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105 lines
2.6 KiB
105 lines
2.6 KiB
/* |
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Copyright 2018 The Kubernetes 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 connrotation implements a connection dialer that tracks and can close |
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// all created connections. |
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// |
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// This is used for credential rotation of long-lived connections, when there's |
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// no way to re-authenticate on a live connection. |
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package connrotation |
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import ( |
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"context" |
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"net" |
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"sync" |
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) |
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// DialFunc is a shorthand for signature of net.DialContext. |
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type DialFunc func(ctx context.Context, network, address string) (net.Conn, error) |
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// Dialer opens connections through Dial and tracks them. |
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type Dialer struct { |
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dial DialFunc |
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mu sync.Mutex |
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conns map[*closableConn]struct{} |
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} |
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// NewDialer creates a new Dialer instance. |
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// |
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// If dial is not nil, it will be used to create new underlying connections. |
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// Otherwise net.DialContext is used. |
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func NewDialer(dial DialFunc) *Dialer { |
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return &Dialer{ |
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dial: dial, |
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conns: make(map[*closableConn]struct{}), |
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} |
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} |
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// CloseAll forcibly closes all tracked connections. |
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// |
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// Note: new connections may get created before CloseAll returns. |
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func (d *Dialer) CloseAll() { |
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d.mu.Lock() |
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conns := d.conns |
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d.conns = make(map[*closableConn]struct{}) |
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d.mu.Unlock() |
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for conn := range conns { |
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conn.Close() |
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} |
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} |
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// Dial creates a new tracked connection. |
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func (d *Dialer) Dial(network, address string) (net.Conn, error) { |
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return d.DialContext(context.Background(), network, address) |
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} |
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// DialContext creates a new tracked connection. |
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func (d *Dialer) DialContext(ctx context.Context, network, address string) (net.Conn, error) { |
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conn, err := d.dial(ctx, network, address) |
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if err != nil { |
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return nil, err |
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} |
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closable := &closableConn{Conn: conn} |
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// Start tracking the connection |
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d.mu.Lock() |
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d.conns[closable] = struct{}{} |
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d.mu.Unlock() |
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// When the connection is closed, remove it from the map. This will |
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// be no-op if the connection isn't in the map, e.g. if CloseAll() |
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// is called. |
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closable.onClose = func() { |
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d.mu.Lock() |
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delete(d.conns, closable) |
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d.mu.Unlock() |
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} |
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return closable, nil |
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} |
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type closableConn struct { |
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onClose func() |
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net.Conn |
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} |
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func (c *closableConn) Close() error { |
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go c.onClose() |
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return c.Conn.Close() |
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}
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