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78 lines
1.6 KiB
Go
78 lines
1.6 KiB
Go
package syncx
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import (
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"sync"
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"time"
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"zero/core/timex"
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)
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const defaultRefreshInterval = time.Second
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type (
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ImmutableResourceOption func(resource *ImmutableResource)
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ImmutableResource struct {
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fetch func() (interface{}, error)
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resource interface{}
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err error
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lock sync.RWMutex
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refreshInterval time.Duration
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lastTime *AtomicDuration
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}
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)
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func NewImmutableResource(fn func() (interface{}, error), opts ...ImmutableResourceOption) *ImmutableResource {
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// cannot use executors.LessExecutor because of cycle imports
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ir := ImmutableResource{
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fetch: fn,
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refreshInterval: defaultRefreshInterval,
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lastTime: NewAtomicDuration(),
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}
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for _, opt := range opts {
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opt(&ir)
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}
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return &ir
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}
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func (ir *ImmutableResource) Get() (interface{}, error) {
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ir.lock.RLock()
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resource := ir.resource
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ir.lock.RUnlock()
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if resource != nil {
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return resource, nil
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}
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ir.maybeRefresh(func() {
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res, err := ir.fetch()
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ir.lock.Lock()
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if err != nil {
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ir.err = err
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} else {
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ir.resource, ir.err = res, nil
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}
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ir.lock.Unlock()
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})
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ir.lock.RLock()
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resource, err := ir.resource, ir.err
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ir.lock.RUnlock()
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return resource, err
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}
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func (ir *ImmutableResource) maybeRefresh(execute func()) {
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now := timex.Now()
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lastTime := ir.lastTime.Load()
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if lastTime == 0 || lastTime+ir.refreshInterval < now {
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ir.lastTime.Set(now)
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execute()
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}
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}
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// Set interval to 0 to enforce refresh every time if not succeeded. default is time.Second.
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func WithRefreshIntervalOnFailure(interval time.Duration) ImmutableResourceOption {
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return func(resource *ImmutableResource) {
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resource.refreshInterval = interval
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}
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}
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