Configure Mock Source

The Mock Source Source A connection to an external system that Drasi monitors for data changes. Learn more generates synthetic data on a timer, so you can test queries and reactions without connecting to a real system.

When to use the Mock source

• Developing and testing continuous queries locally.
• Demo environments where you want predictable, infrastructure-free data generation.
• Load/throughput testing (within reason).

Quick example (Drasi Server config)

Drasi Server source configuration uses camelCase keys.

sources:
  - kind: mock
    id: demo-sensors
    autoStart: true

    # Optional - defaults to generic
    dataType: sensor_reading
    intervalMs: 1000

Configuration reference (Drasi Server)

Fields support Drasi Server config references like ${ENV_VAR} / ${ENV_VAR:-default}.

Data types and generated nodes

The dataType field controls what kind of data the mock source generates. It can be specified as:

• Simple string: "counter", "sensor_reading", or "generic"
• Object with options: { type: sensor_reading, sensor_count: 10 }

Counter

Generates sequential counter values. Each event is an INSERT.

dataType: counter

• Label: Counter
• Element ID: counter_{sequence}
• Properties: value (sequential integer), timestamp (RFC3339 string)

Sensor Reading

Simulates sensor devices. The first reading for each sensor generates an INSERT, subsequent readings generate UPDATE events for the same node.

Simple form (5 sensors):

dataType: sensor_reading

With custom sensor count:

dataType:
  type: sensor_reading
  sensor_count: 10

• Label: SensorReading
• Element ID: sensor_{sensor_id} (one per simulated sensor)
• Properties: sensor_id (integer 0 to sensor_count-1), temperature (float 20.0..30.0), humidity (float 40.0..60.0), timestamp

Generic (default)

Generates random data. Each event is an INSERT.

dataType: generic

• Label: Generic
• Element ID: generic_{sequence}
• Properties: value (random i32), message (“Generic mock data”), timestamp

Example: Testing with sensor data

sources:
  - kind: mock
    id: sensors
    autoStart: true
    dataType:
      type: sensor_reading
      sensor_count: 3
    intervalMs: 1000

queries:
  - id: high-temp
    query: |
      MATCH (s:SensorReading)
      WHERE s.temperature > 25
      RETURN s.sensor_id, s.temperature
    sources:
      - sourceId: sensors
    autoStart: true

reactions:
  - kind: log
    id: alerts
    queries: [high-temp]
    autoStart: true

This configuration:

1. Simulates 3 sensors generating readings every second
2. Monitors for temperatures above 25°C
3. Logs alerts when high temperatures are detected

Performance tuning notes

• Decrease intervalMs to generate more data (higher load).
• Use multiple mock sources with different ids if you want independent streams.
• For sensor_reading, increase sensor_count to simulate more devices.

Troubleshooting

Known limitations

• Sequence counters reset on restart; data is not persisted.
• No relationships are generated.
• sensor_reading generates updates for existing nodes; counter and generic only generate inserts.

Documentation resources