Understanding Iterations

Key Attributes of an Iteration

• Name: Identifier for the iteration.
• HTTP Request: Configuration for the request, including the method, URL, headers, and payload.
• Mode: Defines how the iteration operates (see Iteration Modes).
• Startup Delay: Optional delay before starting the iteration.
• MaximizeThroughput: Set maximizeThroughput: true to push send-rate as fast as other constraints allow. Maximizing the throughput will result in higher CPU and Memory usage

Structure

• The plan is at the document root (no plan: key).
• Rounds are required; each round contains one or more iterations.
• Each iteration typically contains an httpRequest.

Iteration Features

SkipIf

The skipIf property allows conditional execution of an iteration. If the condition evaluates to true, the iteration will be skipped. Conditions can use Flee expressions and may reference session/global variables, placeholders, and metrics.

Example use cases:

• Skip login attempts if login failed to get a response.
• Skip requests when a certain error condition has been met.

skipIf: ${LoginResponse.StatusCode} = 401
skipIf: ${LoginResponse.Body.token} = ""
skipIf: ${Metrics.Load.Heavy.Duration.P90ResponseTime} > 250

Failure Rules

The failureRules property defines rules that are applied after the iteration finishes. These rules classify the outcome of the iteration as either Failed or Success. This is useful for reporting and post-run analysis.

failureRules:
  - metric: "ErrorRate > 0.10"
    errorStatusCodes: ">= 500"
  - metric: "TotalTime.P90 > 250"
  - metric: "TotalTime.P50 > 200"
  - metric: "TotalTime.Avg > 180"

CLI Usage

lps --url https://example.com -rc 1000 --failurerule "ErrorRate > 0.05;>= 500" --failurerule "TotalTime.P90 > 250"

Format: "metric[;errorStatusCodes]"

Termination Rules

The terminationRules property lets you define real-time termination conditions for an iteration. These rules are evaluated continuously by the Master node (aggregating all workers). An iteration will be terminated only if a rule is continuously violated for the entire grace period.

terminationRules:
  - metric: "ErrorRate > 0.2"
    errorStatusCodes: ">= 500"
    gracePeriod: "00:00:10"
  - metric: "TotalTime.P90 > 200"
    gracePeriod: "00:00:05"
  - metric: "TotalTime.P50 > 400"
    gracePeriod: "00:00:15"

CLI Usage

lps --url https://example.com -rc 1000 --terminationrule "ErrorRate > 0.10;00:05:00;>= 500" --terminationrule "TotalTime.P90 > 500;00:00:30"

Format: "metric;gracePeriod[;errorStatusCodes]"

Metric Expression Reference

Both failureRules and terminationRules use the same inline metric expression format.

Expression Format

MetricName[.Statistic] Operator Threshold

Supported Metrics

Supported Operators

Complete Iteration Example

name: IterationFeaturesPlan
rounds:
  - name: FeatureRound
    numberOfClients: 50
    arrivalDelay: 100
    runInParallel: false
    iterations:
      - name: LoginIteration
        httpRequest:
          url: https://httpbin.org/post
          method: POST
          headers:
            Content-Type: application/json
          payload:             
            raw: |
                { "username": "user", "password": "pass" }
      - name: Home
        httpRequest:
          url: https://httpbin.org/
          httpMethod: Get

        # SkipIf (iteration)
        skipIf: ${LoginResponse.StatusCode} = 401

        # Failure Rules (evaluated once the iteration execution is completed)
        failureRules:
          - metric: "ErrorRate > 0.10"
            errorStatusCodes: ">= 400"
          - metric: "TotalTime.P90 > 250"

        # Termination Rules (evaluated in real-time during execution)
        terminationRules:
          - metric: "ErrorRate > 0.2"
            errorStatusCodes: ">= 400"
            gracePeriod: "00:00:03"
          - metric: "TotalTime.P90 > 2000"
            gracePeriod: "00:00:05"

Global Iterations and References

Iterations can also be defined as global iterations and referenced later within rounds using the reference property. This allows for reusable iteration configurations across multiple rounds.

name: GlobalIterationPlan
iterations:
- name: GlobalIteration
  mode: DCB
  duration: 300
  batchSize: 100
  coolDownTime: 1000
  httpRequest:
    url: https://httpbin.org/headers
    httpMethod: GET
    httpVersion: 2.0
rounds:
- name: TestRound
  numberOfClients: 1
  reference: ["GlobalIteration"]