move SFTPGo package to the internal folder

SFTPGo is a daemon and command line tool, not a library.

The public API are provided by the SDK

Signed-off-by: Nicola Murino <nicola.murino@gmail.com>

internal/plugin/metadata.go

@@ -0,0 +1,96 @@
+// Copyright (C) 2019-2022  Nicola Murino
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as published
+// by the Free Software Foundation, version 3.
+//
+// This program 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 Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+package plugin
+
+import (
+	"crypto/sha256"
+	"fmt"
+	"os/exec"
+
+	"github.com/hashicorp/go-hclog"
+	"github.com/hashicorp/go-plugin"
+	"github.com/sftpgo/sdk/plugin/metadata"
+
+	"github.com/drakkan/sftpgo/v2/internal/logger"
+)
+
+type metadataPlugin struct {
+	config    Config
+	metadater metadata.Metadater
+	client    *plugin.Client
+}
+
+func newMetadaterPlugin(config Config) (*metadataPlugin, error) {
+	p := &metadataPlugin{
+		config: config,
+	}
+	if err := p.initialize(); err != nil {
+		logger.Warn(logSender, "", "unable to create metadata plugin: %v, config %+v", err, config)
+		return nil, err
+	}
+	return p, nil
+}
+
+func (p *metadataPlugin) exited() bool {
+	return p.client.Exited()
+}
+
+func (p *metadataPlugin) cleanup() {
+	p.client.Kill()
+}
+
+func (p *metadataPlugin) initialize() error {
+	killProcess(p.config.Cmd)
+	logger.Debug(logSender, "", "create new metadata plugin %#v", p.config.Cmd)
+	var secureConfig *plugin.SecureConfig
+	if p.config.SHA256Sum != "" {
+		secureConfig.Checksum = []byte(p.config.SHA256Sum)
+		secureConfig.Hash = sha256.New()
+	}
+	client := plugin.NewClient(&plugin.ClientConfig{
+		HandshakeConfig: metadata.Handshake,
+		Plugins:         metadata.PluginMap,
+		Cmd:             exec.Command(p.config.Cmd, p.config.Args...),
+		AllowedProtocols: []plugin.Protocol{
+			plugin.ProtocolGRPC,
+		},
+		Managed:      false,
+		AutoMTLS:     p.config.AutoMTLS,
+		SecureConfig: secureConfig,
+		Logger: &logger.HCLogAdapter{
+			Logger: hclog.New(&hclog.LoggerOptions{
+				Name:        fmt.Sprintf("%v.%v", logSender, metadata.PluginName),
+				Level:       pluginsLogLevel,
+				DisableTime: true,
+			}),
+		},
+	})
+	rpcClient, err := client.Client()
+	if err != nil {
+		logger.Debug(logSender, "", "unable to get rpc client for plugin %#v: %v", p.config.Cmd, err)
+		return err
+	}
+	raw, err := rpcClient.Dispense(metadata.PluginName)
+	if err != nil {
+		logger.Debug(logSender, "", "unable to get plugin %v from rpc client for command %#v: %v",
+			metadata.PluginName, p.config.Cmd, err)
+		return err
+	}
+
+	p.client = client
+	p.metadater = raw.(metadata.Metadater)
+
+	return nil
+}