How to Simulate HTTP Errors Using fault

This guide will walk you through emulating application level HTTP errors into your application using fault proxy capabilities.

Prerequisites

• Install fault

  If you haven’t installed fault yet, follow the installation instructions.

• Basic Proxy Setup Be familiar with running fault run --with-[fault] commands from your terminal.

Constant Internal Server Error

• Start the proxy with HTTP Error 500 from the remote server

  fault run \
      --with-http-response \ # (1)!
      --http-response-status 500 \ # (2)!
      --http-response-trigger-probability 1  # (3)!
  

  1. Enable the HTTP error fault support
  2. Set the status to 500
  3. Set the error on all responses

Intermittent Service Unavailable Errors

• Start the proxy with HTTP Error 503 from the remote server

  fault run \
      --with-http-response \ # (1)!
      --http-response-status 503 \ # (2)!
      --http-response-trigger-probability 0.5  # (3)!
  

  1. Enable the HTTP error fault support
  2. Set the status to 503
  3. Set the error on half of the responses

Intermittent Not Found Errors

• Start the proxy with HTTP Error 404 from the remote server

  fault \
      --with-http-response \ # (1)!
      --http-response-status 404 \ # (2)!
      --http-response-trigger-probability 0.5 \ # (3)!
      --http-response-body '{"error": "true"}' # (4)!
  

  1. Enable the HTTP error fault support
  2. Set the status to 404
  3. Set the error on half of the responses
  4. Set a JSON response body