Skip to content

Context implementation improvement proposals #11837

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Open
PerfectSlayer wants to merge 2 commits into
base: master
Choose a base branch
from
Open

Context implementation improvement proposals #11837

Changes from all commits
Commits
Show all changes
2 commits
Select commit Hold shift + click to select a range
2332af2
refactor(context): Introduce context holder swap to deduplicate code
PerfectSlayer Jun 22, 2026
947f415
refactor(context): Introduce event dispatch to deduplicate code
PerfectSlayer Jun 22, 2026
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
52 changes: 21 additions & 31 deletions components/context/src/main/java/datadog/context/ThreadLocalContextManager.java
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -2,6 +2,7 @@

import java.util.Arrays;
import java.util.concurrent.atomic.AtomicIntegerFieldUpdater;
import java.util.function.BiConsumer;
import javax.annotation.Nullable;

/** {@link ContextManager} that uses a {@link ThreadLocal} to track context per thread. */
Expand Down Expand Up @@ -40,10 +41,7 @@ ContextScope doAttach(Context context, @Nullable ContextContinuationImpl continu
return context.asScope(); // convert to scope without attaching
}

ContextListener[] ls = listeners;
notifyDetach(beforeAttach, ls);
holder.current = context;
notifyAttach(context, ls);
doSwap(holder, beforeAttach, context);

if (continuation == null) {
return new ContextScopeImpl(context, holder, beforeAttach);
Expand All @@ -61,10 +59,7 @@ public Context swap(Context context) {
return beforeSwap;
}

ContextListener[] ls = listeners;
notifyDetach(beforeSwap, ls);
holder.current = context;
notifyAttach(context, ls);
doSwap(holder, beforeSwap, context);

return beforeSwap;
}
Expand Down Expand Up @@ -103,46 +98,44 @@ static void notifyAttach(Context context, ContextListener[] listeners) {
if (context == Context.root()) {
return; // don't emit attach events for the default "no context" case
}
for (ContextListener l : listeners) {
try {
l.onAttach(context);
} catch (Throwable ignore) {
}
}
dispatch(context, listeners, ContextListener::onAttach);
}

static void notifyDetach(Context context, ContextListener[] listeners) {
if (context == Context.root()) {
return; // don't emit detach events for the default "no context" case
}
for (ContextListener l : listeners) {
try {
l.onDetach(context);
} catch (Throwable ignore) {
}
}
dispatch(context, listeners, ContextListener::onDetach);
}

static void notifyCapture(Context context, ContextListener[] listeners) {
// only called for non-empty continuations
for (ContextListener l : listeners) {
try {
l.onCapture(context);
} catch (Throwable ignore) {
}
}
dispatch(context, listeners, ContextListener::onCapture);
}

static void notifyRelease(Context context, ContextListener[] listeners) {
// only called for non-empty continuations
dispatch(context, listeners, ContextListener::onRelease);
}

private static void dispatch(
Context context, ContextListener[] listeners, BiConsumer<ContextListener, Context> event) {
for (ContextListener l : listeners) {
try {
l.onRelease(context);
event.accept(l, context);
} catch (Throwable ignore) {
}
}
}

private static void doSwap(ContextHolder holder, Context before, Context after) {
// Snapshot listeners so same listeners will get the two events
ContextListener[] ls = INSTANCE.listeners;
notifyDetach(before, ls);
holder.current = after;
notifyAttach(after, ls);
}

private static class ContextScopeImpl implements ContextScope {

private final Context context;
Expand All @@ -166,10 +159,7 @@ public final Context context() {
public void close() {
// check for out-of-order close to avoid corrupting the current state
if (!closed && context == holder.current) {
ContextListener[] ls = INSTANCE.listeners;
notifyDetach(context, ls);
holder.current = beforeAttach;
notifyAttach(beforeAttach, ls);
doSwap(holder, context, beforeAttach);
closed = true;
}
}
Expand Down