Gatling Wait

A solution built around Gatling DSL for a convenient way to wait for an event. Three key ingredients:

1. A condition to wait for
2. The number of attempts
3. Pauses between attempts

Let's say you have an application with asynchronous logic, and you need to wait for a condition to be met. My real-life example involves creating a process with three statuses: processing, completed, and failed.

For instance, the endpoint to get the process status is https://application.com/status.

Here’s a request that polls and saves the status to the variable status:

 val getProcess = http("Get process")
    .get("/status")
    .check(
      jsonPath("$.status") saveAs "status"
    )

To wait:

import io.github.amerousful.wait._

val waitCompleted = Wait()
  .requestForPolling(getProcess)
  .waitUntil(condition("status")(_ == "completed"))
  .failOn(condition("status")(_ == "failed"))
  .terminalCheck(jsonPath("$.status") is "completed")
  .pauseDuration(1 second)
  .attempts(5)
  .init()

This waits for the status completed with 5 attempts and a 1 second pause between attempts. *Note that the pause duration consists of the pause plus the response time of a polling request, so the pause duration might fluctuate.

Additionally, it will fail if the status is failed, as there’s no need to wait for completed in that case.

Additional info:

condition("status")(_ == "completed")
              ↑             ↑ 
              |             | 
      variable name   condition to satisfy

OR

condition("status")(extracted => extracted == "completed")

You can also declare multiple conditions:

.waitUntil(
  condition("link")(_ != "empty"),
  condition("outdated")(_ == "false"),
)

.terminalCheck(
    jsonPath("$.link") is "empty",
    jsonPath("$.state.outdated") is "true",
  )

Make sure to add the same conditions in both the wait and the terminal check.

terminalCheck() - this check will execute when all attempts are reached, and its purpose is to fail the request if the conditions are not met.

---

This plugin records the number of attempts in the Session. The counter is stored as wait.attemptCounter -> {attemptNumber}.

Installation

Important: This plugin is compatible only with Gatling 3.9.5 and does not work with any versions above 3.9.5.

Maven:

Add to your pom.xml:

<dependency>
    <groupId>io.github.amerousful</groupId>
    <artifactId>gatling-wait</artifactId>
    <version>1.0</version>
</dependency>

SBT

Add to your build.sbt:

libraryDependencies += "io.github.amerousful" % "gatling-wait" % "1.0"

Import:

import io.github.amerousful.wait._

---

Logging

Add this to your logback.xml:

<logger name="io.github.amerousful.wait" level="ALL"/>