String Timer

---

Description

The String Timer processor measures how long a string field maintains a specific value. It supports:

• String value monitoring
• Duration measurement
• Multiple time units
• Configurable output frequency

This processor is essential for:

• Measuring state durations
• Tracking value persistence
• Monitoring string states
• Calculating time periods

---

Required input

The processor requires a data stream containing at least one string field to monitor for value changes.

---

Configuration

String Field

Select the string field to monitor for value changes. This field will be used to measure how long it maintains a specific value.

Output Unit

Choose the time unit for the measured duration:

• Milliseconds (default)
• Seconds
• Minutes

Output Frequency

Define when the processor should emit an output event:

• On Input Event: Emit for every input event
• When String Value Changes: Emit only when the string value changes

Output

The processor creates a new event containing:

• All original fields from the input event
• A measured_time field showing the duration in the selected unit
• A field_value field showing the previous string value

Example

Input Event

{
  "deviceId": "machine01",
  "status": "running",
  "timestamp": 1586380104915
}

Configuration

• String Field: status
• Output Unit: Seconds
• Output Frequency: When String Value Changes

Output Event (when status changes from "running" to "stopped")

{
  "deviceId": "machine01",
  "status": "stopped",
  "timestamp": 1586380106915,
  "measured_time": 2.0,
  "field_value": "running"
}

Use Cases

1. State Monitoring

   • Measure state durations
   • Track value persistence
   • Monitor status changes
   • Calculate time periods

2. Process Control

   • Measure process durations
   • Track state changes
   • Monitor operations
   • Calculate times

Notes

• Only string fields can be monitored
• Time measurement is stateful
• Measurement starts on value change
• Measurement ends on next change
• Output depends on frequency setting