153 lines
4.1 KiB
Go
153 lines
4.1 KiB
Go
package plugins
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import (
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"plugin"
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"github.com/ethereum/go-ethereum/log"
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"gopkg.in/urfave/cli.v1"
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"flag"
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"io/ioutil"
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"strings"
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"path"
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"fmt"
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"reflect"
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)
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type Subcommand func(*cli.Context, []string) error
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type PluginLoader struct{
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Plugins []*plugin.Plugin
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Subcommands map[string]Subcommand
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Flags []*flag.FlagSet
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LookupCache map[string][]interface{}
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}
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func (pl *PluginLoader) Lookup(name string, validate func(interface{}) bool) []interface{} {
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if v, ok := pl.LookupCache[name]; ok { return v }
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results := []interface{}{}
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for _, plugin := range pl.Plugins {
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if v, err := plugin.Lookup(name); err == nil {
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if validate(v) {
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results = append(results, v)
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}
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}
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}
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pl.LookupCache[name] = results
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return results
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}
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func Lookup(name string, validate func(interface{}) bool) []interface{} {
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if DefaultPluginLoader == nil {
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log.Warn("Lookup attempted, but PluginLoader is not initialized", "name", name)
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return []interface{}{}
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}
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return DefaultPluginLoader.Lookup(name, validate)
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}
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var DefaultPluginLoader *PluginLoader
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func NewPluginLoader(target string) (*PluginLoader, error) {
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pl := &PluginLoader{
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Plugins: []*plugin.Plugin{},
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// RPCPlugins: []APILoader{},
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Subcommands: make(map[string]Subcommand),
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Flags: []*flag.FlagSet{},
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LookupCache: make(map[string][]interface{}),
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// CreateConsensusEngine: ethconfig.CreateConsensusEngine,
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// UpdateBlockchainVMConfig: func(cfg *vm.Config) {},
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}
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files, err := ioutil.ReadDir(target)
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if err != nil {
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log.Warn("Could not load plugins directory. Skipping.", "path", target)
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return pl, nil
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}
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for _, file := range files {
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fpath := path.Join(target, file.Name())
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if !strings.HasSuffix(file.Name(), ".so") {
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log.Debug("File inplugin directory is not '.so' file. Skipping.", "file", fpath)
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continue
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}
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plug, err := plugin.Open(fpath)
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if err != nil {
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log.Warn("File in plugin directory could not be loaded: %v", "file", fpath, "error", err.Error())
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continue
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}
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// Any type of plugin can potentially specify flags
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f, err := plug.Lookup("Flags")
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if err == nil {
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flagset, ok := f.(*flag.FlagSet)
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if !ok {
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log.Warn("Found plugin.Flags, but it its not a *FlagSet", "file", fpath)
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} else {
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pl.Flags = append(pl.Flags, flagset)
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}
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}
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sb, err := plug.Lookup("Subcommands")
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if err == nil {
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subcommands, ok := sb.(*map[string]func(*cli.Context, []string) error)
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if !ok {
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log.Warn("Could not cast plugin.Subcommands to `map[string]func(*cli.Context, []string) error`", "file", fpath, "type", reflect.TypeOf(sb))
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} else {
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for k, v := range *subcommands {
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if _, ok := pl.Subcommands[k]; ok {
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log.Warn("Subcommand redeclared", "file", fpath, "subcommand", k)
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}
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pl.Subcommands[k] = v
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}
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}
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}
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pl.Plugins = append(pl.Plugins, plug)
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}
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return pl, nil
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}
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func Initialize(target string, ctx *cli.Context) (err error) {
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DefaultPluginLoader, err = NewPluginLoader(target)
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if err != nil { return err }
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DefaultPluginLoader.Initialize(ctx)
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return nil
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}
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func (pl *PluginLoader) Initialize(ctx *cli.Context) {
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fns := pl.Lookup("Initialize", func(i interface{}) bool {
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_, ok := i.(func(*cli.Context) error)
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return ok
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})
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for _, fni := range fns {
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if fn, ok := fni.(func(*cli.Context)); ok {
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fn(ctx)
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}
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}
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}
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func (pl *PluginLoader) RunSubcommand(ctx *cli.Context) (bool, error) {
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args := ctx.Args()
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if len(args) == 0 { return false, fmt.Errorf("No subcommand arguments")}
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subcommand, ok := pl.Subcommands[args[0]]
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if !ok { return false, fmt.Errorf("Subcommand %v does not exist", args[0])}
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return true, subcommand(ctx, args[1:])
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}
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func RunSubcommand(ctx *cli.Context) (bool, error) {
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if DefaultPluginLoader == nil { return false, fmt.Errorf("Plugin loader not initialized") }
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return DefaultPluginLoader.RunSubcommand(ctx)
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}
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func (pl *PluginLoader) ParseFlags(args []string) bool {
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for _, flagset := range pl.Flags {
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flagset.Parse(args)
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}
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return len(pl.Flags) > 0
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}
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func ParseFlags(args []string) bool {
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if DefaultPluginLoader == nil {
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log.Warn("Attempting to parse flags, but default PluginLoader has not been initialized")
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return false
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}
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return DefaultPluginLoader.ParseFlags(args)
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}
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