143 lines
2.3 KiB
Go
143 lines
2.3 KiB
Go
package logging
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import (
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"context"
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"io"
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"sync"
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)
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// TODO (bradrydzewski) writing to subscribers is currently a blocking
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// operation and does not protect against slow clients from locking
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// the stream. This should be resolved.
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// TODO (bradrydzewski) implement a mux.Info to fetch information and
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// statistics for the multiplexier. Streams, subscribers, etc
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// mux.Info()
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// TODO (bradrydzewski) refactor code to place publisher and subscriber
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// operations in separate files with more encapsulated logic.
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// sub.push()
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// sub.join()
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// sub.start()... event loop
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type subscriber struct {
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handler Handler
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}
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type stream struct {
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sync.Mutex
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path string
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hist []*Entry
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subs map[*subscriber]struct{}
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done chan struct{}
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wait sync.WaitGroup
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}
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type log struct {
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sync.Mutex
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streams map[string]*stream
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}
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// New returns a new logger.
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func New() Log {
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return &log{
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streams: map[string]*stream{},
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}
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}
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func (l *log) Open(c context.Context, path string) error {
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l.Lock()
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_, ok := l.streams[path]
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if !ok {
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l.streams[path] = &stream{
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path: path,
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subs: make(map[*subscriber]struct{}),
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done: make(chan struct{}),
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}
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}
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l.Unlock()
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return nil
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}
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func (l *log) Write(c context.Context, path string, entry *Entry) error {
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l.Lock()
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s, ok := l.streams[path]
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l.Unlock()
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if !ok {
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return ErrNotFound
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}
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s.Lock()
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s.hist = append(s.hist, entry)
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for sub := range s.subs {
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go sub.handler(entry)
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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 (l *log) Tail(c context.Context, path string, handler Handler) error {
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l.Lock()
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s, ok := l.streams[path]
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l.Unlock()
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if !ok {
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return ErrNotFound
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}
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sub := &subscriber{
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handler: handler,
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}
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s.Lock()
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if len(s.hist) != 0 {
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sub.handler(s.hist...)
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}
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s.subs[sub] = struct{}{}
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s.Unlock()
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select {
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case <-c.Done():
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case <-s.done:
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}
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s.Lock()
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delete(s.subs, sub)
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s.Unlock()
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return nil
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}
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func (l *log) Close(c context.Context, path string) error {
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l.Lock()
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s, ok := l.streams[path]
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l.Unlock()
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if !ok {
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return ErrNotFound
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}
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s.Lock()
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close(s.done)
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s.Unlock()
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l.Lock()
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delete(l.streams, path)
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l.Unlock()
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return nil
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}
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func (l *log) Snapshot(c context.Context, path string, w io.Writer) error {
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l.Lock()
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s, ok := l.streams[path]
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l.Unlock()
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if !ok {
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return ErrNotFound
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}
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s.Lock()
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for _, entry := range s.hist {
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w.Write(entry.Data)
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w.Write(cr)
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}
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s.Unlock()
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return nil
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}
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var cr = []byte{'\n'}
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