Proximo

Proximo is a proxy for multiple different publish-subscribe queuing systems.

It is based on a GRPC interface definition, making it easy to create new client libraries. It already supports a number of popular queueing systems, and adding new ones is intended to be simple.

Goals

• Expose multiple consumer (fan out) semantics where needed

• Minimise overhead over direct use of a given queuing system

• Allow configuration of the underlying queue system via runtime configuration of Proximo

• Allow replacement of a queueing system with no change to the Proximo client applications

• Enabling easy creation of client libraries for new languages (anything that has GRPC support)

Non goals

• Exposing specific details of the underlying queue system via the client API

Server

This is the Proximo server implementation, written in Go

proximo server

Proximo client libraries

• go - substrate - we recommend to use substrate to access proximo from go

API definition (protobuf)

protobuf definitions

Access Control

Access Control is supported using an optional config file, using the PROXIMO_ACL_CONFIG.

In this example, all clients can access the topics that start with products but only a client called product-writer has permission to to write to these topics.

default:
  roles: ["read-products"]
roles:
- id: "read-products"
  consume: ["products.*"]
- id: "write-products"
  publish: ["products.*"]
clients:
- id: "product-writer"
  secret: "$2y$10$2AzC3Z8L18cP.crFi.ZDsuFdbwrYu16Lnh8y7U1wMO3QPanYuwJIm" # pass is bcrypted hash of "password"
  roles: ["write-products"]

Add the token to the context, example:

sink, _ := proximo.NewAsyncMessageSink(proximo.AsyncMessageSinkConfig{
  Broker:   "localhost:6868",
  Topic:    "products",
  Insecure: true,
})

token := base64.StdEncoding.EncodeToString(fmt.Sprintf("%s:%s", "product-writer", "password"))
md := metadata.Pairs("Authorization", fmt.Sprintf("Bearer %s", token))
reqCtx := metadata.NewOutgoingContext(ctx, md)

sink.PublishMessage(reqCtx, &Message{Data: []byte("hello world")})