replay — Stream dataset exports over WebSocket

s6 replay replays a StructuredDataset directory and exposes its context["export"] payloads over a lightweight WebSocket service. Unlike s6 track, it does not run inference or mutate the dataset frames; it simply relays what is already recorded.

Usage

# Replay a dataset forever on the default service endpoint
s6 replay ./datasets/session_001 --repeat

# Bind to a different host/port and slow playback down
s6 replay ./datasets/session_001 --host 127.0.0.1 --port 9000 --hz 10

# Disable replay throttling backpressure
s6 replay ./datasets/session_001 --max-queue 0

Behavior

  • Validates that the dataset directory exists and contains data.jsonl.

  • Starts a background producer process that reads the dataset through StructuredDataset and enqueues frame records.

  • Serves WebSocket clients on /ws/telemetry.

  • Also exposes /queue_size for a simple backlog health check.

  • Sends JSON payloads with:

    • export: the recorded context["export"] object, or {} when absent

    • stats.queue_size: the current queue backlog when available

  • --repeat loops the dataset indefinitely.

  • --hz controls playback rate in frames per second; values less than or equal to 0 disable the sleep throttle.

  • --max-queue applies backpressure to the producer; 0 disables that limit.

Notes

  • This command is useful when a downstream consumer only needs recorded export telemetry and not the full pipeline runtime.

  • The default bind address is 0.0.0.0:8001.