added watch support for plugins

backends/plugin/plugin.go

@@ -17,9 +17,7 @@ import (
 
 	"github.com/HeavyHorst/easyKV"
 	berr "github.com/HeavyHorst/remco/backends/error"
-	"github.com/HeavyHorst/remco/log"
 	"github.com/HeavyHorst/remco/template"
-	"github.com/Sirupsen/logrus"
 	"github.com/natefinch/pie"
 )
 
@@ -48,13 +46,6 @@ func (p *Plugin) Connect() (template.Backend, error) {
 		return p.Backend, err
 	}
 
-	if p.Backend.Watch {
-		log.WithFields(logrus.Fields{
-			"backend": p.Backend.Name,
-		}).Warn("Watch is not supported, using interval instead")
-		p.Backend.Watch = false
-	}
-
 	plugin := &plug{client}
 	if err := plugin.Init(p.Config); err != nil {
 		return p.Backend, err
@@ -83,7 +74,32 @@ func (p *plug) Close() {
 	p.client.Close()
 }
 
+type WatchConfig struct {
+	Prefix string
+	Opts   easyKV.WatchOptions
+}
+
 // WatchPrefix is not supported for now
 func (p *plug) WatchPrefix(prefix string, ctx context.Context, opts ...easyKV.WatchOption) (uint64, error) {
-	return 0, easyKV.ErrWatchNotSupported
+	var result uint64
+
+	wc := WatchConfig{Prefix: prefix}
+	for _, option := range opts {
+		option(&wc.Opts)
+	}
+
+	errchan := make(chan error)
+	go func() {
+		select {
+		case errchan <- p.client.Call("Plugin.WatchPrefix", wc, &result):
+		case <-ctx.Done():
+		}
+	}()
+
+	select {
+	case <-ctx.Done():
+		return wc.Opts.WaitIndex, nil
+	case err := <-errchan:
+		return result, err
+	}
 }

docs/content/plugins/index.md

@@ -12,11 +12,13 @@ just compile it and move the executable to /etc/remco/plugins.
 package main
 
 import (
+	"context"
 	"log"
 	"net/rpc/jsonrpc"
 
 	"github.com/HeavyHorst/easyKV"
 	"github.com/HeavyHorst/easyKV/env"
+	"github.com/HeavyHorst/remco/backends/plugin"
 	"github.com/natefinch/pie"
 )
 
@@ -55,6 +57,12 @@ func (e *EnvRPCServer) Close(args interface{}, resp *interface{}) error {
 	e.Impl.Close()
 	return nil
 }
+
+func (e EnvRPCServer) WatchPrefix(args plugin.WatchConfig, resp *uint64) error {
+	var err error
+	*resp, err = e.Impl.WatchPrefix(args.Prefix, context.Background(), easyKV.WithKeys(args.Opts.Keys), easyKV.WithWaitIndex(args.Opts.WaitIndex))
+	return err
+}
 ```
 
 Then create a config file with this backend section.