feat: Enable headless installation without interaction

README.md

@@ -39,6 +39,39 @@ It will install WireGuard (kernel module and tools) on the server, configure it,
 
 Run the script again to add or remove clients!
 
+## Headless installation
+
+It's also possible to run the script headless, e.g. without waiting for user input, in an automated way.
+
+Example usage:
+
+```bash
+APPROVE_INSTALL=y ./wireguard-install.sh
+
+# or
+
+export APPROVE_INSTALL=y
+./wireguard-install.sh
+```
+
+This will set a default set of variables, bypassing any user input.
+
+If you want to customise your installation, you can use variables, as shown below:
+
+```
+export APPROVE_INSTALL=y
+export SERVER_PUB_IP="54.14.1.48"
+export SERVER_PORT=64567
+export CLIENT_NAME=client
+```
+
+If the server is behind NAT, you can specify its endpoint with the `SERVER_PUB_IP` variable. If the endpoint is the public IP address which it is behind, you can use `SERVER_PUB_IP=$(curl -s https://api.ipify.org)` (the script defaults to this). The endpoint can be an IP or a domain.
+
+The headless installation involves adding a new user. Adding `CLIENT_NAME=foo` will change the name of the new user to `foo` instead of the default.
+
+Other variables can be set as required on your choice (`SERVER_NIC`). You can find them in the `installQuestions()` function of the script.
+
+
 ## Providers
 
 I recommend these cheap cloud providers for your VPN server:

wireguard-install.sh

@@ -110,29 +110,38 @@ function installQuestions() {
 	echo ""
 
 	# Detect public IPv4 or IPv6 address and pre-fill for the user
-	SERVER_PUB_IP=$(ip -4 addr | sed -ne 's|^.* inet \([^/]*\)/.* scope global.*$|\1|p' | awk '{print $1}' | head -1)
+	SERVER_PUB_IP=${SERVER_PUB_IP:-$(ip -4 addr | sed -ne 's|^.* inet \([^/]*\)/.* scope global.*$|\1|p' | awk '{print $1}' | head -1)}
 	if [[ -z ${SERVER_PUB_IP} ]]; then
 		# Detect public IPv6 address
 		SERVER_PUB_IP=$(ip -6 addr | sed -ne 's|^.* inet6 \([^/]*\)/.* scope global.*$|\1|p' | head -1)
 	fi
+
+	APPROVE_IP=${APPROVE_IP:-n}
+	if [[ ${APPROVE_IP} =~ n ]]; then
 		read -rp "IPv4 or IPv6 public address: " -e -i "${SERVER_PUB_IP}" SERVER_PUB_IP
+	fi
 
 	# Detect public interface and pre-fill for the user
-	SERVER_NIC="$(ip -4 route ls | grep default | grep -Po '(?<=dev )(\S+)' | head -1)"
+	SERVER_NIC="${SERVER_NIC:-$(ip -4 route ls | grep default | grep -Po '(?<=dev )(\S+)' | head -1)}"
-	until [[ ${SERVER_PUB_NIC} =~ ^[a-zA-Z0-9_]+$ ]]; do
+	APPROVE_NIC=${APPROVE_NIC:-n}
+  if [[ ${APPROVE_IP} =~ n ]]; then
+    until [[ ${SERVER_PUB_NIC} =~ ^[a-zA-Z0-9_]+$ || ${APPROVE_NIC} =~ n ]]; do
       read -rp "Public interface: " -e -i "${SERVER_NIC}" SERVER_PUB_NIC
     done
+  else
+    SERVER_PUB_NIC="${SERVER_NIC}"
+  fi
 
 	until [[ ${SERVER_WG_NIC} =~ ^[a-zA-Z0-9_]+$ && ${#SERVER_WG_NIC} -lt 16 ]]; do
-		read -rp "WireGuard interface name: " -e -i wg0 SERVER_WG_NIC
+		read -rp "WireGuard interface name: " -e -i "${SERVER_WG_NIC_DEFAULT}" SERVER_WG_NIC
 	done
 
 	until [[ ${SERVER_WG_IPV4} =~ ^([0-9]{1,3}\.){3} ]]; do
-		read -rp "Server WireGuard IPv4: " -e -i 10.66.66.1 SERVER_WG_IPV4
+		read -rp "Server WireGuard IPv4: " -e -i "${SERVER_WG_IPV4_DEFAULT}" SERVER_WG_IPV4
 	done
 
 	until [[ ${SERVER_WG_IPV6} =~ ^([a-f0-9]{1,4}:){3,4}: ]]; do
-		read -rp "Server WireGuard IPv6: " -e -i fd42:42:42::1 SERVER_WG_IPV6
+		read -rp "Server WireGuard IPv6: " -e -i "${SERVER_WG_IPV6_DEFAULT}" SERVER_WG_IPV6
 	done
 
 	# Generate random number within private ports range
@@ -143,10 +152,10 @@ function installQuestions() {
 
 	# Adguard DNS by default
 	until [[ ${CLIENT_DNS_1} =~ ^((25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.){3}(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)$ ]]; do
-		read -rp "First DNS resolver to use for the clients: " -e -i 1.1.1.1 CLIENT_DNS_1
+		read -rp "First DNS resolver to use for the clients: " -e -i "${CLIENT_DNS_1_DEFAULT}" CLIENT_DNS_1
 	done
 	until [[ ${CLIENT_DNS_2} =~ ^((25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.){3}(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)$ ]]; do
-		read -rp "Second DNS resolver to use for the clients (optional): " -e -i 1.0.0.1 CLIENT_DNS_2
+		read -rp "Second DNS resolver to use for the clients (optional): " -e -i "${CLIENT_DNS_2_DEFAULT}" CLIENT_DNS_2
 		if [[ ${CLIENT_DNS_2} == "" ]]; then
 			CLIENT_DNS_2="${CLIENT_DNS_1}"
 		fi
@@ -156,17 +165,44 @@ function installQuestions() {
 		echo -e "\nWireGuard uses a parameter called AllowedIPs to determine what is routed over the VPN."
 		read -rp "Allowed IPs list for generated clients (leave default to route everything): " -e -i '0.0.0.0/0,::/0' ALLOWED_IPS
 		if [[ ${ALLOWED_IPS} == "" ]]; then
-			ALLOWED_IPS="0.0.0.0/0,::/0"
+			ALLOWED_IPS="${ALLOWED_IPS_DEFAULTS}"
 		fi
 	done
 
 	echo ""
 	echo "Okay, that was all I needed. We are ready to setup your WireGuard server now."
 	echo "You will be able to generate a client at the end of the installation."
+	APPROVE_INSTALL=${APPROVE_INSTALL:-n}
+	if [[ $APPROVE_INSTALL =~ n ]]; then
 		read -n1 -r -p "Press any key to continue..."
+	fi
 }
 
 function installWireGuard() {
+  SERVER_WG_NIC_DEFAULT="wg0"
+  SERVER_WG_IPV4_DEFAULT="10.66.66.1"
+  SERVER_WG_IPV6_DEFAULT="fd42:42:42::1"
+  CLIENT_DNS_1_DEFAULT="1.1.1.1"
+  CLIENT_DNS_2_DEFAULT="1.0.0.1"
+  ALLOWED_IPS_DEFAULTS="0.0.0.0/0,::/0"
+
+  if [[ ${APPROVE_INSTALL} == "y" ]]; then
+		# Set default choices so that no questions will be asked.
+		APPROVE_IP=${APPROVE_IP:-y}
+		APPROVE_NIC=${APPROVE_NIC:-y}
+		SERVER_WG_NIC=${SERVER_WG_NIC:-$SERVER_WG_NIC_DEFAULT}
+		SERVER_WG_IPV4=${SERVER_WG_IPV4:-$SERVER_WG_IPV4_DEFAULT}
+		SERVER_WG_IPV6=${SERVER_WG_IPV6:-$SERVER_WG_IPV6_DEFAULT}
+		SERVER_PORT=${SERVER_PORT:-$(shuf -i49152-65535 -n1)}
+		CLIENT_DNS_1=${CLIENT_DNS_1:-$CLIENT_DNS_1_DEFAULT}
+		CLIENT_DNS_2=${CLIENT_DNS_2:-$CLIENT_DNS_2_DEFAULT}
+		CLIENT_NAME=${CLIENT_NAME:-client}
+    ALLOWED_IPS=${ALLOWED_IPS:-$ALLOWED_IPS_DEFAULTS}
+
+		# Behind NAT, we'll default to the publicly reachable IPv4.
+		SERVER_PUB_IP=${SERVER_PUB_IP:-$(curl -s https://api.ipify.org)}
+	fi
+
 	# Run setup questions first
 	installQuestions
 
@@ -295,6 +331,7 @@ function newClient() {
 	echo ""
 	echo "The client name must consist of alphanumeric character(s). It may also include underscores or dashes and can't exceed 15 chars."
 
+  CLIENT_EXISTS=$(grep -c -E "^### Client ${CLIENT_NAME}\$" "/etc/wireguard/${SERVER_WG_NIC}.conf")
 	until [[ ${CLIENT_NAME} =~ ^[a-zA-Z0-9_-]+$ && ${CLIENT_EXISTS} == '0' && ${#CLIENT_NAME} -lt 16 ]]; do
 		read -rp "Client name: " -e CLIENT_NAME
 		CLIENT_EXISTS=$(grep -c -E "^### Client ${CLIENT_NAME}\$" "/etc/wireguard/${SERVER_WG_NIC}.conf")
@@ -321,7 +358,11 @@ function newClient() {
 
 	BASE_IP=$(echo "$SERVER_WG_IPV4" | awk -F '.' '{ print $1"."$2"."$3 }')
 	until [[ ${IPV4_EXISTS} == '0' ]]; do
+
+    if [[ $APPROVE_INSTALL =~ n ]]; then
       read -rp "Client WireGuard IPv4: ${BASE_IP}." -e -i "${DOT_IP}" DOT_IP
+    fi
+
 		CLIENT_WG_IPV4="${BASE_IP}.${DOT_IP}"
 		IPV4_EXISTS=$(grep -c "$CLIENT_WG_IPV4/32" "/etc/wireguard/${SERVER_WG_NIC}.conf")
 
@@ -334,7 +375,11 @@ function newClient() {
 
 	BASE_IP=$(echo "$SERVER_WG_IPV6" | awk -F '::' '{ print $1 }')
 	until [[ ${IPV6_EXISTS} == '0' ]]; do
+
+    if [[ $APPROVE_INSTALL =~ n ]]; then
 		  read -rp "Client WireGuard IPv6: ${BASE_IP}::" -e -i "${DOT_IP}" DOT_IP
+    fi
+
 		CLIENT_WG_IPV6="${BASE_IP}::${DOT_IP}"
 		IPV6_EXISTS=$(grep -c "${CLIENT_WG_IPV6}/128" "/etc/wireguard/${SERVER_WG_NIC}.conf")