Description: A Rust library to aid in daemon and application development using types...or What If main() Had Rules?
tags : framework; rust; unix;
categories : programming;
Public Draft - R&D phase
An R&D open source project to explore writing a framework to aid in developing daemons, applications, and REPL s in the Rust programming language that can run in various execution environments (Linux, Linux-like, Docker, Kubernetes, etc).
Professionally I've written quite a few daemons that run in various forms (web servers, system managing, etc) and often repeat myself.
At the day job, I was often given asks that sound conceptually easy, but are often wrought with edge cases and complexity an architect gets to gloss over (e.g. Unix signal handling). As a result I spend far too much trying to take care of the ask instead of focusing on the primary goal (e.g. write a daemon that manages firewalls).
As a user of a framework, I don't want to sacrifice my desire to bring my own libraries/techniques instead of being forced by the framework (e.g. logging). My current employer has environments that require special handling. Being able to move an daemon from one environment to another with only a re-compilation has a lot of value (e.g. going from your local desktop to running on one of the cloud platforms).
I attempted an implementation in Haskell in December 2020 and have a partial working version on my GitHub. Given my lost bet on Haskell begetting a revolution for how programs are written, I've re-focused on using Rust. As of 2022 I am not able to find a language with a thriving, growing, and nurturing ecosystem that surpasses Rust.
Design a system that:
|section||command line options, environment variables, configurations, logging, telemetry|
|control||Interacting with the app via outside controls (either Unix Domain Socket, HTTP, etc)|
|app type||daemon, app, REPL, script, etc|
|computation||a user runs their app type in an environment|
|event||a user defined notable thing that happened|
|metric||a piece of data for telemetry|
|configuration||values relevant to the domain of your application that can be safely changed at run time without restarting|
Supports overriding (or disabling) sections; tracked via the type system:
Supports app types
Supports running unchanged code (re-compilation is allowed) under different environments
Handle/report resource limits, e.g. a programmatic
Periodically/synchronously capture system information and make that information available to the user (e.g. no more parsing
An implementer(/user) will:
Events form the spine of the framework. All notable things that happen get serialized into a channel which n readers and only a single writer. If the user chooses logging output, events become the log entries. Events can be low level: UNIX signals, socket operations, etc or high level: new user added, timer expired, remote host reported down, etc. Event handling is asynchronous. The framework augments each event with the who, when, and where. The data portion of the event should contain the what and/or why.