vendor/github.com/hashicorp/go-plugin/examples/bidirectional/main.go

   1 package main
   2
   3 import (
   4         "fmt"
   5         "io/ioutil"
   6         "log"
   7         "os"
   8         "os/exec"
   9         "strconv"
  10
  11         "github.com/hashicorp/go-plugin"
  12         "github.com/hashicorp/go-plugin/examples/bidirectional/shared"
  13 )
  14
  15 type addHelper struct{}
  16
  17 func (*addHelper) Sum(a, b int64) (int64, error) {
  18         return a + b, nil
  19 }
  20
  21 func main() {
  22         // We don't want to see the plugin logs.
  23         log.SetOutput(ioutil.Discard)
  24
  25         // We're a host. Start by launching the plugin process.
  26         client := plugin.NewClient(&plugin.ClientConfig{
  27                 HandshakeConfig: shared.Handshake,
  28                 Plugins:         shared.PluginMap,
  29                 Cmd:             exec.Command("sh", "-c", os.Getenv("COUNTER_PLUGIN")),
  30                 AllowedProtocols: []plugin.Protocol{
  31                         plugin.ProtocolNetRPC, plugin.ProtocolGRPC},
  32         })
  33         defer client.Kill()
  34
  35         // Connect via RPC
  36         rpcClient, err := client.Client()
  37         if err != nil {
  38                 fmt.Println("Error:", err.Error())
  39                 os.Exit(1)
  40         }
  41
  42         // Request the plugin
  43         raw, err := rpcClient.Dispense("counter")
  44         if err != nil {
  45                 fmt.Println("Error:", err.Error())
  46                 os.Exit(1)
  47         }
  48
  49         // We should have a Counter store now! This feels like a normal interface
  50         // implementation but is in fact over an RPC connection.
  51         counter := raw.(shared.Counter)
  52
  53         os.Args = os.Args[1:]
  54         switch os.Args[0] {
  55         case "get":
  56                 result, err := counter.Get(os.Args[1])
  57                 if err != nil {
  58                         fmt.Println("Error:", err.Error())
  59                         os.Exit(1)
  60                 }
  61
  62                 fmt.Println(result)
  63
  64         case "put":
  65                 i, err := strconv.Atoi(os.Args[2])
  66                 if err != nil {
  67                         fmt.Println("Error:", err.Error())
  68                         os.Exit(1)
  69                 }
  70
  71                 err = counter.Put(os.Args[1], int64(i), &addHelper{})
  72                 if err != nil {
  73                         fmt.Println("Error:", err.Error())
  74                         os.Exit(1)
  75                 }
  76
  77         default:
  78                 fmt.Println("Please only use 'get' or 'put'")
  79                 os.Exit(1)
  80         }
  81 }