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https://github.com/rcourtman/Pulse.git
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pulse-triage[bot]
ca0d4fbdce
Skip saturated live-view deliveries without writing stderr under the broadcaster lock. Bound oversized-entry allocation before copying. Preserve the configured sinks, capped history, writer result and subscriber lifecycle, with unread-pipe, allocation and concurrent-lifecycle controls. Contract-Neutral: Existing best-effort system-log delivery, line and channel limits, writer results and lifecycle APIs are unchanged; remove per-drop stderr I/O and copying beyond the retained prefix. Change-source: pulse-maintainer
142 lines
3.4 KiB
Go
142 lines
3.4 KiB
Go
package logging
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import (
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"container/ring"
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"sync"
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"github.com/google/uuid"
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"github.com/rs/zerolog"
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)
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// DefaultBufferSize is the number of log lines to keep in memory.
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const (
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DefaultBufferSize = 1000
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// Cap each broadcasted log line to bound per-entry memory usage.
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maxBroadcastMessageBytes = 16 * 1024
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broadcastTruncationTag = "...[truncated]"
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)
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var (
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broadcaster *LogBroadcaster
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broadcastMu sync.Once
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)
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// LogBroadcaster captures log writes, buffers them, and broadcasts them to subscribers.
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type LogBroadcaster struct {
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mu sync.RWMutex
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buffer *ring.Ring
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subscribers map[string]chan string
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}
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// GetBroadcaster returns the singleton broadcaster instance.
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func GetBroadcaster() *LogBroadcaster {
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broadcastMu.Do(func() {
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broadcaster = &LogBroadcaster{
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buffer: ring.New(DefaultBufferSize),
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subscribers: make(map[string]chan string),
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}
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})
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return broadcaster
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}
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// Write implements io.Writer. It writes to the internal buffer and notifies subscribers.
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func (b *LogBroadcaster) Write(p []byte) (n int, err error) {
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// Copy at most a bounded prefix so oversized log lines cannot inflate memory.
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var msg string
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if len(p) > maxBroadcastMessageBytes {
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keep := maxBroadcastMessageBytes - len(broadcastTruncationTag)
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msg = string(p[:keep]) + broadcastTruncationTag
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} else {
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msg = string(p)
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}
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b.mu.Lock()
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defer b.mu.Unlock()
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// 1. Write to ring buffer
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b.buffer.Value = msg
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b.buffer = b.buffer.Next()
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// 2. Broadcast to subscribers
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for _, ch := range b.subscribers {
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select {
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case ch <- msg:
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// Sent successfully
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default:
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// A passive log viewer must not stall the producer or other viewers.
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// Skip only this delivery; bounded history and normal log sinks are
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// independent. Do not warn here: stderr can block too, and
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// doing so under this lock would also stall subscribe and shutdown.
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}
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}
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return len(p), nil
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}
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// Subscribe adds a new subscriber and returns a channel of log lines
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// plus a snapshot of the current history.
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func (b *LogBroadcaster) Subscribe() (string, chan string, []string) {
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b.mu.Lock()
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defer b.mu.Unlock()
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subscriberID := uuid.NewString()
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ch := make(chan string, 1000) // Large buffer to prevent blocking
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b.subscribers[subscriberID] = ch
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return subscriberID, ch, ringHistorySnapshot(b.buffer)
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}
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// Unsubscribe removes a subscriber.
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func (b *LogBroadcaster) Unsubscribe(subscriberID string) {
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b.mu.Lock()
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defer b.mu.Unlock()
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if ch, ok := b.subscribers[subscriberID]; ok {
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close(ch)
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delete(b.subscribers, subscriberID)
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}
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}
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// Shutdown closes all subscriber channels and clears the subscriber set.
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func (b *LogBroadcaster) Shutdown() {
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b.mu.Lock()
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defer b.mu.Unlock()
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for id, ch := range b.subscribers {
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close(ch)
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delete(b.subscribers, id)
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}
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}
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// GetHistory returns the current in-memory log log history.
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func (b *LogBroadcaster) GetHistory() []string {
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b.mu.RLock()
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defer b.mu.RUnlock()
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return ringHistorySnapshot(b.buffer)
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}
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func ringHistorySnapshot(buffer *ring.Ring) []string {
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history := make([]string, 0, DefaultBufferSize)
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buffer.Do(func(value any) {
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msg, ok := value.(string)
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if !ok {
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return
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}
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history = append(history, msg)
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})
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return history
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}
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// SetGlobalLevel updates the global zerolog level at runtime.
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func SetGlobalLevel(level string) {
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mu.Lock()
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defer mu.Unlock()
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zerolog.SetGlobalLevel(parseLevel(level))
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}
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// GetGlobalLevel returns the current global level string.
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func GetGlobalLevel() string {
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return zerolog.GlobalLevel().String()
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}
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