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At present, `connlib` communicates with its host app via callbacks. These callbacks are executed synchronously as part of `connlib`s event-loop, meaning `connlib` cannot do anything else whilst the callback is executing in the host app. Additionally, this callback runs within the `Future` that represents `connlib` and thus runs on a `tokio` worker thread. Attempting to interact with the session from within the callback can lead to panics, for example when `Session::disconnect` is called which uses `Runtime::block_on`. This isn't allowed by `tokio`: You cannot block on the execution of an async task from within one of the worker threads. To solve both of these problems, we introduce a thread-pool of size 1 that is responsible for executing `connlib` callbacks. Not only does this allow `connlib` to perform more work such as routing packets or process portal messages, it also means that it is not possible for the host app to cause these panics within the `tokio` runtime because the callbacks run on a different thread.
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.