Configuration - Sluice

Auto-configured settings

The SDK automatically enables three Celery settings that are critical for monitoring. All three are False by default in Celery — which means most Celery deployments emit zero monitoring data out of the box.

Setting	Default	SDK sets to	Purpose
`worker_send_task_events`	`False`	`True`	Enables the real-time event stream. Without this, Sluice receives nothing.
`task_send_sent_event`	`False`	`True`	Emits an event when a task is dispatched. Without this, “sent but not yet received” tasks are invisible — Celery reports them as PENDING (which just means “unknown”).
`task_track_started`	`False`	`True`	Emits an event when a task begins executing. Without this, duration tracking is impossible.

The SDK sets these via the Celery Bootstep it installs. If you’ve explicitly set any of these to False in your Celery config, the SDK will log a warning but respect your setting.

Recommended Celery settings

These aren’t required, but they improve monitoring reliability:

# Prevent tasks from running forever without a timeout.
# This is Celery's #1 silent failure mode — tasks can hang indefinitely
# and occupy a worker slot until the process is killed.
task_time_limit = 600  # seconds (hard kill)
task_soft_time_limit = 540  # seconds (SoftTimeLimitExceeded exception)

# Keep prefetch low for long-running tasks.
# High prefetch means workers grab multiple tasks upfront, which makes
# queue depth readings inaccurate and can cause uneven load distribution.
worker_prefetch_multiplier = 1  # default is 4

# Store results so Sluice can capture return values and errors.
# Without a result backend, failed tasks lose their traceback after
# the event stream window expires.
result_backend = "redis://localhost:6379/0"
result_expires = 86400  # 24 hours (default)

Settings the SDK never touches

Setting	Why we leave it alone
`worker_hijack_root_logger`	Changing logging config in customer infrastructure is too invasive.
`task_time_limit`	Safety-critical — should be an explicit choice, not auto-configured.
`worker_prefetch_multiplier`	Affects throughput characteristics.
`result_backend`	Requires infrastructure (Redis/DB). Can’t be assumed.
`broker_url`	The SDK reads this, but never modifies it.

​Auto-configured settings

​Recommended Celery settings

​Settings the SDK never touches

Auto-configured settings

Recommended Celery settings

Settings the SDK never touches