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* Add metrics probe to the profiler Signed-off-by: Pablo Chacin <pablochacin@gmail.com>
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,175 @@ | ||
| package profiler | ||
|
|
||
| import ( | ||
| "context" | ||
| "fmt" | ||
| "io" | ||
| "os" | ||
| "runtime/metrics" | ||
| "time" | ||
| ) | ||
|
|
||
| // MetricsConfig defines the configuration of a metrics probe | ||
| type MetricsConfig struct { | ||
| Enabled bool | ||
| FileName string | ||
| Rate time.Duration | ||
| } | ||
|
|
||
| type metricsProbe struct { | ||
| config MetricsConfig | ||
| cancel context.CancelFunc | ||
| } | ||
|
|
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| // NewMetricsProbe creates a metrics profiling probe with the given configuration | ||
| func NewMetricsProbe(config MetricsConfig) (Probe, error) { | ||
| if config.FileName == "" { | ||
| return nil, fmt.Errorf("metrics output file name cannot be empty") | ||
| } | ||
|
|
||
| return &metricsProbe{ | ||
| config: config, | ||
| }, nil | ||
| } | ||
|
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| func (m *metricsProbe) Start() (io.Closer, error) { | ||
| metricsFile, err := os.Create(m.config.FileName) | ||
| if err != nil { | ||
| return nil, fmt.Errorf("failed to create metrics output file %q: %w", m.config.FileName, err) | ||
| } | ||
|
|
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| collector := &metricsCollector{ | ||
| metricsFile: metricsFile, | ||
| rate: m.config.Rate, | ||
| } | ||
|
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| ctx, cancel := context.WithCancel(context.Background()) | ||
| err = collector.Start(ctx) | ||
| if err != nil { | ||
| cancel() | ||
| return nil, err | ||
| } | ||
|
|
||
| m.cancel = cancel | ||
| return m, nil | ||
| } | ||
|
|
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| func (m *metricsProbe) Close() error { | ||
| // stops the collector | ||
| m.cancel() | ||
|
|
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| return nil | ||
| } | ||
|
|
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| type stats struct { | ||
| count uint | ||
| minval float64 | ||
| maxval float64 | ||
| total float64 | ||
| } | ||
|
|
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| func (s *stats) add(value float64) { | ||
| // if first sample, use value as min and max | ||
| if s.count == 0 || value < s.minval { | ||
| s.minval = value | ||
| } | ||
| if s.count == 0 || value > s.maxval { | ||
| s.maxval = value | ||
| } | ||
| s.total += value | ||
| s.count++ | ||
| } | ||
|
|
||
| func (s *stats) avg() float64 { | ||
| // avoid division by 0 | ||
| if s.count == 0 { | ||
| return 0 | ||
| } | ||
| return s.total / float64(s.count) | ||
| } | ||
|
|
||
| func (s *stats) min() float64 { | ||
| return s.minval | ||
| } | ||
|
|
||
| func (s *stats) max() float64 { | ||
| return s.maxval | ||
| } | ||
|
|
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| // metricsCollector maintains the state for collecting metrics | ||
| type metricsCollector struct { | ||
| rate time.Duration | ||
| samples []metrics.Sample | ||
| metricsFile *os.File | ||
| stats map[string]*stats | ||
| } | ||
|
|
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| // Start starts the periodic metrics collection. | ||
| // When the context is cancelled, it generates a summary to the metrics file | ||
| func (m *metricsCollector) Start(ctx context.Context) error { | ||
| m.init() | ||
|
|
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| // start periodic sampling in background | ||
| go func() { | ||
| ticks := time.NewTicker(m.rate) | ||
| defer ticks.Stop() | ||
|
|
||
| for { | ||
| select { | ||
| case <-ticks.C: | ||
| m.sample() | ||
| case <-ctx.Done(): | ||
| m.generate() | ||
| return | ||
| } | ||
| } | ||
| }() | ||
|
|
||
| return nil | ||
| } | ||
|
|
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| func (m *metricsCollector) init() { | ||
| m.stats = map[string]*stats{} | ||
|
|
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| for _, metric := range metrics.All() { | ||
| // skip histogram values | ||
| if metric.Kind == metrics.KindUint64 || metric.Kind == metrics.KindFloat64 { | ||
| m.samples = append( | ||
| m.samples, | ||
| metrics.Sample{ | ||
| Name: metric.Name, | ||
| }, | ||
| ) | ||
| m.stats[metric.Name] = &stats{} | ||
| } | ||
| } | ||
|
|
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| m.sample() | ||
| } | ||
|
|
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| func (m *metricsCollector) sample() { | ||
| metrics.Read(m.samples) | ||
| for _, sample := range m.samples { | ||
| stats := m.stats[sample.Name] | ||
|
|
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| var value float64 | ||
| switch sample.Value.Kind() { | ||
| case metrics.KindFloat64: | ||
| value = sample.Value.Float64() | ||
| case metrics.KindUint64: | ||
| value = float64(sample.Value.Uint64()) | ||
| default: | ||
| continue | ||
| } | ||
|
|
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| stats.add(value) | ||
| } | ||
| } | ||
|
|
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| func (m *metricsCollector) generate() { | ||
| fmt.Fprintln(m.metricsFile, "metric,min,max,average") | ||
| for k, v := range m.stats { | ||
| fmt.Fprintf(m.metricsFile, "%s,%.2f,%.2f,%.2f\n", k, v.min(), v.max(), v.avg()) | ||
| } | ||
| _ = m.metricsFile.Close() | ||
| } |
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