forked from luraproject/lura
/
plugin.go
112 lines (96 loc) · 2.4 KB
/
plugin.go
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package plugin
import (
"context"
"fmt"
"net/http"
"plugin"
"strings"
krakendplugin "github.com/devopsfaith/krakend/plugin"
"github.com/devopsfaith/krakend/register"
)
var clientRegister = register.New()
func RegisterClient(
name string,
handler func(context.Context, map[string]interface{}) (http.Handler, error),
) {
clientRegister.Register(Namespace, name, handler)
}
type Registerer interface {
RegisterClients(func(
name string,
handler func(context.Context, map[string]interface{}) (http.Handler, error),
))
}
type RegisterClientFunc func(
name string,
handler func(context.Context, map[string]interface{}) (http.Handler, error),
)
func Load(path, pattern string, rcf RegisterClientFunc) (int, error) {
plugins, err := krakendplugin.Scan(path, pattern)
if err != nil {
return 0, err
}
return load(plugins, rcf)
}
func load(plugins []string, rcf RegisterClientFunc) (int, error) {
errors := []error{}
loadedPlugins := 0
for k, pluginName := range plugins {
if err := open(pluginName, rcf); err != nil {
errors = append(errors, fmt.Errorf("opening plugin %d (%s): %s", k, pluginName, err.Error()))
continue
}
loadedPlugins++
}
if len(errors) > 0 {
return loadedPlugins, loaderError{errors}
}
return loadedPlugins, nil
}
func open(pluginName string, rcf RegisterClientFunc) (err error) {
defer func() {
if r := recover(); r != nil {
var ok bool
err, ok = r.(error)
if !ok {
err = fmt.Errorf("%v", r)
}
}
}()
var p Plugin
p, err = pluginOpener(pluginName)
if err != nil {
return
}
var r interface{}
r, err = p.Lookup("ClientRegisterer")
if err != nil {
return
}
registerer, ok := r.(Registerer)
if !ok {
return fmt.Errorf("http-request-executor plugin loader: unknown type")
}
registerer.RegisterClients(rcf)
return
}
// Plugin is the interface of the loaded plugins
type Plugin interface {
Lookup(name string) (plugin.Symbol, error)
}
// pluginOpener keeps the plugin open function in a var for easy testing
var pluginOpener = defaultPluginOpener
func defaultPluginOpener(name string) (Plugin, error) {
return plugin.Open(name)
}
type loaderError struct {
errors []error
}
// Error implements the error interface
func (l loaderError) Error() string {
msgs := make([]string, len(l.errors))
for i, err := range l.errors {
msgs[i] = err.Error()
}
return fmt.Sprintf("plugin loader found %d error(s): \n%s", len(msgs), strings.Join(msgs, "\n"))
}