Previously, the Rust TUI was writing log files to `/tmp`, which is
world-readable and not available on Windows, so that isn't great.
This PR tries to clean things up by adding a function that provides the
path to the "Codex config dir," e.g., `~/.codex` (though I suppose we
could support `$CODEX_HOME` to override this?) and then defines other
paths in terms of the result of `codex_dir()`.
For example, `log_dir()` returns the folder where log files should be
written which is defined in terms of `codex_dir()`. I updated the TUI to
use this function. On UNIX, we even go so far as to `chmod 600` the log
file by default, though as noted in a comment, it's a bit tedious to do
the equivalent on Windows, so we just let that go for now.
This also changes the default logging level to `info` for `codex_core`
and `codex_tui` when `RUST_LOG` is not specified. I'm not really sure if
we should use a more verbose default (it may be helpful when debugging
user issues), though if so, we should probably also set up log rotation?
As stated in `codex-rs/README.md`:
Today, Codex CLI is written in TypeScript and requires Node.js 22+ to
run it. For a number of users, this runtime requirement inhibits
adoption: they would be better served by a standalone executable. As
maintainers, we want Codex to run efficiently in a wide range of
environments with minimal overhead. We also want to take advantage of
operating system-specific APIs to provide better sandboxing, where
possible.
To that end, we are moving forward with a Rust implementation of Codex
CLI contained in this folder, which has the following benefits:
- The CLI compiles to small, standalone, platform-specific binaries.
- Can make direct, native calls to
[seccomp](https://man7.org/linux/man-pages/man2/seccomp.2.html) and
[landlock](https://man7.org/linux/man-pages/man7/landlock.7.html) in
order to support sandboxing on Linux.
- No runtime garbage collection, resulting in lower memory consumption
and better, more predictable performance.
Currently, the Rust implementation is materially behind the TypeScript
implementation in functionality, so continue to use the TypeScript
implmentation for the time being. We will publish native executables via
GitHub Releases as soon as we feel the Rust version is usable.
