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fix(langfuse): fix latency display showing incorrect huge hours value #688

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9ae11b8
fix(langfuse): fix latency display showing incorrect huge hours value
favbox Feb 10, 2026
4aa7c43
style: translate Chinese comments to English
favbox Feb 10, 2026
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2 changes: 2 additions & 0 deletions callbacks/langfuse/go.mod
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Original file line number Diff line number Diff line change
Expand Up @@ -11,6 +11,8 @@ require (
github.com/stretchr/testify v1.10.0
)

replace github.com/cloudwego/eino-ext/libs/acl/langfuse => ../../libs/acl/langfuse

require (
github.com/bahlo/generic-list-go v0.2.0 // indirect
github.com/buger/jsonparser v1.1.1 // indirect
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39 changes: 31 additions & 8 deletions callbacks/langfuse/langfuse.go
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Original file line number Diff line number Diff line change
Expand Up @@ -181,9 +181,11 @@ type CallbackHandler struct {
}

type langfuseStateKey struct{}

type langfuseState struct {
traceID string
observationID string
startTime time.Time // startTime is used to calculate duration in milliseconds
}

func (c *CallbackHandler) OnStart(ctx context.Context, info *callbacks.RunInfo, input callbacks.CallbackInput) context.Context {
Expand All @@ -197,6 +199,7 @@ func (c *CallbackHandler) OnStart(ctx context.Context, info *callbacks.RunInfo,
}
if info.Component == components.ComponentOfChatModel {
mcbi := model.ConvCallbackInput(input)
startTime := time.Now()

body := &langfuse.GenerationEventBody{
BaseObservationEventBody: langfuse.BaseObservationEventBody{
Expand All @@ -206,7 +209,7 @@ func (c *CallbackHandler) OnStart(ctx context.Context, info *callbacks.RunInfo,
},
TraceID: state.traceID,
ParentObservationID: state.observationID,
StartTime: time.Now(),
StartTime: startTime,
},
InMessages: mcbi.Messages,
}
Expand All @@ -222,6 +225,7 @@ func (c *CallbackHandler) OnStart(ctx context.Context, info *callbacks.RunInfo,
return context.WithValue(ctx, langfuseStateKey{}, &langfuseState{
traceID: state.traceID,
observationID: generationID,
startTime: startTime,
})
}

Expand All @@ -230,6 +234,7 @@ func (c *CallbackHandler) OnStart(ctx context.Context, info *callbacks.RunInfo,
log.Printf("marshal input error: %v, runinfo: %+v", err, info)
return ctx
}
startTime := time.Now()
spanID, err := c.cli.CreateSpan(&langfuse.SpanEventBody{
BaseObservationEventBody: langfuse.BaseObservationEventBody{
BaseEventBody: langfuse.BaseEventBody{
Expand All @@ -238,7 +243,7 @@ func (c *CallbackHandler) OnStart(ctx context.Context, info *callbacks.RunInfo,
Input: in,
TraceID: state.traceID,
ParentObservationID: state.observationID,
StartTime: time.Now(),
StartTime: startTime,
},
})
if err != nil {
Expand All @@ -248,6 +253,7 @@ func (c *CallbackHandler) OnStart(ctx context.Context, info *callbacks.RunInfo,
return context.WithValue(ctx, langfuseStateKey{}, &langfuseState{
traceID: state.traceID,
observationID: spanID,
startTime: startTime,
})
}

Expand All @@ -264,16 +270,18 @@ func (c *CallbackHandler) OnEnd(ctx context.Context, info *callbacks.RunInfo, ou

if info.Component == components.ComponentOfChatModel {
mcbo := model.ConvCallbackOutput(output)
endTime := time.Now()

body := &langfuse.GenerationEventBody{
BaseObservationEventBody: langfuse.BaseObservationEventBody{
BaseEventBody: langfuse.BaseEventBody{
ID: state.observationID,
},
StartTime: state.startTime, // ← 必须保留原始 startTime
},
OutMessage: mcbo.Message,
EndTime: time.Now(),
CompletionStartTime: time.Now(),
EndTime: endTime,
CompletionStartTime: endTime,
}
if mcbo.TokenUsage != nil {
body.Usage = &langfuse.Usage{
Expand All @@ -283,6 +291,12 @@ func (c *CallbackHandler) OnEnd(ctx context.Context, info *callbacks.RunInfo, ou
}
}

// Calculate duration in milliseconds
if !state.startTime.IsZero() {
duration := int64(endTime.Sub(state.startTime).Milliseconds())
body.Duration = &duration
}

err := c.cli.EndGeneration(body)
if err != nil {
log.Printf("end generation error: %v, runinfo: %+v", err, info)
Expand All @@ -295,15 +309,24 @@ func (c *CallbackHandler) OnEnd(ctx context.Context, info *callbacks.RunInfo, ou
log.Printf("marshal output error: %v, runinfo: %+v", err, info)
return ctx
}
err = c.cli.EndSpan(&langfuse.SpanEventBody{
endTime := time.Now()
spanBody := &langfuse.SpanEventBody{
BaseObservationEventBody: langfuse.BaseObservationEventBody{
BaseEventBody: langfuse.BaseEventBody{
ID: state.observationID,
},
Output: out,
Output: out,
StartTime: state.startTime, // Must preserve the original startTime for correct latency calculation
},
EndTime: time.Now(),
})
EndTime: endTime,
}
// Calculate duration in milliseconds
if !state.startTime.IsZero() {
duration := int64(endTime.Sub(state.startTime).Milliseconds())
spanBody.Duration = &duration
}

err = c.cli.EndSpan(spanBody)
if err != nil {
log.Printf("end span fail: %v, runinfo: %+v", err, info)
}
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4 changes: 3 additions & 1 deletion libs/acl/langfuse/event.go
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Original file line number Diff line number Diff line change
Expand Up @@ -226,7 +226,8 @@ type BaseObservationEventBody struct {
type SpanEventBody struct {
BaseObservationEventBody

EndTime time.Time `json:"endTime,omitempty"`
EndTime time.Time `json:"endTime,omitempty"`
Duration *int64 `json:"duration,omitempty"` // Duration in milliseconds
}

type Usage struct {
Expand All @@ -247,6 +248,7 @@ type GenerationEventBody struct {
PromptVersion int `json:"promptVersion,omitempty"`
ModelParameters any `json:"modelParameters,omitempty"`
Usage *Usage `json:"usage,omitempty"`
Duration *int64 `json:"duration,omitempty"` // Duration in milliseconds
}

type EventEventBody struct {
Expand Down
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