soup
fc625fb9cf
Pinterest-style visual bookmarking app with: - URL metadata extraction (OG/Twitter meta, oEmbed fallback) - Image caching in Postgres with 480px thumbnails - Multi-tag filtering with Ctrl/Cmd for OR mode - Fuzzy tag suggestions and inline tag editing - Browser console auth() with first-use password setup - Brutalist UI with Commit Mono font and Pico CSS - Light/dark mode via browser preference
47 lines
1.1 KiB
Go
47 lines
1.1 KiB
Go
package retry
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import (
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"context"
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"math"
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"sync/atomic"
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"time"
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)
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type exponentialBackoff struct {
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base time.Duration
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attempt uint64
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}
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// Exponential is a wrapper around Retry that uses an exponential backoff. See
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// NewExponential.
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func Exponential(ctx context.Context, base time.Duration, f RetryFunc) error {
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return Do(ctx, NewExponential(base), f)
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}
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// NewExponential creates a new exponential backoff using the starting value of
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// base and doubling on each failure (1, 2, 4, 8, 16, 32, 64...), up to max.
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//
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// Once it overflows, the function constantly returns the maximum time.Duration
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// for a 64-bit integer.
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//
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// It panics if the given base is less than zero.
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func NewExponential(base time.Duration) Backoff {
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if base <= 0 {
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panic("base must be greater than 0")
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}
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return &exponentialBackoff{
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base: base,
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}
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}
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// Next implements Backoff. It is safe for concurrent use.
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func (b *exponentialBackoff) Next() (time.Duration, bool) {
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next := b.base << (atomic.AddUint64(&b.attempt, 1) - 1)
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if next <= 0 {
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atomic.AddUint64(&b.attempt, ^uint64(0))
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next = math.MaxInt64
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}
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return next, false
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}
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