76 lines
1.4 KiB
Go
76 lines
1.4 KiB
Go
package main
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import (
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"fmt"
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"io"
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"net"
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"os"
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)
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// gRPC byte prefix (see RPCGRPC in agent/pool/conn.go).
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const bytePrefix byte = 8
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func main() {
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if len(os.Args) != 2 {
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log("usage: %s host:port", os.Args[0])
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os.Exit(1)
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}
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serverAddr := os.Args[1]
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lis, err := net.Listen("tcp", "127.0.0.1:0")
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if err != nil {
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log("failed to start listener: %v", err)
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os.Exit(1)
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}
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defer lis.Close()
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fmt.Println("Proxying connections to Consul's internal gRPC server")
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fmt.Printf("Use this address: %s\n", lis.Addr())
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for {
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conn, err := lis.Accept()
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if err != nil {
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log("failed to accept connection: %v", err)
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continue
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}
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go func(conn net.Conn) {
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if err := handleClient(serverAddr, conn); err != nil {
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log(err.Error())
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}
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}(conn)
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}
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}
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func handleClient(serverAddr string, clientConn net.Conn) error {
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defer clientConn.Close()
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serverConn, err := net.Dial("tcp", serverAddr)
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if err != nil {
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return fmt.Errorf("failed to dial server connection: %w", err)
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}
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defer serverConn.Close()
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if _, err := serverConn.Write([]byte{bytePrefix}); err != nil {
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return fmt.Errorf("failed to write byte prefix: %v", err)
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}
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errCh := make(chan error, 1)
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go func() {
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_, err := io.Copy(serverConn, clientConn)
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errCh <- err
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}()
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go func() {
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_, err := io.Copy(clientConn, serverConn)
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errCh <- err
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}()
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return <-errCh
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}
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func log(message string, args ...interface{}) {
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fmt.Fprintf(os.Stderr, message+"\n", args...)
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}
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