79 lines
2.9 KiB
Go
79 lines
2.9 KiB
Go
// Licensed to Pulumi Corporation ("Pulumi") under one or more
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// contributor license agreements. See the NOTICE file distributed with
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// this work for additional information regarding copyright ownership.
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// Pulumi licenses this file to You under the Apache License, Version 2.0
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// (the "License"); you may not use this file except in compliance with
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// the License. You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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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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package rpcutil
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import (
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"net"
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"os"
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"os/signal"
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"strconv"
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"syscall"
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"github.com/pkg/errors"
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"google.golang.org/grpc"
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"google.golang.org/grpc/reflection"
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)
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// Serve creates a new gRPC server, calls out to the supplied registration functions to bind interfaces, and then
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// listens on the supplied TCP port. If the caller wishes for the kernel to choose a free port automatically, pass 0 as
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// the port number. The return values are: the chosen port (the same as supplied if non-0), a channel that may
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// eventually return an error, and an error, in case something went wrong. The channel is non-nil and waits until
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// the server is finished, in the case of a successful launch of the RPC server.
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func Serve(port int, registers []func(*grpc.Server) error) (int, chan error, error) {
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// Listen on a TCP port, but let the kernel choose a free port for us.
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lis, err := net.Listen("tcp", ":"+strconv.Itoa(port))
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if err != nil {
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return port, nil, errors.Errorf("failed to listen on TCP port ':%v': %v", port, err)
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}
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// Now new up a gRPC server and register any RPC interfaces the caller wants.
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srv := grpc.NewServer()
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for _, register := range registers {
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if err := register(srv); err != nil {
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return port, nil, errors.Errorf("failed to register RPC handler: %v", err)
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}
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}
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reflection.Register(srv) // enable reflection.
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// If the port was 0, look up what port the kernel chosen, by accessing the underlying TCP listener/address.
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if port == 0 {
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tcpl := lis.(*net.TCPListener)
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tcpa := tcpl.Addr().(*net.TCPAddr)
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port = tcpa.Port
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}
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// Now register some signals to gracefully terminate the program upon request.
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sigs := make(chan os.Signal, 1)
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signal.Notify(sigs, syscall.SIGINT, syscall.SIGQUIT, syscall.SIGTERM)
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go func() {
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<-sigs
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srv.Stop()
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}()
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// Finally, serve; this returns only once the server shuts down (e.g., due to a signal).
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done := make(chan error)
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go func() {
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if err := srv.Serve(lis); err != nil {
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done <- errors.Errorf("stopped serving: %v", err)
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} else {
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done <- nil // send a signal so caller knows we're done, even though it's nil.
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}
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close(done)
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}()
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return port, done, nil
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}
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