Fleet Protocol

Fleet Protocol is a communication technology developed by BringAuto to allow for simple and reliable communication between devices deployed in an internet-connection-unstable environment and cloud infrastructure.

Protocol consists of three parts:

• Internal Client (Remote) - part of a device which communicates with a Module Gateway
• Module Gateway (Remote):
  • internal server - communicates with internal clients
  • aggregator - aggregates status messages, gathers and aggragates messages in case of connection outage, ...
  • external client - communicates with an External Server
• External Server (Cloud) - deployed as part of the cloud infrastructure. It provides status messages and can be used to control devices by command messages.

Communication protocol

We use the ProtoBuf library for message format (version Protobuf version) and serialization/deserialization - protocol specification can be found in protobuf folder.

Each message must be prefixed with a four bytes long (uint32_t data type) header, which holds information about the size of the ProtoBuf message.

To read more about the system architecture, check the Fleet Protocol v2 documentation:

• Summary - overall high-level summary
• Fleet Protocol Requirements
• Internal Client
• Module Gateway
• External Server
• Modules - list of implemented modules
• Message Structure
• Internal Client design
• Module Gateway design
• External Server design

Implementation of each respective component:

• Module Gateway impl
• External Server impl
• Internal Client
  • Internal Client C++ impl - C++ implementation, only on Posix, no libraries used
  • Internal Client Python3 impl
  • Internal Client Arduino impl - basic implementation for Arduino 32bit boards
• Modules
  • Mission Module - Autonomy Control module
  • IO Module - Input/Output devices
  • Example Module

All supported modules can be listed by fleet-protocol-module topic.

HTTP Interface

The Fleet Protocol HTTP API represents the protocol in the form of an HTTP API.

A Fleet Protocol Module can use the HTTP API to provide its statuses and retrieve commands through a simple and understandable REST API for easy integration with other services.

Fleet Protocol HTTP API is a standalone project and is not part of the Fleet Protocol v2 core specification.

• HTTP API
• HTTP API C++ Client
• HTTP API Python3 Client
• HTTP API Wait Mechanism

Protocol messages

Messages are described by ProtoBuf v3.

If a message field is not mandatory, then it's marked as OPTIONAL by "OPTIONAL" as the last comment in documentation for the given field. Optional fields have defaults as described in the ProtoBuf v3 doc.

Repo structure

Examples

Samples of fleet-protocol features usage.

Use CMake option BRINGAUTO_SAMPLES=ON to configure them.

Lib

Header files of interfaces

Protobuf

Compiled and non-compiled protobuf files

Usage

Requirements

• CMlib

Installation

To install the library, first configure the project with the CMake option BRINGAUTO_INSTALL=ON and BRINGAUTO_PACKAGE=ON, and then install it.

mkdir _build && cd _build
cmake -DBRINGAUTO_INSTALL=ON -DBRINGAUTO_PACKAGE=ON ..
make install

Package

To create a package, configure the project with CMake option BRINGAUTO_PACKAGE=ON and then create it using cpack.

mkdir _build && cd _build
cmake -DBRINGAUTO_INSTALL=ON -DBRINGAUTO_PACKAGE=ON ..
cpack

Using library in CMake projects

Once the library is installed, it can be used in other projects by adding the following lines to the CMakeLists.txt file:

FIND_PACKAGE(fleet-protocol-interface REQUIRED)
TARGET_LINK_LIBRARIES(<target> PUBLIC fleet-protocol-interface::fleet-protocol-interface)

This will link all interfaces. If you want to only link a specific interface, chose from the interfaces listed below:

• fleet-protocol-interface::common-headers-interface
• fleet-protocol-interface::internal-client-interface
• fleet-protocol-interface::module-gateway-interface
• fleet-protocol-interface::module-maintainer-external-server-interface
• fleet-protocol-interface::module-maintainer-module-gateway-interface
• fleet-protocol-interface::protobuf-cpp-interface

Note that protobuf-cpp-interface also needs protobuf::libprotobuf to be linked to the target