https://github.com/elcritch/rpclib_port_driver
https://github.com/elcritch/rpclib_port_driver
Last synced: 5 months ago
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- Host: GitHub
- URL: https://github.com/elcritch/rpclib_port_driver
- Owner: elcritch
- Created: 2018-04-09T19:14:44.000Z (over 7 years ago)
- Default Branch: master
- Last Pushed: 2018-05-14T04:37:15.000Z (over 7 years ago)
- Last Synced: 2025-05-07T13:57:09.793Z (5 months ago)
- Language: C++
- Size: 2.49 MB
- Stars: 0
- Watchers: 2
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
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README
# RpclibPortDriver
Library for creating C++11 Erlang port drivers using `rpclib`, which is a "Modern rpclib - modern rpclib-rpc for C++".
Status: Usable but may require tinkering
## Installation
```elixir
def deps do
[
{:rpclib_port_driver, "~> 0.1.2", github: "elcritch/rpclib_port_driver"},
]
end
```
## Setup
This library provides a `Mix.Task` for setting up an appropriate Makefile and `rpclib_driver.cpp` file.
After adding to your dependencies and downloaing, run:
```sh
mix rpclib.gen.project --subdirs=src/
```
```sh
mix rpclib.gen.driver --subdir=src/
```
Note: The first step is not necessary if you already have a Makfile in your project.
These Mix tasks create a simple Makefile and setup a link to the appropriate dependency paths. It should be possible to update the `dispatcher` library code by updating this library in your mix dependencies.
## Why?
The Erlang port drivers are somewhat tedious and adding new functions requires ensuring arguments are defined correectly. This project builds on the very handy [rpclib](http://rpclib.net/) which utilizes modern C++11 features to automatically find functions. Functions can be directly bound or lambda functions can be provided. Most basic C/C++ types are handled and automatically cast. See [RPCLib: What Does it Look like?](http://rpclib.net/#what-does-it-look-like) and [RPCLib: Using custom types as parameters](http://rpclib.net/primer/#using-custom-types-as-parameters)
The networking / socket stack has been removed and replaced with a very simple stdio based driver. The driver can be found in the `erl_comm.hpp` header. It listens on `stdin` and parses the Erlang ports communication protocol (it's a very simple protocol and worth reading `erl_comm.hpp` file or Erlang port documentation).
## Example
C++ example:
```c++
/* rpc example functions */
int bar(int x, int y) {
std::cerr << "`bar`` was called! Adding: " << x << " and " << y << std::endl;
int r = x + y;
return r;
}
int main() {
// Configure dispatcher
Dispatcher dispatcher;
dispatcher.bind("bar", &bar);
dispatcher.bind("echo", [](std::string const& s) {return std::string("> ") + s;});
// Start erl_comm port driver loop
// Notes: Uses a static buffer and not thread safe
return port_cmd_loop(dispatcher);
}
```
On the Elixir side:
```elixir
0 = MyProject.Rpclib.call_port({:bar, [10, -10]})
msg = "hello world"
^msg = MyProject.Rpclib.call_port({:echo, [msg]})
```
## Current Limitations
- WIP! No tests currently (though working on them)
- The port driver is _not_ thread safe
- Do _not_ print / write / std::cout anything to `stdout`.
+ Any messages will cause the port driver to error and usually hang indefinitely.
- Exception handling is currently not handled well (at all?)