Middleware
Choria communicates almost exclusively over the middleware, this document describes the target names and messages you might find on the middleware. You might use this for debuging or learning purposes using the choria tool pub and choria tool sub commands.
The Choria broker is a managed instance of the NATS Server, target syntax shown here matches the standards it supports.
Core RPC Messages
Unfederated
This is the core RPC related message targets, this is how machines discover nodes and communicate with them either 1:1 or 1:n.
These are namespaced on collective allowing one to make something like a VLAN - where servers and clients in a particular Subcollective can only find others configured with the same.
| Target | Description | Schema |
|---|---|---|
collective.reply.> |
Replies to requests made by clients, example mcollective.reply.dev1.example.net.c2a764e6013a44adb848904ff7d74ff4 | choria:transport:1 with a choria:secure:reply:1 payload |
collective.broadcast.agent.> |
Requests from clients to specific agents broadcasted to all servers interested | choria:transport:1 with a choria:secure:request:1 payload |
collective.broadcast.service.> |
Requests from clients to specific Service Agents broadcasted to all servers interested, handled by only 1 of those hosting the Service. | choria:transport:1 with a choria:secure:request:1 payload |
collective.broadcast.agent.registration |
The default destination for registration messages when no custom targets are configured | choria:transport:1 |
collective.node.> |
Requests from clients to specific nodes regardless of the agent aka directed | choria:transport:1 with a choria:secure:request:1 payload |
Federated
Federation is a router between different networks, when a client makes a request it publishes to a specific address instead of the usual ones, the Federation Broker will then publish to the above targets on the user’s behalf.
Likewise replies are received on a different target and the Federation Broker will send them to the usual client locations on the servers behalf.
These are namespaced on collective here, each Federation Member Collective has a unique name.
| Target | Description | Schema |
|---|---|---|
choria.federation.collective.collective |
When federated, replies to clients from server that would typically go to collective.reply.> are directed here instead |
choria:transport:1 with a choria:secure:reply:1 payload |
choria.federation.collective.federation |
When federated, requests to servers that would typically go to collective.broadcast.> or collective.node> goes here instead | choria:transport:1 with a choria:secure:request:1 payload |
Lifecycle
Lifecycle messages are small events the various Choria components publish indicating they are alive, starting, stopping etc.
Read our introductory blog post about events.
| Target | Description | Schema |
|---|---|---|
choria.lifecycle.event.TYPE.COMPONENT |
A specific event from a specific component, example choria.lifecycle.event.startup.server when a server starts | various |
Others
| Target | Description | Schema |
|---|---|---|
| > | Custom registration target set using plugin.choria.registration.file_content.target | choria:transport:1 with a choria:registration:filecontent:1 payload |
| > | Custom sources for consuming messages by the adapters like those set by plugin.choria.adapter.xx.ingest.topic | choria:transport:1 with a payload depending on the producer settings |