Update: add ynh_add_swap

scripts/_common.sh

@@ -11,6 +11,8 @@ auth_version="1.17.1"
 api_gateway_version="1.24.0"
 extensions_version="2021.07.06"
 
+swap_needed=1536
+
 # dependencies used by the app
 pkg_dependencies=""
 

scripts/install

@@ -7,6 +7,7 @@
 #=================================================
 
 source _common.sh
+source ynh_add_swap
 source ynh_install_ruby__2
 source ynh_redis
 source ynh_send_readme_to_admin__2
@@ -162,6 +163,13 @@ ynh_add_nginx_config
 #=================================================
 # SPECIFIC SETUP
 #=================================================
+#=================================================
+# ADD SWAP
+#=================================================
+ynh_script_progression --message="Adding swap..."
+
+ynh_add_swap --size=$swap_needed
+
 #=================================================
 # MODIFY A CONFIG FILE
 #=================================================

scripts/remove

@@ -7,6 +7,7 @@
 #=================================================
 
 source _common.sh
+source ynh_add_swap
 source ynh_install_ruby__2
 source ynh_redis
 source /usr/share/yunohost/helpers
@@ -135,6 +136,12 @@ ynh_remove_fail2ban_config
 #=================================================
 # SPECIFIC REMOVE
 #=================================================
+#=================================================
+# REMOVE SWAP
+#=================================================
+ynh_script_progression --message="Removing swap..."
+
+ynh_del_swap
 
 #=================================================
 # GENERIC FINALIZATION

scripts/restore

@@ -8,6 +8,7 @@
 
 #Keep this path for calling _common.sh inside the execution's context of backup and restore scripts
 source ../settings/scripts/_common.sh
+source ../settings/scripts/ynh_add_swap
 source ../settings/scripts/ynh_install_ruby__2
 source ../settings/scripts/ynh_redis
 source /usr/share/yunohost/helpers
@@ -115,6 +116,14 @@ chown -R $app: "/var/log/$app"
 
 #=================================================
 # SPECIFIC RESTORATION
+#=================================================
+#=================================================
+# ADD SWAP
+#=================================================
+ynh_script_progression --message="Adding swap..."
+
+ynh_add_swap --size=$swap_needed
+
 #=================================================
 # REINSTALL DEPENDENCIES
 #=================================================

scripts/upgrade

@@ -7,6 +7,7 @@
 #=================================================
 
 source _common.sh
+source ynh_add_swap
 source ynh_install_ruby__2
 source ynh_redis
 source ynh_send_readme_to_admin__2
@@ -381,6 +382,13 @@ ynh_install_extra_app_dependencies --repo="deb https://dl.yarnpkg.com/debian/ st
 #=================================================
 # SPECIFIC UPGRADE
 #=================================================
+#=================================================
+# ADD SWAP
+#=================================================
+ynh_script_progression --message="Adding swap..."
+
+ynh_add_swap --size=$swap_needed
+
 #=================================================
 # MODIFY A CONFIG FILE
 #=================================================

scripts/ynh_add_swap

@@ -0,0 +1,94 @@
+#!/bin/bash
+
+# Add swap
+#
+# usage: ynh_add_swap --size=SWAP in Mb
+# | arg: -s, --size= - Amount of SWAP to add in Mb.
+ynh_add_swap () {
+	# Declare an array to define the options of this helper.
+	declare -Ar args_array=( [s]=size= )
+	local size
+	# Manage arguments with getopts
+	ynh_handle_getopts_args "$@"
+
+	local swap_max_size=$(( $size * 1024 ))
+
+	local free_space=$(df --output=avail / | sed 1d)
+	# Because we don't want to fill the disk with a swap file, divide by 2 the available space.
+	local usable_space=$(( $free_space / 2 ))
+
+ 	SD_CARD_CAN_SWAP=${SD_CARD_CAN_SWAP:-0}
+
+	# Swap on SD card only if it's is specified
+	if ynh_is_main_device_a_sd_card && [ "$SD_CARD_CAN_SWAP" == "0" ]
+	then
+		ynh_print_warn --message="The main mountpoint of your system '/' is on an SD card, swap will not be added to prevent some damage of this one, but that can cause troubles for the app $app. If you still want activate the swap, you can relaunch the command preceded by 'SD_CARD_CAN_SWAP=1'"
+		return
+	fi
+
+	# Compare the available space with the size of the swap.
+	# And set a acceptable size from the request
+	if [ $usable_space -ge $swap_max_size ]
+	then
+		local swap_size=$swap_max_size
+	elif [ $usable_space -ge $(( $swap_max_size / 2 )) ]
+	then
+		local swap_size=$(( $swap_max_size / 2 ))
+	elif [ $usable_space -ge $(( $swap_max_size / 3 )) ]
+	then
+		local swap_size=$(( $swap_max_size / 3 ))
+	elif [ $usable_space -ge $(( $swap_max_size / 4 )) ]
+	then
+		local swap_size=$(( $swap_max_size / 4 ))
+	else
+		echo "Not enough space left for a swap file" >&2
+		local swap_size=0
+	fi
+
+	# If there's enough space for a swap, and no existing swap here
+	if [ $swap_size -ne 0 ] && [ ! -e /swap_$app ]
+	then
+		# Preallocate space for the swap file, fallocate may sometime not be used, use dd instead in this case
+		if ! fallocate -l ${swap_size}K /swap_$app
+		then
+			dd if=/dev/zero of=/swap_$app bs=1024 count=${swap_size}
+		fi
+		chmod 0600 /swap_$app
+		# Create the swap
+		mkswap /swap_$app
+		# And activate it
+		swapon /swap_$app
+		# Then add an entry in fstab to load this swap at each boot.
+		echo -e "/swap_$app swap swap defaults 0 0 #Swap added by $app" >> /etc/fstab
+	fi
+}
+
+ynh_del_swap () {
+	# If there a swap at this place
+	if [ -e /swap_$app ]
+	then
+		# Clean the fstab
+		sed -i "/#Swap added by $app/d" /etc/fstab
+		# Desactive the swap file
+		swapoff /swap_$app
+		# And remove it
+		rm /swap_$app
+	fi
+}
+
+# Check if the device of the main mountpoint "/" is an SD card
+#
+# [internal]
+#
+# return 0 if it's an SD card, else 1
+ynh_is_main_device_a_sd_card () {
+	local main_device=$(lsblk --output PKNAME --noheadings $(findmnt / --nofsroot --uniq --output source --noheadings --first-only))
+
+	if echo $main_device | grep --quiet "mmc" && [ $(tail -n1 /sys/block/$main_device/queue/rotational) == "0" ]
+	then
+		return 0
+	else
+		return 1
+	fi
+}
+