woodpecker/server/logging/log.go
Jacob Floyd a0d008e071
Move cncd/{logging,pubsub,queue}/ to server/{logging,pubsub,queue}/ (#346)
* Move cncd/{logging,pubsub,queue}/ to server/{logging,pubsub,queue}/

* Update REAMDEs and include history

Co-authored-by: Anbraten <anton@ju60.de>

Co-authored-by: Anbraten <anton@ju60.de>
2021-09-23 22:29:09 +02:00

143 lines
2.3 KiB
Go

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