X-Git-Url: https://git.xandkar.net/?p=khatus.git;a=blobdiff_plain;f=README.md;h=601bf4ce8bf8dbcee4999a8fe3f7d8c99f193605;hp=62036c9eb2a2a356a80507768e00b262e0623f05;hb=91ad8a2f8ae61d45c0958b26bb0978bf0a9ab7f1;hpb=7daecd248d2531ed281841958525364e3c6d1c4b diff --git a/README.md b/README.md index 62036c9..601bf4c 100644 --- a/README.md +++ b/README.md @@ -2,43 +2,193 @@ khatus ====== ![mascot](mascot.jpg) -Experimental, system monitor and status (bar) reporter I use with +Experimental system-monitor and status (bar) reporter I use with [dwm](https://dwm.suckless.org/) on GNU/Linux. ![screenshot](screenshot.jpg) +Usage +----- + +In my `~/.xinitrc` I have something like the following: + +```sh +( $BIN/khatus \ + --wifi_interface 'wlp3s0' \ +| stdbuf -o L tee \ + >(stdbuf -o L "$BIN"/khatus_bar \ + -v Opt_Mpd_Song_Max_Chars=10 \ + -v Opt_Net_Interfaces_To_Show=wlp3s0 \ + -v Opt_Pulseaudio_Sink=0 \ + | "$BIN"/khatus_actuate_status_bar_to_xsetroot_name \ + ) \ + >(stdbuf -o L "$BIN"/khatus_monitor_energy \ + | "$BIN"/khatus_actuate_alert_to_notify_send \ + ) \ + >(stdbuf -o L "$BIN"/khatus_monitor_errors \ + | "$BIN"/khatus_actuate_alert_to_notify_send \ + ) \ +) \ +2> >($BIN/twrap.sh >> $HOME/var/log/khatus/main.log) \ +1> /dev/null \ +& +``` +(where `twrap` is a simple script which prefixes a timestamp to each line) + +The idea is to support appending any number of ad-hoc, experimental monitors by +giving maximum flexibility for what to do with the sensor outputs, while +maintaining some uniformity of msg formats (again, to ease ad-hoc combinations +(e.g. Does the CPU get hotter when MPD is playing Wu-Tang?)). `khatus_bar`, +`khatus_monitor_energy` and `khatus_monitor_errors` are just some initial +examples. Design ------ +### 2.0 + +In an effort to simplify the components and their interfaces, I removed the +concept of a global controller from the previous design (which, at least for +now, is superfluous), so now it is essentially a pub-sub - parallel publishers +(sensors) write to a pipe, which is then copied to any number of interested +subscribers that can filter-out what they need and then do whatever they want +with the data. Status bar is one such subscriber: + +`P1 > pipe&; P2 > pipe&; ... PN > pipe&; tail -f pipe | tee >(S1) >(S2) ... >(SN) > /dev/null` + +The cool thing is that, because the pipe is always read (`tail -f ... > /dev/null`), +the publishers are never blocked, so we get a live stream of events to which we +can attach any number of interested subscribers (` ... tee ... `) and, because +the pipe is named, if a subscriber needs to - it too can publish something to +the pipe without being blocked. + +``` +parallel +----------+ +----------+ +----------+ +stateless | sensor_1 | | sensor_2 | ... | sensor_n | +collectors +----------+ +----------+ +----------+ + | | | | + data data data data + | | | | + V V V V +multiplexing +-------------+-----------+---------+ +to a pipe | + | + V +copying to +-------------+-+---------+---------+ +subscribers | | | | + V V V V + +------------+ ... +----------------+ +any number of | status bar | | energy monitor | +parallel +------------+ +----------------+ +subscribers | | + V V + +----------------+ +-------------+ + | xsetroot -name | | notify-send | + +----------------+ +-------------+ +``` + +### 1.0 + +This was an improvement of having everything in one script, but the controller +was still way too complicated for no good reason. + ``` - parallel +----------+ +----------+ +----------+ - stateless | sensor_1 | | sensor_2 | ... | sensor_n | - collectors +----------+ +----------+ +----------+ - | | | - data data data - | | | - V V V - serial +-----------------------------------------+ - stateful | controller | - observer +-----------------------------------------+ - | - decisions - | - V - serial +-----------------------------------------+ - stateless | actuator | - executor +-----------------------------------------+ - | - system commands - | - V - ~~~~~~ - ~ OS ~ - ~~~~~~ +parallel +----------+ +----------+ +----------+ +stateless | sensor_1 | | sensor_2 | ... | sensor_n | +collectors +----------+ +----------+ +----------+ + | | | | + data data data data + | | | | + V V V V +serial +----------------------------------------------+ +stateful | controller | +observer +----------------------------------------------+ + | + decision messages +decision | +messages | +copied to | +any number | +of interested | +filter/actuator | +combinations | + | + V + +-------------+-+---------+---------+ + | | | | + V V V V +parallel +------------+ +------------+ +------------+ +stateless | filter_1 | | filter_2 | ... | filter_n | +filters +------------+ +------------+ +------------+ + | | | | + V V V V +parallel +------------+ +------------+ +------------+ +stateless | actuator_1 | | actuator_2 | ... | actuator_n | +executors +------------+ +------------+ +------------+ + | | | | + commands commands commands commands + | | | | + V V V V + ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + ~~~~~~~~~~~~~ operating system ~~~~~~~~~~~~~~~~~ + ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ``` +### 0.x + +A single script, re-executed in a loop at some intervals, serially grabbing all +the needed data and outputting a status bar string, then passed to `xsetroot -name`, +while saving state in files (e.g. previous totals, to be converted to deltas). + +This actually worked surprisingly-OK, but had limitations: + +- I use an SSD and want to minimize disk writes +- not flexible-enough to support my main goal - easy experimentation with + various ad-hoc monitors: + - I want to set different update intervals for different data sources + - I don't want long-running data collectors to block the main loop + +### Actuator +Actuator is anything that takes action upon controller messages. A few generic +ones are included: + +- `khatus_actuate_alert_to_notify_send` +- `khatus_actuate_status_bar_to_xsetroot_name` + +and, by default, are left disconnected from the data feed, so if desired - need +to be manually attached when starting `khatus`. See usage section. + +### Errors Any errors encountered by any sensor are propagated as alerts by the controller, which are in turn actualized as desktop notifications by the -actuator: +`khatus_actuate_alert_to_notify_send` actuator: + ![screenshot-self-error-propagation](screenshot-self-error-propagation.jpg) + +TODO +---- + +- status bar templating language +- retry/cache for sensors fetching flaky remote resources (such as weather) +- throttling of broken sensors (constantly returns errors) +- alert specification language + - trigger threshold + - above/bellow/equal to threshold value + - priority + - snooze time (if already alerted, when to re-alert?) + - text: subject/body + +Redesign notes +-------------- + +- controller should not do formatting +- need in-memory db for diskless feedback/throttling and cache +- decouple sensor execution from sleep, i.e. a sensor is blocked not by sleep + process directly, but by reading of a pipe, to where a sleep process will + write a message announcing interval completion and thus signaling execution. + This will allow us to manually signal a sensor to update (concretely - I just + openned my laptop from sleep and want to force the weather to update + immediately); likewise, the sleep process should be blocked on pipe-read + until sensor execution is complete - this will allow us to reconfigure + intervals at runtime (which seems like a better idea than the above in-memory + DB one).