This repository contains the Java (JAX-RS and Helidon) and Go implementation of a tiny microservice.

The service provides the following endpoints:

• /uppercase converts the input string s to uppercase
• /count returns the length of the input string s
• /metrics returns Prometheus formatted metrics for the runtime and application metrics

Set JMETER_HOME enviroment variable to the JMeter installation directory. Set GRAALVM_HOME environment variable to the GraalVM installation.

Set the desired JAVA_HOME. Java implementation requires JDK11+.

Scripts are written and tested using MacOS.

Use the run-go-tests.sh script which builds, runs the microservices application and JMeter. Parameters:

1. logging|no-logging (mandatory): Switching log level between INFO (logging) and ERROR (no-logging). This option is introduced because logging can cause significant performance degradation.
2. warmup (optional): 1000 "warm up" calls before the load test.

For example:

run-go-tests.sh no-logging warmup

Console log contains information about RSS memory size. Before the warmup, before the load test and at the end of the load test.

Use the run-helidon-tests.sh script which builds, runs the microservices application and JMeter. Parameters are the following:

1. logging|no-logging (mandatory): Switching log level between INFO (logging) and ERROR (no-logging). This option is introduced because logging can cause significant performance degradation.
2. warmup|no-warmup (mandatory): 1000 "warm up" calls before the load test.
3. nmt|no-nmt (mandatory): Native Memory Tracking to get details about Java/JVM memory usage. Note that enabling this will cause 5-10% performance overhead.
4. Xms/Xmx (mandatory): The initial and minimum Java heap size in MB. Both will get the same value.
5. javaopts (optional): Additional JVM options e.g. -XX:+UseG1GC

For example:

run-helidon-tests.sh no-logging warmup no-nmt 32

In case of Native Memory Tracking console log contains initial memory snapshot and increment at the end of the load test.

For the record the script saves the available and selected/used JDK version into a java.version.txt in the corresponding test-result folder.

Use the run-nativeimage-tests.sh script which builds, runs the microservices application and JMeter. Parameters are the following:

1. logging|no-logging (mandatory): Switching log level between INFO (logging) and ERROR (no-logging). This option is introduced because logging can cause significant performance degradation.
2. warmup|no-warmup (mandatory): 1000 "warm up" calls before the load test.
3. nobuild (optional): Skip Native Image build which can take a lot of time. In this case trying to use previously built executable binary.

For example:

run-nativeimage-tests.sh no-logging warmup

Console log contains information about RSS memory size. Before the warmup, before the load test and at the end of the load test.

After the successful run the test results available in the test-results folder.