ed6e2a4e7d
When connlib processes DoH queries, we need to pass the server's URL around a lot. In order to bootstrap the HTTP client, we need to extract the host part of this URL and resolve it for IP addresses using the system resolver. A regular URL doesn't necessarily have a host: It could be relative. This creates an error path within our code that _should_ never get hit for DoH URLs as those are always absolute. To avoid this error path, we follow the "parse, don't validate" approach typical among strongly typed languages. We create our own type that can only be constructed from absolute URLs. If we receive a URL from the portal that is not absolute, we already fail at the deserialization step. Using data privacy of the encapsulated url, we can then guarantee that the host-part of the URL is always there and can access it in an infallible way. Given that we are now already parsing the URL to begin with, I've also opted to directly implement an optimisation where we create a fast-path for the 4 known DoH providers that we have which allows us to pass them around and copy them without incurring extra allocations. Finally, this custom type also comes with its own Display/Debug implementation, making the log output a bit easier to read.
Rust development guide
Firezone uses Rust for all data plane components. This directory contains the Linux and Windows clients, and low-level networking implementations related to STUN/TURN.
We target the last stable release of Rust using rust-toolchain.toml.
If you are using rustup, that is automatically handled for you.
Otherwise, ensure you have the latest stable version of Rust installed.
Reading Client logs
The Client logs are written as JSONL for machine-readability.
To make them more human-friendly, pipe them through jq like this:
cd path/to/logs # e.g. `$HOME/.cache/dev.firezone.client/data/logs` on Linux
cat *.log | jq -r '"\(.time) \(.severity) \(.message)"'
Resulting in, e.g.
2024-04-01T18:25:47.237661392Z INFO started log
2024-04-01T18:25:47.238193266Z INFO GIT_VERSION = 1.0.0-pre.11-35-gcc0d43531
2024-04-01T18:25:48.295243016Z INFO No token / actor_name on disk, starting in signed-out state
2024-04-01T18:25:48.295360641Z INFO null
Benchmarking on Linux
The recommended way for benchmarking any of the Rust components is Linux' perf utility.
For example, to attach to a running application, do:
- Ensure the binary you are profiling is compiled with the
releaseprofile. sudo perf record -g --freq 10000 --pid $(pgrep <your-binary>).- Run the speed test or whatever load-inducing task you want to measure.
sudo perf script > profile.perf- Open profiler.firefox.com and load
profile.perf
Instead of attaching to a process with --pid, you can also specify the path to executable directly.
That is useful if you want to capture perf data for a test or a micro-benchmark.