docs(messaging): add gcp_pubsub as a messaging system

[alevenberg]

Changes

Adds gcp_pubsub as a messaging system value

Note: if the PR is touching an area that is not listed in the existing areas, or the area does not have sufficient domain experts coverage, the PR might be tagged as experts needed and move slowly until experts are identified.

Merge requirement checklist

• CONTRIBUTING.md guidelines followed.

Waiting to sign the CLA until the PR is created.
Also I ran make fix, but it generated some diffs in CONTRIBUTING.md (* -> -) and CHANGELOG.md (whitespace), so I left those out.

• CHANGELOG.md updated for non-trivial changes.

Skipped, since it is a trivial change

• schema-next.yaml updated with changes to existing conventions.

Skipped since it only affects the docs

[linux-foundation-easycla]

The committers listed above are authorized under a signed CLA.

• ✅ login: alevenberg / name: Anna Levenberg (2263163, 226fc20, 637968d, 3373dd6, 119b45d, b4dfb60)
• ✅ login: joaopgrassi / name: Joao Grassi (b4dfb60)
• ✅ login: arminru / name: Armin Ruech (c76bb03)

[alevenberg]

Disclaimer: I'm not familiar with Otel Semantic Conventions.

Is there a place to specify a semantic convention for a value (not a key). This value (gcp_pubsub) will be used in multiple languages. Is there a place we can define it upstream so it appears in a file like opentelemetry/trace/semantic_conventions.h(for C++)?

[pyohannes]

Hi @alevenberg . I'd recommend you introduce a dedicated document for GCP PubSub, as it exists for Kafka or RabbitMQ. There you define additional requirements for GCP PubSub instrumentation, like it's done here: https://github.com/open-telemetry/semantic-conventions/blob/main/docs/messaging/rocketmq.md?plain=1#L13

You might just start out with defining the value for messaging.system, you can then add definitions for more system-specific attributes there if needed. Ideally you (or somebody else with domain knowledge) would then be willing to own and maintain this document specific to GCP PubSub.

Is there a place we can define it upstream so it appears in a file like opentelemetry/trace/semantic_conventions.h(for C++)?

No, that's still a manual process and requires changes for each supported language.

[alevenberg]

Hi @alevenberg . I'd recommend you introduce a dedicated document for GCP PubSub, as it exists for Kafka or RabbitMQ. There you define additional requirements for GCP PubSub instrumentation, like it's done here: main/docs/messaging/rocketmq.md?plain=1#L13

You might just start out with defining the value for messaging.system, you can then add definitions for more system-specific attributes there if needed. Ideally you (or somebody else with domain knowledge) would then be willing to own and maintain this document specific to GCP PubSub.

Sounds good! I added it, and I will add more information about tracing semantic conventions in GCP Pub/Sub. I can own this document for now.

Is there a place we can define it upstream so it appears in a file like opentelemetry/trace/semantic_conventions.h(for C++)?

No, that's still a manual process and requires changes for each supported language.

Ack, thanks for answering!

[alevenberg]

cc @dbolduc

[dbolduc]

Should we link to gcp-pubsub.md in /docs/messaging/README.md ?

semantic-conventions/docs/messaging/README.md

Lines 18 to 22 in 6a9acef

	Technology specific semantic conventions are defined for the following messaging systems:
	* [Kafka](kafka.md): Semantic Conventions for *Apache Kafka*.
	* [RabbitMQ](rabbitmq.md): Semantic Conventions for *RabbitMQ*.
	* [RocketMQ](rocketmq.md): Semantic Conventions for *Apache RocketMQ*.

[alevenberg]

Should we link to gcp-pubsub.md in /docs/messaging/README.md ?

semantic-conventions/docs/messaging/README.md

Lines 18 to 22 in 6a9acef

	Technology specific semantic conventions are defined for the following messaging systems:
	* [Kafka](kafka.md): Semantic Conventions for *Apache Kafka*.
	* [RabbitMQ](rabbitmq.md): Semantic Conventions for *RabbitMQ*.
	* [RocketMQ](rocketmq.md): Semantic Conventions for *Apache RocketMQ*.

Good catch. Done

[alevenberg]

I ran make table-generation to generate the markdown files from the yaml

[joaopgrassi]

Please also add a changelog entry

[joaopgrassi]

Just the changelog entry missing now.