TUN-6724: Migrate to sentry-go from raven-go

vendor/github.com/getsentry/sentry-go/internal/ratelimit/rate_limits.go

@@ -0,0 +1,76 @@
+package ratelimit
+
+import (
+	"errors"
+	"math"
+	"strconv"
+	"strings"
+	"time"
+)
+
+var errInvalidXSRLRetryAfter = errors.New("invalid retry-after value")
+
+// parseXSentryRateLimits returns a RateLimits map by parsing an input string in
+// the format of the X-Sentry-Rate-Limits header.
+//
+// Example
+//
+//      X-Sentry-Rate-Limits: 60:transaction, 2700:default;error;security
+//
+// This will rate limit transactions for the next 60 seconds and errors for the
+// next 2700 seconds.
+//
+// Limits for unknown categories are ignored.
+func parseXSentryRateLimits(s string, now time.Time) Map {
+	// https://github.com/getsentry/relay/blob/0424a2e017d193a93918053c90cdae9472d164bf/relay-server/src/utils/rate_limits.rs#L44-L82
+	m := make(Map, len(knownCategories))
+	for _, limit := range strings.Split(s, ",") {
+		limit = strings.TrimSpace(limit)
+		if limit == "" {
+			continue
+		}
+		components := strings.Split(limit, ":")
+		if len(components) == 0 {
+			continue
+		}
+		retryAfter, err := parseXSRLRetryAfter(strings.TrimSpace(components[0]), now)
+		if err != nil {
+			continue
+		}
+		categories := ""
+		if len(components) > 1 {
+			categories = components[1]
+		}
+		for _, category := range strings.Split(categories, ";") {
+			c := Category(strings.ToLower(strings.TrimSpace(category)))
+			if _, ok := knownCategories[c]; !ok {
+				// skip unknown categories, keep m small
+				continue
+			}
+			// always keep the deadline furthest into the future
+			if retryAfter.After(m[c]) {
+				m[c] = retryAfter
+			}
+		}
+	}
+	return m
+}
+
+// parseXSRLRetryAfter parses a string into a retry-after rate limit deadline.
+//
+// Valid input is a number, possibly signed and possibly floating-point,
+// indicating the number of seconds to wait before sending another request.
+// Negative values are treated as zero. Fractional values are rounded to the
+// next integer.
+func parseXSRLRetryAfter(s string, now time.Time) (Deadline, error) {
+	// https://github.com/getsentry/relay/blob/0424a2e017d193a93918053c90cdae9472d164bf/relay-quotas/src/rate_limit.rs#L88-L96
+	f, err := strconv.ParseFloat(s, 64)
+	if err != nil {
+		return Deadline{}, errInvalidXSRLRetryAfter
+	}
+	d := time.Duration(math.Ceil(math.Max(f, 0.0))) * time.Second
+	if d < 0 {
+		d = 0
+	}
+	return Deadline(now.Add(d)), nil
+}