minio/cmd/service.go

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/*
* MinIO Cloud Storage, (C) 2016 MinIO, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package cmd
import (
"context"
"os"
"os/exec"
"syscall"
)
// Type of service signals currently supported.
type serviceSignal int
const (
serviceRestart serviceSignal = iota // Restarts the server.
serviceStop // Stops the server.
serviceReloadDynamic // Reload dynamic config values.
// Add new service requests here.
)
// Global service signal channel.
var globalServiceSignalCh chan serviceSignal
// GlobalServiceDoneCh - Global service done channel.
var GlobalServiceDoneCh <-chan struct{}
// GlobalContext context that is canceled when server is requested to shut down.
var GlobalContext context.Context
// cancelGlobalContext can be used to indicate server shutdown.
var cancelGlobalContext context.CancelFunc
func initGlobalContext() {
GlobalContext, cancelGlobalContext = context.WithCancel(context.Background())
GlobalServiceDoneCh = GlobalContext.Done()
globalServiceSignalCh = make(chan serviceSignal)
}
// restartProcess starts a new process passing it the active fd's. It
// doesn't fork, but starts a new process using the same environment and
// arguments as when it was originally started. This allows for a newly
// deployed binary to be started. It returns the pid of the newly started
// process when successful.
func restartProcess() error {
// Use the original binary location. This works with symlinks such that if
// the file it points to has been changed we will use the updated symlink.
argv0, err := exec.LookPath(os.Args[0])
if err != nil {
return err
}
// Invokes the execve system call.
// Re-uses the same pid. This preserves the pid over multiple server-respawns.
return syscall.Exec(argv0, os.Args, os.Environ())
}