77 lines
2.2 KiB
Go
77 lines
2.2 KiB
Go
package ratelimit
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import (
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"errors"
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"math"
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"strconv"
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"strings"
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"time"
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)
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var errInvalidXSRLRetryAfter = errors.New("invalid retry-after value")
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// parseXSentryRateLimits returns a RateLimits map by parsing an input string in
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// the format of the X-Sentry-Rate-Limits header.
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//
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// Example
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//
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// X-Sentry-Rate-Limits: 60:transaction, 2700:default;error;security
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//
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// This will rate limit transactions for the next 60 seconds and errors for the
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// next 2700 seconds.
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//
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// Limits for unknown categories are ignored.
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func parseXSentryRateLimits(s string, now time.Time) Map {
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// https://github.com/getsentry/relay/blob/0424a2e017d193a93918053c90cdae9472d164bf/relay-server/src/utils/rate_limits.rs#L44-L82
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m := make(Map, len(knownCategories))
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for _, limit := range strings.Split(s, ",") {
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limit = strings.TrimSpace(limit)
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if limit == "" {
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continue
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}
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components := strings.Split(limit, ":")
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if len(components) == 0 {
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continue
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}
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retryAfter, err := parseXSRLRetryAfter(strings.TrimSpace(components[0]), now)
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if err != nil {
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continue
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}
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categories := ""
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if len(components) > 1 {
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categories = components[1]
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}
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for _, category := range strings.Split(categories, ";") {
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c := Category(strings.ToLower(strings.TrimSpace(category)))
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if _, ok := knownCategories[c]; !ok {
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// skip unknown categories, keep m small
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continue
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}
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// always keep the deadline furthest into the future
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if retryAfter.After(m[c]) {
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m[c] = retryAfter
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}
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}
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}
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return m
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}
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// parseXSRLRetryAfter parses a string into a retry-after rate limit deadline.
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//
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// Valid input is a number, possibly signed and possibly floating-point,
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// indicating the number of seconds to wait before sending another request.
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// Negative values are treated as zero. Fractional values are rounded to the
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// next integer.
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func parseXSRLRetryAfter(s string, now time.Time) (Deadline, error) {
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// https://github.com/getsentry/relay/blob/0424a2e017d193a93918053c90cdae9472d164bf/relay-quotas/src/rate_limit.rs#L88-L96
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f, err := strconv.ParseFloat(s, 64)
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if err != nil {
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return Deadline{}, errInvalidXSRLRetryAfter
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}
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d := time.Duration(math.Ceil(math.Max(f, 0.0))) * time.Second
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if d < 0 {
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d = 0
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}
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return Deadline(now.Add(d)), nil
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}
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