Change client.port from recommended to opt-in on HTTP server spans

CHANGELOG.md

@@ -32,6 +32,8 @@ release.
   ([#409](https://github.com/open-telemetry/semantic-conventions/pull/409))
 - Remove `url.path` default value.
   ([#462](https://github.com/open-telemetry/semantic-conventions/pull/462))
+- Change `client.port` from recommended to opt-in on HTTP server spans
+  ([#999](https://github.com/open-telemetry/semantic-conventions/pull/999))
 
 ### Features
 

docs/http/http-spans.md

@@ -343,7 +343,7 @@ For an HTTP server span, `SpanKind` MUST be `Server`.
 | Attribute  | Type | Description  | Examples  | Requirement Level |
 |---|---|---|---|---|
 | [`client.address`](../general/attributes.md) | string | Client address - domain name if available without reverse DNS lookup; otherwise, IP address or Unix domain socket name. [1] | `83.164.160.102` | Recommended |
-| [`client.port`](../general/attributes.md) | int | The port of the original client behind all proxies, if known (e.g. from [Forwarded](https://developer.mozilla.org/docs/Web/HTTP/Headers/Forwarded) or a similar header). Otherwise, the immediate client peer port. [2] | `65123` | Recommended |
+| [`client.port`](../general/attributes.md) | int | The port of the original client behind all proxies, if known (e.g. from [Forwarded](https://developer.mozilla.org/docs/Web/HTTP/Headers/Forwarded) or a similar header). Otherwise, the immediate client peer port. [2] | `65123` | Opt-In |
 | [`http.route`](../attributes-registry/http.md) | string | The matched route, that is, the path template in the format used by the respective server framework. [3] | `/users/:userID?`; `{controller}/{action}/{id?}` | Conditionally Required: If and only if it's available |
 | [`network.local.address`](../attributes-registry/network.md) | string | Local socket address. Useful in case of a multi-IP host. | `10.1.2.80`; `/tmp/my.sock` | Opt-In |
 | [`network.local.port`](../attributes-registry/network.md) | int | Local socket port. Useful in case of a multi-port host. | `65123` | Opt-In |

model/trace/http.yaml

@@ -74,6 +74,7 @@ groups:
             Otherwise, the immediate client peer address.
         examples: ['83.164.160.102']
       - ref: client.port
+        requirement_level: opt_in
         brief: >
             The port of the original client behind all proxies, if
             known (e.g. from [Forwarded](https://developer.mozilla.org/docs/Web/HTTP/Headers/Forwarded) or a similar header).