rajeshkumarchandolu commented on code in PR #11607: URL: https://github.com/apache/ozone/pull/11607#discussion_r4369837161
########## hadoop-hdds/common/src/main/java/org/apache/hadoop/hdds/tracing/OzoneContextStorageProvider.java: ########## @@ -0,0 +1,87 @@ +/* + * Licensed to the Apache Software Foundation (ASF) under one or more + * contributor license agreements. See the NOTICE file distributed with + * this work for additional information regarding copyright ownership. + * The ASF licenses this file to You under the Apache License, Version 2.0 + * (the "License"); you may not use this file except in compliance with + * the License. You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ + +package org.apache.hadoop.hdds.tracing; + +import io.opentelemetry.api.trace.Span; +import io.opentelemetry.api.trace.SpanContext; +import io.opentelemetry.context.Context; +import io.opentelemetry.context.ContextStorage; +import io.opentelemetry.context.ContextStorageProvider; +import io.opentelemetry.context.Scope; +import org.slf4j.MDC; + +/** + * Registered through {@code META-INF/services} so OpenTelemetry uses {@link OzoneContextStorage}, + * which wraps the default thread-local storage. + */ +public final class OzoneContextStorageProvider implements ContextStorageProvider { + public static final String MDC_TRACE_ID = "trace_id"; + public static final String MDC_SPAN_ID = "span_id"; + + @Override + public ContextStorage get() { + return new OzoneContextStorage(ContextStorage.defaultStorage()); + } + + /** + * {@link ContextStorage} that keeps the logging MDC in sync with the current span. + * Every {@code makeCurrent()} / {@code Context.wrap(...)} goes through {@link #attach(Context)}, + * so trace and span IDs are available to log patterns without changes at the call sites. + * The MDC is always derived from the current context (never saved and restored), + * so values inherited by child threads through the MDC are overwritten on the next attach or close. + */ + static final class OzoneContextStorage implements ContextStorage { + private final ContextStorage delegate; + + OzoneContextStorage(ContextStorage delegate) { + this.delegate = delegate; + } + + @Override + public Scope attach(Context toAttach) { + Scope scope = delegate.attach(toAttach); + updateMdc(delegate.current()); + return () -> { + scope.close(); + updateMdc(delegate.current()); + }; + } + + @Override + public Context current() { + return delegate.current(); + } + + @Override + public Context root() { + return delegate.root(); + } + + private static void updateMdc(Context context) { + SpanContext spanContext = context == null ? SpanContext.getInvalid() + : Span.fromContext(context).getSpanContext(); + if (spanContext.isValid()) { + MDC.put(MDC_TRACE_ID, spanContext.getTraceId()); + MDC.put(MDC_SPAN_ID, spanContext.getSpanId()); + } else { + MDC.remove(MDC_TRACE_ID); Review Comment: Thanks for the suggestion! I switched to ContextStorage.addWrapper and now install it only from Ozone services and CLIs, so client apps keep their own MDC. -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected] --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
