Documentation
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Overview ¶
Package poller maintains a single "current value" that is refreshed by periodically calling a Getter. It is the read-side counterpart to worker.Loop: instead of performing work on each tick, it caches the latest successfully fetched value so hot paths can read it without blocking on the source.
Typical uses are feature flags, dynamic config, exchange rates, or any slowly-changing remote value that callers want cheaply and concurrently. A Poller is a worker.Runnable, so it can be supervised alongside servers and other workers in a worker.Group.
Index ¶
Constants ¶
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Variables ¶
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Functions ¶
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Types ¶
type Config ¶
type Config struct {
// Name identifies the poller in logs and panic metrics (defaults to "poller").
Name string
// Interval between polls. Required (> 0).
Interval time.Duration
// PollTimeout bounds each Getter call (0 = inherit the run context).
PollTimeout time.Duration
// OnError is invoked with each failed poll's error; may be nil (the error is
// then only logged).
OnError func(error)
// OnPanic is invoked when a poll panics; may be nil.
OnPanic safetick.PanicHandler
}
Config configures a Poller.
type Getter ¶
Getter fetches the next value. It is called on each tick (and synchronously by Poll). A returned error leaves the current value unchanged.
type Poller ¶
type Poller[T any] struct { // contains filtered or unexported fields }
Poller caches the latest value returned by its Getter, refreshing it on a fixed interval. Reads via Current are safe for concurrent use.
func New ¶
New builds a Poller seeded with initial, which Current returns until the first successful poll. log may be nil.
func (*Poller[T]) Current ¶
func (p *Poller[T]) Current() T
Current returns the most recently fetched value (the New initial value until the first successful poll). Safe for concurrent use.
func (*Poller[T]) Poll ¶
Poll fetches once, synchronously, and updates the current value on success. On error the value is left unchanged and OnError (if set) is invoked. A panic in the Getter is recovered so a single bad poll cannot crash the supervisor.
Source Files