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package main
import (
"fmt"
"io/ioutil"
"log"
"os"
"os/exec"
"github.com/hashicorp/go-plugin"
"github.com/hashicorp/go-plugin/examples/grpc/shared"
)
func main() {
// We don't want to see the plugin logs.
log.SetOutput(ioutil.Discard)
plugins := map[int]plugin.PluginSet{}
// Both version can be supported, but switch the implementation to
// demonstrate version negoation.
switch os.Getenv("KV_PROTO") {
case "netrpc":
plugins[2] = plugin.PluginSet{
"kv": &shared.KVPlugin{},
}
case "grpc":
plugins[3] = plugin.PluginSet{
"kv": &shared.KVGRPCPlugin{},
}
default:
fmt.Println("must set KV_PROTO to netrpc or grpc")
os.Exit(1)
}
// We're a host. Start by launching the plugin process.
client := plugin.NewClient(&plugin.ClientConfig{
HandshakeConfig: shared.Handshake,
VersionedPlugins: plugins,
Cmd: exec.Command("./kv-plugin"),
AllowedProtocols: []plugin.Protocol{
plugin.ProtocolNetRPC, plugin.ProtocolGRPC},
})
defer client.Kill()
rpcClient, err := client.Client()
if err != nil {
fmt.Println("Error:", err.Error())
os.Exit(1)
}
// Request the plugin
raw, err := rpcClient.Dispense("kv")
if err != nil {
fmt.Println("Error:", err.Error())
os.Exit(1)
}
// We should have a KV store now! This feels like a normal interface
// implementation but is in fact over an RPC connection.
kv := raw.(shared.KV)
os.Args = os.Args[1:]
switch os.Args[0] {
case "get":
result, err := kv.Get(os.Args[1])
if err != nil {
fmt.Println("Error:", err.Error())
os.Exit(1)
}
fmt.Println(string(result))
case "put":
err := kv.Put(os.Args[1], []byte(os.Args[2]))
if err != nil {
fmt.Println("Error:", err.Error())
os.Exit(1)
}
default:
fmt.Println("Please only use 'get' or 'put'")
os.Exit(1)
}
}
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