Files
firezone/rust
Thomas Eizinger ead1f40101 chore(gateway): only log skipped NAT entry if IP differs (#10285)
When we resolve a DNS resource domain name on the Gateway, we establish
the mapping between proxy IPs and resolved IPs in order to correctly NAT
traffic. These domains are re-resolved every time the Client sees a DNS
query for it. Thus, established connections could be interrupted if the
IPs returned by consecutive DNS queries are different.

Many SaaS products (GitHub for example) use DNS to load balance between
different IPs. In order to not interrupt those connections, we check
whether we have an open NAT session for an existing mapping every time
we re-resolve DNS.

This log is currently printed too often though because it doesn't take
into account whether the IPs actually changed. If the IP is the same, we
don't need to print this because the update is a no-op.
2025-09-04 21:12:46 +00:00
..
2025-09-03 03:18:46 +00:00
2023-05-10 07:58:32 -07:00

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:

  1. Ensure the binary you are profiling is compiled with the release profile.
  2. sudo perf record -g --freq 10000 --pid $(pgrep <your-binary>).
  3. Run the speed test or whatever load-inducing task you want to measure.
  4. sudo perf script > profile.perf
  5. 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.