Merge pull request #1256 from tendermint/feature/more-priv-val

PrivValidatorAddr -> PrivValidatorListenAddr. Update ADR008

cmd/tendermint/commands/run_node.go

@@ -15,7 +15,7 @@ func AddNodeFlags(cmd *cobra.Command) {
 	cmd.Flags().String("moniker", config.Moniker, "Node Name")
 
 	// priv val flags
-	cmd.Flags().String("priv_validator_addr", config.PrivValidatorAddr, "Socket address for private validator")
+	cmd.Flags().String("priv_validator_laddr", config.PrivValidatorListenAddr, "Socket address to listen on for connections from external priv_validator process")
 
 	// node flags
 	cmd.Flags().Bool("fast_sync", config.FastSync, "Fast blockchain syncing")

config/config.go

@@ -104,8 +104,9 @@ type BaseConfig struct {
 	// A custom human readable name for this node
 	Moniker string `mapstructure:"moniker"`
 
-	// TCP or UNIX socket address of the PrivValidator server
-	PrivValidatorAddr string `mapstructure:"priv_validator_addr"`
+	// TCP or UNIX socket address for Tendermint to listen on for
+	// connections from an external PrivValidator process
+	PrivValidatorListenAddr string `mapstructure:"priv_validator_laddr"`
 
 	// TCP or UNIX socket address of the ABCI application,
 	// or the name of an ABCI application compiled in with the Tendermint binary

docs/architecture/adr-008-priv-validator.md

@@ -29,8 +29,17 @@ Tendermint node's should support only two in-process PrivValidator implementatio
 - PrivValidatorSocket uses a socket to send signing requests to another process - user is responsible for starting that process themselves.
 
 The PrivValidatorSocket address can be provided via flags at the command line -
-doing so will cause Tendermint to ignore any "priv_validator.json" file and to attempt
-to connect over the socket.
+doing so will cause Tendermint to ignore any "priv_validator.json" file and to listen
+on the given address for incoming connections from an external priv_validator process.
+It will halt any operation until at least one external process succesfully
+connected.
+
+The external priv_validator process will dial the address to connect to Tendermint,
+and then Tendermint will send requests on the ensuing connection to sign votes and proposals.
+Thus the external process initiates the connection, but the Tendermint process makes all requests.
+In a later stage we're going to support multiple validators for fault
+tolerance. To prevent double signing they need to be synced, which is deferred
+to an external solution (see #1185).
 
 In addition, Tendermint will provide implementations that can be run in that external process.
 These include:
@@ -103,7 +112,7 @@ It wraps the PrivValidatorUnencrypted and persists it to disk after every signat
 
 ## Status
 
-Proposed.
+Accepted.
 
 ## Consequences
 

node/node.go

@@ -173,13 +173,16 @@ func NewNode(config *cfg.Config,
 	// reload the state (it may have been updated by the handshake)
 	state = sm.LoadState(stateDB)
 
-	// Connect to external signing process, if an address is provided.
-	if config.PrivValidatorAddr != "" {
+	// If an address is provided, listen on the socket for a
+	// connection from an external signing process.
+	if config.PrivValidatorListenAddr != "" {
 		var (
+			// TODO: persist this key so external signer
+			// can actually authenticate us
 			privKey = crypto.GenPrivKeyEd25519()
 			pvsc    = priv_val.NewSocketClient(
 				logger.With("module", "priv_val"),
-				config.PrivValidatorAddr,
+				config.PrivValidatorListenAddr,
 				&privKey,
 			)
 		)
@@ -395,7 +398,7 @@ func (n *Node) OnStart() error {
 	n.sw.AddListener(l)
 
 	// Generate node PrivKey
-	// TODO: pass in like priv_val
+	// TODO: pass in like privValidator
 	nodeKey, err := p2p.LoadOrGenNodeKey(n.config.NodeKeyFile())
 	if err != nil {
 		return err

types/priv_validator.go

@@ -34,7 +34,7 @@ func voteToStep(vote *Vote) int8 {
 }
 
 //--------------------------------------------------------------
-// PrivValidator is being upgraded! See types/priv_validator
+// PrivValidator is being upgraded! See types/priv_validator/
 
 // ValidatorID contains the identity of the validator.
 type ValidatorID struct {
@@ -82,6 +82,7 @@ func (ds *DefaultTestSigner) Sign(msg []byte) (crypto.Signature, error) {
 }
 
 //--------------------------------------------------------------
+// TODO: Deprecate!
 
 // PrivValidator defines the functionality of a local Tendermint validator
 // that signs votes, proposals, and heartbeats, and never double signs.