mirror of https://github.com/caddyserver/caddy.git
71 lines
1.8 KiB
Go
71 lines
1.8 KiB
Go
package caddy2
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import (
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"fmt"
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"net"
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"sync"
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"sync/atomic"
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)
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// Listen returns a listener suitable for use in a Caddy module.
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func Listen(proto, addr string) (net.Listener, error) {
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lnKey := proto + "/" + addr
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listenersMu.Lock()
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defer listenersMu.Unlock()
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// if listener already exists, return it
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if ln, ok := listeners[lnKey]; ok {
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return &fakeCloseListener{Listener: ln}, nil
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}
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// or, create new one and save it
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ln, err := net.Listen(proto, addr)
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if err != nil {
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return nil, err
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}
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listeners[lnKey] = ln
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return &fakeCloseListener{Listener: ln}, nil
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}
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// fakeCloseListener's Close() method is a no-op. This allows
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// stopping servers that are using the listener without giving
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// up the socket; thus, servers become hot-swappable while the
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// listener remains running. Listeners should be re-wrapped in
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// a new fakeCloseListener each time the listener is reused.
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type fakeCloseListener struct {
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closed int32
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net.Listener
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}
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// Accept accepts connections until Close() is called.
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func (fcl *fakeCloseListener) Accept() (net.Conn, error) {
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if atomic.LoadInt32(&fcl.closed) == 1 {
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return nil, ErrSwappingServers
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}
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return fcl.Listener.Accept()
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}
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// Close stops accepting new connections, but does not
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// actually close the underlying listener.
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func (fcl *fakeCloseListener) Close() error {
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atomic.StoreInt32(&fcl.closed, 1)
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return nil
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}
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// CloseUnderlying actually closes the underlying listener.
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func (fcl *fakeCloseListener) CloseUnderlying() error {
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return fcl.Listener.Close()
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}
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// ErrSwappingServers is returned by fakeCloseListener when
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// Close() is called, indicating that it is pretending to
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// be closed so that the server using it can terminate.
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var ErrSwappingServers = fmt.Errorf("listener 'closed' 😉")
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var (
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listeners = make(map[string]net.Listener)
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listenersMu sync.Mutex
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)
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