[feature] Add rate limit exceptions option, use ISO8601 for rate limit reset (#2151)

* start updating rate limiting, add exceptions

* tests, comments, tidying up

* add rate limiting exceptions to example config

* envparsing

* nolint

* apply kimbediff

* add examples

4 files changed, 29 insertions, 1 deletions

diff --git a/internal/config/config.go b/internal/config/config.go
index 86f6b00dd..612947c5e 100644
--- a/internal/config/config.go
+++ b/internal/config/config.go
@@ -148,6 +148,7 @@ type Configuration struct {
 
 	AdvancedCookiesSamesite      string        `name:"advanced-cookies-samesite" usage:"'strict' or 'lax', see https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Set-Cookie/SameSite"`
 	AdvancedRateLimitRequests    int           `name:"advanced-rate-limit-requests" usage:"Amount of HTTP requests to permit within a 5 minute window. 0 or less turns rate limiting off."`
+	AdvancedRateLimitExceptions  []string      `name:"advanced-rate-limit-exceptions" usage:"Slice of CIDRs to exclude from rate limit restrictions."`
 	AdvancedThrottlingMultiplier int           `name:"advanced-throttling-multiplier" usage:"Multiplier to use per cpu for http request throttling. 0 or less turns throttling off."`
 	AdvancedThrottlingRetryAfter time.Duration `name:"advanced-throttling-retry-after" usage:"Retry-After duration response to send for throttled requests."`
 	AdvancedSenderMultiplier     int           `name:"advanced-sender-multiplier" usage:"Multiplier to use per cpu for batching outgoing fedi messages. 0 or less turns batching off (not recommended)."`
diff --git a/internal/config/defaults.go b/internal/config/defaults.go
index 3703d8372..9ad9c125c 100644
--- a/internal/config/defaults.go
+++ b/internal/config/defaults.go
@@ -122,7 +122,8 @@ var Defaults = Configuration{
 
 	AdvancedCookiesSamesite:      "lax",
 	AdvancedRateLimitRequests:    300, // 1 per second per 5 minutes
-	AdvancedThrottlingMultiplier: 8,   // 8 open requests per CPU
+	AdvancedRateLimitExceptions:  []string{},
+	AdvancedThrottlingMultiplier: 8, // 8 open requests per CPU
 	AdvancedThrottlingRetryAfter: time.Second * 30,
 	AdvancedSenderMultiplier:     2, // 2 senders per CPU
 	AdvancedCSPExtraURIs:         []string{},
diff --git a/internal/config/flags.go b/internal/config/flags.go
index 927f4ddfb..ad07ec2ef 100644
--- a/internal/config/flags.go
+++ b/internal/config/flags.go
@@ -149,6 +149,7 @@ func (s *ConfigState) AddServerFlags(cmd *cobra.Command) {
 		// Advanced flags
 		cmd.Flags().String(AdvancedCookiesSamesiteFlag(), cfg.AdvancedCookiesSamesite, fieldtag("AdvancedCookiesSamesite", "usage"))
 		cmd.Flags().Int(AdvancedRateLimitRequestsFlag(), cfg.AdvancedRateLimitRequests, fieldtag("AdvancedRateLimitRequests", "usage"))
+		cmd.Flags().StringSlice(AdvancedRateLimitExceptionsFlag(), cfg.AdvancedRateLimitExceptions, fieldtag("AdvancedRateLimitExceptions", "usage"))
 		cmd.Flags().Int(AdvancedThrottlingMultiplierFlag(), cfg.AdvancedThrottlingMultiplier, fieldtag("AdvancedThrottlingMultiplier", "usage"))
 		cmd.Flags().Duration(AdvancedThrottlingRetryAfterFlag(), cfg.AdvancedThrottlingRetryAfter, fieldtag("AdvancedThrottlingRetryAfter", "usage"))
 		cmd.Flags().Int(AdvancedSenderMultiplierFlag(), cfg.AdvancedSenderMultiplier, fieldtag("AdvancedSenderMultiplier", "usage"))
diff --git a/internal/config/helpers.gen.go b/internal/config/helpers.gen.go
index ab7d38a8a..801d4f667 100644
--- a/internal/config/helpers.gen.go
+++ b/internal/config/helpers.gen.go
@@ -2274,6 +2274,31 @@ func GetAdvancedRateLimitRequests() int { return global.GetAdvancedRateLimitRequ
 // SetAdvancedRateLimitRequests safely sets the value for global configuration 'AdvancedRateLimitRequests' field
 func SetAdvancedRateLimitRequests(v int) { global.SetAdvancedRateLimitRequests(v) }
 
+// GetAdvancedRateLimitExceptions safely fetches the Configuration value for state's 'AdvancedRateLimitExceptions' field
+func (st *ConfigState) GetAdvancedRateLimitExceptions() (v []string) {
+	st.mutex.RLock()
+	v = st.config.AdvancedRateLimitExceptions
+	st.mutex.RUnlock()
+	return
+}
+
+// SetAdvancedRateLimitExceptions safely sets the Configuration value for state's 'AdvancedRateLimitExceptions' field
+func (st *ConfigState) SetAdvancedRateLimitExceptions(v []string) {
+	st.mutex.Lock()
+	defer st.mutex.Unlock()
+	st.config.AdvancedRateLimitExceptions = v
+	st.reloadToViper()
+}
+
+// AdvancedRateLimitExceptionsFlag returns the flag name for the 'AdvancedRateLimitExceptions' field
+func AdvancedRateLimitExceptionsFlag() string { return "advanced-rate-limit-exceptions" }
+
+// GetAdvancedRateLimitExceptions safely fetches the value for global configuration 'AdvancedRateLimitExceptions' field
+func GetAdvancedRateLimitExceptions() []string { return global.GetAdvancedRateLimitExceptions() }
+
+// SetAdvancedRateLimitExceptions safely sets the value for global configuration 'AdvancedRateLimitExceptions' field
+func SetAdvancedRateLimitExceptions(v []string) { global.SetAdvancedRateLimitExceptions(v) }
+
 // GetAdvancedThrottlingMultiplier safely fetches the Configuration value for state's 'AdvancedThrottlingMultiplier' field
 func (st *ConfigState) GetAdvancedThrottlingMultiplier() (v int) {
 	st.mutex.RLock()