Hi again, I had a deeper look at the implementation and I compared it with the other components. As you suggested in your first message, the most convenient approach would be to map all headers, excluding those that we're certain are not needed. This is the strategy applied to most of the components. Once that is in place, any context propagation mechanism (traceparent in otel, but also any other header used in different technologies) will work out of the box.
I've tracked a Jira issue [1]. Feel free to pick it up and work to a final implementation. If you're needing any support, don't hesitate to write a comment on the same issue. Regards, Pasquale. [1] https://issues.apache.org/jira/browse/CAMEL-22403 On Wed, Sep 3, 2025 at 1:42 PM Pasquale Congiusti < pasquale.congiu...@gmail.com> wrote: > Hi Valentin, > thanks for providing all the info and working on a POC. I'll be giving a > look during the next days in order to see how we can enhance the telemetry > component. In general the components should be agnostic to any side feature > like telemetry, but let's see what we can achieve starting from the POC > you're done. > > Pasquale. > > On Wed, Sep 3, 2025 at 1:30 PM Valentin Brückel <bruec...@predic8.de> > wrote: > >> Hello everybody, >> >> A customer of ours is planning to use Google PubSub for their Camel >> projects. As they are using OpenTelemetry, >> they need to propagate tracing data through PubSub messages. >> >> As including camel-google-pubsub-starter and camel-opentelemetry2-starter >> did not work out of the box and initially >> attempted to propagate the "traceparent" Exchange header using >> interceptors. While they succeeded in attaching the >> header to published PubSub messages and reading it back from consumed >> messages, they found that this had no effect on >> OpenTelemetry and a new trace was created for each Exchange. >> >> After a bit of digging, we found that OpenTelemetry hooks into >> RoutePolicySupport.onExchangeBegin() and >> RoutePolicySupport.onExchangeDone() and any write access to the Exchange >> headers is too late in the Exchange's lifecycle >> to have any effect. >> >> Since we couldn't find a way to hook into the camel-google-pubsub >> component's behavior, our workaround was to clone the >> component, adding a couple of lines to add handling for the "traceparent" >> header. >> A POC is found at: >> https://github.com/bridgerdier/pubsub-trace-propagation >> >> Actual changes: >> * >> https://github.com/bridgerdier/pubsub-trace-propagation/blob/d69503510c0929cc98e7a5be9d0133ea202a2c6a/src/main/java/de/predic8/customers/pubsubtracepropagation/pubsubopentelemetry/CamelOpentelemetryMessagereceiver.java#L53 >> * >> https://github.com/bridgerdier/pubsub-trace-propagation/blob/d69503510c0929cc98e7a5be9d0133ea202a2c6a/src/main/java/de/predic8/customers/pubsubtracepropagation/pubsubopentelemetry/GooglePubsubOpentelemetryConsumer.java#L181 >> * >> https://github.com/bridgerdier/pubsub-trace-propagation/blob/d69503510c0929cc98e7a5be9d0133ea202a2c6a/src/main/java/de/predic8/customers/pubsubtracepropagation/pubsubopentelemetry/GooglePubsubOpentelemetryProducer.java#L75 >> >> Since this solution is intrusive and not really maintainable, we would be >> very grateful for a way to support using >> OpenTelemetry with the google-pubsub component out-of-the-box. The >> preferred solution would probably run along the >> lines of mapping all Exchange headers to Message attributes and vice >> versa. >> https://cloud.google.com/pubsub/docs/publisher#using-attributes >> >> I am however not very well versed in PubSub semantics or Camel/Tracing >> internals, so there might be a better way to >> achieve the desired result. >> >> Thanks in advance, >> >> Valentin Brückel >> >> >> >> *predic8 GmbH* >> >> Koblenzer Str. 65 >> >> 53173 Bonn >> >> >> >> predic8.de <https://www.predic8.de/> >> >> Tel: +4 >> <https://predic8-wiki.atlassian.net/wiki/spaces/inet/pages/372670466/Outlook#>9 >> (0) 228 5552576-0 >> >> Fax: +49 (0) 228 5552576-50 >> >> >> >> Amtsgericht Bonn >> >> HRB 16152 >> >> Geschäftsführer: Thomas Bayer, Tobias Polley >> >
