mirror of
https://github.com/zrepl/zrepl.git
synced 2025-07-11 19:55:13 +02:00
- make `logging.GetLogger(ctx, Subsys)` the authoritative `logger.Logger` factory function - the context carries a linked list of injected fields which `logging.GetLogger` adds to the logger it returns - introduce the concept of tasks and spans, also tracked as linked list within ctx - [ ] TODO automatic logging of span begins and ends, with a unique ID stack that makes it easy to follow a series of log entries in concurrent code - ability to produce a chrome://tracing-compatible trace file, either via an env variable or a `zrepl pprof` subcommand - this is not a CPU profile, we already have go pprof for that - but it is very useful to visually inspect where the replication / snapshotter / pruner spends its time ( fixes #307 )
42 lines
748 B
Go
42 lines
748 B
Go
package semaphore
|
|
|
|
import (
|
|
"context"
|
|
|
|
wsemaphore "golang.org/x/sync/semaphore"
|
|
|
|
"github.com/zrepl/zrepl/daemon/logging"
|
|
)
|
|
|
|
type S struct {
|
|
ws *wsemaphore.Weighted
|
|
}
|
|
|
|
func New(max int64) *S {
|
|
return &S{wsemaphore.NewWeighted(max)}
|
|
}
|
|
|
|
type AcquireGuard struct {
|
|
s *S
|
|
released bool
|
|
}
|
|
|
|
// The returned AcquireGuard is not goroutine-safe.
|
|
func (s *S) Acquire(ctx context.Context) (*AcquireGuard, error) {
|
|
defer logging.WithSpanFromStackUpdateCtx(&ctx)()
|
|
if err := s.ws.Acquire(ctx, 1); err != nil {
|
|
return nil, err
|
|
} else if err := ctx.Err(); err != nil {
|
|
return nil, err
|
|
}
|
|
return &AcquireGuard{s, false}, nil
|
|
}
|
|
|
|
func (g *AcquireGuard) Release() {
|
|
if g == nil || g.released {
|
|
return
|
|
}
|
|
g.released = true
|
|
g.s.ws.Release(1)
|
|
}
|