Feature: Protonvpn filter servers with FREE_ONLY

Dockerfile

@@ -99,6 +99,8 @@ ENV VPNSP=pia \
     SERVER_NUMBER= \
     # NordVPN and ProtonVPN only:
     SERVER_NAME= \
+    # ProtonVPN only:
+    FREE_ONLY= \
     # Openvpn
     OPENVPN_CIPHER= \
     OPENVPN_AUTH= \

internal/configuration/openvpn_test.go

@@ -40,7 +40,8 @@ func Test_OpenVPN_JSON(t *testing.T) {
       "owned": false,
       "custom_port": 0,
       "numbers": null,
-      "encryption_preset": ""
+      "encryption_preset": "",
+      "free_only": false
     },
     "extra_config": {
       "encryption_preset": "",

internal/configuration/protonvpn.go

@@ -2,6 +2,7 @@ package configuration
 
 import (
 	"github.com/qdm12/gluetun/internal/constants"
+	"github.com/qdm12/golibs/params"
 )
 
 func (settings *Provider) protonvpnLines() (lines []string) {
@@ -25,6 +26,10 @@ func (settings *Provider) protonvpnLines() (lines []string) {
 		lines = append(lines, lastIndent+"Hostnames: "+commaJoin(settings.ServerSelection.Hostnames))
 	}
 
+	if settings.ServerSelection.FreeOnly {
+		lines = append(lines, lastIndent+"Free only: yes")
+	}
+
 	return lines
 }
 
@@ -71,5 +76,10 @@ func (settings *Provider) readProtonvpn(r reader) (err error) {
 		return err
 	}
 
+	settings.ServerSelection.FreeOnly, err = r.env.YesNo("FREE_ONLY", params.Default("no"))
+	if err != nil {
+		return err
+	}
+
 	return nil
 }

internal/configuration/selection.go

@@ -32,6 +32,9 @@ type ServerSelection struct { //nolint:maligned
 
 	// PIA
 	EncryptionPreset string `json:"encryption_preset"`
+
+	// ProtonVPN
+	FreeOnly bool `json:"free_only"`
 }
 
 type ExtraConfigOptions struct {

internal/provider/protonvpn/filter.go

@@ -1,6 +1,8 @@
 package protonvpn
 
 import (
+	"strings"
+
 	"github.com/qdm12/gluetun/internal/configuration"
 	"github.com/qdm12/gluetun/internal/models"
 	"github.com/qdm12/gluetun/internal/provider/utils"
@@ -15,7 +17,8 @@ func (p *Protonvpn) filterServers(selection configuration.ServerSelection) (
 			utils.FilterByPossibilities(server.Region, selection.Regions),
 			utils.FilterByPossibilities(server.City, selection.Cities),
 			utils.FilterByPossibilities(server.Hostname, selection.Hostnames),
-			utils.FilterByPossibilities(server.Name, selection.Names):
+			utils.FilterByPossibilities(server.Name, selection.Names),
+			selection.FreeOnly && !strings.Contains(strings.ToLower(server.Name), "free"):
 		default:
 			servers = append(servers, server)
 		}

internal/provider/utils/formatting.go

@@ -113,6 +113,10 @@ func NoServerFoundError(selection configuration.ServerSelection) (err error) {
 		messageParts = append(messageParts, part)
 	}
 
+	if selection.FreeOnly {
+		messageParts = append(messageParts, "free tier only")
+	}
+
 	message := "for " + strings.Join(messageParts, "; ")
 
 	return fmt.Errorf("%w: %s", ErrNoServerFound, message)