Make nodejs helpers easier to use

data/helpers.d/nodejs

@@ -28,14 +28,37 @@ SOURCE_SUM=3983fa3f00d4bf85ba8e21f1a590f6e28938093abe0bb950aeea52b1717471fc" > "
 # Load the version of node for an app, and set variables.
 #
 # ynh_use_nodejs has to be used in any app scripts before using node for the first time.
+# This helper will provide alias and variables to use in your scripts.
 #
-# 2 variables are available:
-#   - $nodejs_path: The absolute path of node for the chosen version.
+# To use npm or node, use the alias `ynh_npm` and `ynh_node`
+# Those alias will use the correct version installed for the app
+# For example: use `ynh_npm install` instead of `npm install`
+#
+# With `sudo` or `ynh_exec_as`, use instead the fallback variables `$ynh_npm` and `$ynh_node`
+# Exemple: `ynh_exec_as $app $ynh_npm install`
+#
+# $PATH contains the path of the requested version of node.
+# However, $PATH is duplicated into $node_PATH to outlast any manipulation of $PATH
+# You can use the variable `$ynh_node_load_PATH` to quickly load your node version
+#  in $PATH for an usage into a separate script.
+# Exemple: $ynh_node_load_PATH $final_path/script_that_use_npm.sh`
+#
+#
+# Finally, to start a nodejs service with the correct version, 2 solutions
+#  Either the app is dependent of node or npm, but does not called it directly.
+#  In such situation, you need to load PATH
+#    `Environment="__NODE_ENV_PATH__"`
+#    `ExecStart=__FINALPATH__/my_app`
+#     You will replace __NODE_ENV_PATH__ with $ynh_node_load_PATH
+#
+#  Or node start the app directly, then you don't need to load the PATH variable
+#    `ExecStart=__YNH_NODE__ my_app run`
+#     You will replace __YNH_NODE__ with $ynh_node
+#
+#
+# 2 other variables are also available
+#   - $nodejs_path: The absolute path to node binaries for the chosen version.
 #   - $nodejs_version: Just the version number of node for this app. Stored as 'nodejs_version' in settings.yml.
-# And 2 alias stored in variables:
-#   - $nodejs_use_version: An old variable, not used anymore. Keep here to not break old apps
-#     NB: $PATH will contain the path to node, it has to be propagated to any other shell which needs to use it.
-#     That's means it has to be added to any systemd script.
 #
 # usage: ynh_use_nodejs
 #
@@ -43,13 +66,24 @@ SOURCE_SUM=3983fa3f00d4bf85ba8e21f1a590f6e28938093abe0bb950aeea52b1717471fc" > "
 ynh_use_nodejs () {
 	nodejs_version=$(ynh_app_setting_get --app=$app --key=nodejs_version)
 
-	nodejs_use_version="echo \"Deprecated command, should be removed\""
-
 	# Get the absolute path of this version of node
 	nodejs_path="$node_version_path/$nodejs_version/bin"
 
+	# Allow alias to be used into bash script
+	shopt -s expand_aliases
+
+	# Create an alias for the specific version of node and a variable as fallback
+	ynh_node="$nodejs_path/node"
+	alias ynh_node="$ynh_node"
+	# And npm
+	ynh_npm="$nodejs_path/npm"
+	alias ynh_npm="$ynh_npm"
+
 	# Load the path of this version of node in $PATH
 	[[ :$PATH: == *":$nodejs_path"* ]] || PATH="$nodejs_path:$PATH"
+	node_PATH="$PATH"
+	# Create an alias to easily load the PATH
+	ynh_node_load_PATH="PATH=$node_PATH"
 }
 
 # Install a specific version of nodejs
@@ -62,6 +96,8 @@ ynh_use_nodejs () {
 # usage: ynh_install_nodejs --nodejs_version=nodejs_version
 # | arg: -n, --nodejs_version - Version of node to install. When possible, your should prefer to use major version number (e.g. 8 instead of 8.10.0). The crontab will then handle the update of minor versions when needed.
 #
+# Refer to ynh_use_nodejs for more information about available commands and variables
+#
 # Requires YunoHost version 2.7.12 or higher.
 ynh_install_nodejs () {
 	# Use n, https://github.com/tj/n to manage the nodejs versions