added basic plugin structure

pkg/register/plugin_register.go

@@ -0,0 +1,147 @@
+package register
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"os"
+	"os/exec"
+
+	"github.com/hashicorp/go-hclog"
+	"github.com/hashicorp/go-plugin"
+	"golang.org/x/sync/errgroup"
+)
+
+type PluginRegisterBuilder struct {
+	plugins map[string]PluginAPI
+}
+
+func NewPluginRegisterBuilder() *PluginRegisterBuilder {
+	return &PluginRegisterBuilder{}
+}
+
+func (pr *PluginRegisterBuilder) Add(name, path string) *PluginRegisterBuilder {
+	pr.plugins[name] = PluginAPI{}
+
+	return pr
+}
+
+func (pr *PluginRegisterBuilder) Build(ctx context.Context) (*PluginRegister, error) {
+	clients := make(map[string]*pluginClientWrapper, 0)
+	errgroup, _ := errgroup.WithContext(ctx)
+
+	for name, p := range pr.plugins {
+		name, p := name, p
+
+		errgroup.Go(func() error {
+			client := plugin.NewClient(&plugin.ClientConfig{
+				HandshakeConfig: plugin.HandshakeConfig{
+					ProtocolVersion:  1,
+					MagicCookieKey:   "BASIC_PLUGIN",
+					MagicCookieValue: "char",
+				},
+				Logger: hclog.New(&hclog.LoggerOptions{
+					Name:   "char",
+					Output: os.Stdout,
+					Level:  hclog.Debug,
+				}),
+				Cmd: exec.Command("sh", "-c", fmt.Sprintf(
+					"(cd ./.char/plugins/%s; go run plugins/%s/main.go)",
+					name,
+					name,
+				)),
+				Plugins: map[string]plugin.Plugin{
+					name: &p,
+				},
+			})
+
+			rpcClient, err := client.Client()
+			if err != nil {
+				return err
+			}
+
+			raw, err := rpcClient.Dispense(name)
+			if err != nil {
+				return err
+			}
+
+			pluginApi, ok := raw.(Plugin)
+			if !ok {
+				return errors.New("could not cast as plugin")
+			}
+
+			clients[name] = &pluginClientWrapper{
+				plugin: pluginApi,
+				client: client,
+			}
+
+			return nil
+		})
+	}
+
+	err := errgroup.Wait()
+	if err != nil {
+		return nil, err
+	}
+
+	return &PluginRegister{
+		clients: clients,
+	}, nil
+}
+
+// ---
+
+type pluginClientWrapper struct {
+	plugin Plugin
+	client *plugin.Client
+}
+
+func (pcw *pluginClientWrapper) Close() {
+	pcw.client.Kill()
+}
+
+// ---
+
+type PluginRegister struct {
+	clients map[string]*pluginClientWrapper
+}
+
+func (pr *PluginRegister) Close() error {
+	errgroup, _ := errgroup.WithContext(context.Background())
+
+	for _, c := range pr.clients {
+		c := c
+
+		errgroup.Go(func() error {
+			c.Close()
+			return nil
+		})
+	}
+
+	if err := errgroup.Wait(); err != nil {
+		return err
+	}
+	return nil
+}
+
+func (pr *PluginRegister) About(ctx context.Context) (map[string]string, error) {
+	list := make(map[string]string, len(pr.clients))
+
+	errgroup, ctx := errgroup.WithContext(ctx)
+
+	for n, c := range pr.clients {
+		n, c := n, c
+		errgroup.Go(func() error {
+			about := c.plugin.About()
+
+			list[n] = about
+			return nil
+		})
+	}
+
+	if err := errgroup.Wait(); err != nil {
+		return nil, err
+	}
+
+	return list, nil
+}