[FAB-1351] New chain config client for Kafka

https://jira.hyperledger.org/browse/FAB-1351

As things stand right now, the configuration transaction posted by the
broadcast_config sample client only works for solo. This is because the
genesis block for the Kafka orderer contains extra keys.

This changeset:

1. Introduces an extra flag that allows us to specify the consenter
type, and then, by using the provisional bootstrapper, it creates the
appropriate configuration transaction.

2. Refactors/simplifies the client to bring it more in line with the rest
of the sample_clients in the `orderer` package and make future
maintenance easier.

Change-Id: I61ce5dfb36a11ab58d41a65267768cf0948263dc
Signed-off-by: Kostas Christidis <kostas@christidis.io>

orderer/sample_clients/broadcast_config/client.go

@@ -0,0 +1,108 @@
+/*
+Copyright IBM Corp. 2016 All Rights Reserved.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+                 http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package main
+
+import (
+	"context"
+	"flag"
+	"fmt"
+
+	"google.golang.org/grpc"
+
+	"github.com/hyperledger/fabric/orderer/localconfig"
+	cb "github.com/hyperledger/fabric/protos/common"
+	ab "github.com/hyperledger/fabric/protos/orderer"
+)
+
+var conf *config.TopLevel
+
+type broadcastClient struct {
+	ab.AtomicBroadcast_BroadcastClient
+}
+
+func (bc *broadcastClient) broadcast(env *cb.Envelope) error {
+	var err error
+	var resp *ab.BroadcastResponse
+
+	err = bc.Send(env)
+	if err != nil {
+		return err
+	}
+
+	resp, err = bc.Recv()
+	if err != nil {
+		return err
+	}
+
+	fmt.Println("Status:", resp)
+	return nil
+}
+
+// cmdImpl holds the command and its arguments.
+type cmdImpl struct {
+	name string
+	args argsImpl
+}
+
+// argsImpl holds all the possible arguments for all possible commands.
+type argsImpl struct {
+	consensusType  string
+	creationPolicy string
+	chainID        string
+}
+
+func init() {
+	conf = config.Load()
+}
+
+func main() {
+	cmd := new(cmdImpl)
+	var srv string
+
+	flag.StringVar(&srv, "server", fmt.Sprintf("%s:%d", conf.General.ListenAddress, conf.General.ListenPort), "The RPC server to connect to.")
+	flag.StringVar(&cmd.name, "cmd", "newChain", "The action that this client is requesting via the config transaction.")
+	flag.StringVar(&cmd.args.consensusType, "consensusType", conf.General.OrdererType, "In case of a newChain command, the type of consensus the ordering service is running on.")
+	flag.StringVar(&cmd.args.creationPolicy, "creationPolicy", "AcceptAllPolicy", "In case of a newChain command, the chain creation policy this request should be validated against.")
+	flag.StringVar(&cmd.args.chainID, "chainID", "NewChainID", "In case of a newChain command, the chain ID to create.")
+	flag.Parse()
+
+	conn, err := grpc.Dial(srv, grpc.WithInsecure())
+	defer func() {
+		_ = conn.Close()
+	}()
+	if err != nil {
+		fmt.Println("Error connecting:", err)
+		return
+	}
+
+	client, err := ab.NewAtomicBroadcastClient(conn).Broadcast(context.TODO())
+	if err != nil {
+		fmt.Println("Error connecting:", err)
+		return
+	}
+
+	bc := &broadcastClient{client}
+
+	switch cmd.name {
+	case "newChain":
+		env := newChainRequest(cmd.args.consensusType, cmd.args.creationPolicy, cmd.args.chainID)
+		fmt.Println("Requesting the creation of chain", cmd.args.chainID)
+		fmt.Println(bc.broadcast(env))
+	default:
+		panic("Invalid command given")
+	}
+}

orderer/sample_clients/broadcast_config/newchain.go

@@ -18,18 +18,13 @@ package main
 
 import (
 	"github.com/hyperledger/fabric/orderer/common/bootstrap/provisional"
-	"github.com/hyperledger/fabric/orderer/localconfig"
 	cb "github.com/hyperledger/fabric/protos/common"
 	"github.com/hyperledger/fabric/protos/utils"
 )
 
-var genesisBlock *cb.Block
-
-func init() {
-	genesisBlock = provisional.New(config.Load()).GenesisBlock()
-}
-
-func newChainRequest(creationPolicy, newChainID string) *cb.Envelope {
+func newChainRequest(consensusType, creationPolicy, newChainID string) *cb.Envelope {
+	conf.General.OrdererType = consensusType
+	genesisBlock := provisional.New(conf).GenesisBlock()
 	oldGenesisTx := utils.ExtractEnvelopeOrPanic(genesisBlock, 0)
 	oldGenesisTxPayload := utils.ExtractPayloadOrPanic(oldGenesisTx)
 	oldConfigEnv := utils.UnmarshalConfigurationEnvelopeOrPanic(oldGenesisTxPayload.Data)