chore(env): VPN_SERVICE_PROVIDER variable

- With retro-compatibility with `VPNSP`

Dockerfile

@@ -66,7 +66,7 @@ LABEL \
     org.opencontainers.image.source="https://github.com/qdm12/gluetun" \
     org.opencontainers.image.title="VPN swiss-knife like client for multiple VPN providers" \
     org.opencontainers.image.description="VPN swiss-knife like client to tunnel to multiple VPN servers using OpenVPN, IPtables, DNS over TLS, Shadowsocks, an HTTP proxy and Alpine Linux"
-ENV VPNSP=pia \
+ENV VPN_SERVICE_PROVIDER=pia \
     VPN_TYPE=openvpn \
     # Common VPN options
     VPN_ENDPOINT_IP= \

README.md

@@ -110,7 +110,7 @@ services:
       - /yourpath:/gluetun
     environment:
       # See https://github.com/qdm12/gluetun/wiki
-      - VPNSP=ivpn
+      - VPN_SERVICE_PROVIDER=ivpn
       - VPN_TYPE=openvpn
       # OpenVPN:
       - OPENVPN_USER=

internal/configuration/sources/env/provider.go

@@ -10,7 +10,7 @@ import (
 )
 
 func (r *Reader) readProvider(vpnType string) (provider settings.Provider, err error) {
-	provider.Name = readVPNServiceProvider(vpnType)
+	provider.Name = r.readVPNServiceProvider(vpnType)
 	var providerName string
 	if provider.Name != nil {
 		providerName = *provider.Name
@@ -29,8 +29,9 @@ func (r *Reader) readProvider(vpnType string) (provider settings.Provider, err e
 	return provider, nil
 }
 
-func readVPNServiceProvider(vpnType string) (vpnProviderPtr *string) {
-	s := strings.ToLower(os.Getenv("VPNSP"))
+func (r *Reader) readVPNServiceProvider(vpnType string) (vpnProviderPtr *string) {
+	_, s := r.getEnvWithRetro("VPN_SERVICE_PROVIDER", "VPNSP")
+	s = strings.ToLower(s)
 	switch {
 	case vpnType != constants.Wireguard &&
 		os.Getenv("OPENVPN_CUSTOM_CONFIG") != "": // retro compatibility