Update client address to be consistent with server address (#302)

Co-authored-by: Armin Ruech <[email protected]>

CHANGELOG.md

@@ -71,6 +71,8 @@ release.
   ([#270](https://github.com/open-telemetry/semantic-conventions/pull/270))
 - Moved RPC streaming notes from metric brief section to notes section.
   ([#275](https://github.com/open-telemetry/semantic-conventions/pull/275))
+- Updates `client.address` to allow domain names for consistency with `server.address`.
+  ([#302](https://github.com/open-telemetry/semantic-conventions/pull/302))
 - BREAKING: Generate System metrics semconv from YAML.
   ([#89](https://github.com/open-telemetry/semantic-conventions/pull/89))
   - Rename attributes for `system.cpu.*` metrics:

docs/general/attributes.md

@@ -128,7 +128,7 @@ if they do not cause breaking changes to HTTP semantic conventions.
 <!-- semconv client -->
 | Attribute  | Type | Description  | Examples  | Requirement Level |
 |---|---|---|---|---|
-| `client.address` | string | Client address - IP address or Unix domain socket name. [1] | `/tmp/my.sock`; `10.1.2.80` | Recommended |
+| `client.address` | string | Client address - domain name if available without reverse DNS lookup, otherwise IP address or Unix domain socket name. [1] | `/tmp/my.sock`; `10.1.2.80` | Recommended |
 | `client.port` | int | Client port number. [2] | `65123` | Recommended |
 | `client.socket.address` | string | Client address of the socket connection - IP address or Unix domain socket name. [3] | `/tmp/my.sock`; `127.0.0.1` | Recommended: If different than `client.address`. |
 | `client.socket.port` | int | Client port number of the socket connection. [4] | `35555` | Recommended: If different than `client.port`. |

docs/http/http-spans.md

@@ -376,7 +376,7 @@ If the route cannot be determined, the `name` attribute MUST be set as defined i
 | Attribute  | Type | Description  | Examples  | Requirement Level |
 |---|---|---|---|---|
 | `http.route` | string | The matched route (path template in the format used by the respective server framework). See note below [1] | `/users/:userID?`; `{controller}/{action}/{id?}` | Conditionally Required: If and only if it's available |
-| [`client.address`](../general/attributes.md) | string | Client address - IP address or Unix domain socket name. [2] | `83.164.160.102` | Recommended |
+| [`client.address`](../general/attributes.md) | string | Client address - domain name if available without reverse DNS lookup, otherwise IP address or Unix domain socket name. [2] | `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/en-US/docs/Web/HTTP/Headers/Forwarded) or a similar header). Otherwise, the immediate client peer port. [3] | `65123` | Recommended |
 | [`client.socket.address`](../general/attributes.md) | string | Client address of the socket connection - IP address or Unix domain socket name. [4] | `/tmp/my.sock`; `127.0.0.1` | Recommended: If different than `client.address`. |
 | [`client.socket.port`](../general/attributes.md) | int | Client port number of the socket connection. [5] | `35555` | Recommended: If different than `client.port`. |

docs/rpc/rpc-spans.md

@@ -161,7 +161,7 @@ Generally, a user SHOULD NOT set `peer.service` to a fully qualified RPC service
 <!-- semconv rpc.server -->
 | Attribute  | Type | Description  | Examples  | Requirement Level |
 |---|---|---|---|---|
-| [`client.address`](../general/attributes.md) | string | Client address - IP address or Unix domain socket name. [1] | `/tmp/my.sock`; `10.1.2.80` | Recommended |
+| [`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] | `/tmp/my.sock`; `10.1.2.80` | Recommended |
 | [`client.port`](../general/attributes.md) | int | Client port number. [2] | `65123` | Recommended |
 | [`client.socket.address`](../general/attributes.md) | string | Client address of the socket connection - IP address or Unix domain socket name. [3] | `/tmp/my.sock`; `127.0.0.1` | Recommended: If different than `client.address`. |
 | [`client.socket.port`](../general/attributes.md) | int | Client port number of the socket connection. [4] | `35555` | Recommended: If different than `client.port`. |

model/client.yaml

@@ -12,7 +12,7 @@ groups:
     attributes:
       - id: address
         type: string
-        brief: Client address - IP address or Unix domain socket name.
+        brief: Client address - domain name if available without reverse DNS lookup, otherwise IP address or Unix domain socket name.
         note: >
           When observed from the server side, and when communicating through an intermediary, `client.address` SHOULD represent
           the client address behind any intermediaries (e.g. proxies) if it's available.