This is the CDN for Harmony. The public API is readonly, and the server interfacing with the protected API can write to the CDN provided an Authorization secret.
All uploaded files are stored in /srv/cdn/ by default, but this can be configured by passing CDN_DIRECTORY as an environment variable. All images uploaded to the CDN are converted to webp since they compress much better than png.
Our file structure for the resources are /[denominator]/[identifier]/[md5hash].webp. The denominator is what group it belongs to, avatars being an example. Identifier is the ID of the resource.
The identifier folders are singleton, meaning that there shouldn't ever be more than 1 file in those directories at any given time.
cdn/
avatars/
user_1/
[md5hash].webp
user_2/
[md5hash].webp
icons/
server_1/
[md5hash].webp