Added license statement and brief description at top of script

psi-alerts.sh

@@ -1,19 +1,53 @@
 #!/usr/bin/env zsh
+
+# Send alerts when Pressure Stall Information is high
 # 
+#    Copyright © 2023 Trey Blancher
+#
+#    This program is free software: you can redistribute it and/or modify it
+#    under the terms of the GNU General Public License as published by the Free
+#    Software Foundation, either version 3 of the License, or (at your option)
+#    any later version.
+#
+#    This program is distributed in the hope that it will be useful, but
+#    WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+#    or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+#    for more details.
+#
+#    You should have received a copy of the GNU General Public License along
+#    with this program.  If not, see <https://www.gnu.org/licenses/>.
+# 
+# This script monitors the systemd journal, specifically the
+# `psi-monitor.service` and waits for Pressure State Information monitor events
+# to be logged.  The monitor program is shipped in the psi-by-example submodule
+# in this git repository;  it is released under the three-clause BSD license
+# (see its LICENSE file for details).
+#
+# It is designed to send desktop notifications to a desktop system, it also
+# uses the local mail transport agent to send notifications via SMS and email.
+# It is assumed the desktop notification system is remote, and it uses the
+# local ssh client to connect to the notification daemon on the remote host.
+#
+# This script expects a number of environment variables to be set, in the
+# systemd psi-alerts@<user>.service overrides (will be placed in
+# /etc/systemd/system/psi-alerts@<user>.service.d/override.conf. See the
+# README.md for details.
+
 
 svc="psi-monitor.service"
 cpu="/proc/pressure/cpu"
 mem="/proc/pressure/memory"
 io="/proc/pressure/io"
-email_to="trey@blancher.net"
+host="$(hostname)"
-sms_dst="2517511550@msg.fi.google.com"
+email_to="${EMAIL_TO}"
-sms_domain="msg.fi.google.com"
+sms_dst="${SMS_DST}"
-port="5999"
+sms_domain="$(awk -F@ '{print $NF}' <<< ${SMS_DST})"
-ssh_host="localhost"
+ssh_port="${SSH_PORT}"
-clear_threshold="5.0"
+ssh_host="${SSH_HOST}"
-notification_cmd="dunstify"
+clear_threshold="${CLEAR_THRESHOLD}"
-notification_opts="--timeout=0 --printid --urgency=critical --icon=/usr/share/icons/breeze-dark/emblems/16/emblem-warning.svg"
+notification_cmd="${NOTIFICATION_CMD}"
-id_idx=15
+notification_opts="${NOTIFICATION_OPTS}"
+id_idx="${NOTIFICATION_IDX}"
 
 print_psi () {
     local psi_file="${1}"
@@ -25,14 +59,14 @@ print_pidstat () {
     local opts="-l --human"
 
     case "${psi_type}" in
-        MEM)
+        CPU)
-            opts="-r ${opts}"
+            opts="-u ${opts}"
             ;;
         IO)
             opts="-d ${opts}"
             ;;
-        CPU)
+        MEM)
-            opts="-u ${opts}"
+            opts="-r ${opts}"
             ;;
         *)
             print "Invalid psi_type:  ${psi_type}" >&2
@@ -61,13 +95,13 @@ send_notice () {
             ;;
     esac
 
-    integer dunst_id
+    integer notification_id
-    if ! dunst_id=$(ssh -q "${ssh_host}" -p ${port} \
+    if ! notification_id=$(ssh -q "${ssh_host}" -p ${ssh_port} \
-        "${notification_cmd} ${notification_opts} 'deltachunk:  PSI ${psi_type} triggered!' '${psi}'"); then
+        "${notification_cmd} ${notification_opts} '${host}:  PSI ${psi_type} triggered!' '${psi}'"); then
-            print "Connection to dunst failed!" >&2
+            print "Connection to notification daemon failed!" >&2
             false
     else
-        echo ${dunst_id}
+        echo ${notification_id}
         true
     fi
 }
@@ -169,7 +203,7 @@ check_dunst_id_is_visible () {
     local dunst_id="${1}"
 
     typeset -a ids
-    if ids=$(ssh -q "${ssh_host}" -p ${port} \
+    if ids=$(ssh -q "${ssh_host}" -p ${ssh_port} \
         "dunstctl history | jq '.data[0][][${id_idx}].data'"); then
             echo "Connection to dunst failed!" >&2
             return 2