Simulate errors from Microsoft Graph APIs

Microsoft Graph is a collection of APIs that give you access to data and insights on Microsoft 365. When you use Microsoft Graph in your app, you should test how your app handles API errors. Dev Proxy allows you to simulate errors on any Microsoft Graph API using the GraphRandomErrorPlugin.

The GraphRandomErrorPlugin is optimized to work with Microsoft Graph and simulates the specific errors that Microsoft Graph can return.

To start, enable the GraphRandomErrorPlugin in your configuration file.

{
  "$schema": "https://raw.githubusercontent.com/microsoft/dev-proxy/main/schemas/v0.14.1/rc.schema.json",
  "plugins": [
    {
      "name": "GraphRandomErrorPlugin",
      "enabled": true,
      "pluginPath": "~appFolder/plugins/dev-proxy-plugins.dll",
      "configSection": "graphRandomErrorPlugin",
      "urlsToWatch": [
        "https://graph.microsoft.com/v1.0/*",
        "https://graph.microsoft.com/beta/*",
        "https://graph.microsoft.us/v1.0/*",
        "https://graph.microsoft.us/beta/*",
        "https://dod-graph.microsoft.us/v1.0/*",
        "https://dod-graph.microsoft.us/beta/*",
        "https://microsoftgraph.chinacloudapi.cn/v1.0/*",
        "https://microsoftgraph.chinacloudapi.cn/beta/*"
      ]
    }
  ]
}

Tip

The above snippet listens for requests to Microsoft Graph in all Microsoft clouds. If you only want to simulate errors in a specific Microsoft cloud, remove the URLs that you don't need.

Start Dev Proxy with your configuration file and use your app to see how it handles the errors. For each matching request, Dev Proxy determines whether to simulate an error or pass the request through to Microsoft Graph using the configured failure rate. When Dev Proxy simulates an error, it randomly selects one of the errors that Microsoft Graph uses, and returns an error response to your app.

Configure errors to simulate

By default, the GraphRandomErrorPlugin simulates the following errors.

HTTP method	Possible errors
GET	429 Too Many Requests, 500 Internal Server Error, 502 Bad Gateway, 503 Service Unavailable, 504 Gateway Timeout
POST	429 Too Many Requests, 500 Internal Server Error, 502 Bad Gateway, 503 Service Unavailable, 504 Gateway Timeout, 507 Insufficient Storage
PUT	429 Too Many Requests, 500 Internal Server Error, 502 Bad Gateway, 503 Service Unavailable, 504 Gateway Timeout, 507 Insufficient Storage
PATCH	429 Too Many Requests, 500 Internal Server Error, 502 Bad Gateway, 503 Service Unavailable, 504 Gateway Timeout
DELETE	429 Too Many Requests, 500 Internal Server Error, 502 Bad Gateway, 503 Service Unavailable, 504 Gateway Timeout, 507 Insufficient Storage

If you want to test specific behaviors, such as throttling, configure the plugin to only use the relevant errors using the --allowed-errors option.

devproxy --allowed-errors 429

Alternatively, you can configure the allowedErrors property in the graphRandomErrorPlugin object in your configuration file.

{
  "graphRandomErrorPlugin": {
    "allowedErrors": [ 429 ]
  }
}

Simulate errors in Microsoft Graph batch requests

Dev Proxy simulates errors in batch requests to Microsoft Graph in the same way as it does for regular requests. When Dev Proxy fails one or more requests in a batch request, it returns a 424 Failed Dependency response for the whole batch request, just like Microsoft Graph would.