Configuration

SchedulerConfig

Controls scheduling behavior. Set via builder methods or pass directly to Scheduler::new().

Field	Type	Default	Description
max_concurrency	usize	4	Maximum concurrent running tasks. Adjustable at runtime via set_max_concurrency().
max_retries	i32	3	Retry limit before a task is permanently failed.
preempt_priority	Priority	REALTIME (0)	Tasks at or above this priority trigger preemption of lower-priority work.
poll_interval	Duration	500ms	Sleep between scheduler dispatch cycles. The scheduler also wakes on Notify signals.
throughput_sample_size	i32	20	Number of recent completions used for throughput-based progress extrapolation.
shutdown_mode	ShutdownMode	Hard	Hard cancels all tasks immediately. Graceful(Duration) waits up to the timeout.

Builder methods

use std::time::Duration;
use taskmill::{Scheduler, Priority, ShutdownMode};

let scheduler = Scheduler::builder()
    .max_concurrency(8)
    .max_retries(5)
    .preempt_priority(Priority::HIGH)
    .poll_interval(Duration::from_millis(250))
    .shutdown_mode(ShutdownMode::Graceful(Duration::from_secs(30)))
    .build()
    .await?;

StoreConfig

Controls the SQLite connection pool and history retention.

Field	Type	Default	Description
max_connections	u32	16	SQLite connection pool size.
retention_policy	Option<RetentionPolicy>	None	Automatic history pruning. MaxCount(n) or MaxAgeDays(n).
prune_interval	u64	100	Number of task completions between automatic prune runs.

Builder method

use taskmill::{StoreConfig, RetentionPolicy};

let scheduler = Scheduler::builder()
    .store_config(StoreConfig {
        max_connections: 32,
        retention_policy: Some(RetentionPolicy::MaxCount(10_000)),
        prune_interval: 50,
        ..Default::default()
    })
    .build()
    .await?;

SamplerConfig

Controls the resource monitoring background loop.

Field	Type	Default	Description
interval	Duration	1s	How often to sample system resources.
ewma_alpha	f64	0.3	EWMA smoothing factor. Higher = more responsive to changes, lower = smoother.

Builder method

use std::time::Duration;
use taskmill::SamplerConfig;

let scheduler = Scheduler::builder()
    .with_resource_monitoring()
    .sampler_config(SamplerConfig {
        interval: Duration::from_millis(500),
        ewma_alpha: 0.5,
    })
    .build()
    .await?;

ShutdownMode

Variant	Behavior
Hard	Cancel all running tasks immediately when the scheduler stops.
Graceful(Duration)	Stop dispatching new tasks, wait for running tasks to complete (up to the timeout), then force-cancel any remaining. Stops the resource sampler afterward.

RetentionPolicy

Variant	Behavior
MaxCount(i64)	Keep the N most recent history records, prune the rest.
MaxAgeDays(i64)	Keep records from the last N days, prune older entries.

Priority constants

Constant	Value	Notes
Priority::REALTIME	0	Highest. Never throttled. Triggers preemption.
Priority::HIGH	64
Priority::NORMAL	128	Default for most tasks.
Priority::BACKGROUND	192
Priority::IDLE	255	Lowest.

Custom: Priority::new(n) for any u8 value.

Feature flags

Feature	Default	Description
sysinfo-monitor	Enabled	Cross-platform CPU and disk IO monitoring via sysinfo. Disable for mobile targets or custom samplers.

Disabling platform monitoring

[dependencies]
taskmill = { path = "crates/taskmill", default-features = false }

When disabled, you can still provide a custom ResourceSampler via .resource_sampler().

Builder reference

All SchedulerBuilder methods:

Method	Description
store_path(path)	Path to the SQLite database file.
store(store)	Use a pre-opened TaskStore.
store_config(config)	Pool size and retention settings.
executor(name, executor)	Register a TaskExecutor by name.
typed_executor::<T>(executor)	Register using T::TASK_TYPE as the name.
max_concurrency(n)	Set initial max concurrent tasks.
max_retries(n)	Set retry limit.
preempt_priority(p)	Set preemption threshold.
poll_interval(d)	Set dispatch cycle interval.
shutdown_mode(mode)	Set shutdown behavior.
pressure_source(source)	Add a PressureSource to the composite.
throttle_policy(policy)	Set a custom ThrottlePolicy.
with_resource_monitoring()	Enable platform resource monitoring.
resource_sampler(sampler)	Provide a custom ResourceSampler.
sampler_config(config)	Configure sample interval and smoothing.
bandwidth_limit(bytes_per_sec)	Set a network bandwidth cap; registers a built-in NetworkPressure source.
default_group_concurrency(n)	Default concurrency limit for grouped tasks (0 = unlimited).
group_concurrency(group, n)	Per-group concurrency limit override.
app_state(state)	Register a state type (multiple types can coexist).
app_state_arc(arc)	Register a state type from a pre-existing Arc.
build()	Build and return the Scheduler.