Rename net peer/host attributes to align with ECS

[trask]

What are you trying to achieve?

Rename net.* attributes to the corresponding ECS names under client.* and server.* (see open-telemetry/oteps#222 for motivation).

HTTP client attributes:

• net.peer.name -> server.address
• net.peer.port -> server.port
• net.sock.peer.name
  • when it represents a proxy -> server.nat.address (as a new field in ECS)
  • (is there any other case?)
• net.sock.peer.addr
  • when it represents the ip address of the server.address -> server.ip
  • when it represents a proxy -> server.nat.ip
  • when it represents a unix socket -> server.socket.address (as a new field in ECS)
  • (is there any other case?)
• net.sock.peer.port
  • when it represents proxy -> server.nat.port
  • (is there any other case?)

HTTP server attributes:

• net.host.name -> server.address
• net.host.port -> server.port
• net.sock.host.addr -> server.socket.ip (as a new field in ECS)
  • when it represents a unix socket -> server.socket.address (as a new field in ECS)
• net.sock.host.port -> server.socket.port (as a new field in ECS)
• net.sock.peer.name -> (remove from OTel, not needed)
• net.sock.peer.addr -> client.ip
  • when it represents a unix socket -> client.socket.address (as a new field in ECS)
• net.sock.peer.port -> client.port

[trask]

We discussed in HTTP semconv stability WG today that the nat field create some difficulty for observability where some instrumentation (e.g. Java's netty) may not be aware of whether its talking to a proxy or not.

And it seems confusing to use nat namespace when we aren't sure we're talking to a proxy/intermediary.

So here's an alternate proposal to the above:

HTTP client attributes:

• net.peer.name -> server.address
• net.peer.port -> server.port
• net.sock.peer.name -> server.socket.address (new field in ECS)
• net.sock.peer.addr -> server.socket.ip (new field in ECS)
  • when it represents a unix socket -> server.socket.address (new field in ECS)
• net.sock.peer.port -> server.socket.port (new field in ECS)

HTTP server attributes:

• net.host.name -> server.address
• net.host.port -> server.port
• net.sock.host.addr -> server.socket.ip (new field in ECS)
  • when it represents a unix socket -> server.socket.address (new field in ECS)
• net.sock.host.port -> server.socket.port (new field in ECS)
• net.sock.peer.name -> (remove from OTel, not needed)
  • if needed -> client.socket.address (new field in ECS)
• net.sock.peer.addr -> client.ip
  • when it represents a unix socket -> client.socket.address (new field in ECS)
• net.sock.peer.port -> client.port