Per message logging

[kgiusti]

Feature Request

For rpc-client, rpc-server, listener, and notifier add the ability to log details of each message transfer.

A new option for the above modes will be added: "--output". It takes a single argument: a file in which the per-message information will be stored. The output will be json formatted.

For rpc-client and notifier, each message transfer will result in an entry added to the output file. The format of the entry will be:

{"id": "<string>", "start": <float>, "stop": <float> [, "error": "<string>"]}

The id string will be a unique identifier for this message. Start is the time value (in seconds since epoch) when the message was passed to oslo.messaging for transmit. Stop is the time value when the call to oslo.messaging returns. An optional error string will appear if an error occurred during the transmit.

For rpc-server and listener, the entry will be in the following format:

{"id": "<string>", "start": <float>, "recv": <float> [, "error": "<string>"]}

Where id is the message id assigned by the sender (rpc-client or notifier) which can be used to correlate the message with its sender. Start is the same value from the corresponding client's start time value. The recv value is the time when the server received the message. An optional error string will appear if an error occurred during receive.