add track_anything.sh and use it for volume and mute

README.md

@@ -3,3 +3,83 @@
 My personal eww config.
 
 Install by linking or cloning to ~/.config/eww
+
+## `track_anything.sh`
+
+This config includes a helper bash source which may be used
+to setup trackers of values.  It requires an on_event emitter
+to already exist and should have one of the three output
+formats: integer, boolean, and string.
+
+When specifying a string output, you may include a custom regex
+which will not be searched (it will be wrapped in `^`...`$`).
+
+### `poll`
+
+In addition to the configuration, you must provide a poll function.
+
+Your provided poll function must return a valid output as its first
+line and may provide log data on subsequent lines which will be
+emitted at the info level (stderr, single -v).
+
+A simple example is the pulseaudio mute state poller:
+
+```bash
+poll() {
+  pamixer --get-mute
+}
+```
+
+### `Configuration`
+
+Options:
+
+ - rate_limit
+   - seconds to wait between running poll
+     (default: `1`)
+
+ - poll_interval
+   - seconds to wait for an update before forcing a poll
+     (default: `60`)
+   - NOTE: must satisfy poll_interval >= rate_limit
+
+ - filter: an arbitrary command to filter the total output of the poller in a loop
+   (default: `uniq`)
+   - NOTE: all arguments are collected and executed with eval.
+   - Example: `cat` will allow duplicates.  `uniq` will filter them.
+
+Event Emitters:
+
+ - `on_volume`
+   - emits on changes to pulseaudio sinks
+
+ - `on_sway`
+   - emits on changes to sway windows or workspaces
+
+ - `on`
+   - uses your own function to trigger an event
+     which should be passed as the only argument to `on`
+   - NOTE: the function in question _must_ emit events
+     as newlines with no text.  multiple events may be
+     emitted in general safety if `rate_limit` is > 0
+
+
+Outputs:
+
+ - `output_integer`
+   - output a decimal integer
+
+ - `output_boolean`
+   - output a boolean (true, false)
+
+ - `output_string`
+   - output an arbitrary string, validated by a regex
+   - args:
+     - a validation regex string as the first argument
+       (default: `.*`)
+
+ - `output_json`
+   - output an arbitrary json value, validated by jq
+   - args:
+     - a validation jq query which must not fail or return null
+       (default: `.`)

scripts/track_anything.sh

@@ -0,0 +1,164 @@
+export ZERO="$0"
+HELP="$ZERO: tracker [-1] [-v [-v ...]] [q [-q ...]]
+  -1     run once and exit
+  -v     increase verbosity (default >= warn)
+  -q     decrease verbosity
+"
+EXITING=0
+trap 'EXITING=1' INT
+
+trace() { (( LOG_LEVEL > 2 ))  && (exec 1>&2; builtin echo "$@"|grep .||true); }
+debug() { (( LOG_LEVEL > 1 ))  && (exec 1>&2; builtin echo "$@"|grep .||true); }
+info()  { (( LOG_LEVEL > 0 ))  && (exec 1>&2; builtin echo "$@"|grep .||true); }
+warn()  { (( LOG_LEVEL > -1 )) && (exec 1>&2; builtin echo "$@"|grep .||true); }
+error() { (( LOG_LEVEL > -2 )) && (exec 1>&2; builtin echo "$@"|grep .||true); }
+fatal() {                         (exec 1>&2; builtin echo "$@"|grep .||true); exit 4; }
+log()   { info "$@"; }
+
+start() {
+  if ! options="$(getopt vq1 -- "$@")";then
+    fatal "$HELP"
+  fi
+
+  eval set "$options"                           
+
+  while [ $# -gt 0 ];do                            
+    case "$1" in                                  
+      -1) shift;ONCE=1 ;;
+      -h) echo "requesting help" ; help; exit 0 ;;
+      -v) LOG_LEVEL=$(( LOG_LEVEL + 1 )) ;echo increased log level ;;
+      -q) LOG_LEVEL=$(( LOG_LEVEL - 1 )) ;;
+      --) shift;break;;  # we're _explicitly_ done with options
+      *) break;;  # we're done with options.   
+    esac                                                                       
+    shift                                              
+  done
+
+  if [ $VALIDATION ];then
+    # fix up the validation regex to not search.
+    VALIDATION="${VALIDATION#^}"
+    VALIDATION="${VALIDATION%'$'}"
+    VALIDATION='^'"$VALIDATION"'$'
+  fi
+
+  info "Running with LOG_LEVEL=$LOG_LEVEL"
+
+  debug "   VALIDATION: $VALIDATION"
+  debug "   RATE_LIMIT: $RATE_LIMIT"
+  debug "POLL_INTERVAL: $POLL_INTERVAL"
+  debug "    watch_cmd: $watch_cmd"
+
+  if [ $(echo "$POLL_INTERVAL < $RATE_LIMIT"|bc) -eq 1 ];then
+    warn "POLL_INTERVAL cannot be less than RATE_LIMIT."
+    info "increasing POLL_INTERVAL to $RATE_LIMIT."
+    POLL_INTERVAL=$RATE_LIMIT
+  fi
+
+  while ! (( EXITING ));do
+    (
+      _poll || exit $?
+      (( ONCE )) && EXITING=1
+
+      $watch_cmd | while ! (( EXITING ));do
+        sleep $RATE_LIMIT
+
+        # read with a maximum of the poll interval minus the previous rate limit.
+        # rounding _up_ to the nearest second.  (bc floors when scale is unset.)
+        if read -t $( echo "$POLL_INTERVAL - $RATE_LIMIT + .5 " | bc );then
+          debug "received poll.  removing other poll requests."
+        else
+          debug "reached the polling interval.  forcing poll."
+        fi
+        N=0
+        while read -t 0;do read; N=$((N + 1));done
+        debug "removed $N extra events"
+        _poll
+        debug "sleeping for $RATE_LIMIT"
+      done
+    ) | eval "$_filter"
+    (( EXITING == 0 )) && (warn "tracker died.  restarting after $RATE_LIMIT seconds.";sleep $RATE_LIMIT)
+  done
+  info "bye"
+}
+
+_poll() {
+  NEWVAL="$(poll | head -1)"
+  local skipped=0
+  echo "$NEWVAL" | while read -r LINE;do
+    (( skipped )) && info "$LINE"
+    skipped=1
+  done
+
+  local failed=0
+  if [ $JQ_VALIDATION ];then
+    echo "$NEWVAL" | jq -e "$JQ_VALIDATION" > /dev/null || failed=1
+  fi
+  if [ $VALIDATION ];then
+    echo "$NEWVAL" | grep -qE "$VALIDATION" || failed=1
+  fi
+  if (( failed ));then
+    warn "$NEWVAL failed validation"
+  else
+    echo "$NEWVAL"
+  fi
+}
+
+# MODULE OPTIONS
+
+RATE_LIMIT=.1
+rate_limit() {
+  RATE_LIMIT=$1
+}
+
+POLL_INTERVAL=60
+poll_interval() {
+  POLL_INTERVAL=$1
+}
+
+_filter=uniq
+filter() {
+  _filter="$(printf " %q" "$@")"
+}
+
+# VALIDATORS
+
+VALIDATION=.
+output_integer() {
+  VALIDATION='^-?[0-9]+$'
+}
+
+output_boolean() {
+  VALIDATION='^true|false$'
+}
+
+output_string() {
+  VALIDATION="${1-.*}"
+}
+
+output_json() {
+  JQ_VALIDATION="${1-.}"
+}
+
+# EVENT HANDLERS
+
+# each event source needs to emit a single _EMPTY_ line per event.
+# poll will be called for each line.
+on_volume() { on _on_volume; }
+_on_volume() {
+  pactl subscribe | while read -r ;do
+    case "$REPLY" in
+      *change*) echo;;
+    esac
+  done
+}
+
+on_sway() { on _on_sway; }
+_on_sway() {
+  swaymsg -t subscribe -m '[ "workspace", "window" ]' |
+    jq --unbuffered -c . |
+    while read -r;do
+      echo
+    done
+}
+
+on() { watch_cmd="$1"; }

scripts/track_mute

@@ -1,7 +1,16 @@
-#!/bin/sh
+#!/usr/bin/env bash
 
-pactl subscribe | while read -r ;do
-  case "$REPLY" in
-    *change*)  pamixer --get-mute ;;
-  esac
-done
+. "$(dirname "$0")/track_anything.sh"
+
+
+poll() {
+  pamixer --get-mute
+}
+
+rate_limit .1
+poll_interval 60
+on_volume
+output_boolean
+filter uniq
+
+start "$@"

scripts/track_volume

@@ -1,11 +1,14 @@
-#!/bin/sh
+#!/usr/bin/env bash
+
+. "$(dirname "$0")/track_anything.sh"
 
 poll() {
-  pamixer --get-volume | grep -E '^[0-9]+$'
+  pamixer --get-volume
 }
 
-pactl subscribe | while read -r ;do
-  case "$REPLY" in
-    *change*)  poll ;;
-  esac
-done
+on_volume
+output_integer
+poll_interval 10
+rate_limit .1
+
+start "$@"