/
ratelimiter.go
51 lines (42 loc) · 1.41 KB
/
ratelimiter.go
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package middleware
import (
"errors"
"fmt"
"net/http"
"github.com/honeycombio/beeline-go"
"golang.org/x/time/rate"
)
var (
errInvalidAuthHeaderFormat = errors.New("INVALID_AUTH_HEADER_FORMAT")
errInvalidAuthTokenFormat = errors.New("INVALID_AUTH_TOKEN_FORMAT")
errInvalidAuthToken = errors.New("INVALID_AUTH_TOKEN")
)
func rateLimitHandler(next http.Handler, rateLimiter *rate.Limiter) http.Handler {
return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
ctx := r.Context()
clientID := clientIDFromContext(ctx)
if rateLimiter == nil {
beeline.AddField(r.Context(), "rate_limit_result", "skipped_disabled")
next.ServeHTTP(w, r)
return
}
// If a known API key is provided, no rate limiting is necessary
if clientID != "" {
beeline.AddField(r.Context(), "rate_limit_result", "skipped_authenticated")
next.ServeHTTP(w, r)
return
}
if !rateLimiter.Allow() {
beeline.AddField(r.Context(), "rate_limit_result", "denied_anonymous")
sendRateLimitError(w, rateLimiter)
return
}
beeline.AddField(r.Context(), "rate_limit_result", "allowed_anonymous")
next.ServeHTTP(w, r)
})
}
func sendRateLimitError(w http.ResponseWriter, rl *rate.Limiter) {
w.Header().Set("Content-Type", "application/json")
w.WriteHeader(http.StatusTooManyRequests)
_, _ = fmt.Fprintf(w, `{"error": "Anonymous request rate limit of %0f req/sec exceeded. Try again later."}`, rl.Limit())
}