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Diffstat (limited to '')
-rw-r--r-- | dependencies/pkg/mod/go.uber.org/zap@v1.23.0/zapcore/sampler.go | 230 |
1 files changed, 230 insertions, 0 deletions
diff --git a/dependencies/pkg/mod/go.uber.org/zap@v1.23.0/zapcore/sampler.go b/dependencies/pkg/mod/go.uber.org/zap@v1.23.0/zapcore/sampler.go new file mode 100644 index 0000000..dc51805 --- /dev/null +++ b/dependencies/pkg/mod/go.uber.org/zap@v1.23.0/zapcore/sampler.go @@ -0,0 +1,230 @@ +// Copyright (c) 2016-2022 Uber Technologies, Inc. +// +// Permission is hereby granted, free of charge, to any person obtaining a copy +// of this software and associated documentation files (the "Software"), to deal +// in the Software without restriction, including without limitation the rights +// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell +// copies of the Software, and to permit persons to whom the Software is +// furnished to do so, subject to the following conditions: +// +// The above copyright notice and this permission notice shall be included in +// all copies or substantial portions of the Software. +// +// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR +// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, +// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE +// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER +// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, +// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN +// THE SOFTWARE. + +package zapcore + +import ( + "time" + + "go.uber.org/atomic" +) + +const ( + _numLevels = _maxLevel - _minLevel + 1 + _countersPerLevel = 4096 +) + +type counter struct { + resetAt atomic.Int64 + counter atomic.Uint64 +} + +type counters [_numLevels][_countersPerLevel]counter + +func newCounters() *counters { + return &counters{} +} + +func (cs *counters) get(lvl Level, key string) *counter { + i := lvl - _minLevel + j := fnv32a(key) % _countersPerLevel + return &cs[i][j] +} + +// fnv32a, adapted from "hash/fnv", but without a []byte(string) alloc +func fnv32a(s string) uint32 { + const ( + offset32 = 2166136261 + prime32 = 16777619 + ) + hash := uint32(offset32) + for i := 0; i < len(s); i++ { + hash ^= uint32(s[i]) + hash *= prime32 + } + return hash +} + +func (c *counter) IncCheckReset(t time.Time, tick time.Duration) uint64 { + tn := t.UnixNano() + resetAfter := c.resetAt.Load() + if resetAfter > tn { + return c.counter.Inc() + } + + c.counter.Store(1) + + newResetAfter := tn + tick.Nanoseconds() + if !c.resetAt.CAS(resetAfter, newResetAfter) { + // We raced with another goroutine trying to reset, and it also reset + // the counter to 1, so we need to reincrement the counter. + return c.counter.Inc() + } + + return 1 +} + +// SamplingDecision is a decision represented as a bit field made by sampler. +// More decisions may be added in the future. +type SamplingDecision uint32 + +const ( + // LogDropped indicates that the Sampler dropped a log entry. + LogDropped SamplingDecision = 1 << iota + // LogSampled indicates that the Sampler sampled a log entry. + LogSampled +) + +// optionFunc wraps a func so it satisfies the SamplerOption interface. +type optionFunc func(*sampler) + +func (f optionFunc) apply(s *sampler) { + f(s) +} + +// SamplerOption configures a Sampler. +type SamplerOption interface { + apply(*sampler) +} + +// nopSamplingHook is the default hook used by sampler. +func nopSamplingHook(Entry, SamplingDecision) {} + +// SamplerHook registers a function which will be called when Sampler makes a +// decision. +// +// This hook may be used to get visibility into the performance of the sampler. +// For example, use it to track metrics of dropped versus sampled logs. +// +// var dropped atomic.Int64 +// zapcore.SamplerHook(func(ent zapcore.Entry, dec zapcore.SamplingDecision) { +// if dec&zapcore.LogDropped > 0 { +// dropped.Inc() +// } +// }) +func SamplerHook(hook func(entry Entry, dec SamplingDecision)) SamplerOption { + return optionFunc(func(s *sampler) { + s.hook = hook + }) +} + +// NewSamplerWithOptions creates a Core that samples incoming entries, which +// caps the CPU and I/O load of logging while attempting to preserve a +// representative subset of your logs. +// +// Zap samples by logging the first N entries with a given level and message +// each tick. If more Entries with the same level and message are seen during +// the same interval, every Mth message is logged and the rest are dropped. +// +// For example, +// +// core = NewSamplerWithOptions(core, time.Second, 10, 5) +// +// This will log the first 10 log entries with the same level and message +// in a one second interval as-is. Following that, it will allow through +// every 5th log entry with the same level and message in that interval. +// +// If thereafter is zero, the Core will drop all log entries after the first N +// in that interval. +// +// Sampler can be configured to report sampling decisions with the SamplerHook +// option. +// +// Keep in mind that Zap's sampling implementation is optimized for speed over +// absolute precision; under load, each tick may be slightly over- or +// under-sampled. +func NewSamplerWithOptions(core Core, tick time.Duration, first, thereafter int, opts ...SamplerOption) Core { + s := &sampler{ + Core: core, + tick: tick, + counts: newCounters(), + first: uint64(first), + thereafter: uint64(thereafter), + hook: nopSamplingHook, + } + for _, opt := range opts { + opt.apply(s) + } + + return s +} + +type sampler struct { + Core + + counts *counters + tick time.Duration + first, thereafter uint64 + hook func(Entry, SamplingDecision) +} + +var ( + _ Core = (*sampler)(nil) + _ leveledEnabler = (*sampler)(nil) +) + +// NewSampler creates a Core that samples incoming entries, which +// caps the CPU and I/O load of logging while attempting to preserve a +// representative subset of your logs. +// +// Zap samples by logging the first N entries with a given level and message +// each tick. If more Entries with the same level and message are seen during +// the same interval, every Mth message is logged and the rest are dropped. +// +// Keep in mind that zap's sampling implementation is optimized for speed over +// absolute precision; under load, each tick may be slightly over- or +// under-sampled. +// +// Deprecated: use NewSamplerWithOptions. +func NewSampler(core Core, tick time.Duration, first, thereafter int) Core { + return NewSamplerWithOptions(core, tick, first, thereafter) +} + +func (s *sampler) Level() Level { + return LevelOf(s.Core) +} + +func (s *sampler) With(fields []Field) Core { + return &sampler{ + Core: s.Core.With(fields), + tick: s.tick, + counts: s.counts, + first: s.first, + thereafter: s.thereafter, + hook: s.hook, + } +} + +func (s *sampler) Check(ent Entry, ce *CheckedEntry) *CheckedEntry { + if !s.Enabled(ent.Level) { + return ce + } + + if ent.Level >= _minLevel && ent.Level <= _maxLevel { + counter := s.counts.get(ent.Level, ent.Message) + n := counter.IncCheckReset(ent.Time, s.tick) + if n > s.first && (s.thereafter == 0 || (n-s.first)%s.thereafter != 0) { + s.hook(ent, LogDropped) + return ce + } + s.hook(ent, LogSampled) + } + return s.Core.Check(ent, ce) +} |