transportThe transport package implements the communication substrate that microservices use to exchange messages. It abstracts the details of the underlying messaging system behind a single Conn type that supports both NATS-based distributed messaging and an in-process short-circuit path for co-located microservices.
A Conn is opened with Open and closed with Close. Messages are sent with Publish (one-to-many), Request (one-to-one) and Response (reply to a request). Interest in a subject is expressed with Subscribe (all subscribers receive every message) or QueueSubscribe (messages are load-balanced across members of the same queue group).
Messages are represented by the Msg type, which carries the raw bytes alongside the parsed *http.Request or *http.Response. The MsgHandler function type processes incoming messages.
Subjects support wildcards: * matches a single segment and > matches the remainder of the subject. A prefix tree is used internally for efficient subject routing over the short-circuit transport.