					</excludes>
 				</configuration>
 			</plugin>
+			<plugin>
+				<groupId>io.gatling</groupId>
+				<artifactId>gatling-maven-plugin</artifactId>
+				<version>4.5.0</version>
+				<configuration>
+					<simulationClass>
+						com.github.piotryuxuan.springbootplayground.api.ApiControllerLoadSimulationTest</simulationClass>
+				</configuration>
+			</plugin>
 		</plugins>
 	</build>
 
diff --git a/src/test/java/com/github/piotryuxuan/springbootplayground/api/ApiControllerLoadSimulationTest.java b/src/test/java/com/github/piotryuxuan/springbootplayground/api/ApiControllerLoadSimulationTest.java
new file mode 100644
index 0000000..bc54d4a
--- /dev/null
+++ b/src/test/java/com/github/piotryuxuan/springbootplayground/api/ApiControllerLoadSimulationTest.java
@@ -0,0 +1,29 @@
+package com.github.piotryuxuan.springbootplayground.api;
+
+import io.gatling.javaapi.core.*;
+import io.gatling.javaapi.http.*;
+
+import static io.gatling.javaapi.core.CoreDsl.*;
+import static io.gatling.javaapi.http.HttpDsl.*;
+
+import java.util.Random;
+
+public class ApiControllerLoadSimulationTest extends Simulation {
+
+	HttpProtocolBuilder httpProtocol = http.baseUrl("http://localhost:8080");
+	Random randomGenerator = new Random();
+
+	ScenarioBuilder scn = scenario("BasicSimulation")
+			.exec(http("request_addition").get("/api/v1/addition")
+					.queryParam("a", String.valueOf(randomGenerator.nextLong()))
+					.queryParam("b", String.valueOf(randomGenerator.nextLong())));
+
+	{
+		setUp(
+				scn.injectOpen(
+						atOnceUsers(100),
+						constantUsersPerSec(100).during(30),
+						rampUsers(1_500).during(60),
+						constantUsersPerSec(1_500).during(10)).protocols(httpProtocol));
+	}
+}