package plugins import ( "flag" "fmt" "io/ioutil" "path" "plugin" "reflect" "strings" "github.com/ethereum/go-ethereum/event" "github.com/ethereum/go-ethereum/log" "github.com/openrelayxyz/plugeth-utils/core" "github.com/urfave/cli/v2" ) type Subcommand func(core.Context, []string) error type pluginDetails struct { p *plugin.Plugin name string } type PluginLoader struct { Plugins []pluginDetails Subcommands map[string]Subcommand Flags []*flag.FlagSet LookupCache map[string][]interface{} } func (pl *PluginLoader) Lookup(name string, validate func(interface{}) bool) []interface{} { if v, ok := pl.LookupCache[name]; ok { return v } results := []interface{}{} for _, plugin := range pl.Plugins { if v, err := plugin.p.Lookup(name); err == nil { if validate(v) { results = append(results, v) } else { log.Warn("Plugin matches hook but not signature", "plugin", plugin.name, "hook", name) } } } pl.LookupCache[name] = results return results } func Lookup(name string, validate func(interface{}) bool) []interface{} { if DefaultPluginLoader == nil { log.Warn("Lookup attempted, but PluginLoader is not initialized", "name", name) return []interface{}{} } return DefaultPluginLoader.Lookup(name, validate) } var DefaultPluginLoader *PluginLoader func NewPluginLoader(target string) (*PluginLoader, error) { log.Info("Loading plugins from directory", "path", target) pl := &PluginLoader{ Plugins: []pluginDetails{}, Subcommands: make(map[string]Subcommand), Flags: []*flag.FlagSet{}, LookupCache: make(map[string][]interface{}), } files, err := ioutil.ReadDir(target) if err != nil { log.Warn("Could not load plugins directory. Skipping.", "path", target) return pl, nil } for _, file := range files { fpath := path.Join(target, file.Name()) if !strings.HasSuffix(file.Name(), ".so") { log.Debug("File in plugin directory is not '.so' file. Skipping.", "file", fpath) continue } plug, err := plugin.Open(fpath) if err != nil { log.Warn("File in plugin directory could not be loaded", "file", fpath, "error", err) continue } // Any type of plugin can potentially specify flags f, err := plug.Lookup("Flags") if err == nil { flagset, ok := f.(*flag.FlagSet) if !ok { log.Warn("Found plugin.Flags, but it its not a *FlagSet", "file", fpath) } else { pl.Flags = append(pl.Flags, flagset) } } sb, err := plug.Lookup("Subcommands") if err == nil { subcommands, ok := sb.(*map[string]func(core.Context, []string) error) if !ok { log.Warn("Could not cast plugin.Subcommands to `map[string]func(core.Context, []string) error`", "file", fpath, "type", reflect.TypeOf(sb)) } else { for k, v := range *subcommands { if _, ok := pl.Subcommands[k]; ok { log.Warn("Subcommand redeclared", "file", fpath, "subcommand", k) } pl.Subcommands[k] = v } } } pl.Plugins = append(pl.Plugins, pluginDetails{plug, fpath}) } return pl, nil } func Initialize(target string, ctx core.Context) (err error) { DefaultPluginLoader, err = NewPluginLoader(target) if err != nil { return err } DefaultPluginLoader.Initialize(ctx) return nil } func (pl *PluginLoader) Initialize(ctx core.Context) { fns := pl.Lookup("Initialize", func(i interface{}) bool { _, ok := i.(func(core.Context, core.PluginLoader, core.Logger)) return ok }) for _, fni := range fns { if fn, ok := fni.(func(core.Context, core.PluginLoader, core.Logger)); ok { fn(ctx, pl, log.Root()) } } } func (pl *PluginLoader) RunSubcommand(ctx *cli.Context) (bool, error) { args := ctx.Args().Slice() if len(args) == 0 { return false, fmt.Errorf("no subcommand arguments") } subcommand, ok := pl.Subcommands[args[0]] if !ok { return false, fmt.Errorf("Subcommand %v does not exist", args[0]) } return true, subcommand(ctx, args[1:]) } func RunSubcommand(ctx *cli.Context) (bool, error) { if DefaultPluginLoader == nil { return false, fmt.Errorf("Plugin loader not initialized") } return DefaultPluginLoader.RunSubcommand(ctx) } func (pl *PluginLoader) ParseFlags(args []string) bool { for _, flagset := range pl.Flags { flagset.Parse(args) } return len(pl.Flags) > 0 } func ParseFlags(args []string) bool { if DefaultPluginLoader == nil { log.Warn("Attempting to parse flags, but default PluginLoader has not been initialized") return false } return DefaultPluginLoader.ParseFlags(args) } type feedWrapper struct { feed *event.Feed } func (f *feedWrapper) Send(item interface{}) int { return f.feed.Send(item) } func (f *feedWrapper) Subscribe(ch interface{}) core.Subscription { return f.feed.Subscribe(ch) } func (pl *PluginLoader) GetFeed() core.Feed { return &feedWrapper{&event.Feed{}} }