Hi there, We have recently had the opportunity to utilize Proton on embedded devices to talk to Azure. The class of embedded devices we are working with require some strict design constraints on the AMQP library we can use:
* Library must be AMQP 1.0 compatible * Library must run on embedded devices running a micro RTOS, TCP/IP and SSL * Library should avoid heap fragmentation * Library RAM use must be less than 25K * Library Flash use must be less than 75k These requirements are not met by Proton out of the box, but we do think they align with the Proton roadmap to support this class of devices. In order to accomplish these goals, we are proposing to alter some of the underlying Proton-C architecture. Here is an overview of the changes we are proposing: Target Micro RTOS, TCP/IP, and SSL - Introduce a porting layer to provide abstractions for required RTOS constructs. These constructs are limited to basic constructs- threads, queues, semaphores. Some changes may be necessary to adapt the socket and network interface to RTOS requirements and improve portability across RTOS and network stacks. Devices running without an RTOS are not supported. A porting layer provides abstractions for the required Embedded SSL constructs. Memory Allocation and Management - To make more efficient use of the available memory and avoid fragmentation, calls to malloc() may be replaced by specially tailored memory allocation routines and/or block pools. Limited Protocol Features - In order to meet RAM and flash usage targets, protocol features can be limited. The allowable limits are set to assure the implementation remains 1.0 compatible. These limits will be documented. Initially, we would target the following platforms and libraries: RTOS: * ThreadX * FreeRTOS TCP/IP stacks: * NetX * LwIP SSL Libraries: * Mocana * Matrix Although we would prefer to contribute these changes back to the Proton-C source tree, we think these changes would radically alter the Proton-C codebase as it stands now. A better solution may be to introduce a new class of Proton- call it Proton Embedded or Proton-e. We have already kicked off this work and would like to contribute these changes back to the community, most likely in a branch so that the community can review the code thoroughly before deciding on a final home. Would there be interest in this work added to the Proton project? Chris Busbey Senior Program Manager Microsoft Open Technologies, Inc. A subsidiary of Microsoft Corporation
