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add debug log for context stack #29

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add debug log for context stack #29

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1cb79af
add debug log for context stack
jslching Nov 3, 2023
9c43091
add max_depth
jslching Nov 6, 2023
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99 changes: 65 additions & 34 deletions util/ctxutil/stack.go
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Original file line number Diff line number Diff line change
Expand Up @@ -5,63 +5,94 @@ import (
"encoding/json"
"runtime/debug"
"sync"
"time"

"github.com/eluv-io/common-go/util/goutil"
"github.com/eluv-io/common-go/util/traceutil/trace"
)

// NewStack creates a new ContextStack.
func NewStack() ContextStack {
return &contextStack{stacks: map[int64]*entry{}}
c := &contextStack{stacks: map[int64]*entry{}}
go func() {
for {
// Log stack info every 5 min for debugging
time.Sleep(time.Minute * 5)
c.mutex.Lock()
size := len(c.stacks)
depths := map[int64]int{}
maxDepth := 0
for gid, entry := range c.stacks {
depth := stackDepth(entry.stack)
depths[gid] = depth
if depth > maxDepth {
maxDepth = depth
}
}
c.mutex.Unlock()
log.Warn("ContextStack", "size", size, "max_depth", maxDepth, "depths", depths)
}
}()
return c
}

func stackDepth(s *stack) int {
depth := 1
for s.parent != nil {
s = s.parent
depth++
}
return depth
}

// ContextStack provides access to a stack of context.Context values individually managed per goroutine. It is
// essentially a thead-local implementation that offers an alternative to passing context object in each call along a
// call chain.
//
// The "standard" way of using contexts in go is passing it to each function in a call chain:
// type anObject struct {}
//
// func (r *anObject) A(ctx context.Context) {
// ctx = context.WithValue(context.Background(), "key", "val")
// r.B(ctx)
// ...
// }
// type anObject struct {}
//
// func (r *anObject) A(ctx context.Context) {
// ctx = context.WithValue(context.Background(), "key", "val")
// r.B(ctx)
// ...
// }
//
// func (r *anObject) B(ctx context.Context) {
// ...
// r.C(ctx)
// ...
// }
// func (r *anObject) B(ctx context.Context) {
// ...
// r.C(ctx)
// ...
// }
//
// func (r *anObject) C(ctx context.Context) string {
// val := ctx.Value("key")
// ...
// }
// func (r *anObject) C(ctx context.Context) string {
// val := ctx.Value("key")
// ...
// }
//
// ContextStack achieves the same without adding a context to each method call:
//
// type anObject struct {
// cs *ctxutil.ContextStack
// }
// type anObject struct {
// cs *ctxutil.ContextStack
// }
//
// func (r *anObject) A() string {
// release := r.cs.WithValue("key", "val")
// defer release()
// r.B()
// ...
// }
// func (r *anObject) A() string {
// release := r.cs.WithValue("key", "val")
// defer release()
// r.B()
// ...
// }
//
// func (r *anObject) B() string {
// ...
// r.C()
// ...
// }
// func (r *anObject) B() string {
// ...
// r.C()
// ...
// }
//
// func (r *anObject) C() string {
// val := r.Ctx().Value("key")
// ...
// }
// func (r *anObject) C() string {
// val := r.Ctx().Value("key")
// ...
// }
type ContextStack interface {
// Ctx retrieves the current context for the current goroutine.
Ctx() context.Context
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