node: allow registration of custom reactors while creating node (#3771)

* change invocation of NewNode across

* custom reactor name are prefixed with CUSTOM_

* upgate changelog pending

* improve comments

* node: refactor NewNode to use functional options

node/node_test.go

@@ -21,6 +21,7 @@ import (
 	"github.com/tendermint/tendermint/libs/log"
 	mempl "github.com/tendermint/tendermint/mempool"
 	"github.com/tendermint/tendermint/p2p"
+	p2pmock "github.com/tendermint/tendermint/p2p/mock"
 	"github.com/tendermint/tendermint/privval"
 	"github.com/tendermint/tendermint/proxy"
 	sm "github.com/tendermint/tendermint/state"
@@ -100,7 +101,10 @@ func TestNodeDelayedStart(t *testing.T) {
 	n.GenesisDoc().GenesisTime = now.Add(2 * time.Second)
 	require.NoError(t, err)
 
-	n.Start()
+	err = n.Start()
+	require.NoError(t, err)
+	defer n.Stop()
+
 	startTime := tmtime.Now()
 	assert.Equal(t, true, startTime.After(n.GenesisDoc().GenesisTime))
 }
@@ -279,6 +283,34 @@ func TestCreateProposalBlock(t *testing.T) {
 	assert.NoError(t, err)
 }
 
+func TestNodeNewNodeCustomReactors(t *testing.T) {
+	config := cfg.ResetTestRoot("node_new_node_custom_reactors_test")
+	defer os.RemoveAll(config.RootDir)
+
+	cr := p2pmock.NewReactor()
+
+	nodeKey, err := p2p.LoadOrGenNodeKey(config.NodeKeyFile())
+	require.NoError(t, err)
+
+	n, err := NewNode(config,
+		privval.LoadOrGenFilePV(config.PrivValidatorKeyFile(), config.PrivValidatorStateFile()),
+		nodeKey,
+		proxy.DefaultClientCreator(config.ProxyApp, config.ABCI, config.DBDir()),
+		DefaultGenesisDocProviderFunc(config),
+		DefaultDBProvider,
+		DefaultMetricsProvider(config.Instrumentation),
+		log.TestingLogger(),
+		CustomReactors(map[string]p2p.Reactor{"FOO": cr}),
+	)
+	require.NoError(t, err)
+
+	err = n.Start()
+	require.NoError(t, err)
+	defer n.Stop()
+
+	assert.True(t, cr.IsRunning())
+}
+
 func state(nVals int, height int64) (sm.State, dbm.DB) {
 	vals := make([]types.GenesisValidator, nVals)
 	for i := 0; i < nVals; i++ {