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// Copyright 2013-2015 Docker, Inc.
// Copyright 2014 CoreOS, Inc.
// Copyright 2015 Luke Shumaker
//
// 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 sd
import (
"errors"
"net"
"os"
)
// errNotifyNoSocket is an error returned if no socket was specified.
var errNotifyNoSocket = errors.New("No socket")
// Notify sends a message to the service manager aobout state
// changes. It is common to ignore the error.
//
// If unsetEnv is true, then (regarless of whether the function call
// itself succeeds or not) it will unset the environmental variable
// NOTIFY_SOCKET, which will cause further calls to this function to
// fail.
//
// The state parameter should countain a newline-separated list of
// variable assignments.
//
// See the documentation for sd_notify(3) for well-known variable
// assignments.
func Notify(unsetEnv bool, state string) error {
if unsetEnv {
defer func() { _ = os.Unsetenv("NOTIFY_SOCKET") }()
}
socketAddr := &net.UnixAddr{
Name: os.Getenv("NOTIFY_SOCKET"),
Net: "unixgram",
}
if socketAddr.Name == "" {
return errNotifyNoSocket
}
conn, err := net.DialUnix(socketAddr.Net, nil, socketAddr)
if err != nil {
return err
}
defer func() { _ = conn.Close() }()
_, err = conn.Write([]byte(state))
return err
}
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