feat: plugin support (#71)

* example plugin

* plugins

* simplify

* simplify

* use `*cobra.Command` instead of a func

cmd/spawn/main.go

@@ -2,15 +2,19 @@ package main
 
 import (
 	"fmt"
+	"io/fs"
 	"log"
 	"log/slog"
 	"os"
+	"path"
+	"plugin"
 	"strings"
 	"time"
 
 	"github.com/lmittmann/tint"
 	"github.com/mattn/go-isatty"
 	"github.com/spf13/cobra"
+	"gitub.com/strangelove-ventures/spawn/plugins"
 )
 
 // Set in the makefile ld_flags on compile
@@ -19,11 +23,14 @@ var SpawnVersion = ""
 var LogLevelFlag = "log-level"
 
 func main() {
+
 	rootCmd.AddCommand(newChain)
 	rootCmd.AddCommand(LocalICCmd)
 	rootCmd.AddCommand(versionCmd)
 	rootCmd.AddCommand(ModuleCmd())
 
+	applyPluginCmds()
+
 	rootCmd.PersistentFlags().String(LogLevelFlag, "info", "log level (debug, info, warn, error)")
 
 	if err := rootCmd.Execute(); err != nil {
@@ -50,6 +57,83 @@ func GetLogger() *slog.Logger {
 	return slog.Default()
 }
 
+func applyPluginCmds() {
+	plugins := &cobra.Command{
+		Use:   "plugins",
+		Short: "Manage plugins",
+		Run: func(cmd *cobra.Command, args []string) {
+			if err := cmd.Help(); err != nil {
+				log.Fatal(err)
+			}
+		},
+	}
+
+	for _, plugin := range loadPlugins() {
+		plugins.AddCommand(plugin.Cmd())
+	}
+
+	rootCmd.AddCommand(plugins)
+}
+
+func loadPlugins() map[string]*plugins.SpawnPluginBase {
+	p := make(map[string]*plugins.SpawnPluginBase)
+
+	homeDir, err := os.UserHomeDir()
+	if err != nil {
+		panic(err)
+	}
+
+	pluginsDir := path.Join(homeDir, ".spawn", "plugins")
+
+	d := os.DirFS(pluginsDir)
+	if _, err := d.Open("."); err != nil {
+		if os.IsNotExist(err) {
+			if err := os.MkdirAll(pluginsDir, 0755); err != nil {
+				panic(err)
+			}
+		} else {
+			panic(err)
+		}
+	}
+
+	err = fs.WalkDir(d, ".", func(relPath string, d fs.DirEntry, e error) error {
+		if d.IsDir() {
+			return nil
+		}
+
+		if !strings.Contains(relPath, ".so") {
+			return nil
+		}
+
+		absPath := path.Join(pluginsDir, relPath)
+
+		// read the absolute path
+		plug, err := plugin.Open(absPath)
+		if err != nil {
+			return fmt.Errorf("error opening plugin %s: %w", absPath, err)
+		}
+
+		base, err := plug.Lookup("Plugin")
+		if err != nil {
+			return fmt.Errorf("error looking up symbol: %w", err)
+		}
+
+		pluginInstance, ok := base.(plugins.SpawnPlugin)
+		if !ok {
+			log.Fatal("Symbol 'Plugin' does not implement the SpawnPlugin interface")
+		}
+
+		p[relPath] = plugins.NewSpawnPluginBase(pluginInstance.Cmd())
+
+		return nil
+	})
+	if err != nil {
+		panic(err)
+	}
+
+	return p
+}
+
 var rootCmd = &cobra.Command{
 	Use:   "spawn",
 	Short: "Entry into the Interchain",

plugins/example/build.sh

@@ -0,0 +1,4 @@
+EXPORT_LOC=$HOME/.spawn/plugins
+mkdir -p $EXPORT_LOC
+
+go build -buildmode=plugin -o $EXPORT_LOC/example.so plugins/example/example-plugin.go

plugins/example/example-plugin.go

@@ -0,0 +1,61 @@
+package main
+
+import (
+	"log"
+	"os"
+	"path"
+
+	"github.com/spf13/cobra"
+	plugins "gitub.com/strangelove-ventures/spawn/plugins"
+)
+
+// Make the plugin public
+var Plugin SpawnMainExamplePlugin
+
+var _ plugins.SpawnPlugin = &SpawnMainExamplePlugin{}
+
+const (
+	cmdName = "example"
+)
+
+type SpawnMainExamplePlugin struct {
+	Impl plugins.SpawnPluginBase
+}
+
+// Cmd implements plugins.SpawnPlugin.
+func (e *SpawnMainExamplePlugin) Cmd() *cobra.Command {
+	rootCmd := &cobra.Command{
+		Use:   cmdName,
+		Short: cmdName + " plugin command",
+		Run: func(cmd *cobra.Command, args []string) {
+			if err := cmd.Help(); err != nil {
+				log.Fatal(err)
+			}
+		},
+	}
+
+	rootCmd.AddCommand(&cobra.Command{
+		Use:   "touch-file [name]",
+		Short: "An example plugin sub command",
+		Args:  cobra.ExactArgs(1),
+		Run: func(cmd *cobra.Command, args []string) {
+			cwd, err := os.Getwd()
+			if err != nil {
+				log.Fatal(err)
+			}
+
+			fileName := args[0]
+
+			filePath := path.Join(cwd, fileName)
+			file, err := os.Create(filePath)
+			if err != nil {
+				log.Fatal(err)
+			}
+			defer file.Close()
+
+			cmd.Printf("Created file: %s\n", filePath)
+		},
+	})
+
+	return rootCmd
+}

plugins/plugin.go

@@ -0,0 +1,25 @@
+package plugins
+
+import "github.com/spf13/cobra"
+
+// SpawnPlugin is the interface that we're exposing as a plugin.
+type SpawnPlugin interface {
+	Cmd() *cobra.Command
+}
+
+var _ SpawnPlugin = &SpawnPluginBase{}
+
+type SpawnPluginBase struct {
+	cmd *cobra.Command
+}
+
+func NewSpawnPluginBase(cmd *cobra.Command) *SpawnPluginBase {
+	return &SpawnPluginBase{
+		cmd: cmd,
+	}
+}
+
+// Cmd implements SpawnPlugin.
+func (s *SpawnPluginBase) Cmd() *cobra.Command {
+	return s.cmd
+}