Курнат Андрей
33 lines
985 B
Go
33 lines
985 B
Go
package util
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import (
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"github.com/open-policy-agent/opa/v1/metrics"
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)
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// This prevents getting blocked forever writing to a full buffer, in case another routine fills the last space.
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// Retrying maxEventRetry times to drop the oldest event. Dropping the incoming event if there still isn't room.
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const maxEventRetry = 1000
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// PushFIFO pushes data into a buffered channel without blocking when full, making room by dropping the oldest data.
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// An optional metric can be recorded when data is dropped.
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func PushFIFO[T any](buffer chan T, data T, metrics metrics.Metrics, metricName string) {
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for range maxEventRetry {
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// non-blocking send to the buffer, to prevent blocking if buffer is full so room can be made.
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select {
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case buffer <- data:
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return
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default:
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}
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// non-blocking drop from the buffer to make room for incoming event
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select {
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case <-buffer:
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if metrics != nil && metricName != "" {
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metrics.Counter(metricName).Incr()
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}
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default:
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}
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}
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}
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