feat(backend): allow using environment variables to set settings

[ravenclaw900]

Adds an actual configuration library, uses serde without serde_json, and uses jsonwebtoken instead of biscuit. Increases binary size quite a bit, so now optimizes some packages for size instead of speed.

[ravenclaw900]

That's odd, the size reported in the artifact download is about .5 MB off from the actual downloaded size of the binary.

[MichaIng]

Cleans up our code but adds significant dependency code. Do you think it's worth it? For config parsing, the benefit is obvious, but what is the benefit of using jsonwebtoken instead of biscuit?

[ravenclaw900]

jsonwebtoken is actually more lightweight, but it requires serde to use it. biscuit (actually a fork of jsonwebtoken) is larger, with more dependencies, but it doesn't need serde. Output of cargo-bloat before (note that this is compiled on my own machine, for gnu instead of musl):

 File  .text     Size Crate
 5.6%  16.6% 411.9KiB h2
 4.0%  11.7% 290.8KiB hyper
 2.9%   8.5% 211.4KiB core
 2.4%   7.2% 179.3KiB rustls
 2.3%   6.7% 166.1KiB ring
 2.1%   6.2% 153.4KiB dietpi_dashboard
 1.9%   5.7% 142.0KiB std
 1.4%   4.2% 105.3KiB tokio
 1.2%   3.4%  84.6KiB [Unknown]
 1.1%   3.3%  82.6KiB warp
 1.0%   2.8%  70.5KiB data_encoding
 0.8%   2.3%  56.8KiB http
 0.7%   2.0%  50.5KiB toml
 0.6%   1.9%  46.4KiB alloc
 0.6%   1.6%  41.0KiB addr2line
 0.5%   1.4%  34.4KiB psutil
 0.4%   1.2%  31.1KiB biscuit
 0.4%   1.2%  30.7KiB miniz_oxide
 0.3%   0.9%  21.8KiB rustc_demangle
 0.3%   0.8%  20.1KiB hashbrown
 3.1%   9.2% 228.8KiB And 51 more crates. Use -n N to show more.
33.9% 100.0%   2.4MiB .text section size, the file size is 7.2MiB

After (with size optimizations):

 File  .text     Size Crate
 5.4%  15.6% 368.9KiB h2
 4.2%  12.1% 286.6KiB hyper
 2.8%   8.1% 191.0KiB dietpi_dashboard
 2.7%   7.8% 184.4KiB core
 2.3%   6.6% 156.5KiB rustls
 1.8%   5.3% 124.3KiB ring
 1.7%   5.0% 117.8KiB std
 1.5%   4.4% 104.8KiB tokio
 1.3%   3.8%  89.8KiB warp
 1.2%   3.4%  80.6KiB alloc
 1.1%   3.2%  76.5KiB figment
 1.1%   3.2%  75.3KiB [Unknown]
 1.0%   3.0%  70.3KiB jsonwebtoken
 0.6%   1.9%  44.0KiB http
 0.6%   1.8%  42.3KiB toml
 0.6%   1.7%  41.0KiB addr2line
 0.5%   1.5%  34.4KiB psutil
 0.3%   0.9%  21.8KiB rustc_demangle
 0.3%   0.8%  18.4KiB serde_json
 0.3%   0.8%  18.3KiB miniz_oxide
 3.0%   8.5% 201.9KiB And 60 more crates. Use -n N to show more.
34.6% 100.0%   2.3MiB .text section size, the file size is 6.7MiB

Do you think it's worth it?

Honestly, now that I've done it, I'm not completely sure. I'll see the size comparison if I can find another config library that doesn't require serde and use that with biscuit. However, I might keep those optimizations on, while still disabling them for specific higher-performance crates.

[MichaIng]

Ah, and since figment requires serde anyway, switching to jsonwebtoken makes it actually lighter. I understand.

Honestly, now that I've done it, I'm not completely sure.

Well, I mean the size of the assets with size optimisations is lower than latest main assets. Not sure whether the performance decrease for turning on size optimisation is in any way noticeable. Always good to have a look at alternatives, but while I did no performance tests, IMO it is fine as it is, simplifying (our) code for both, config parsing and token validation quite significantly.

[ravenclaw900]

Originally I was using the jwts library, which was very lightweight, however I'm now trying to use officially endorsed ones. One consolation, at least, is that we're still below the original Go binary size, when compressed. (1.4 MB vs. 2.3)

Actually, the compressed size is a lot less than I thought it would be, still smaller than 0.4.1. Plus, the inclusion of serde, without the monstrous serde_json, will allow us to now use other more popular and maintained crates.