diff options
author | Emile <git@emile.space> | 2024-10-25 15:55:50 +0200 |
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committer | Emile <git@emile.space> | 2024-10-25 15:55:50 +0200 |
commit | c90f36e3dd179d2de96f4f5fe38d8dc9a9de6dfe (patch) | |
tree | 89e9afb41c5bf76f48cfb09305a2d3db8d302b06 /vendor/github.com/rs/zerolog/sampler.go | |
parent | 98bbb0f559a8883bc47bae80607dbe326a448e61 (diff) |
Diffstat (limited to 'vendor/github.com/rs/zerolog/sampler.go')
-rw-r--r-- | vendor/github.com/rs/zerolog/sampler.go | 134 |
1 files changed, 134 insertions, 0 deletions
diff --git a/vendor/github.com/rs/zerolog/sampler.go b/vendor/github.com/rs/zerolog/sampler.go new file mode 100644 index 0000000..83ce2ed --- /dev/null +++ b/vendor/github.com/rs/zerolog/sampler.go @@ -0,0 +1,134 @@ +package zerolog + +import ( + "math/rand" + "sync/atomic" + "time" +) + +var ( + // Often samples log every ~ 10 events. + Often = RandomSampler(10) + // Sometimes samples log every ~ 100 events. + Sometimes = RandomSampler(100) + // Rarely samples log every ~ 1000 events. + Rarely = RandomSampler(1000) +) + +// Sampler defines an interface to a log sampler. +type Sampler interface { + // Sample returns true if the event should be part of the sample, false if + // the event should be dropped. + Sample(lvl Level) bool +} + +// RandomSampler use a PRNG to randomly sample an event out of N events, +// regardless of their level. +type RandomSampler uint32 + +// Sample implements the Sampler interface. +func (s RandomSampler) Sample(lvl Level) bool { + if s <= 0 { + return false + } + if rand.Intn(int(s)) != 0 { + return false + } + return true +} + +// BasicSampler is a sampler that will send every Nth events, regardless of +// their level. +type BasicSampler struct { + N uint32 + counter uint32 +} + +// Sample implements the Sampler interface. +func (s *BasicSampler) Sample(lvl Level) bool { + n := s.N + if n == 1 { + return true + } + c := atomic.AddUint32(&s.counter, 1) + return c%n == 1 +} + +// BurstSampler lets Burst events pass per Period then pass the decision to +// NextSampler. If Sampler is not set, all subsequent events are rejected. +type BurstSampler struct { + // Burst is the maximum number of event per period allowed before calling + // NextSampler. + Burst uint32 + // Period defines the burst period. If 0, NextSampler is always called. + Period time.Duration + // NextSampler is the sampler used after the burst is reached. If nil, + // events are always rejected after the burst. + NextSampler Sampler + + counter uint32 + resetAt int64 +} + +// Sample implements the Sampler interface. +func (s *BurstSampler) Sample(lvl Level) bool { + if s.Burst > 0 && s.Period > 0 { + if s.inc() <= s.Burst { + return true + } + } + if s.NextSampler == nil { + return false + } + return s.NextSampler.Sample(lvl) +} + +func (s *BurstSampler) inc() uint32 { + now := TimestampFunc().UnixNano() + resetAt := atomic.LoadInt64(&s.resetAt) + var c uint32 + if now > resetAt { + c = 1 + atomic.StoreUint32(&s.counter, c) + newResetAt := now + s.Period.Nanoseconds() + reset := atomic.CompareAndSwapInt64(&s.resetAt, resetAt, newResetAt) + if !reset { + // Lost the race with another goroutine trying to reset. + c = atomic.AddUint32(&s.counter, 1) + } + } else { + c = atomic.AddUint32(&s.counter, 1) + } + return c +} + +// LevelSampler applies a different sampler for each level. +type LevelSampler struct { + TraceSampler, DebugSampler, InfoSampler, WarnSampler, ErrorSampler Sampler +} + +func (s LevelSampler) Sample(lvl Level) bool { + switch lvl { + case TraceLevel: + if s.TraceSampler != nil { + return s.TraceSampler.Sample(lvl) + } + case DebugLevel: + if s.DebugSampler != nil { + return s.DebugSampler.Sample(lvl) + } + case InfoLevel: + if s.InfoSampler != nil { + return s.InfoSampler.Sample(lvl) + } + case WarnLevel: + if s.WarnSampler != nil { + return s.WarnSampler.Sample(lvl) + } + case ErrorLevel: + if s.ErrorSampler != nil { + return s.ErrorSampler.Sample(lvl) + } + } + return true +} |