yonlu
8fc075c24a
- backend/explore/ratelimiter.go - backend/explore/cache.go - backend/database/sql/schemas/explore_cache.sql - backend/database/database.go
38 lines
1.1 KiB
Go
38 lines
1.1 KiB
Go
// Package explore provides MusicBrainz and ListenBrainz API clients
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// with rate-limited HTTP access and a SQLite response cache.
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package explore
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import (
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"context"
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"time"
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"golang.org/x/time/rate"
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)
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// RateLimiter enforces a maximum request rate using a token bucket.
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// MusicBrainz requires ≤1 request per second and rejects ALL
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// requests (not just excess) when the rate is exceeded, so callers
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// block proactively via Wait rather than retrying reactively.
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//
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// RateLimiter is safe for concurrent use.
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type RateLimiter struct {
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limiter *rate.Limiter
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}
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// NewRateLimiter returns a rate limiter that allows exactly one
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// request per second with a burst size of 1. The first call to
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// Wait returns immediately; subsequent calls block until the next
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// token is available.
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func NewRateLimiter() *RateLimiter {
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return &RateLimiter{
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limiter: rate.NewLimiter(rate.Every(time.Second), 1),
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}
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}
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// Wait blocks until the rate limiter allows the caller to proceed
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// or the context is cancelled. Returns ctx.Err() if the context
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// expires before a token becomes available.
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func (r *RateLimiter) Wait(ctx context.Context) error {
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return r.limiter.Wait(ctx)
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}
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