[OpenTelemetry] Enable OpenTelemetry stitching with Logs for Dataflow worker by stankiewicz · Pull Request #39625 · apache/beam

stankiewicz · 2026-08-05T08:43:58Z

This change will add trace, spanId and sampled fields supported by Logging if Spans are available in current context and if feature is enabled (disabled by default).

Outcome is trace link visible in logging and logging visible in trace:

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codecov · 2026-08-05T09:38:13Z

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 58.15%. Comparing base (f2c622b) to head (945ffdd).
⚠️ Report is 8 commits behind head on master.

Additional details and impacted files

@@             Coverage Diff              @@
##             master   #39625      +/-   ##
============================================
- Coverage     58.15%   58.15%   -0.01%     
+ Complexity    13085    13084       -1     
============================================
  Files          2521     2521              
  Lines        264850   264863      +13     
  Branches      10788    10788              
============================================
- Hits         154023   154020       -3     
- Misses       105051   105066      +15     
- Partials       5776     5777       +1

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scwhittle

Do you also want to add this to LogRecordHandler in BeamFnLoggingClient.java?
That is used with the dataflow portable runner harness.

scwhittle · 2026-08-05T12:28:23Z

            .setTimestamp(Instant.ofEpochMilli(record.getMillis()))
            .setSeverity(severityFor(record.getLevel()));
-
+    SpanContext spanContext = Span.current().getSpanContext();


maybe better to just get the current span context if logOpenTelemetryTraceSpanIdAndSampled is enabled in case there is some overhead like a thread-local

good point, will do

scwhittle · 2026-08-05T12:28:35Z

      writeIfNotEmpty(generator, "logger", record.getLoggerName());
      writeIfNotEmpty(generator, "exception", formatException(record.getThrown()));
+      SpanContext spanContext = Span.current().getSpanContext();
+      if (logOpenTelemetryTraceSpanIdAndSampled.get() && spanContext.isValid()) {


scwhittle · 2026-08-05T12:30:00Z

      writeIfNotEmpty(generator, "exception", formatException(record.getThrown()));
+      SpanContext spanContext = Span.current().getSpanContext();
+      if (logOpenTelemetryTraceSpanIdAndSampled.get() && spanContext.isValid()) {
+        generator.writeStringField("trace", spanContext.getTraceId());


does isValid imply that the trace id and span id are not empty? otherwise use writeIfNotEmpty

correct, it means that there is something non empty and not default (different to "00000000000000000000000000000000")

scwhittle · 2026-08-05T12:30:30Z

+      if (logOpenTelemetryTraceSpanIdAndSampled.get() && spanContext.isValid()) {
+        generator.writeStringField("trace", spanContext.getTraceId());
+        generator.writeStringField("spanId", spanContext.getSpanId());
+        generator.writeBooleanField("traceSampled", spanContext.isSampled());


would it be better to reduce overhead by just writing this if it is true and omitting it if false?

maybe this should be trace_sampled as well instead of camel-case to match custom_data?

hmm the documented agent format is also inconsistent https://docs.cloud.google.com/logging/docs/structured-logging#structured_logging_special_fields

uses trace_sampled and spanId

but json is format used between dataflow worker and agent that reads data and sends asynchronously to clod logging. Happy to change field names.

on skipping writing when sampled=false - sounds like good idea, will implement that as well.

scwhittle · 2026-08-05T12:31:12Z

      @Nullable DataflowExecutionState executionState,
      ImmutableMap<String, String> defaultResourceLabels) {
    Struct.Builder payloadBuilder = Struct.newBuilder();
+    //


github-actions · 2026-08-05T13:07:14Z

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… direct logging and file based

stankiewicz requested a review from scwhittle August 5, 2026 08:44

github-actions Bot added java runners dataflow labels Aug 5, 2026

scwhittle requested changes Aug 5, 2026

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github-actions Bot added the Next Action: Reviewers label Aug 5, 2026

stankiewicz force-pushed the tace_logs_stitch branch from 945ffdd to 20804a3 Compare August 5, 2026 13:19

Enable OpenTelemetry stiching with Logs for Dataflow worker, both for…

873e645

… direct logging and file based

stankiewicz force-pushed the tace_logs_stitch branch from 20804a3 to 873e645 Compare August 5, 2026 13:51

stankiewicz requested a review from scwhittle August 5, 2026 13:51

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stankiewicz commented Aug 5, 2026

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stankiewicz Aug 5, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

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stankiewicz Aug 5, 2026 •

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