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fix: Propagate trace context across async boundaries #811

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Merged
copybara-service merged 1 commit into from
Feb 4, 2026
+52 −23
Merged

fix: Propagate trace context across async boundaries #811

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38 changes: 28 additions & 10 deletions core/src/main/java/com/google/adk/flows/llmflows/BaseLlmFlow.java
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -144,11 +144,15 @@ protected Flowable<Event> postprocess(
})
.map(ResponseProcessingResult::updatedResponse);
}
Context parentContext = Context.current();

return currentLlmResponse.flatMapPublisher(
updatedResponse ->
buildPostprocessingEvents(
updatedResponse, eventIterables, context, baseEventForLlmResponse, llmRequest));
updatedResponse -> {
try (Scope scope = parentContext.makeCurrent()) {
return buildPostprocessingEvents(
updatedResponse, eventIterables, context, baseEventForLlmResponse, llmRequest);
}
});
}

/**
Expand All @@ -160,7 +164,10 @@ protected Flowable<Event> postprocess(
* callbacks. Callbacks should not rely on its ID if they create their own separate events.
*/
private Flowable<LlmResponse> callLlm(
InvocationContext context, LlmRequest llmRequest, Event eventForCallbackUsage) {
InvocationContext context,
LlmRequest llmRequest,
Event eventForCallbackUsage,
Context parentTracingContext) {
LlmAgent agent = (LlmAgent) context.agent();

LlmRequest.Builder llmRequestBuilder = llmRequest.toBuilder();
Expand All @@ -180,7 +187,7 @@ private Flowable<LlmResponse> callLlm(
Span llmCallSpan =
Tracing.getTracer()
.spanBuilder("call_llm")
.setParent(Context.current())
.setParent(parentTracingContext)
.startSpan();

try (Scope scope = llmCallSpan.makeCurrent()) {
Expand Down Expand Up @@ -333,6 +340,7 @@ private Single<LlmResponse> handleAfterModelCallback(
* @throws IllegalStateException if a transfer agent is specified but not found.
*/
private Flowable<Event> runOneStep(InvocationContext context) {
Context parentContext = Context.current();
AtomicReference<LlmRequest> llmRequestRef = new AtomicReference<>(LlmRequest.builder().build());
Flowable<Event> preprocessEvents = preprocess(context, llmRequestRef);

Expand Down Expand Up @@ -363,10 +371,12 @@ private Flowable<Event> runOneStep(InvocationContext context) {
// events with fresh timestamp.
mutableEventTemplate.setTimestamp(0L);

return callLlm(context, llmRequestAfterPreprocess, mutableEventTemplate)
return callLlm(
context, llmRequestAfterPreprocess, mutableEventTemplate, parentContext)
.concatMap(
llmResponse ->
postprocess(
llmResponse -> {
try (Scope scope = parentContext.makeCurrent()) {
return postprocess(
context,
mutableEventTemplate,
llmRequestAfterPreprocess,
Expand All @@ -380,7 +390,9 @@ private Flowable<Event> runOneStep(InvocationContext context) {
+ " next LlmResponse",
oldId,
mutableEventTemplate.id());
}))
});
}
})
.concatMap(
event -> {
Flowable<Event> postProcessedEvents = Flowable.just(event);
Expand Down Expand Up @@ -421,6 +433,7 @@ private Flowable<Event> run(InvocationContext invocationContext, int stepsComple
return currentStepEvents;
}

Context parentContext = Context.current();
return currentStepEvents.concatWith(
currentStepEvents
.toList()
Expand All @@ -435,7 +448,12 @@ private Flowable<Event> run(InvocationContext invocationContext, int stepsComple
return Flowable.empty();
} else {
logger.debug("Continuing to next step of the flow.");
return Flowable.defer(() -> run(invocationContext, stepsCompleted + 1));
return Flowable.defer(
() -> {
try (Scope scope = parentContext.makeCurrent()) {
return run(invocationContext, stepsCompleted + 1);
}
});
}
}));
}
Expand Down
37 changes: 24 additions & 13 deletions core/src/main/java/com/google/adk/flows/llmflows/Functions.java
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -245,6 +245,7 @@ private static Function<FunctionCall, Maybe<Event>> getFunctionCallMapper(
Map<String, BaseTool> tools,
Map<String, ToolConfirmation> toolConfirmations,
boolean isLive) {
Context parentContext = Context.current();
return functionCall -> {
BaseTool tool = tools.get(functionCall.name().get());
ToolContext toolContext =
Expand All @@ -259,14 +260,19 @@ private static Function<FunctionCall, Maybe<Event>> getFunctionCallMapper(
maybeInvokeBeforeToolCall(invocationContext, tool, functionArgs, toolContext)
.switchIfEmpty(
Maybe.defer(
() ->
isLive
() -> {
try (Scope scope = parentContext.makeCurrent()) {
return isLive
? processFunctionLive(
invocationContext, tool, toolContext, functionCall, functionArgs)
: callTool(tool, functionArgs, toolContext)));
: callTool(tool, functionArgs, toolContext);
}
}));

return postProcessFunctionResult(
maybeFunctionResult, invocationContext, tool, functionArgs, toolContext, isLive);
try (Scope scope = parentContext.makeCurrent()) {
return postProcessFunctionResult(
maybeFunctionResult, invocationContext, tool, functionArgs, toolContext, isLive);
}
};
}

Expand Down Expand Up @@ -372,6 +378,7 @@ private static Maybe<Event> postProcessFunctionResult(
Map<String, Object> functionArgs,
ToolContext toolContext,
boolean isLive) {
Context parentContext = Context.current();
return maybeFunctionResult
.map(Optional::of)
.defaultIfEmpty(Optional.empty())
Expand All @@ -393,14 +400,17 @@ private static Maybe<Event> postProcessFunctionResult(
.defaultIfEmpty(Optional.ofNullable(initialFunctionResult))
.flatMapMaybe(
finalOptionalResult -> {
Map<String, Object> finalFunctionResult = finalOptionalResult.orElse(null);
if (tool.longRunning() && finalFunctionResult == null) {
return Maybe.empty();
try (Scope scope = parentContext.makeCurrent()) {
Map<String, Object> finalFunctionResult =
finalOptionalResult.orElse(null);
if (tool.longRunning() && finalFunctionResult == null) {
return Maybe.empty();
}
Event functionResponseEvent =
buildResponseEvent(
tool, finalFunctionResult, toolContext, invocationContext);
return Maybe.just(functionResponseEvent);
}
Event functionResponseEvent =
buildResponseEvent(
tool, finalFunctionResult, toolContext, invocationContext);
return Maybe.just(functionResponseEvent);
});
});
}
Expand Down Expand Up @@ -552,12 +562,13 @@ private static Maybe<Map<String, Object>> maybeInvokeAfterToolCall(
private static Maybe<Map<String, Object>> callTool(
BaseTool tool, Map<String, Object> args, ToolContext toolContext) {
Tracer tracer = Tracing.getTracer();
Context parentContext = Context.current();
return Maybe.defer(
() -> {
Span span =
tracer
.spanBuilder("tool_call [" + tool.name() + "]")
.setParent(Context.current())
.setParent(parentContext)
.startSpan();
try (Scope scope = span.makeCurrent()) {
Tracing.traceToolCall(args);
Expand Down