using password file, some method comments, working getCode for contract

Former-commit-id: 087f9d471291ba6361c8d8e905935227849d57ea [formerly 79568804120e8aa8914977967e3233ba5397b26c]
Former-commit-id: aeabcb2d2ca2622defd3f04420cde73df42be53f

cmd/geth/shardingcmd.go

@@ -13,7 +13,7 @@ var (
 		Name:        "shard",
 		Usage:       "Start a sharding client",
 		ArgsUsage:   "[endpoint]",
-		Flags:       append(consoleFlags, utils.DataDirFlag),
+		Flags:       append(append(consoleFlags, utils.DataDirFlag), utils.PasswordFileFlag),
 		Category:    "SHARDING COMMANDS",
 		Description: "TODO(prestonvanloon)- Add sharding client description",
 	}

sharding/client.go

@@ -13,16 +13,19 @@ import (
 )
 
 const (
-	// TODO: Can this be referenced from main.clientIdentifier?
+	// TODO(prestonvanloon): Can this be referenced from main.clientIdentifier?
 	clientIdentifier = "geth" // Client identifier to advertise over the network
 )
 
+// Client for sharding. Communicates to geth node via JSON RPC.
 type Client struct {
-	endpoint string
-	client   *ethclient.Client
+	endpoint string             // Endpoint to JSON RPC
+	client   *ethclient.Client  // Ethereum RPC client.
 	keystore *keystore.KeyStore // Keystore containing the single signer
+	ctx      *cli.Context       // Command line context
 }
 
+// MakeShardingClient for interfacing with geth full node.
 func MakeShardingClient(ctx *cli.Context) *Client {
 	path := node.DefaultDataDir()
 	if ctx.GlobalIsSet(utils.DataDirFlag.Name) {
@@ -35,7 +38,7 @@ func MakeShardingClient(ctx *cli.Context) *Client {
 	}
 	scryptN, scryptP, keydir, err := config.AccountConfig()
 	if err != nil {
-		panic(err) // TODO: handle this
+		panic(err) // TODO(prestonvanloon): handle this
 	}
 
 	ks := keystore.NewKeyStore(keydir, scryptN, scryptP)
@@ -43,9 +46,13 @@ func MakeShardingClient(ctx *cli.Context) *Client {
 	return &Client{
 		endpoint: endpoint,
 		keystore: ks,
+		ctx:      ctx,
 	}
 }
 
+// Start the sharding client.
+// * Connects to node.
+// * Verifies the validator management contract.
 func (c *Client) Start() error {
 	log.Info("Starting sharding client")
 	rpcClient, err := dialRPC(c.endpoint)
@@ -58,15 +65,17 @@ func (c *Client) Start() error {
 		return err
 	}
 
-	// TODO: Wait to be selected?
+	// TODO: Wait to be selected in goroutine?
 
 	return nil
 }
 
+// Wait until sharding client is shutdown.
 func (c *Client) Wait() {
 	// TODO: Blocking lock
 }
 
+// dialRPC endpoint to node.
 func dialRPC(endpoint string) (*rpc.Client, error) {
 	if endpoint == "" {
 		endpoint = node.DefaultIPCEndpoint(clientIdentifier)

sharding/config.go

@@ -10,7 +10,7 @@ var (
 	// Number of network shards
 	shardCount = 100
 	// Address of the validator management contract
-	validatorManagerAddress = common.StringToAddress("0x315e4c3c34e27Dd28c7dCC27eC233618e76adcAc") // TODO
+	validatorManagerAddress = common.HexToAddress("0xd76b5bf01b55d75733de3997f54a7becc2be3f4a") // TODO
 	// Gas limit for verifying signatures
 	sigGasLimit = 40000
 	// Number of blocks in a period