62 lines
1.6 KiB
Go
62 lines
1.6 KiB
Go
![]() |
/*
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Package to allow go applications to immediately start
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listening on a socket, unix, tcp, udp but hold connections
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until the application has booted and is ready to accept them
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*/
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package socketactivation
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import (
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"fmt"
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"net"
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"time"
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)
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// NewActivationListener returns a listener listening on addr with the protocol. It sets the
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// timeout to wait on first connection before an error is returned
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func NewActivationListener(proto, addr string, activate chan struct{}, timeout time.Duration) (net.Listener, error) {
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wrapped, 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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return &defaultListener{
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wrapped: wrapped,
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activate: activate,
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timeout: timeout,
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}, nil
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}
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type defaultListener struct {
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wrapped net.Listener // the real listener to wrap
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ready bool // is the listner ready to start accpeting connections
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activate chan struct{}
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timeout time.Duration // how long to wait before we consider this an error
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}
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func (l *defaultListener) Close() error {
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return l.wrapped.Close()
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}
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func (l *defaultListener) Addr() net.Addr {
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return l.wrapped.Addr()
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}
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func (l *defaultListener) Accept() (net.Conn, error) {
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// if the listen has been told it is ready then we can go ahead and
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// start returning connections
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if l.ready {
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return l.wrapped.Accept()
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}
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select {
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case <-time.After(l.timeout):
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// close the connection so any clients are disconnected
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l.Close()
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return nil, fmt.Errorf("timeout (%s) reached waiting for listener to become ready", l.timeout.String())
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case <-l.activate:
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l.ready = true
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return l.Accept()
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}
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panic("unreachable")
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}
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