Gatling-gRPC

A Gatling load test plugin for gRPC.

Java/Kotlin API

Since 3.7, Gatling adds Java API for the test to be written in Java or Kotlin. Since Gatling-gRPC 0.14.0, a binding is written in Kotlin for Java and Kotlin users. It is demoed in the gatling-grpc-gradle-demo project.

Usage

Because of gRPC's need of code generation, I assume you are running the tests using a build tool, e.g. the SBT plugin. For a quickstart guide, see this Medium article.

For usage with the Gradle Gatling plugin, see this example project.

To use this library, add this library to the test dependencies along with the two required by Gatling.

libraryDependencies ++= Seq(
  "io.gatling.highcharts" % "gatling-charts-highcharts" % gatlingVersion % "test",
  "io.gatling" % "gatling-test-framework" % gatlingVersion % "test",
  "com.github.phisgr" % "gatling-grpc" % "0.16.0" % "test"
)
enablePlugins(GatlingPlugin)

For setting up the code generation, see the documentation in ScalaPB.

If your protobuf files are in src/test/protobuf instead of src/main/protobuf, change Compile to Test.

Test / PB.targets := Seq(
  scalapb.gen() -> (Test / sourceManaged).value
)

To make a gRPC call:

exec(
  grpc("my_request")
    .rpc(ChatServiceGrpc.METHOD_GREET)
    .payload(GreetRequest(
      username = "myUserName",
      name = "My name"
    ))
)

For a complete demo and various examples including the proper syntax to include session attributes (e.g. from a feeder, or saved in a check), see GrpcExample in test.

For more complex manipulations with session attributes and protobuf objects, like repeated fields and map fields, see the unit test.

Dynamic Payload

There are helper methods in gatling-grpc for generating dynamic ScalaPB objects with Lenses, as demonstrated in the example linked above. It makes uses of extension methods, and requires importing com.github.phisgr.gatling.pb._.

If you want to use Java Protobuf classes, you can use the gatling-javapb library.

If the expressive power of these two plumbing tools are not enough, you can always resort to writing a lambda. Because an Expression[T]is just an alias for Session => Validation[T].

Logging

In logback.xml, add
<logger name="com.github.phisgr.gatling.grpc" level="DEBUG" />
to log the requests that are failed; or set the level to TRACE to log all gRPC requests.

Development

sbt clean coverage test Gatling/test coverageReport for a coverage report.
sbt clean bench/clean 'bench/jmh:run -i 3 -wi 3 -f10 -t1 -prof gc' for JMH tests.