Rust Blocks

A lightweight i3/sway status bar written in Rust.

Background

Linux window managers / compositors such as i3 and sway allow the specification of a command for generating the status bar. There are many alternatives available but they often seem to be unnecessarily complex or surprisingly resource hungry, so here is an implementation that is neither of those things.

NB this project is quite highly tuned for my own setup. If you run into problems please open an issue!

See the i3bar protocol for details on the protocol.

Installation

1. Get Rust
2. Clone this repo (optional)
3. Run cargo install --path <repo path> (if you did step 2) or cargo install rs-blocks
4. Use rs-blocks! (See rs-blocks --help for options)

Configuration

rs-blocks will look for $XDG_CONFIG_HOME/rs-blocks/config for a config file. Alternatively, a config file can be specified by using the argument --config/-c.

Config files should be in toml format. The section title must match an available block type, and the remaining config within each section will be used to configure that block.

A basic config file looks like:

[memory]

[cpu]

[battery]

[time]

Multiple entries of the same block can be given as long as they specify different names. E.g.:

[time]
name = "time1"
format = "%D"

[time]
name = "time2"
format = "%S"

Blocks will appear in the order they are given in the config file, with the topmost sections appearing as leftmost entries in the status bar.

Available blocks are:

• Battery
• Brightness
• CPU
• Memory
• Network
• Time
• Volume (using pulsemixer)

See the documentation under src/blocks/ for more details on each block.

Signals

Some blocks will listen for signals to trigger updates immediately. This gives immediate feedback on the status bar when using keyboard shortcuts to change the brightness, for example. The current blocks implementing this are:

• Brightness
• Volume

In these cases the signal to listen for can be specified using the block's update_signal value in the config file. In the window manager / compositor configuration, the sending of this signal will need to be added to the relevant event. In sway for example, this may look like:

bindsym XF86MonBrightnessUp exec brightness +10 && pkill -SIGUSR1 rs-blocks

and corresponding config section:

[brightness]
update_signal = 10 # SIGUSR1 is 10 on most Linux system

More information on signals can be found in the Linux man pages.

Implementation Details

• Most blocks read information from kernel files (/proc/* or /sys/class/*). This might cause issues for some Linux distributions. So far it's been tested only on alpine and arch.
• Blocks are represented by infinite loops in threads sending (name, text) tuples through a channel, received (and then published) on the main thread.
• The trait Configure is used to configure a block based on the configuration file (toml string is passed as the config argument). This trait must be implemented for all blocks.
• The Sender trait should be implemented for creating a message sending function (see these traits for details).