chore(all): memory and thread safe storage

- settings: get filter choices from storage for settings validation
- updater: update servers to the storage
- storage: minimal deep copying and data duplication
- storage: add merged servers mutex for thread safety
- connection: filter servers in storage
- formatter: format servers to Markdown in storage
- PIA: get server by name from storage directly
- Updater: get servers count from storage directly
- Updater: equality check done in storage, fix #882

internal/provider/privateinternetaccess/connection.go

@@ -2,6 +2,7 @@ package privateinternetaccess
 
 import (
 	"github.com/qdm12/gluetun/internal/configuration/settings"
+	"github.com/qdm12/gluetun/internal/constants/providers"
 	"github.com/qdm12/gluetun/internal/models"
 	"github.com/qdm12/gluetun/internal/provider/privateinternetaccess/presets"
 	"github.com/qdm12/gluetun/internal/provider/utils"
@@ -20,5 +21,6 @@ func (p *Provider) GetConnection(selection settings.ServerSelection) (
 		defaults.OpenVPNUDPPort = 1197
 	}
 
-	return utils.GetConnection(p.servers, selection, defaults, p.randSource)
+	return utils.GetConnection(providers.PrivateInternetAccess,
+		p.storage, selection, defaults, p.randSource)
 }

internal/provider/privateinternetaccess/portforward.go

@@ -15,25 +15,24 @@ import (
 	"strings"
 	"time"
 
-	"github.com/qdm12/gluetun/internal/models"
+	"github.com/qdm12/gluetun/internal/constants/providers"
 	"github.com/qdm12/gluetun/internal/provider/utils"
 	"github.com/qdm12/golibs/format"
 )
 
 var (
-	ErrGatewayIPIsNil  = errors.New("gateway IP address is nil")
-	ErrServerNameEmpty = errors.New("server name is empty")
+	ErrServerNameNotFound = errors.New("server name not found in servers")
+	ErrGatewayIPIsNil     = errors.New("gateway IP address is nil")
+	ErrServerNameEmpty    = errors.New("server name is empty")
 )
 
 // PortForward obtains a VPN server side port forwarded from PIA.
 func (p *Provider) PortForward(ctx context.Context, client *http.Client,
 	logger utils.Logger, gateway net.IP, serverName string) (
 	port uint16, err error) {
-	var server models.Server
-	for _, server = range p.servers {
-		if server.ServerName == serverName {
-			break
-		}
+	server, ok := p.storage.GetServerByName(providers.PrivateInternetAccess, serverName)
+	if !ok {
+		return 0, fmt.Errorf("%w: %s", ErrServerNameNotFound, serverName)
 	}
 
 	if !server.PortForward {

internal/provider/privateinternetaccess/provider.go

@@ -5,11 +5,11 @@ import (
 	"time"
 
 	"github.com/qdm12/gluetun/internal/constants/openvpn"
-	"github.com/qdm12/gluetun/internal/models"
+	"github.com/qdm12/gluetun/internal/provider/common"
 )
 
 type Provider struct {
-	servers    []models.Server
+	storage    common.Storage
 	randSource rand.Source
 	timeNow    func() time.Time
 	// Port forwarding
@@ -17,11 +17,11 @@ type Provider struct {
 	authFilePath    string
 }
 
-func New(servers []models.Server, randSource rand.Source,
+func New(storage common.Storage, randSource rand.Source,
 	timeNow func() time.Time) *Provider {
 	const jsonPortForwardPath = "/gluetun/piaportforward.json"
 	return &Provider{
-		servers:         servers,
+		storage:         storage,
 		timeNow:         timeNow,
 		randSource:      randSource,
 		portForwardPath: jsonPortForwardPath,