Refactor proposer

Former-commit-id: 2c934014a8624f84a33850a748dc41227f6a64e8 [formerly eebbc1a6350e0895f770c89efee80204cfd63fba]
Former-commit-id: 74dca03e825ee2a5af2f8e4bce21c8ae0cae70ee

cmd/geth/shardingcmd.go

@@ -2,7 +2,7 @@ package main
 
 import (
 	"github.com/ethereum/go-ethereum/sharding/collator"
-	//"github.com/ethereum/go-ethereum/sharding/proposer"
+	"github.com/ethereum/go-ethereum/sharding/proposer"
 
 	"github.com/ethereum/go-ethereum/cmd/utils"
 	cli "gopkg.in/urfave/cli.v1"
@@ -41,11 +41,6 @@ func collatorClient(ctx *cli.Context) error {
 }
 
 func proposerClient(ctx *cli.Context) error {
-	/*p := proposer.NewProposerClient(ctx)
-	if err := proposer.ProposerStart(p); err != nil {
-		return err
-	}
-	p.Wait()
-	*/
-	return nil
+	p := proposer.NewProposer(ctx)
+	return p.Start()
 }

sharding/proposer/proposer_client.go

@@ -1,21 +1,34 @@
 package proposer
 
 import (
-	"github.com/ethereum/go-ethereum/sharding/client"
 	"github.com/ethereum/go-ethereum/log"
+	"github.com/ethereum/go-ethereum/sharding/client"
 	cli "gopkg.in/urfave/cli.v1"
 )
 
-func NewProposerClient(ctx *cli.Context) *client.ShardingClient {
-	c := client.MakeClient(ctx)
-	return c
-
+type Proposer interface {
+	Start() error
 }
 
-func ProposerStart(sclient *client.ShardingClient) error {
+type proposer struct {
+	client client.Client
+}
+
+func NewProposer(ctx *cli.Context) Proposer {
+	return &proposer{
+		client: client.NewClient(ctx),
+	}
+}
+
+func (p *proposer) Start() error {
 	log.Info("Starting proposer client")
-	sclient.Start()
+	err := p.client.Start()
+	if err != nil {
+		return err
+	}
+	defer p.client.Close()
+
+	// TODO: Propose collations
 
 	return nil
-
 }