forked from cadey/xesite
203 lines
8.5 KiB
Markdown
203 lines
8.5 KiB
Markdown
---
|
|
title: "Wasmcloud Progress: Rewritten in Rust"
|
|
date: 2020-10-31
|
|
series: olin
|
|
tags:
|
|
- wasm
|
|
- wasmcloud
|
|
- wasmer
|
|
---
|
|
|
|
# Wasmcloud Progress: Rewritten in Rust
|
|
|
|
It's been a while since I had the [last update for
|
|
Wasmcloud](/blog/wasmcloud-progress-2019-12-08). In that time I have gotten a
|
|
lot done. As the title mentions I have completely rewritten Wasmcloud's entire
|
|
stack in Rust. Part of the reason was for [increased
|
|
speed](/blog/pahi-benchmarks-2020-03-26) and the other part was to get better at
|
|
Rust. I also wanted to experiment with running Rust in production and this has
|
|
been an excellent way to do that.
|
|
|
|
Wasmcloud is going to have a few major parts:
|
|
- The API (likely to be hosted at `api.wasmcloud.app`)
|
|
- The Executor (likely to be hosted at `run.wasmcloud.lgbt`)
|
|
- The Panel (likely to be hosted at `panel.wasmcloud.app`)
|
|
- The command line tool `wasmcloud`
|
|
- The Documentation site (likely to be hosted at `docs.wasmcloud.app`)
|
|
|
|
These parts will work together to implement a functions as a service platform.
|
|
|
|
[The executor is on its own domain to prevent problems like <a
|
|
href="https://github.blog/2013-04-05-new-github-pages-domain-github-io/">this
|
|
GitHub Pages vulnerability</a> from 2013. It is on a `.lgbt` domain because LGBT
|
|
rights are human rights.](conversation://Mara/hacker)
|
|
|
|
I have also set up a (slightly sarcastic) landing page at
|
|
[wasmcloud.app](https://wasmcloud.app) and a twitter account at
|
|
[@usewasmcloud](https://twitter.com/usewasmcloud). Right now these are
|
|
placeholders. I wanted to register the domains before they were taken by anyone
|
|
else.
|
|
|
|
## Architecture
|
|
|
|
My previous attempt at Wasmcloud had more of a four tier webapp setup. The
|
|
overall stack looked something like this:
|
|
|
|
- Nginx in front of everything
|
|
- The api server that did about everything
|
|
- The executors that waited on message queues to run code and push results to
|
|
the requester
|
|
- Postgres
|
|
- A message queue to communicate with the executors
|
|
- IPFS to store WebAssembly modules
|
|
|
|
In simple testing, this works amazingly. The API server will send execution
|
|
requests to the executors and everything will usually work out. However, the
|
|
message queue I used was very "fire and forget" and had difficulties with
|
|
multiple executors set up to listen on the queue. Additionally, the added
|
|
indirection of needing to send the data around twice means that it would have
|
|
difficulties scaling globally due to ingress and egress data costs. This model
|
|
is solid and _probably would have worked_ with some compression or other
|
|
improvements like that, but overall I was not happy with it and decided to scrap
|
|
it while I was porting the executor component to Rust. If you want to read the
|
|
source code of this iteration of Wasmcloud, take a look
|
|
[here](https://tulpa.dev/within/wasmcloud).
|
|
|
|
The new architecture of Wasmcloud looks something like this:
|
|
|
|
- Nginx in front of everything
|
|
- An API server that handles login with my gitea instance
|
|
- The executor server that listens over https
|
|
- Postgres
|
|
- Backblaze B2 to store WebAssembly modules
|
|
|
|
The main change here is the fact that the executor listens over HTTPS, avoiding
|
|
_a lot_ of the overhead involved in running this on a message queue. It's also
|
|
much simpler to implement and allows me to reuse a vast majority of the
|
|
boilerplate that I developed for the Wasmcloud API server.
|
|
|
|
This new version of Wasmcloud is also built on top of
|
|
[Wasmer](https://wasmer.io/). Wasmer is a seriously fantastic library for this
|
|
and getting up and running was absolutely trivial, even though I knew very
|
|
little Rust when I was writing [pa'i](/blog/pahi-hello-world-2020-02-22). I
|
|
cannot recommend it enough if you ever want to execute WebAssembly on a server.
|
|
|
|
## Roadmap
|
|
|
|
At this point, I can create new functions, upload them to the API server and
|
|
then trigger them to be executed. The output of those functions is not returned
|
|
to the user at this point. I am working on ways to implement that. There is also
|
|
very little accounting for what resources and system calls are used, however it
|
|
does keep track of execution time. The executor also needs to have the request
|
|
body of the client be wired to the standard in of the underlying module, which
|
|
will enable me to parse CGI replies from WebAssembly functions. This will allow
|
|
you to host HTTP endpoints on Wasmcloud using the same code that powers
|
|
[this](https://olin.within.website) and
|
|
[this](http://cetacean.club/cgi-bin/olinfetch.wasm).
|
|
|
|
I also need to go in and completely refactor the
|
|
[olin](https://github.com/Xe/pahi/tree/main/wasm/olin/src) crate and make the
|
|
APIs much more ergonomic, not to mention make the HTTP client actually work
|
|
again.
|
|
|
|
Then comes the documentation. Oh god there will be so much documentation. I will
|
|
be _drowning_ in documentation by the end of this.
|
|
|
|
I need to write the panel and command line tool for Wasmcloud. I want to write
|
|
the panel in [Elm](https://elm-lang.org/) and the command line tool in Rust.
|
|
|
|
There is basically zero validation for anything submitted to the Wasmcloud API.
|
|
I will need to write validation in order to make it safer.
|
|
|
|
I may also explore enabling support for [WASI](https://wasi.dev/) in the future,
|
|
but as I have stated before I do not believe that WASI works very well for the
|
|
futuristic plan-9 inspired model I want to use on Wasmcloud.
|
|
|
|
Right now the executor shells out to pa'i, but I want to embed pa'i into the
|
|
executor binary so there are fewer moving parts involved.
|
|
|
|
I also need to figure out what I should do with this project in general. It
|
|
feels like it is close to being productizable, but I am in a very bad stage of
|
|
my life to be able to jump in headfirst and build a company around this. Visa
|
|
limitations also don't help here.
|
|
|
|
## Things I Learned
|
|
|
|
[Rocket](https://rocket.rs) is an absolutely fantastic web framework and I
|
|
cannot recommend it enough. I am able to save _so much time_ with Rocket and its
|
|
slightly magic use of proc-macros. For an example, here is the entire source
|
|
code of the `/whoami` route in the Wasmcloud API:
|
|
|
|
```rust
|
|
#[get("/whoami")]
|
|
#[instrument]
|
|
pub fn whoami(user: models::User) -> Json<models::User> {
|
|
Json(user)
|
|
}
|
|
```
|
|
|
|
The `FromRequest` instance I have on my database user model allows me to inject
|
|
the user associated with an API token purely based on the (validated against the
|
|
database) claims associated with the JSON Web Token that the user uses for
|
|
authentication. This then allows me to make API routes protected by simply
|
|
putting the user model as an input to the handler function. It's magic and I
|
|
love it.
|
|
|
|
Postgres lets you use triggers to automatically update `updated_at` fields for
|
|
free. You just need a function that looks like this:
|
|
|
|
```sql
|
|
CREATE OR REPLACE FUNCTION trigger_set_timestamp()
|
|
RETURNS TRIGGER AS $$
|
|
BEGIN
|
|
NEW.updated_at = NOW();
|
|
RETURN NEW;
|
|
END;
|
|
$$ LANGUAGE plpgsql;
|
|
```
|
|
|
|
And then you can make triggers for your tables like this:
|
|
|
|
```sql
|
|
CREATE TRIGGER set_timestamp_users
|
|
BEFORE UPDATE ON users
|
|
FOR EACH ROW
|
|
EXECUTE PROCEDURE trigger_set_timestamp();
|
|
```
|
|
|
|
Every table in Wasmcloud uses this in order to make programming against the
|
|
database easier.
|
|
|
|
The symbol/number layer on my Moonlander has been _so good_. It looks something
|
|
like this:
|
|
|
|
|
|
|
|
And it makes using programming sigils _so much easier_. I don't have to stray
|
|
far from the homerow to hit the most common ones. The only one that I still have
|
|
to reach for is `_`, but I think I will bind that to the blank key under the `]`
|
|
key.
|
|
|
|
The best programming music is [lofi hip hop radio - beats to study/relax
|
|
to](https://www.youtube.com/watch?v=5qap5aO4i9A). Second best is [Animal
|
|
Crossing music](https://www.youtube.com/watch?v=2nYNJLfktds). They both have
|
|
this upbeat quality that makes the ideas melt into code and flow out of your
|
|
hands.
|
|
|
|
---
|
|
|
|
Overall I'd say this is pretty good for a week of hacking while learning a new
|
|
keyboard layout. I will do more in the future. I have plans. To read through the
|
|
(admittedly kinda hacky/awful) code I've written this week, check out [this git
|
|
repo](https://tulpa.dev/wasmcloud/wasmcloud). If you have any feedback, please
|
|
[contact me](/contact). I will be happy to answer any questions.
|
|
|
|
As far as signups go, I am not accepting any signups at the moment. This is
|
|
pre-alpha software. The abuse story will need to be figured out, but I am fairly
|
|
sure it will end up being some kind of "pay or you can only run the precompiled
|
|
example code in the documentation" with some kind of application process for the
|
|
"free tier" of Wasmcloud. Of course, this is all theoretical and hinges on
|
|
Wasmcloud actually being productizable; so who knows?
|
|
|
|
Be well.
|