From 15e4775679e924b347e1eda6744c0a146d720387 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Alexander=20Sch=C3=A4ferdiek?= <alexander@schaeferdiek.eu>
Date: Tue, 21 Mar 2023 18:48:46 +0100
Subject: [PATCH] Notifier allows to override global configuration files on a
 per-command base by checking for existence of all required configuration
 values as environment values.

---
 README.md                                   | 15 ++++++++++++++
 _man/src/notifier.1.md                      |  2 ++
 usr/local/bin/notifier                      | 23 +++++++++++++++------
 usr/share/man/man1/check_updates.1          |  4 ++--
 usr/share/man/man1/disk_space_alert.1       |  4 ++--
 usr/share/man/man1/docker_check.1           |  4 ++--
 usr/share/man/man1/docker_compose_update.1  |  4 ++--
 usr/share/man/man1/dynv6.1                  |  4 ++--
 usr/share/man/man1/memory_usage_alert.1     |  4 ++--
 usr/share/man/man1/notifier.1               | 11 +++++++---
 usr/share/man/man1/smart_tests_long.1       |  4 ++--
 usr/share/man/man1/system-helpers.1         |  4 ++--
 usr/share/man/man1/systemd_check.1          |  4 ++--
 usr/share/man/man1/systemd_failure_notify.1 |  4 ++--
 14 files changed, 62 insertions(+), 29 deletions(-)

diff --git a/README.md b/README.md
index 5f3ffd8..e7444c2 100644
--- a/README.md
+++ b/README.md
@@ -61,6 +61,21 @@ NOTIFIER_MAIL_ENABLED=true
 NOTIFIER_GOTIFY_ENABLED=false
 ```
 
+**Important:** You can also change notifier behavior on a per-command basis, e.g. disable mail or gotify by providing ALL notifier variables as environment variables where the command is issued, for example in a systemd .service file.
+
+```shell
+# ...
+
+[Service]
+# ...
+Environment="NOTIFIER_GOTIFY_ENABLED=false"
+Environment="NOTIFIER_MAIL_ENABLED=true"
+Environment="NOTIFIER_MAIL_ADDRESS=another-mail-different-from-your-global-config@domain.tld"
+
+# ...
+```
+
+
 Otherwise, services and scripts don't depend on each other, but have hints that they can be combined (out-commented line in service files for `systemd_failure_notify@.service` for example).
 
 Examples are given inside `usr/share/doc/system-helpers` and *man pages* are also available.
diff --git a/_man/src/notifier.1.md b/_man/src/notifier.1.md
index 6ad15c8..c797335 100644
--- a/_man/src/notifier.1.md
+++ b/_man/src/notifier.1.md
@@ -15,6 +15,8 @@ It's part of **system-helpers**.
 
 By default, **notifier** tries to read from *$HOME/.notifier.conf* and */etc/notifier.conf* for configuration. It will exit with a non-zero exit code if it cannot find a proper configuration file.
 
+If all of the below variables are set and not empty as environment variables, then **notifier** skips sourcing config files. This allows a per-command configuration without relying on the global configs.
+
 The following configuration values can be set, defaults are shown as well:\
 
 - **NOTIFIER_MAIL_ENABLED="true"** which enables or disables notification via mail to *NOTIFIER_MAIL_ADDRESS*.
diff --git a/usr/local/bin/notifier b/usr/local/bin/notifier
index ccea046..fa6a4b6 100755
--- a/usr/local/bin/notifier
+++ b/usr/local/bin/notifier
@@ -29,13 +29,9 @@ if [ -z "$NOTIFIER_CONTENT" ]; then
 	exit 1;
 fi
 
-NOTIFIER_MAIL_ENABLED="true";
-NOTIFIER_GOTIFY_ENABLED="false";
-NOTIFIER_MAIL_ADDRESS=$3;
-
 argsMailProvided="false"
 
-if [[ -n "${NOTIFIER_MAIL_ADDRESS}" ]]; then
+if [[ -n "$3" ]]; then
   argsMailProvided="true"
 fi
 
@@ -88,6 +84,17 @@ source_config() {
   local configFallback=$1;
   local configGlobalFallback=$2;
 
+  checkMailEnabled=${NOTIFIER_MAIL_ENABLED:-1}
+  checkGotifyEnabled=${NOTIFIER_GOTIFY_ENABLED:-1}
+  checkMailAddress=${NOTIFIER_MAIL_ADDRESS:-1}
+
+  if [[ ! -v "$checkMailEnabled" && ! -v "$checkGotifyEnabled" && ! -v "$checkMailAddress" ]]; then
+    echo "Using environment variables for configuration instead of configuration files";
+    return;
+  else
+    echo "Using configuration files";
+  fi
+
   if [[ -f "$configFallback" ]]; then
     apply_config "$configFallback";
     return;
@@ -106,12 +113,16 @@ if [[ "${argsMailProvided}" == "true" ]]; then
   echo "Overwriting mail with argument value"
 fi
 
+echo "Using NOTIFIER_MAIL_ENABLED=${NOTIFIER_MAIL_ENABLED}"
+echo "Using NOTIFIER_GOTIFY_ENABLED=${NOTIFIER_GOTIFY_ENABLED}"
+echo "Using NOTIFIER_MAIL_ADDRESS=${NOTIFIER_MAIL_ADDRESS}"
+
 SUBJECT="${NOTIFIER_SUBJECT}"
 MESSAGE="${NOTIFIER_CONTENT}"
 
 if [[ "${NOTIFIER_MAIL_ENABLED}" == "true" ]]; then
   echo "$MESSAGE"|mailx -Ssendwait -s "$SUBJECT" "$NOTIFIER_MAIL_ADDRESS";
-  echo "Sent notifiction via mail"
+  echo "Sent notifiction via mail to $NOTIFIER_MAIL_ADDRESS"
 else
   echo "Sending notifictions via mail is disabled"
 fi
diff --git a/usr/share/man/man1/check_updates.1 b/usr/share/man/man1/check_updates.1
index 5359458..5f03ea9 100644
--- a/usr/share/man/man1/check_updates.1
+++ b/usr/share/man/man1/check_updates.1
@@ -1,4 +1,4 @@
-.\" Automatically generated by Pandoc 2.19.2
+.\" Automatically generated by Pandoc 3.0.1
 .\"
 .\" Define V font for inline verbatim, using C font in formats
 .\" that render this, and otherwise B font.
@@ -76,4 +76,4 @@ Error
 .PP
 \f[B]notifier\f[R] - used as notification application
 .SH AUTHORS
-Alexander Sch\[:a]ferdiek.
+Alexander Schäferdiek.
diff --git a/usr/share/man/man1/disk_space_alert.1 b/usr/share/man/man1/disk_space_alert.1
index 2896b30..b1aabf7 100644
--- a/usr/share/man/man1/disk_space_alert.1
+++ b/usr/share/man/man1/disk_space_alert.1
@@ -1,4 +1,4 @@
-.\" Automatically generated by Pandoc 2.19.2
+.\" Automatically generated by Pandoc 3.0.1
 .\"
 .\" Define V font for inline verbatim, using C font in formats
 .\" that render this, and otherwise B font.
@@ -73,4 +73,4 @@ Error
 .PP
 \f[B]notifier\f[R] - used as notification application
 .SH AUTHORS
-Alexander Sch\[:a]ferdiek.
+Alexander Schäferdiek.
diff --git a/usr/share/man/man1/docker_check.1 b/usr/share/man/man1/docker_check.1
index 583dc1b..96a9367 100644
--- a/usr/share/man/man1/docker_check.1
+++ b/usr/share/man/man1/docker_check.1
@@ -1,4 +1,4 @@
-.\" Automatically generated by Pandoc 2.19.2
+.\" Automatically generated by Pandoc 3.0.1
 .\"
 .\" Define V font for inline verbatim, using C font in formats
 .\" that render this, and otherwise B font.
@@ -80,4 +80,4 @@ Error
 .PP
 \f[B]notifier\f[R] - used as notification application
 .SH AUTHORS
-Alexander Sch\[:a]ferdiek.
+Alexander Schäferdiek.
diff --git a/usr/share/man/man1/docker_compose_update.1 b/usr/share/man/man1/docker_compose_update.1
index c54c73f..c40cf7c 100644
--- a/usr/share/man/man1/docker_compose_update.1
+++ b/usr/share/man/man1/docker_compose_update.1
@@ -1,4 +1,4 @@
-.\" Automatically generated by Pandoc 2.19.2
+.\" Automatically generated by Pandoc 3.0.1
 .\"
 .\" Define V font for inline verbatim, using C font in formats
 .\" that render this, and otherwise B font.
@@ -98,4 +98,4 @@ Success
 \f[B]1\f[R]
 Error
 .SH AUTHORS
-Alexander Sch\[:a]ferdiek.
+Alexander Schäferdiek.
diff --git a/usr/share/man/man1/dynv6.1 b/usr/share/man/man1/dynv6.1
index 8c5ca39..0e6473f 100644
--- a/usr/share/man/man1/dynv6.1
+++ b/usr/share/man/man1/dynv6.1
@@ -1,4 +1,4 @@
-.\" Automatically generated by Pandoc 2.19.2
+.\" Automatically generated by Pandoc 3.0.1
 .\"
 .\" Define V font for inline verbatim, using C font in formats
 .\" that render this, and otherwise B font.
@@ -85,4 +85,4 @@ Error
 .PP
 \f[B]notifier\f[R] - used as notification application
 .SH AUTHORS
-Alexander Sch\[:a]ferdiek.
+Alexander Schäferdiek.
diff --git a/usr/share/man/man1/memory_usage_alert.1 b/usr/share/man/man1/memory_usage_alert.1
index 4946365..1b810a8 100644
--- a/usr/share/man/man1/memory_usage_alert.1
+++ b/usr/share/man/man1/memory_usage_alert.1
@@ -1,4 +1,4 @@
-.\" Automatically generated by Pandoc 2.19.2
+.\" Automatically generated by Pandoc 3.0.1
 .\"
 .\" Define V font for inline verbatim, using C font in formats
 .\" that render this, and otherwise B font.
@@ -64,4 +64,4 @@ Error
 .PP
 \f[B]notifier\f[R] - used as notification application
 .SH AUTHORS
-Alexander Sch\[:a]ferdiek.
+Alexander Schäferdiek.
diff --git a/usr/share/man/man1/notifier.1 b/usr/share/man/man1/notifier.1
index 51e2f9d..8ffc91e 100644
--- a/usr/share/man/man1/notifier.1
+++ b/usr/share/man/man1/notifier.1
@@ -1,4 +1,4 @@
-.\" Automatically generated by Pandoc 2.19.2
+.\" Automatically generated by Pandoc 3.0.1
 .\"
 .\" Define V font for inline verbatim, using C font in formats
 .\" that render this, and otherwise B font.
@@ -39,6 +39,11 @@ configuration.
 It will exit with a non-zero exit code if it cannot find a proper
 configuration file.
 .PP
+If all of the below variables are set and not empty as environment
+variables, then \f[B]notifier\f[R] skips sourcing config files.
+This allows a per-command configuration without relying on the global
+configs.
+.PP
 The following configuration values can be set, defaults are shown as
 well:
 .PD 0
@@ -50,7 +55,7 @@ notification via mail to \f[I]NOTIFIER_MAIL_ADDRESS\f[R].
 .IP \[bu] 2
 \f[B]NOTIFIER_MAIL_ADDRESS=\[lq]\[lq]\f[R] which requires
 \f[I]mail.rc\f[R] to be configured and `\f[I]mailx\f[R]' command has be
-available\[ac]
+available¸
 .IP \[bu] 2
 \f[B]NOTIFIER_GOTIFY_ENABLED=\[lq]false\[rq]\f[R] which `gotify' command
 has be available and needs to be properly configured by having a
@@ -77,4 +82,4 @@ Error
 .PP
 \f[B]system-helpers\f[R]
 .SH AUTHORS
-Alexander Sch\[:a]ferdiek.
+Alexander Schäferdiek.
diff --git a/usr/share/man/man1/smart_tests_long.1 b/usr/share/man/man1/smart_tests_long.1
index 31d9eaf..25c9c27 100644
--- a/usr/share/man/man1/smart_tests_long.1
+++ b/usr/share/man/man1/smart_tests_long.1
@@ -1,4 +1,4 @@
-.\" Automatically generated by Pandoc 2.19.2
+.\" Automatically generated by Pandoc 3.0.1
 .\"
 .\" Define V font for inline verbatim, using C font in formats
 .\" that render this, and otherwise B font.
@@ -68,4 +68,4 @@ Error
 .PP
 \f[B]notifier\f[R] - used as notification application
 .SH AUTHORS
-Alexander Sch\[:a]ferdiek.
+Alexander Schäferdiek.
diff --git a/usr/share/man/man1/system-helpers.1 b/usr/share/man/man1/system-helpers.1
index 113ad21..3f207ea 100644
--- a/usr/share/man/man1/system-helpers.1
+++ b/usr/share/man/man1/system-helpers.1
@@ -1,4 +1,4 @@
-.\" Automatically generated by Pandoc 2.19.2
+.\" Automatically generated by Pandoc 3.0.1
 .\"
 .\" Define V font for inline verbatim, using C font in formats
 .\" that render this, and otherwise B font.
@@ -58,4 +58,4 @@ See \f[I]/usr/share/doc/system-helpers/system-helpers\f[R] for example
 configurations which should be copied inside \f[B]$HOME\f[R] or
 \f[B]/etc\f[R] depending on the helper script.
 .SH AUTHORS
-Alexander Sch\[:a]ferdiek.
+Alexander Schäferdiek.
diff --git a/usr/share/man/man1/systemd_check.1 b/usr/share/man/man1/systemd_check.1
index b5cb934..54cfdd5 100644
--- a/usr/share/man/man1/systemd_check.1
+++ b/usr/share/man/man1/systemd_check.1
@@ -1,4 +1,4 @@
-.\" Automatically generated by Pandoc 2.19.2
+.\" Automatically generated by Pandoc 3.0.1
 .\"
 .\" Define V font for inline verbatim, using C font in formats
 .\" that render this, and otherwise B font.
@@ -71,4 +71,4 @@ Error
 .PP
 \f[B]notifier\f[R] - used as notification application
 .SH AUTHORS
-Alexander Sch\[:a]ferdiek.
+Alexander Schäferdiek.
diff --git a/usr/share/man/man1/systemd_failure_notify.1 b/usr/share/man/man1/systemd_failure_notify.1
index ec70309..ce86461 100644
--- a/usr/share/man/man1/systemd_failure_notify.1
+++ b/usr/share/man/man1/systemd_failure_notify.1
@@ -1,4 +1,4 @@
-.\" Automatically generated by Pandoc 2.19.2
+.\" Automatically generated by Pandoc 3.0.1
 .\"
 .\" Define V font for inline verbatim, using C font in formats
 .\" that render this, and otherwise B font.
@@ -71,4 +71,4 @@ Error
 .PP
 \f[B]notifier\f[R] - used as notification application
 .SH AUTHORS
-Alexander Sch\[:a]ferdiek.
+Alexander Schäferdiek.