docs(messaging): add gcp_pubsub ordering key attribute

CHANGELOG.md

@@ -24,6 +24,8 @@ release.
   ([#503](https://github.com/open-telemetry/semantic-conventions/pull/503))
 - Add Semantic conventions for TLS/SSL encrypted communication.
   ([#21](https://github.com/open-telemetry/semantic-conventions/pull/21))
+- Add `messaging.gcp_pubsub.message.ordering_key` attribute.
+  ([#528](https://github.com/open-telemetry/semantic-conventions/pull/528))
 
 ### Fixes
 
@@ -123,7 +125,7 @@ stabilized.
 
 - Remove experimental Kafka metrics ([#338](https://github.com/open-telemetry/semantic-conventions/pull/338))
 - Adds `session.id` and session.md to general docs and model
-([#215](https://github.com/open-telemetry/semantic-conventions/pull/215))
+  ([#215](https://github.com/open-telemetry/semantic-conventions/pull/215))
 - Add `container.labels.<key>` attributes.
   ([#125](https://github.com/open-telemetry/semantic-conventions/pull/125))
 - Add `cluster.name` and `node.name` attributes to Elasticsearch semantic conventions.

CONTRIBUTING.md

@@ -161,14 +161,14 @@ make misspell-correction
 
 A PR (pull request) is considered to be **ready to merge** when:
 
-* It has received at least two approvals from the [code
+- It has received at least two approvals from the [code
   owners](./.github/CODEOWNERS) (if approvals are from only one company, they
   won't count).
-* There is no `request changes` from the [code owners](./.github/CODEOWNERS).
-* It has been at least two working days since the last modification (except for
+- There is no `request changes` from the [code owners](./.github/CODEOWNERS).
+- It has been at least two working days since the last modification (except for
   the trivial updates, such like typo, cosmetic, rebase, etc.). This gives
   people reasonable time to review.
-* Trivial changes (typos, cosmetic changes, CI improvements, etc.) don't have to
+- Trivial changes (typos, cosmetic changes, CI improvements, etc.) don't have to
   wait for two days.
 
 Any [maintainer](./README.md#contributing) can merge the PR once it is **ready

docs/attributes-registry/messaging.md

@@ -16,6 +16,7 @@
 | `messaging.destination.temporary` | boolean | A boolean that is true if the message destination is temporary and might not exist anymore after messages are processed. |  |
 | `messaging.destination_publish.anonymous` | boolean | A boolean that is true if the publish message destination is anonymous (could be unnamed or have auto-generated name). |  |
 | `messaging.destination_publish.name` | string | The name of the original destination the message was published to [4] | `MyQueue`; `MyTopic` |
+| `messaging.gcp_pubsub.message.ordering_key` | string | The ordering key for a given message. If the attribute is not present, the message does not have an ordering key. | `ordering_key` |
 | `messaging.kafka.consumer.group` | string | Name of the Kafka Consumer Group that is handling the message. Only applies to consumers, not producers. | `my-group` |
 | `messaging.kafka.destination.partition` | int | Partition the message is sent to. | `2` |
 | `messaging.kafka.message.key` | string | Message keys in Kafka are used for grouping alike messages to ensure they're processed on the same partition. They differ from `messaging.message.id` in that they're not unique. If the key is `null`, the attribute MUST NOT be set. [5] | `myKey` |

docs/messaging/gcp-pubsub.md

@@ -10,4 +10,13 @@ The Semantic Conventions for [Google Cloud Pub/Sub](https://cloud.google.com/pub
 
 `messaging.system` MUST be set to `"gcp_pubsub"`.
 
+## Span attributes
+
+For Google Cloud Pub/Sub, the following additional attributes are defined:
+<!-- semconv messaging.gcp_pubsub(full,tag=tech-specific-gcp-pubsub) -->
+| Attribute  | Type | Description  | Examples  | Requirement Level |
+|---|---|---|---|---|
+| [`messaging.gcp_pubsub.message.ordering_key`](../attributes-registry/messaging.md) | string | The ordering key for a given message. If the attribute is not present, the message does not have an ordering key. | `ordering_key` | Conditionally Required: If the message type has an ordering key set. |
+<!-- endsemconv -->
+
 [DocumentStatus]: https://github.com/open-telemetry/opentelemetry-specification/tree/v1.26.0/specification/document-status.md

model/registry/messaging.yaml

@@ -202,6 +202,11 @@ groups:
         brief: >
           Namespace of RocketMQ resources, resources in different namespaces are individual.
         examples: 'myNamespace'
+      - id: gcp_pubsub.message.ordering_key
+        type: string
+        brief: >
+         The ordering key for a given message. If the attribute is not present, the message does not have an ordering key.
+        examples: 'ordering_key'
       - id: system
         brief: >
           An identifier for the messaging system being used. See below for a list of well-known identifiers.

model/trace/messaging.yaml

@@ -170,3 +170,13 @@ groups:
         tag: tech-specific-rocketmq
       - ref: messaging.rocketmq.consumption_model
         tag: tech-specific-rocketmq
+  - id: messaging.gcp_pubsub
+    type: attribute_group
+    extends: messaging
+    brief: >
+      Attributes for Google Cloud Pub/Sub
+    attributes:
+      - ref: messaging.gcp_pubsub.message.ordering_key
+        tag: tech-specific-gcp-pubsub
+        requirement_level:
+          conditionally_required: If the message type has an ordering key set.