Presets

Last updated 2026-10-02

This page explains PresetConfig, how a preset sets a task's priority and base timeout, and what an undefined preset name resolves to.

PresetConfig

type PresetConfig struct {
    Priority Priority
    Timeout  time.Duration
}

Field	Zero Value	Description
`Priority`	`PriorityImmediate`	Initial priority for tasks using this preset
`Timeout`	`0`	When `> 0`, replaces `Config.Timeout` as this preset's base timeout

A preset name missing from the map (including "") resolves to the zero PresetConfig{}, which means PriorityImmediate plus the global base timeout.

Example

q := core.New(&core.Config{
    Workers: 8,
    Size:    1024,
    Timeout: 30 * time.Second,
    Preset: map[string]core.PresetConfig{
        "payment": {Priority: core.PriorityHigh},
        "email":   {Priority: core.PriorityNormal},
        "report":  {Priority: core.PriorityLow, Timeout: 60 * time.Second},
    },
})

Preset	Priority	Effective Timeout	Promotion
`payment`	High	`30s ÷ 2 = 15s`	None
`email`	Normal	`30s`	To High after 60s waiting
`report`	Low	`min(60s × 2, 120s) = 120s`	To Normal after 30s waiting
`""` or undefined	Immediate	`max(30s ÷ 4, 15s) = 15s`	None

Promotion thresholds read only Config.Timeout, never a preset's Timeout. The rules behind each column: Priority Levels, Timeout Derivation, Anti-Starvation Promotion.