github.com/coreos/mantle@v0.13.0/network/retrydialer.go (about)

     1  // Copyright 2015 CoreOS, Inc.
     2  //
     3  // Licensed under the Apache License, Version 2.0 (the "License");
     4  // you may not use this file except in compliance with the License.
     5  // You may obtain a copy of the License at
     6  //
     7  //     http://www.apache.org/licenses/LICENSE-2.0
     8  //
     9  // Unless required by applicable law or agreed to in writing, software
    10  // distributed under the License is distributed on an "AS IS" BASIS,
    11  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    12  // See the License for the specific language governing permissions and
    13  // limitations under the License.
    14  
    15  package network
    16  
    17  import (
    18  	"net"
    19  	"time"
    20  )
    21  
    22  const (
    23  	// DefaultTimeout sets the default timeout for RetryDialer.
    24  	DefaultTimeout = 5 * time.Second
    25  
    26  	// DefaultKeepAlive sets the default keepalive for RetryDialer.
    27  	DefaultKeepAlive = 30 * time.Second
    28  
    29  	// DefaultRetries sets the default number of retries for RetryDialer.
    30  	DefaultRetries = 7
    31  )
    32  
    33  // RetryDialer is intended to timeout quickly and retry connecting instead
    34  // of just failing. Particularly useful for waiting on a booting machine.
    35  type RetryDialer struct {
    36  	net.Dialer
    37  	Retries int
    38  }
    39  
    40  // NewRetryDialer initializes a RetryDialer with reasonable default settings.
    41  func NewRetryDialer() *RetryDialer {
    42  	return &RetryDialer{
    43  		Dialer: net.Dialer{
    44  			Timeout:   DefaultTimeout,
    45  			KeepAlive: DefaultKeepAlive,
    46  		},
    47  		Retries: DefaultRetries,
    48  	}
    49  }
    50  
    51  // Dial connects to a remote address, retrying on failure.
    52  func (d *RetryDialer) Dial(network, address string) (c net.Conn, err error) {
    53  	for i := 0; i < d.Retries; i++ {
    54  		c, err = d.Dialer.Dial(network, address)
    55  		if err == nil {
    56  			return
    57  		}
    58  	}
    59  	return
    60  }