feat(GODT-2255): Randomize the focus service port.

internal/service/config.go

@@ -0,0 +1,79 @@
+// Copyright (c) 2023 Proton AG
+//
+// This file is part of Proton Mail Bridge.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 service
+
+import (
+	"encoding/json"
+	"os"
+	"path/filepath"
+)
+
+// Config is a structure containing the service configuration data that are exchanged by the gRPC server and client.
+type Config struct {
+	Port           int    `json:"port"`
+	Cert           string `json:"cert"`
+	Token          string `json:"token"`
+	FileSocketPath string `json:"fileSocketPath"`
+}
+
+// save saves a gRPC service configuration to file.
+func (s *Config) save(path string) error {
+	// Another process may be waiting for this file to be available. In order to prevent this process to open
+	// the file while we are writing in it, we write it with a temp file name, then rename it.
+	tempPath := path + "_"
+	if err := s._save(tempPath); err != nil {
+		return err
+	}
+
+	return os.Rename(tempPath, path)
+}
+
+func (s *Config) _save(path string) error {
+	f, err := os.Create(path) //nolint:errcheck,gosec
+	if err != nil {
+		return err
+	}
+
+	defer func() { _ = f.Close() }()
+
+	return json.NewEncoder(f).Encode(s)
+}
+
+// Load loads a gRPC service configuration from file.
+func (s *Config) Load(path string) error {
+	f, err := os.Open(path) //nolint:errcheck,gosec
+	if err != nil {
+		return err
+	}
+
+	defer func() { _ = f.Close() }()
+
+	return json.NewDecoder(f).Decode(s)
+}
+
+// SaveGRPCServerConfigFile save GRPC configuration file.
+func SaveGRPCServerConfigFile(locations Locator, config *Config, filename string) (string, error) {
+	settingsPath, err := locations.ProvideSettingsPath()
+	if err != nil {
+		return "", err
+	}
+
+	configPath := filepath.Join(settingsPath, filename)
+
+	return configPath, config.save(configPath)
+}

internal/service/config_test.go

@@ -0,0 +1,57 @@
+// 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 service
+
+import (
+	"path/filepath"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+const (
+	dummyPort    = 12
+	dummyCert    = "A dummy cert"
+	dummyToken   = "A dummy token"
+	tempFileName = "test.json"
+	socketPath   = "/a/socket/file/path"
+)
+
+func TestConfig(t *testing.T) {
+	conf1 := Config{
+		Port:           dummyPort,
+		Cert:           dummyCert,
+		Token:          dummyToken,
+		FileSocketPath: socketPath,
+	}
+
+	// Read-back test
+	tempDir := t.TempDir()
+	tempFilePath := filepath.Join(tempDir, tempFileName)
+	require.NoError(t, conf1.save(tempFilePath))
+
+	conf2 := Config{}
+	require.NoError(t, conf2.Load(tempFilePath))
+	require.Equal(t, conf1, conf2)
+
+	// failure to load
+	require.Error(t, conf2.Load(tempFilePath+"_"))
+
+	// failure to save
+	require.Error(t, conf2.save(filepath.Join(tempDir, "non/existing/folder", tempFileName)))
+}

internal/service/types.go

@@ -0,0 +1,22 @@
+// Copyright (c) 2023 Proton AG
+//
+// This file is part of Proton Mail Bridge.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 service
+
+type Locator interface {
+	ProvideSettingsPath() (string, error)
+}