Stub Application Filter

The FilterStubApplication is a simple synthetic filter that outputs structured events without analyzing image frames. It is ideal for testing and debugging pipelines that expect a stream of JSON events.

Features

• Two Output Modes

  • echo: Emits real events from a static JSON file
  • random: Emits synthetic events generated from a user-defined JSON schema
    Select the mode using the output_mode parameter.

• Schema-Based Random Generation
  The random mode uses JSON Schema to generate realistic test events.

• Configurable Output
  Events are streamed to the location defined by output_json_path in newline-delimited JSON format.

• Debug Logging
  Enable debug: true to activate verbose logs for insight into behavior and issues.

• Graceful Setup and Shutdown
  The filter ensures proper file handling by opening and closing resources as needed.

Example Output

Each event is emitted to the output file as a single JSON line, e.g.:

{
  "event_type": "EXAMPLE",
  "payload": {
    "field1": "value",
    "field2": 123
  }
}

When to Use

Use this filter when:

• You want to simulate event streams for integration or performance testing
• You want to test downstream processing logic without requiring real input data
• You want to verify pipeline stability with synthetic or controlled data

Configuration Reference

Key	Type	Default	Description
output_mode	string	"echo"	Mode of operation: "echo" or "random"
debug	boolean	false	Enable debug logging
output_json_path	string	"./output/output.json"	Path to save emitted JSON events
input_json_events_file_path	string	"./input/events.json"	Path to input file for echo mode
input_json_template_file_path	string	"./input/events_template.json"	Path to JSON schema template for random mode

Tip

Echo mode is great for replaying fixed data during development. Use random mode to test edge cases with synthetic variety.