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limited_conn_listener.go
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/
limited_conn_listener.go
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// Copyright 2015 CoreOS, 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 transport
import (
"errors"
"net"
"github.com/coreos/etcd/Godeps/_workspace/src/github.com/coreos/pkg/capnslog"
"github.com/coreos/etcd/pkg/runtime"
)
var plog = capnslog.NewPackageLogger("github.com/coreos/etcd/pkg", "transport")
type LimitedConnListener struct {
net.Listener
RuntimeFDLimit uint64
}
func (l *LimitedConnListener) Accept() (net.Conn, error) {
conn, err := l.Listener.Accept()
if err != nil {
return nil, err
}
n, err := runtime.FDUsage()
// Check whether fd number in use exceeds the set limit.
if err == nil && n >= l.RuntimeFDLimit {
conn.Close()
plog.Errorf("accept error: closing connection, exceed file descriptor usage limitation (fd limit=%d)", l.RuntimeFDLimit)
return nil, &acceptError{error: errors.New("exceed file descriptor usage limitation"), temporary: true}
}
return conn, nil
}
type acceptError struct {
error
temporary bool
}
func (e *acceptError) Timeout() bool { return false }
func (e *acceptError) Temporary() bool { return e.temporary }