section	x-masysma-name	title	date	lang	author	keywords	x-masysma-version	x-masysma-repository	x-masysma-website	x-masysma-owned	x-masysma-copyright
32	i3bar	Ma_Sys.ma i3bar Scripts	2020/05/18 23:44:10	en-US	Linux-Fan, Ma_Sys.ma (Ma_Sys.ma@web.de)	i3 i3bar mdvl package perl monitoring statusbar	1.0.0	https://www.github.com/m7a/lp-i3bar	https://masysma.net/32/i3bar.xhtml	1	Copyright (c) 2020 Ma_Sys.ma. For further info send an e-mail to Ma_Sys.ma@web.de.

Summary

This repository contains a collection of different scripts for configuring a status bar. The most recent script version works in combination with i3bar(1), older versions work with conky(1).

The installable Debian package can be created by running ant package.

Introduction

A status bar can be used to display system information. Usually, date and time information is provided along with other information the user may consider useful.

For example, some people display the state of multimedia applications, others display network information like IP addresses and hostnames and some like to have a permanent glance at the system's load in terms of disk usage, processor load, memory etc.

Background

Programs like conky(1) and i3status(1) exist to aid in solving this task, but require extensive and often machine-dependent configuration. The necessity for configuration is natural, as the design and rationale behind a good status bar seems to be a very personal thing.

However, being machine-dependent is not really a “nice” property for people who know their personal status bar style but want to use their configuration across many systems. In these cases one either has to edit the configuration for every system or come up with some kind of automation.

This repository provides exactly that: Some examples of more or less advanced automated status bar “creation“ for a single user's personal configuration style. As a result, it is most unlikely that anybody will use the provided scripts or status bar directly, but it may serve as an inspiration of how to go about it. Additionally, for the most recent version, the reasons for including specific figures in the status bar output are explained with the expectation that this may serve a user who wants to thoughtfully craft their own status bar.

Auxiliary Scripts

On the way towards creating a status bar, one may be tempted to create scripts to simplify processing some status information. Beware that calling external processes from status bars can be resource-intensive.

That warning given, here are two scripts which may be useful in other contexts than status bars, too:

ma_perc_bar -- progress bar

Script ma_perc_bar is the absolute minimum of a status-bar script. It takes as input a number from 0 to 100 (both inclusive) and outputs a progress bar made of block characters.

Example:

$ ./ma_perc_bar 30
███░░░░░░░

The idea here is that the script may be used in rarely-called status scripts or may serve as a building block for conky configuration generation scripts (see section ma_genconkyconf_new)

ma_acpi_status -- formatted ACPI output

Uses ma_perc_bar to format the output of the acpi command. This is intended to be called rarely (e. g. once per minute) to output Laptop battery status information as part of a possibly larger status bar.

Example:

$ ./ma_acpi_status
D █████████░ 96% 10:17:57

The Legacy

The Ma_Sys.ma journey through status bars was roughly like this:

• XFCE (3?) integrated status bar. That time, mostly disk usage and CPU load were checked and space was used rather inefficiently.
• Standalone conky. Initially a hand-crafted configuration file and soon a script to generate a configuration file dependent on the presence of certain file systems and information on different machines. There was only one script this way, but a few machine-specific lines here and there. See section xond/ma_genconkyconf.
• Conky and i3bar. For integration with the i3 window manager, it turned out to be nice using the i3bar e.g. as to display and be able to change the different workspaces etc. Integration with i3bar is either text only or colorized text by using a JSON interface. ma_genconkyconf_new used this approach to generate a conky configuration which could be used in combination with wrapper script ma_i3conkystatus to output a colorized status bar in i3bar.
• mai3bar and i3bar. This (new!) variant is the first not to contain strictly machine-specific code and also the first for a long time to not rely on conky for gathering system information. See section Current Ma_Sys.ma i3bar for details.

xond/ma_genconkyconf

The script in xond/ma_genconkyconf contains instructions to generate a status bar for standalone Conky usage which used to look like this:

Back then, conky had a different configuration file format which means that by now, the script is no longer compatible with new Conky versions and hence only of historic interest.

The following items were in the status bar.

First row

• CPU information in red. The first gauge displays the overall CPU load and the followup gauges display the individual processor cores. The script was intended to distinguish different physical processor cores by leaving a little space. In the example screenshot, it displays four physical cores (because it is running in a virtual machine, it cannot know that it only has e.g. two physical cores).
• Screenindex information in gray. The SCR gauge visualizes the output of screenindex -v d current -r, see screenindex(32) for details.
• Red text which may contain CPU temperature information if detected, inside the VM that is just N_SUPPORT to indicate not supported.
• The system load averages
• The current date and time in dd.MM.YYYY HH:mm:ss format.

Second row

• RAM usage in green.
• Swap usage in cyan (SWP).
• Disk usage in blue (SYS). The script considers some specific Ma_Sys.ma mountpoints to display as additional gauges here, if they are present. By default, however, it only shows the disk usage of the root filesystem.
• Network information across all interfaces from left to right: total data uploaded, total data downloaded, current upload speed, current download speed (yes, the VM was downloading from local network with 95.4 MiB/s!)

Evaluation

Most of the information selected for being displayed back then, is still considered interesting in the most recent Ma_Sys.ma status bar versions. However, some measures have been taken to reduce the space occupied for things which may not require large gauges. Today, you can really see that the design from xond/ma_genconkyconf was not intended to display more than four or eight processor cores.

Standalone conky works well for stacking window managers. Back then, Fluxbox was being used, but others are expected to work, too. For tiling window managers, there was often need for additional configuration, but at least i3 and spectrwm allow for conky to be used as a “standalone” status bar.

ma_genconkyconf_new

For about five years, this was the prevalent status bar used at the Ma_Sys.ma. It ran on a few physical as well as virtual machines and supported energy-efficient laptop as well as desktop usage.

To use screen space efficiently, this status bar uses only a single line. In terms of colors, it closely resembles its predecessor. The following information is displayed:

• System hostname (recent versions like the one included in the repository also included the IP address)
• red CPU load gauge for all cores together
• red indivudal tiny vertical CPU load gauges for each individual core. Like before, some automation to detect Hyperthreading etc. is part of the script to generate the configuration file.
• green RAM gauge (displays as empty in the example, because the VM has much more RAM assigned than used)
• cyan Swap gauge
• blue root filesystem disk usage gauge
• grey Screenindex gauge
• Magenta network information. The first (unlabelled) entry displays the current upload/download activity. The other (potentially multiple) entries display the totally uploaded and downloaded data by interface. The leading 0 indicates that the interface's name ends on 0 (e. g. eth0).
• One-Minute Load average indicator
• Local time

Some system-specific code allows special file systems to appear as additional gauges. Automatic detection of the apcupsd daemon or the use on a Laptop allow for battery monitoring gauges to appear on those systems, where they make sense.

The configuration format is already conky's new format such that script ma_genconkyconf_new may still be used if one wants to create a similar status bar.

The disadvantage of the integration with i3bar is complexity: To generate the JSON output needed by i3bar, a very convoluted Conky configuration file is generated and one cannot run conky directly from i3bar -- a wrapper script for displaying a leading {"version:1"}[ string is needed. Additionally, conky occasionally crashed when network interfaces were changing or ACPI information was garbled.

Other noteworthy features

• Script ma_genconkyconf_new can be used in conjunction with a standalone conky if called with the -t option instead of -j.
• Temperature information is displayed if detected (some potential sensors for Ma_Sys.ma computers are hard-coded in the script...)

ma_i3conkystatus

In case you are interested in running ma_genconkyconf_new in conjunction with i3bar, the steps are as follows:

1. Generate a Conky configuration file: ma_genconkyconf_new -j > ~/.mdvl/conkyrc_i3
2. Configure to use ma_i3conkystatus in i3. This script in turn invokes conky with the configuration file generated in the previous step and produces the static part of the necessary output for i3bar integration. Additionally, in case of conky crashes, it attempts to re-start conky without leaving i3bar in an error state.
3. Restart/Reload i3 for the changes to take effect.

Here is an example of an i3 configuration file snippet to invoke ma_i3conkystatus.

bar {
	status_command /usr/bin/ma_i3conkystatus
	position top
	tray_output primary
	colors {
		#                   border  bg      fg
		focused_workspace   #cc4040 #cc4040 #ffffff
		active_workspace    #806060 #806060 #aaaaaa
		inactive_workspace  #201818 #201818 #505050
		urgent_workspace    #ffaa00 #ffaa00 #ffffff
		background                  #000000
		statusline                          #ffffff
		separator                           #333333
	}
}

Current Ma_Sys.ma i3bar

The current Ma_Sys.ma status bar is no longer dependent on conky. Instead, it is a Perl script which directly outputs JSON that can be processed by i3bar. Most notable change compared to the previous variants is the use of less colors: Instead of coloring different ressource types differntly, mai3bar colors resources depending on whether they can be considered to be in a critical, warning or normal state. This is intended to have the following advantages:

• Draw less attention to the status bar as to focus more on the actual problems at hand.
• Use less space for less important metrics (e.,g. CPU and RAM) but draw attention to them if they are critical by means of color.

Additionally, no longer using conky, it becomes feasible to implement gauges which have text written on them. This allows for higher density in information. Additionally, actual figures can be presented for resources like disk space and RAM. While it might seem a minor detail, having these values as numbers is useful in the context of virtual and old machines where limits might be very low e.,g. for RAM or disk space compared to what one expects from modern physical systems.

Here are a few other newly added features compared to the previous status bars used at the Ma_Sys.ma. A few of them are somewhat experimental because they may not fit the common expectations of how values would appear in a status bar:

• The CPU load gauges' layout provides more advanced CPU topology information as detected by an integrated copy of Perl package CpuTopology.
• Automatic choice of units for displayed metrics: For storage and RAM, current systems may have a wide range from a few gigabytes to terabytes. As a result, there does not seem to be a one size fits all unit of measure and hence, the status bar automatically chooses between megabytes and gigabytes for RAM and file systems. On systems with little RAM (e.g. 4 GiB), RAM is displayed in megabytes, whereas on systems with much RAM (e.g. 16 GiB), RAM is displayed in GiB. As there is currently no explicit indicator for which unit is being used, there is some potential for confusion here and new status bar versions might add a (potentially indirect) indicator for the unit of measure.
• To give compact (e.g. one or two letter) names to file systems and network interfaces, a special name shortening algorithm is integrated.
• The refresh interval of the status bar uses different (hard-coded) delays depending on the situation: If a discharging laptop battery is detected, the refresh rate is once every 20 sec. Under regular circumstances, the refresh rate is once per second and it may slow down if slow processing is noticed (as not to give too many of the scarce resources to status bar computation).
• The refresh interval of the status bar is attempted to be aligned to the actual turning of seconds such that the clock is expected to be more accurate than with other status bars.

Summary of items displayed:

• MDADM RAID resync progress (only if happening at the time)
• Hostname
• C for CPU indicates a CPU section with vertical gauges for each processor (core).
• R for RAM indicates the RAM memory section with figures in GiB (if total RAM large) or MiB (if total RAM small) .
• SW for Swap indicates the use of swap space. At the time of the screenshot there were 48 GiB swap and 1 GiB of it used.
• Filesystem sections. For each file system, the structure is as follows: FS name (/, d, e, l ... as generated by the name shortening algoritm), filesystem usage, total filesystme size.
• SC section if screenindex(32) is installed.
• Network interface sections. For each interface: Interface name as generated by the name shortening algorithm, IP address, current upload speed, current download speed (units displayed and dynamically adjusting to the order of magnitude).
• In case it reports a battery level and is installed, a formatted output of acpi(1) will be displayed (useful for mobile devices),
• APC UPS section if apcupsd(8) is installed. Displays the battery's fill level and the estimated time the system could run on battery under current load.
• Load AVG section
• Date and Time section (DD.MM.YYYY hh:mm:ss)

Name Shortening Algorithm

In order to display the names of file systems and network interfaces in a recognizable and compact fashion, a special algorithm for shortening the names of file system mountpoints and network interfaces has been devised. It should still be considered experimental, but seems to work in many “common” cases so far.

The algorithm does the following steps:

1. Given a list of names to process.
2. Sort the list of names (lexicographically) to obtain a sorted list
3. Process names starting from the first item in the sorted list. For the current and all subsequent names in the sorted list. Remove their longest common prefix.
4. Continue with the prefix reduced list.
5. Process each item in the prefix reduced list:
6. Take the shortest prefix of the item such that it is not a prefix of any other item in the list.
7. Output the resulting names.

Example shortenings:

Input Prefix Reduced List Output

---

eno1, ens1 o1, s1 o, s eno1, eno2, ens1 o1, o2, s1 o1, o2, s /*, /data, /, data, e01, ll /, d, e, l /fs/e01, /fs/ll

*) As a special execption, an empty string is kept to be / instead of being reduced to the empty string for being a prefix of each other entry.