| 1 | // SPDX-License-Identifier: GPL-3.0-or-later |
| 2 | |
| 3 | package logger |
| 4 | |
| 5 | import ( |
| 6 | "fmt" |
| 7 | "log/slog" |
| 8 | "sync" |
| 9 | "time" |
| 10 | ) |
| 11 | |
| 12 | const ( |
| 13 | rateLimiterSweepEvery = 4096 |
| 14 | rateLimiterTTL = time.Hour |
| 15 | ) |
| 16 | |
| 17 | type limitMode uint8 |
| 18 | |
| 19 | const ( |
| 20 | modeOnce limitMode = iota + 1 |
| 21 | modeLimit |
| 22 | ) |
| 23 | |
| 24 | type limitKey struct { |
| 25 | mode limitMode |
| 26 | key string |
| 27 | } |
| 28 | |
| 29 | type limitEntry struct { |
| 30 | limit int |
| 31 | window time.Duration |
| 32 | count int |
| 33 | windowStart time.Time |
| 34 | lastSeen time.Time |
| 35 | } |
| 36 | |
| 37 | type rateLimiter struct { |
| 38 | mu sync.Mutex |
| 39 | entries map[limitKey]*limitEntry |
| 40 | sweepEvery uint64 |
| 41 | ttl time.Duration |
| 42 | calls uint64 |
| 43 | now func() time.Time |
| 44 | } |
| 45 | |
| 46 | func newRateLimiter() *rateLimiter { |
| 47 | return &rateLimiter{ |
| 48 | entries: make(map[limitKey]*limitEntry), |
| 49 | sweepEvery: rateLimiterSweepEvery, |
| 50 | ttl: rateLimiterTTL, |
| 51 | now: time.Now, |
| 52 | } |
| 53 | } |
| 54 | |
| 55 | type LimitedLogger struct { |
| 56 | l *Logger |
| 57 | mode limitMode |
| 58 | key string |
| 59 | limit int |
| 60 | window time.Duration |
| 61 | } |
| 62 | |
| 63 | func (l *Logger) Once(key string) LimitedLogger { |
| 64 | return LimitedLogger{ |
| 65 | l: l, |
| 66 | mode: modeOnce, |
| 67 | key: key, |
| 68 | limit: 1, |
| 69 | window: 0, |
| 70 | } |
| 71 | } |
| 72 | |
| 73 | func (l *Logger) Limit(key string, n int, d time.Duration) LimitedLogger { |
| 74 | if n <= 0 { |
| 75 | n = 1 |
| 76 | } |
| 77 | if d < 0 { |
| 78 | d = 0 |
| 79 | } |
| 80 | return LimitedLogger{ |
| 81 | l: l, |
| 82 | mode: modeLimit, |
| 83 | key: key, |
| 84 | limit: n, |
| 85 | window: d, |
| 86 | } |
| 87 | } |
| 88 | |
| 89 | func (l *Logger) ResetAllOnce() { |
| 90 | if l == nil || l.rl == nil { |
| 91 | return |
| 92 | } |
| 93 | l.rl.resetAllMode(modeOnce) |
| 94 | } |
| 95 | |
| 96 | func (l LimitedLogger) Error(a ...any) { |
| 97 | l.logArgs(slog.LevelError, a...) |
| 98 | } |
| 99 | |
| 100 | func (l LimitedLogger) Warning(a ...any) { |
| 101 | l.logArgs(slog.LevelWarn, a...) |
| 102 | } |
| 103 | |
| 104 | func (l LimitedLogger) Notice(a ...any) { |
| 105 | l.logArgs(levelNotice, a...) |
| 106 | } |
| 107 | |
| 108 | func (l LimitedLogger) Info(a ...any) { |
| 109 | l.logArgs(slog.LevelInfo, a...) |
| 110 | } |
| 111 | |
| 112 | func (l LimitedLogger) Debug(a ...any) { |
| 113 | l.logArgs(slog.LevelDebug, a...) |
| 114 | } |
| 115 | |
| 116 | func (l LimitedLogger) Errorf(format string, a ...any) { |
| 117 | l.logf(slog.LevelError, format, a...) |
| 118 | } |
| 119 | |
| 120 | func (l LimitedLogger) Warningf(format string, a ...any) { |
| 121 | l.logf(slog.LevelWarn, format, a...) |
| 122 | } |
| 123 | |
| 124 | func (l LimitedLogger) Noticef(format string, a ...any) { |
| 125 | l.logf(levelNotice, format, a...) |
| 126 | } |
| 127 | |
| 128 | func (l LimitedLogger) Infof(format string, a ...any) { |
| 129 | l.logf(slog.LevelInfo, format, a...) |
| 130 | } |
| 131 | |
| 132 | func (l LimitedLogger) Debugf(format string, a ...any) { |
| 133 | l.logf(slog.LevelDebug, format, a...) |
| 134 | } |
| 135 | |
| 136 | func (l LimitedLogger) logArgs(level slog.Level, a ...any) { |
| 137 | if !l.l.canLog(level) || !l.allow() { |
| 138 | return |
| 139 | } |
| 140 | l.l.log(level, fmt.Sprint(a...)) |
| 141 | } |
| 142 | |
| 143 | func (l LimitedLogger) logf(level slog.Level, format string, a ...any) { |
| 144 | if !l.l.canLog(level) || !l.allow() { |
| 145 | return |
| 146 | } |
| 147 | l.l.log(level, fmt.Sprintf(format, a...)) |
| 148 | } |
| 149 | |
| 150 | func (l LimitedLogger) allow() bool { |
| 151 | if l.l == nil || l.l.rl == nil { |
| 152 | // Preserve nil logger behavior: no panic and no additional suppression. |
| 153 | return true |
| 154 | } |
| 155 | return l.l.rl.allow(l.mode, l.key, l.limit, l.window) |
| 156 | } |
| 157 | |
| 158 | func (r *rateLimiter) allow(mode limitMode, key string, limit int, window time.Duration) bool { |
| 159 | now := r.now() |
| 160 | allow := false |
| 161 | |
| 162 | r.mu.Lock() |
| 163 | defer r.mu.Unlock() |
| 164 | |
| 165 | r.calls++ |
| 166 | if r.sweepEvery > 0 && r.calls%r.sweepEvery == 0 { |
| 167 | r.sweep(now) |
| 168 | } |
| 169 | |
| 170 | k := limitKey{mode: mode, key: key} |
| 171 | e, ok := r.entries[k] |
| 172 | if !ok { |
| 173 | e = &limitEntry{ |
| 174 | limit: limit, |
| 175 | window: window, |
| 176 | windowStart: now, |
| 177 | } |
| 178 | r.entries[k] = e |
| 179 | } |
| 180 | |
| 181 | e.lastSeen = now |
| 182 | |
| 183 | // d==0 means infinite window, so rollover must be disabled. |
| 184 | if e.window > 0 && now.Sub(e.windowStart) >= e.window { |
| 185 | e.windowStart = now |
| 186 | e.count = 0 |
| 187 | } |
| 188 | |
| 189 | if e.count < e.limit { |
| 190 | e.count++ |
| 191 | allow = true |
| 192 | } |
| 193 | |
| 194 | return allow |
| 195 | } |
| 196 | |
| 197 | func (r *rateLimiter) resetAllMode(mode limitMode) { |
| 198 | r.mu.Lock() |
| 199 | defer r.mu.Unlock() |
| 200 | |
| 201 | for k := range r.entries { |
| 202 | if k.mode == mode { |
| 203 | delete(r.entries, k) |
| 204 | } |
| 205 | } |
| 206 | } |
| 207 | |
| 208 | func (r *rateLimiter) sweep(now time.Time) { |
| 209 | cutoff := now.Add(-r.ttl) |
| 210 | for k, e := range r.entries { |
| 211 | if e.lastSeen.Before(cutoff) { |
| 212 | delete(r.entries, k) |
| 213 | } |
| 214 | } |
| 215 | } |