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Zaqar/specs/Protocols/Wire Transport

< Zaqar
Revision as of 13:07, 16 July 2013 by Flaper87 (talk | contribs) (Structure)

Marconi ZMQ API: v1 Blueprint

Since zmq is all about messages and there's no *defined* high level protocol, Marconi defined its own which tries to be as much compliant as possible with HTTP structure.

Serialization

Marconi's ZMQ transport uses either messagepack or json as serialization format. It's recommended to use messagepack since it is faster and smaller than normal json.

Structure

{
    resource: "",
    action: "",
    headers: {
    },
    payload: {
    }
}

Headers

Even though Marconi's endpoints try to be as much similar as possible, there are some slightly difference between them. Note that ZMQ transport doesn't implement some of the HTTP headers since they're meaningless for it, like:

  • Host
  • Content-Length
  • Accept-Encoding


Header Description
User-Agent The name and version of the Marconi client, as well as a UUID for that client. Marconi uses the UUID to distinguish publishers from subscribers, i.e., to avoid echoing an agent's own messages back to it.
Date The current date and time, using the standard RFC 1123 HTTP date format
Accept Media type desired; Either `application/json` or `application/messagepack`; If none was specified, the later will be used.
X-Auth-Token Keystone auth token
X-Project-ID An ID for a project to which the value of X-Auth-Token grants access. Queues will be created under this project.
Client-ID A unique ID for each client instance. In Marconi, this is used to avoid echoing a sender's messages back to the same instance, and may be logged by the server for future use. Should be generated once and persisted between restarts of the client.

Example

{
    "header": {
        "User-Agent": "python/2.7 killer-rabbit/1.2 uuid/30387f00-39a0-11e2-be4d-a8d15f34bae2",
        "Date": "Wed, 2    8 Nov 2012 21:14:19 GMT",
        "Accept": "application/messagepack",
        "X-Auth-Token": "7d2f63fd-4dcc-4752-8e9b-1d08f989cc00"
    },
    "body": {
        ...
    }
}