# Issue #25 — Add structured JSONL logger for track lifecycle events

[Devnil434]

Description

Currently lifecycle events (BORN, LOST, DEAD) are only printed to the console.

Add a structured JSONL logger that appends lifecycle events into:

data/logs/tracks.jsonl

Each event should be stored as one JSON object per line so events can later
be replayed, inspected, or analyzed offline.

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Example Output

{"event":"BORN","track_id":3,"frame_id":0,"zones":["restricted_door"],"timestamp_ms":1718000000000}
{"event":"DEAD","track_id":3,"frame_id":900,"dwell_time_seconds":30.1,"timestamp_ms":1718000030000}

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Files to Touch

libs/utils/lifecycle_logger.py
services/tracking/tracker.py
tests/test_lifecycle_logger.py

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Implementation Notes

• Create reusable helper:

  lifecycle_logger.log(event)

• Call logger inside _emit_lifecycle()

• Logger should append safely without overwriting previous events

• Support configurable path via:

  LIFECYCLE_LOG_PATH

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Acceptance Criteria

• JSONL file created automatically
• Events appended correctly
• Path configurable through env variable
• Unit tests mock file writes (no real disk I/O)
• Existing tests remain green

[byebyewe86-alt]

Hi @Devnil434, I’d like to work on this issue under GSSoC 2026. I’m currently exploring the lifecycle flow and logger structure before starting implementation. Could you please assign this to me?

[byebyewe86-alt]

Hi @Devnil434, thanks for assigning this issue to me.

I don’t think I’ll be able to give this task enough time right now, so I’d prefer to step back rather than block progress on the issue. Please feel free to unassign me and open it up for other contributors.

Thanks!

[SaurabhD19]

hey @Devnil434 , I would like to work on this issue under GSSoC 2026.
Could you assign it to me ?