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

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