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runner.go
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runner.go
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package bridge
import (
"fmt"
"net"
"os"
"time"
"code.cloudfoundry.org/lager"
"github.com/cloudfoundry-incubator/switchboard/domain"
)
type Runner struct {
logger lager.Logger
port uint
TrafficEnabledChan chan bool
ActiveBackendChan chan *domain.Backend
timeout time.Duration
}
func NewRunner(
port uint,
timeout time.Duration,
logger lager.Logger,
) Runner {
backendChan := make(chan *domain.Backend)
trafficEnabledChan := make(chan bool)
return Runner{
logger: logger,
ActiveBackendChan: backendChan,
TrafficEnabledChan: trafficEnabledChan,
port: port,
timeout: timeout,
}
}
func (r Runner) Run(signals <-chan os.Signal, ready chan<- struct{}) error {
r.logger.Info(fmt.Sprintf("Proxy listening on port %d", r.port))
listener, err := net.Listen("tcp", fmt.Sprintf("0.0.0.0:%d", r.port))
if err != nil {
return err
}
shutdown := make(chan interface{})
go func(shutdown <-chan interface{}, listener net.Listener) {
trafficEnabled := true
var activeBackend *domain.Backend
e := make(chan error)
c := make(chan net.Conn)
for {
go blockingAccept(listener, c, e)
select {
case <-shutdown:
return
case t := <-r.TrafficEnabledChan:
// ENABLED -> DISABLED
if trafficEnabled && !t {
if activeBackend != nil {
activeBackend.SeverConnections()
}
}
trafficEnabled = t
case a := <-r.ActiveBackendChan:
// NEW ACTIVE BACKEND
if activeBackend != nil {
activeBackend.SeverConnections()
}
activeBackend = a
if a != nil {
r.logger.Info("Done severing connections, new active backend:", lager.Data{"backend": a.AsJSON()})
} else {
r.logger.Info("Done severing connections, new active backend:", lager.Data{"backend": nil})
}
case clientConn := <-c:
if !trafficEnabled {
clientConn.Close()
continue
}
go func(clientConn net.Conn, activeBackend *domain.Backend) {
if activeBackend == nil {
clientConn.Close()
r.logger.Error("No active backend", err)
return
}
err := activeBackend.Bridge(clientConn)
if err != nil {
clientConn.Close()
r.logger.Error("Error routing to backend", err)
}
}(clientConn, activeBackend)
case err := <-e:
if err != nil {
r.logger.Error("Error accepting client connection", err)
continue
}
}
}
}(shutdown, listener)
close(ready)
signal := <-signals
r.logger.Info("Received signal", lager.Data{"signal": signal})
time.Sleep(r.timeout)
close(shutdown)
listener.Close()
r.logger.Info("Proxy runner has exited")
return nil
}
func blockingAccept(l net.Listener, c chan<- net.Conn, e chan<- error) {
clientConn, err := l.Accept()
if err != nil {
e <- err
return
}
c <- clientConn
}