service-mesh-nats-ruby

service-mesh-nats-ruby is the Ruby implementation of the Service Mesh API Specification over NATS. It implements the Ruby contract in the service_mesh gem, from service-mesh-ruby, on top of the nats-pure client.

The ServiceMeshNats module provides:

• Client, which implements the contract's Client over one NATS connection
• Runtime, which implements the contract's Runtime on a Client's connection
• the configuration keys it reads
• the errors it defines

The contract types it works with, such as ServiceMesh::Target, ServiceMesh::Message, ServiceMesh::Endpoint, and ServiceMesh::Subscriber, come from the service_mesh gem.

# Gemfile
gem "service_mesh_nats"

Requires Ruby 3.3 or newer and a reachable NATS server. The gem depends on service_mesh and nats-pure.

require "service_mesh_nats"

echo    = ServiceMesh::Target.new(segments: %w[demo echo], kind: :route)
created = ServiceMesh::Target.new(segments: %w[demo created], kind: :topic)
map     = ServiceMesh::ServiceMap.new(targets: [echo, created])

config = {
  "url" => "nats://127.0.0.1:4222",
  "deployment_group" => "demo"
}

client = ServiceMeshNats::Client.new(config, map)
# Connects. Raises BadConfig or the connection failure.

runtime = ServiceMeshNats::Runtime.new(client, config,
  endpoints: [
    ServiceMesh::Endpoint.new(target: echo, handler: ->(m) { ServiceMesh::Message.new(target: echo, payload: m.payload) })
  ],
  subscribers: [
    ServiceMesh::Subscriber.new(target: created, handler: ->(m) { puts "created: #{m.payload}" })
  ])
# Raises NoDeploymentGroup, BadConfig, KindMismatch, or InvalidTarget, and
# ArgumentError for a handler that does not respond to call.

runtime.start
at_exit { runtime.stop(10) }

reply = client.request(ServiceMesh::Message.new(target: echo, payload: "hi"))
client.publish(ServiceMesh::Message.new(target: created, payload: "order 42"))

The client is the runtime's connection. runtime.client returns it in every state, and runtime.stop closes it. A process that only requests and publishes builds a client itself and calls close when done. runtime.service_map and client.service_map return the map the client was built with.

• Examples: a server process, a call-only client process, and consumer groups
• Public API: every public constant and method in ServiceMeshNats
• Transport Specific Implementation: subjects, configuration, metadata, delivery, handler failure, timeouts, concurrency, lifecycle, and errors
• Development: the recipes and the tests