83 lines
1.6 KiB
Go
83 lines
1.6 KiB
Go
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// Copyright 2019 Drone.IO Inc. All rights reserved.
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// Use of this source code is governed by the Drone Non-Commercial License
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// that can be found in the LICENSE file.
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package livelog
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import (
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"context"
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"sync"
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"github.com/drone/drone/core"
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)
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// this is the amount of items that are stored in memory
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// in the buffer. This should result in approximately 10kb
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// of memory allocated per-stream and per-subscriber, not
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// including any logdata stored in these structures.
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const bufferSize = 5000
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type stream struct {
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sync.Mutex
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hist []*core.Line
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list map[*subscriber]struct{}
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}
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func newStream() *stream {
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return &stream{
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list: map[*subscriber]struct{}{},
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}
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}
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func (s *stream) write(line *core.Line) error {
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s.Lock()
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s.hist = append(s.hist, line)
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for l := range s.list {
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l.publish(line)
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}
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// the history should not be unbounded. The history
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// slice is capped and items are removed in a FIFO
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// ordering when capacity is reached.
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if size := len(s.hist); size >= bufferSize {
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s.hist = s.hist[size-bufferSize:]
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}
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s.Unlock()
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return nil
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}
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func (s *stream) subscribe(ctx context.Context) (<-chan *core.Line, <-chan error) {
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sub := &subscriber{
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handler: make(chan *core.Line, bufferSize),
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closec: make(chan struct{}),
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}
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err := make(chan error)
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s.Lock()
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for _, line := range s.hist {
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sub.publish(line)
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}
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s.list[sub] = struct{}{}
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s.Unlock()
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go func() {
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defer close(err)
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select {
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case <-sub.closec:
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case <-ctx.Done():
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sub.close()
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}
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}()
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return sub.handler, err
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}
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func (s *stream) close() error {
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s.Lock()
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defer s.Unlock()
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for sub := range s.list {
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delete(s.list, sub)
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sub.close()
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}
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return nil
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}
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