Fileserver-gr

A Wagi static fileserver written in Grain.

DeisLabs is experimenting with many WASM technologies right now. This is one of a multitude of projects designed to test the limits of WebAssembly as a cloud-based runtime. This code is not stable or production ready.

Getting a Binary

We periodically release Wasm modules in binary form. To get the latest, go to the releases page. In the future, we will also publish bindles.

Building and Running Locally

You will need the Grain toolkit to work with this repo.

To run:

$ make run 

To compile:

$ make build

You can run unit tests with make test-unit or full tests with make test:

$ make test
grain compile fileserver.gr
grain tests.gr
✅ PASS         Env.splitEnvVar should parse
✅ PASS         Util.reverse should reverse string
✅ PASS         Util.lastIndexOf should find Some
===== Expected: =====
Some(19)
======= Got: ========
Some(18)
=====================
⛔️ FAIL         UtillastIndexOf should find Some
✅ PASS         Util.lastIndexOf should find None
✅ PASS         Mediatype.guess should find text/plain
✅ PASS         Mediatype.guess should find default type
❌ Total failed tests: 1❌
make: *** [test-unit] Error 1

Running in Wagi

You have two options for running in Wagi:

1. Use hippofactory to build and push a bindle, then use wagi -b $YOUR_BINDLE
2. Write a modules.toml file and use wagi -c modules.toml.

Using hippofactory

Edit the HIPPOFACTS file to taste.

To use hippofactory, you can just run this command from the repo root:

$ hippofactory -s http://localhost:8080/v1 .
pushed: fileserver/0.1.0-technosophos-2021.06.03.17.25.54.484

Then run it in Wagi like this:

$ wagi -b fileserver/0.1.0-technosophos-2021.06.03.17.25.54.484 --bindle-server http://localhost:8080/v1
[2021-06-03T23:26:54Z INFO  wagi] => Starting server on 127.0.0.1:3000
[2021-06-03T23:26:54Z DEBUG wagi::runtime::bindle] loaded 1 modules from the default group (parcels that do not have conditions.memberOf set)
[2021-06-03T23:26:54Z DEBUG wagi::runtime] module cache miss. Loading module parcel:fileserver/0.1.0-technosophos-2021.06.03.17.25.54.484#110f6f54401b80d9d80dae9257969468a5a70248dba8d96ce74b9bc5bc104fdd from remote.
[2021-06-03T23:26:54Z INFO  wagi::runtime] (load_routes) instantiation time for module parcel:fileserver/0.1.0-technosophos-2021.06.03.17.25.54.484#110f6f54401b80d9d80dae9257969468a5a70248dba8d96ce74b9bc5bc104fdd: 107.802106ms

Using modules.toml

Here is an example modules.toml for Wagi:

[[module]]
route = "/static/..."
module = "/path/to/fileserver/fileserver.gr.wasm"
volumes = {"/" = "/path/to/fileserver"}

The above configures Wagi to map the path /static/... to the fileserver.gr.wasm module. Then it serves all of the files in this project.

Environment Variables

The following environment variables can be passed via Wagi's -e flag:

• CACHE_CONTROL: The string value of a cache-control header. If not specified, this will set cache-control to no-cache. Google recommends setting this value to CACHE_CONTROL="max-age=31536000" (cache for up to 1 year).
• Type-specific cache controls can be set using the following env vars (all of which default to CACHE_CONTROL if not set):
  • CSS_CACHE_CONTROL
  • FONT_CACHE_CONTROL
  • IMAGE_CACHE_CONTROL
  • JS_CACHE_CONTROL

Testing the Static Fileserver with curl

This step is the same whether you use Bindle or a modules.toml.

Assuming you have Wagi running on http://localhost:3000, you can then run this command:

$ curl -v localhost:3000/static/LICENSE.txt
*   Trying 127.0.0.1...
* TCP_NODELAY set
* Connected to localhost (127.0.0.1) port 3000 (#0)
> GET /static/LICENSE.txt HTTP/1.1
> Host: localhost:3000
> User-Agent: curl/7.64.1
> Accept: */*
>
< HTTP/1.1 200 OK
< content-type: text/plain
< content-length: 1104
< date: Fri, 04 Jun 2021 00:16:14 GMT
<
The MIT License (MIT)

Copyright (c) Microsoft Corporation. All rights reserved.

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE
* Connection #0 to host localhost left intact
* Closing connection 0

The fileserver took /static/filserver.gr, removed the /static/ part from the front, and then loaded fileserver.gr from the directory mounted in the modules.toml. Note that any subdirectories are also served. So /static/foo/bar would translate to the path foo/bar inside of the WebAssembly module (which in the example above would fully resolve to "/path/to/fileserver/foo/bar").

Prefixing a Path

PATH_PREFIX is an environment variable you can set. This allows you to add -e PATH_PREFIX=/some/prefix as an env var to fileserver.gr.wasm.

This will allow the fileserver to set a specific path prefix for files before it looks them up. So instead of doing http://example.com/static/static/foo.png, you can set wagi -e PATH_PREFIX=static/ and then http://example.com/static/foo.png will resolve on the filesystem, to static/foo.png instead of foo.png.

Security Note

The Wagi fileserver is designed to serve any file mounted in the volume. Do not mount a volume that contains files you do not want served.

Code of Conduct

This project has adopted the Microsoft Open Source Code of Conduct.

For more information see the Code of Conduct FAQ or contact opencode@microsoft.com with any additional questions or comments.