Testing Java Applications for Resilience by Simulating Network Problems with Toxiproxy, JUnit and the Docker Maven Plugin

<properties>
	[..]
	<java.version>9</java.version>
	<maven.compiler.source>${java.version}</maven.compiler.source>
	<maven.compiler.target>${java.version}</maven.compiler.target>
</properties>

package com.hascode.tutorial;

import java.net.URI;
import java.time.Duration;
import java.time.Instant;
import jdk.incubator.http.HttpClient;
import jdk.incubator.http.HttpClient.Version;
import jdk.incubator.http.HttpRequest;
import jdk.incubator.http.HttpRequest.BodyProcessor;
import jdk.incubator.http.HttpResponse;

public class UpstreamService {

  public void callRestEndpoint(String url) {
    HttpRequest request = HttpRequest.newBuilder()
        .uri(URI.create(url))
        .header("Accept", "application/json")
        .GET().build();
    Instant start = Instant.now();
    HttpClient
        .newBuilder()
        .version(Version.HTTP_1_1)
        .build()
        .sendAsync(request, HttpResponse.BodyHandler.asString()).thenApply(HttpResponse::body)
        .thenAccept(System.out::println).join();
    long durationInSeconds = Duration.between(start, Instant.now()).getSeconds();
    System.out.printf("the request took %d seconds%n", durationInSeconds);
  }

  public void sendToRestEndpoint(String url, int size) {
    byte[] body = new byte[size];

    HttpRequest request = HttpRequest.newBuilder()
        .uri(URI.create(url))
        .header("Content-type", " application/octet-stream")
        .POST(BodyProcessor.fromByteArray(body)).build();
    Instant start = Instant.now();
    HttpClient
        .newBuilder()
        .version(Version.HTTP_1_1)
        .build()
        .sendAsync(request, HttpResponse.BodyHandler.asString()).thenApply(HttpResponse::body)
        .thenAccept(System.out::println).join();
    long durationInSeconds = Duration.between(start, Instant.now()).getSeconds();
    System.out.printf("uploading %d kb took %d seconds%n", (size/1024), durationInSeconds);
  }
}

module toxiproxy.tutorial {
  requires jdk.incubator.httpclient;
}

<dependencies>
	<dependency>
	  <groupId>eu.rekawek.toxiproxy</groupId>
	  <artifactId>toxiproxy-java</artifactId>
	  <version>2.1.3</version>
	</dependency>
	<dependency>
	  <groupId>com.github.tomakehurst</groupId>
	  <artifactId>wiremock</artifactId>
	  <version>2.18.0</version>
	  <scope>test</scope>
	</dependency>
	<dependency>
	  <groupId>junit</groupId>
	  <artifactId>junit</artifactId>
	  <version>4.12</version>
	  <scope>test</scope>
	</dependency>
</dependencies>

<build>
	<plugins>
	  <!-- start toxiproxy via docker and docker-maven-plugin -->
	  <plugin>
		<groupId>io.fabric8</groupId>
		<artifactId>docker-maven-plugin</artifactId>
		<version>0.26.0</version>
		<executions>
		  <execution>
			<id>prepare-it-toxiproxy</id>
			<phase>pre-integration-test</phase>
			<goals>
			  <goal>start</goal>
			</goals>
			<configuration>
			  <images>
				<image>
				  <name>shopify/toxiproxy</name>
				  <alias>it-toxiproxy</alias>
				  <run>
					<network>
					  <mode>host</mode>
					</network>
					<wait>
					  <tcp>
						<host>localhost</host>
						<ports>
						  <port>8474</port>
						</ports>
					  </tcp>
					  <kill>2000</kill>
					</wait>
				  </run>
				</image>
			  </images>
			</configuration>
		  </execution>
		  <execution>
			<id>remove-it-toxiproxy</id>
			<phase>post-integration-test</phase>
			<goals>
			  <goal>stop</goal>
			</goals>
			<configuration>
			  <removeVolumes>true</removeVolumes>
			</configuration>
		  </execution>
		</executions>
	  </plugin>
	</plugins>
</build>

$ mvn integration-test
[..]
[INFO] --- docker-maven-plugin:0.26.0:start (prepare-it-toxiproxy) @ toxiproxy-tutorial ---
[INFO] DOCKER> [shopify/toxiproxy:latest] "it-toxiproxy": Start container cf2f0b20f6c1
[INFO] DOCKER> [shopify/toxiproxy:latest] "it-toxiproxy": Waiting for ports [8474] directly on container with IP ().
[INFO] DOCKER> [shopify/toxiproxy:latest] "it-toxiproxy": Waited on tcp port '[localhost/127.0.0.1:8474]' 521 ms
[INFO]
[INFO] --- maven-failsafe-plugin:2.22.0:integration-test (default) @ toxiproxy-tutorial ---
[INFO]
[INFO] -------------------------------------------------------
[INFO]  T E S T S
[INFO] -------------------------------------------------------
[INFO] Running it.RestConnectionIT
SLF4J: Failed to load class "org.slf4j.impl.StaticLoggerBinder".
SLF4J: Defaulting to no-operation (NOP) logger implementation
SLF4J: See http://www.slf4j.org/codes.html#StaticLoggerBinder for further details.
{"now":"2018-07-29T16:10:38.042490"}
the request took 12 seconds
data received
uploading 1024 kb took 7 seconds
[INFO] Tests run: 2, Failures: 0, Errors: 0, Skipped: 0, Time elapsed: 20.272 s - in it.RestConnectionIT
[INFO]
[INFO] Results:
[INFO]
[INFO] Tests run: 2, Failures: 0, Errors: 0, Skipped: 0
[INFO]
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------

docker exec -it $TPROXY_ID /bin/sh -c '/go/bin/toxiproxy-cli ls'
Name                    Listen          Upstream                Enabled         Toxics
======================================================================================
http-tproxy             127.0.0.1:8888  app.hascode.com:80      enabled         1

docker exec -it $TPROXY_ID /bin/sh -c '/go/bin/toxiproxy-cli inspect http-tproxy'
Name: http-tproxy       Listen: 127.0.0.1:8888  Upstream: app.hascode.com:80
======================================================================
Upstream toxics:
Proxy has no Upstream toxics enabled.

Downstream toxics:
latency-toxic:  type=latency    stream=downstream       toxicity=1.00   attributes=[    jitter=15       latency=20      ]

Hint: add a toxic with `toxiproxy-cli toxic add`