75 lines
1.6 KiB
Go
75 lines
1.6 KiB
Go
/*
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Copyright The containerd Authors.
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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package dialer
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import (
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"context"
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"fmt"
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"net"
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"time"
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)
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type dialResult struct {
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c net.Conn
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err error
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}
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// ContextDialer returns a GRPC net.Conn connected to the provided address
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func ContextDialer(ctx context.Context, address string) (net.Conn, error) {
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if deadline, ok := ctx.Deadline(); ok {
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return timeoutDialer(address, time.Until(deadline))
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}
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return timeoutDialer(address, 0)
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}
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func timeoutDialer(address string, timeout time.Duration) (net.Conn, error) {
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var (
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stopC = make(chan struct{})
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synC = make(chan *dialResult)
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)
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go func() {
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defer close(synC)
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for {
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select {
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case <-stopC:
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return
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default:
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c, err := dialer(address, timeout)
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if isNoent(err) {
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<-time.After(10 * time.Millisecond)
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continue
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}
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synC <- &dialResult{c, err}
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return
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}
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}
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}()
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select {
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case dr := <-synC:
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return dr.c, dr.err
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case <-time.After(timeout):
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close(stopC)
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go func() {
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dr := <-synC
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if dr != nil && dr.c != nil {
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dr.c.Close()
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}
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}()
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return nil, fmt.Errorf("dial %s: timeout", address)
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}
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}
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