chore(GODT-2799): Move Identifier interface to separate module

Required so we can move the smtp backend into the smtp service module.

internal/bridge/bridge.go

@@ -38,6 +38,7 @@ import (
 	"github.com/ProtonMail/proton-bridge/v3/internal/constants"
 	"github.com/ProtonMail/proton-bridge/v3/internal/events"
 	"github.com/ProtonMail/proton-bridge/v3/internal/focus"
+	"github.com/ProtonMail/proton-bridge/v3/internal/identifier"
 	"github.com/ProtonMail/proton-bridge/v3/internal/safe"
 	"github.com/ProtonMail/proton-bridge/v3/internal/sentry"
 	"github.com/ProtonMail/proton-bridge/v3/internal/telemetry"
@@ -59,7 +60,7 @@ type Bridge struct {
 	// api manages user API clients.
 	api        *proton.Manager
 	proxyCtl   ProxyController
-	identifier Identifier
+	identifier identifier.Identifier
 
 	// tlsConfig holds the bridge TLS config used by the IMAP and SMTP servers.
 	tlsConfig *tls.Config
@@ -140,7 +141,7 @@ func New(
 
 	apiURL string, // the URL of the API to use
 	cookieJar http.CookieJar, // the cookie jar to use
-	identifier Identifier, // the identifier to keep track of the user agent
+	identifier identifier.Identifier, // the identifier to keep track of the user agent
 	tlsReporter TLSReporter, // the TLS reporter to report TLS errors
 	roundTripper http.RoundTripper, // the round tripper to use for API requests
 	proxyCtl ProxyController, // the DoH controller
@@ -207,7 +208,7 @@ func newBridge(
 	reporter reporter.Reporter,
 
 	api *proton.Manager,
-	identifier Identifier,
+	identifier identifier.Identifier,
 	proxyCtl ProxyController,
 	uidValidityGenerator imap.UIDValidityGenerator,
 

internal/bridge/identifier.go

@@ -45,6 +45,30 @@ type bridgeUserAgentUpdater struct {
 	*Bridge
 }
 
+func (b *bridgeUserAgentUpdater) GetUserAgent() string {
+	return b.identifier.GetUserAgent()
+}
+
+func (b *bridgeUserAgentUpdater) HasClient() bool {
+	return b.identifier.HasClient()
+}
+
+func (b *bridgeUserAgentUpdater) SetClient(name, version string) {
+	b.identifier.SetClient(name, version)
+}
+
+func (b *bridgeUserAgentUpdater) SetPlatform(platform string) {
+	b.identifier.SetPlatform(platform)
+}
+
+func (b *bridgeUserAgentUpdater) SetClientString(client string) {
+	b.identifier.SetClientString(client)
+}
+
+func (b *bridgeUserAgentUpdater) GetClientString() string {
+	return b.identifier.GetClientString()
+}
+
 func (b *bridgeUserAgentUpdater) SetUserAgent(name, version string) {
 	b.setUserAgent(name, version)
 }

internal/bridge/smtp.go

@@ -36,7 +36,7 @@ func (bridge *Bridge) restartSMTP(ctx context.Context) error {
 func newSMTPServer(bridge *Bridge, accounts *bridgesmtp.Accounts, tlsConfig *tls.Config, logSMTP bool) *smtp.Server {
 	logrus.WithField("logSMTP", logSMTP).Info("Creating SMTP server")
 
-	smtpServer := smtp.NewServer(&smtpBackend{bridge: bridge, accounts: accounts})
+	smtpServer := smtp.NewServer(&smtpBackend{userAgent: &bridgeUserAgentUpdater{Bridge: bridge}, accounts: accounts})
 
 	smtpServer.TLSConfig = tlsConfig
 	smtpServer.Domain = constants.Host

internal/bridge/smtp_backend.go

@@ -24,6 +24,7 @@ import (
 	"io"
 	"strings"
 
+	"github.com/ProtonMail/proton-bridge/v3/internal/identifier"
 	smtpservice "github.com/ProtonMail/proton-bridge/v3/internal/services/smtp"
 	"github.com/ProtonMail/proton-bridge/v3/internal/useragent"
 	"github.com/emersion/go-smtp"
@@ -32,12 +33,12 @@ import (
 
 type smtpBackend struct {
 	accounts  *smtpservice.Accounts
-	userAgent UserAgentUpdater
+	userAgent identifier.UserAgentUpdater
 }
 
 type smtpSession struct {
 	accounts  *smtpservice.Accounts
-	userAgent UserAgentUpdater
+	userAgent identifier.UserAgentUpdater
 
 	userID string
 	authID string

internal/bridge/types.go

@@ -34,20 +34,6 @@ type Locator interface {
 	Clear(...string) error
 }
 
-type Identifier interface {
-	GetUserAgent() string
-	HasClient() bool
-	SetClient(name, version string)
-	SetPlatform(platform string)
-	SetClientString(client string)
-	GetClientString() string
-}
-
-type UserAgentUpdater interface {
-	Identifier
-	SetUserAgent(name, version string)
-}
-
 type ProxyController interface {
 	AllowProxy()
 	DisallowProxy()

internal/identifier/identifier.go

@@ -0,0 +1,32 @@
+// Copyright (c) 2023 Proton AG
+//
+// This file is part of Proton Mail Bridge.
+//
+// Proton Mail Bridge is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// Proton Mail Bridge is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Proton Mail Bridge.  If not, see <https://www.gnu.org/licenses/>.
+
+package identifier
+
+type Identifier interface {
+	GetUserAgent() string
+	HasClient() bool
+	SetClient(name, version string)
+	SetPlatform(platform string)
+	SetClientString(client string)
+	GetClientString() string
+}
+
+type UserAgentUpdater interface {
+	Identifier
+	SetUserAgent(name, version string)
+}