Adding SystemD integration LSB override

In certain conditions, such as configuring a dedicated user for
Shellinabox, system tend to crash or not to be reboot proof.

This is because Shellinaboxd starts before essential elements, such as
slapd, and can't recover from failure.

Adding such feature enables Respawn directove to be handled by SystemD.
Boot order is placed after YunoHost's Slapd

conf/shellinabox.service

@@ -0,0 +1,38 @@
+# Make it bootable at startup
+[Install]
+WantedBy=multi-user.target
+
+[Unit]
+Documentation=man:shellinaboxd(1)
+
+# Sourcing LSB Path
+SourcePath=/etc/init.d/shellinabox
+Description=LSB: Shell In A Box Daemon
+Before=multi-user.target
+Before=graphical.target
+After=network-online.target
+
+# Awaits LDAP is specific user binding at startup
+After=slapd.service
+After=remote-fs.target
+Wants=network-online.target
+Requires=slapd.service
+
+[Service]
+Type=forking
+
+# Calls for restart when there is a fail
+Restart=on-failure
+RestartSec=5min
+TimeoutSec=5min
+IgnoreSIGPIPE=no
+KillMode=process
+GuessMainPID=no
+RemainAfterExit=no
+SuccessExitStatus=5 6
+
+# Gracefully wait for every service to come up
+ExecStartPre=/bin/sleep 3
+ExecStart=/etc/init.d/shellinabox start
+ExecStop=/etc/init.d/shellinabox stop
+ExecReload=/etc/init.d/shellinabox reload

scripts/backup

@@ -33,6 +33,7 @@ ynh_script_progression --message="Backing up the main app directory..."
 
 ynh_backup --src_path="/etc/shellinabox"
 ynh_backup --src_path="/etc/default/shellinabox"
+ynh_backup --src_path="/etc/systemd/system/shellinabox.service"
 
 #=================================================
 # BACKUP THE NGINX CONFIGURATION

scripts/install

@@ -77,10 +77,14 @@ ynh_script_progression --message="Configuring shellinabox..." --weight=2
 cp ../conf/shellinabox /etc/default/shellinabox
 ynh_replace_string --match_string="__PORT__" --replace_string="$port" --target_file="/etc/default/shellinabox"
 
+
 # Allow the service to log in syslog
 ynh_replace_string --match_string=" -- -q --background" --replace_string=" -- --background" --target_file="/etc/init.d/shellinabox"
-systemctl daemon-reload
 
+# Enable SystemD respawn feature and boot order to avoid premature crashs
+cp ../conf/shellinabox.service /etc/systemd/system/shellinabox.service
+
+systemctl daemon-reload
 ynh_systemd_action --service_name=shellinabox --action=restart
 
 #=================================================
@@ -89,6 +93,7 @@ ynh_systemd_action --service_name=shellinabox --action=restart
 
 # Calculate and store the config file checksum into the app settings
 ynh_store_file_checksum --file="/etc/default/shellinabox"
+ynh_store_file_checksum --file="/etc/systemd/system/shellinabox.service"
 
 #=================================================
 # GENERIC FINALIZATION

scripts/remove

@@ -38,6 +38,9 @@ ynh_script_progression --message="Removing shellinabox..." --weight=20
 
 ynh_package_autopurge shellinabox
 
+# Remove Systemd auto-created daemon
+rm -f /etc/systemd/system/shellinabox.service
+
 #=================================================
 # REMOVE NGINX CONFIGURATION
 #=================================================

scripts/restore

@@ -57,6 +57,7 @@ ynh_script_progression --message="Restoring the app main directory..." --weight=
 
 ynh_restore_file --origin_path="/etc/shellinabox"
 ynh_restore_file --origin_path="/etc/default/shellinabox"
+ynh_restore_file --origin_path="/etc/systemd/system/shellinabox.service"
 
 # Allow the service to log in syslog
 ynh_replace_string --match_string=" -- -q --background" --replace_string=" -- --background" --target_file="/etc/init.d/shellinabox"

scripts/upgrade

@@ -68,10 +68,13 @@ ynh_script_progression --message="Upgrading shellinabox configuration..." --weig
 
 # Verify the checksum and backup the file if it's different
 ynh_backup_if_checksum_is_different --file="/etc/default/shellinabox"
+ynh_backup_if_checksum_is_different --file="/etc/systemd/system/shellinabox.service"
 
 cp ../conf/shellinabox /etc/default/shellinabox
 ynh_replace_string --match_string="__PORT__" --replace_string="$port" --target_file="/etc/default/shellinabox"
 
+cp ../conf/shellinabox.service /etc/systemd/system/shellinabox.service
+
 ynh_replace_string --match_string=" -- -q --background" --replace_string=" -- --background" --target_file="/etc/init.d/shellinabox"
 systemctl daemon-reload