To be used as status command in Sway config (status_command /path/to/sway_status_bar).
Example:
There are no config files, so you will have to edit the source code (main.go mostly).
Logic consists of two main parts: units array and renderBlocks() fucntion. Units read, process and store some system data (like temperature values) which then formatted and sent to stdout in renderBlocks.
Unit is any struct with Update(iter int64) error method which will be called every second. iter is incremented by 1 after each call and my be used to perform some action each N second only.
If unit needs to listen and react to some events (like volume change), it should also implement StartInBackground(onUpdate func(), onError func(error)).
Just reads integer from file FPath, divides it by Denum and saved to Num field. Useful for temperatures in /sys/devices/.../hwmon1/temp1_input stored as celsius * 1000.
Parses /proc/stat, stores whole CPU load in CpuLoad and max single core load in MaxCoreLoad.
Parses /proc/meminfo, stores MemTotal, MemFree and MemAvailable in Total, Free and Available fields. Additionaly has field Percent = (Total - Available) * 100 / Total.
Listens for volume changes, updates Volume and IsMuted fields. Requires libpulse (pactl) and pulseaudio (pacmd).
Gathers network interfaces stats from /proc/net/dev, saves them to Networks array and NetworkByDevName map.
SkipFunc may be used to ignore some interfeces: SkipFunc: func(name string) bool { return name == "lo" }
Parses /sys/class/block/<DevName>/stat, updates SectorsRead, SectorsWritten, ReadSpeed and WriteSpeed (as bytes/second) fields.
Runs swaymsg -t subscribe -m <Events>, calls OnEvent for each event. Useful for updating current window title.
Should ouput JSON-like structure (man swaybar-protocol). Uses p(string) which is shortcut to os.Stdout.Write and pBlock(underlineCol, format, args) which outputs block with underline and enabled pango markup. They both do not JSON-escape arguments (although this is almost never needed).
Icons can be added using emoji or some special fonts like font-awesome (which is currently used and requires otf-font-awesome package, more icons can be found at https://fontawesome.com/icons?d=gallery&m=free).