Remove TMSP Commit/Rollback; Add CheckTx

README.md

@@ -16,24 +16,20 @@ For more information on TMSP, motivations, and tutorials, please visit [our blog
   * __Usage__:<br/>
     Append and run a transaction.  The transaction may or may not be final.
 
-#### GetHash
-  * __Returns__:
-    * `RetCode (int8)`
-    * `Hash ([]byte)`
-  * __Usage__:<br/>
-    Return a Merkle root hash of the application state
-
-#### Commit
+#### CheckTx
+  * __Arguments__:
+    * `TxBytes ([]byte)`
   * __Returns__:
     * `RetCode (int8)`
   * __Usage__:<br/>
-    Finalize all appended transactions
+    Validate a transaction.  This message should not mutate the state.
 
-#### Rollback
+#### GetHash
   * __Returns__:
     * `RetCode (int8)`
+    * `Hash ([]byte)`
   * __Usage__:<br/>
-    Roll back to the last commit
+    Return a Merkle root hash of the application state
 
 #### AddListener
   * __Arguments__:
@@ -70,3 +66,17 @@ For more information on TMSP, motivations, and tutorials, please visit [our blog
   * __Usage__:<br/>
     Set application options.  E.g. Key="mode", Value="mempool" for a mempool connection, or Key="mode", Value="consensus" for a consensus connection.
     Other options are application specific.
+
+## Changelog
+
+### Jan 8th, 2016
+
+Tendermint/TMSP now comes to consensus on the order first before AppendTx.
+This means that we no longer need the Commit/Rollback TMSP messages.
+Instead, there’s a “CheckTx” message for mempool to check the validity of a message.
+One consequence is that txs in blocks now may include invalid txs that are ignored.
+In the future, we can include a bitarray or merkle structure in the block so anyone can see which txs were valid.
+To prevent spam, applications can implement their “CheckTx” messages to deduct some balance, so at least spam txs will cost something.  This isn’t any more work that what we already needed to do, so it’s not any worse.
+You can see the new changes in the tendermint/tendermint “order_first” branch, and tendermint/tmsp “order_first” branch.  If you your TMSP apps to me I can help with the transition.
+Please take a look at how the examples in TMSP changed, e.g. how AppContext was removed, CheckTx was added, how the TMSP msg bytes changed, and how commit/rollback messages were removed.
+

cmd/tmsp-cli/tmsp-cli.go

@@ -76,24 +76,17 @@ func main() {
 			},
 		},
 		{
-			Name:  "get_hash",
-			Usage: "Get application Merkle root hash",
+			Name:  "check_tx",
+			Usage: "Validate a tx",
 			Action: func(c *cli.Context) {
-				cmdGetHash(c)
+				cmdCheckTx(c)
 			},
 		},
 		{
-			Name:  "commit",
-			Usage: "Commit the application state",
-			Action: func(c *cli.Context) {
-				cmdCommit(c)
-			},
-		},
-		{
-			Name:  "rollback",
-			Usage: "Roll back the application state to the latest commit",
+			Name:  "get_hash",
+			Usage: "Get application Merkle root hash",
 			Action: func(c *cli.Context) {
-				cmdRollback(c)
+				cmdGetHash(c)
 			},
 		},
 	}
@@ -209,31 +202,36 @@ func cmdAppendTx(c *cli.Context) {
 	fmt.Println("Response:", res)
 }
 
-// Get application Merkle root hash
-func cmdGetHash(c *cli.Context) {
-	res, err := makeRequest(conn, types.RequestGetHash{})
-	if err != nil {
-		Exit(err.Error())
+// Validate a tx
+func cmdCheckTx(c *cli.Context) {
+	args := c.Args()
+	if len(args) != 1 {
+		Exit("append_tx takes 1 argument")
+	}
+	txString := args[0]
+	tx := []byte(txString)
+	if len(txString) > 2 && strings.HasPrefix(txString, "0x") {
+		var err error
+		tx, err = hex.DecodeString(txString[2:])
+		if err != nil {
+			Exit(err.Error())
+		}
 	}
-	fmt.Printf("%X\n", res.(types.ResponseGetHash).Hash)
-}
 
-// Commit the application state
-func cmdCommit(c *cli.Context) {
-	_, err := makeRequest(conn, types.RequestCommit{})
+	res, err := makeRequest(conn, types.RequestCheckTx{tx})
 	if err != nil {
 		Exit(err.Error())
 	}
-	fmt.Println("Committed.")
+	fmt.Println("Response:", res)
 }
 
-// Roll back the application state to the latest commit
-func cmdRollback(c *cli.Context) {
-	_, err := makeRequest(conn, types.RequestRollback{})
+// Get application Merkle root hash
+func cmdGetHash(c *cli.Context) {
+	res, err := makeRequest(conn, types.RequestGetHash{})
 	if err != nil {
 		Exit(err.Error())
 	}
-	fmt.Println("Rolled back.")
+	fmt.Printf("%X\n", res.(types.ResponseGetHash).Hash)
 }
 
 //--------------------------------------------------------------------------------

example/golang/counter.go

@@ -2,111 +2,77 @@ package example
 
 import (
 	"encoding/binary"
-	"sync"
 
 	. "github.com/tendermint/go-common"
 	"github.com/tendermint/tmsp/types"
 )
 
 type CounterApplication struct {
-	mtx         sync.Mutex
-	hashCount   int
-	txCount     int
-	commitCount int
-	serial      bool
+	hashCount int
+	txCount   int
+	serial    bool
 }
 
 func NewCounterApplication(serial bool) *CounterApplication {
 	return &CounterApplication{serial: serial}
 }
 
-func (app *CounterApplication) Open() types.AppContext {
-	return &CounterAppContext{
-		app:         app,
-		hashCount:   app.hashCount,
-		txCount:     app.txCount,
-		commitCount: app.commitCount,
-		serial:      app.serial,
-	}
-}
-
-//--------------------------------------------------------------------------------
-
-type CounterAppContext struct {
-	app         *CounterApplication
-	hashCount   int
-	txCount     int
-	commitCount int
-	serial      bool
-}
-
-func (appC *CounterAppContext) Echo(message string) string {
+func (app *CounterApplication) Echo(message string) string {
 	return message
 }
 
-func (appC *CounterAppContext) Info() []string {
-	return []string{Fmt("hash, tx, commit counts:%d, %d, %d", appC.hashCount, appC.txCount, appC.commitCount)}
+func (app *CounterApplication) Info() []string {
+	return []string{Fmt("hashes:%v, txs:%v", app.hashCount, app.txCount)}
 }
 
-func (appC *CounterAppContext) SetOption(key string, value string) types.RetCode {
+func (app *CounterApplication) SetOption(key string, value string) types.RetCode {
 	if key == "serial" && value == "on" {
-		appC.serial = true
+		app.serial = true
 	}
 	return 0
 }
 
-func (appC *CounterAppContext) AppendTx(tx []byte) ([]types.Event, types.RetCode) {
-	if appC.serial {
+func (app *CounterApplication) AppendTx(tx []byte) ([]types.Event, types.RetCode) {
+	if app.serial {
 		tx8 := make([]byte, 8)
 		copy(tx8, tx)
 		txValue := binary.LittleEndian.Uint64(tx8)
-		if txValue != uint64(appC.txCount) {
+		if txValue != uint64(app.txCount) {
 			return nil, types.RetCodeInternalError
 		}
 	}
-	appC.txCount += 1
+	app.txCount += 1
 	return nil, 0
 }
 
-func (appC *CounterAppContext) GetHash() ([]byte, types.RetCode) {
-	appC.hashCount += 1
-	if appC.txCount == 0 {
+func (app *CounterApplication) CheckTx(tx []byte) types.RetCode {
+	if app.serial {
+		tx8 := make([]byte, 8)
+		copy(tx8, tx)
+		txValue := binary.LittleEndian.Uint64(tx8)
+		if txValue < uint64(app.txCount) {
+			return types.RetCodeInternalError
+		}
+	}
+	return 0
+}
+
+func (app *CounterApplication) GetHash() ([]byte, types.RetCode) {
+	app.hashCount += 1
+
+	if app.txCount == 0 {
 		return nil, 0
 	} else {
 		hash := make([]byte, 32)
-		binary.LittleEndian.PutUint64(hash, uint64(appC.txCount))
+		binary.LittleEndian.PutUint64(hash, uint64(app.txCount))
 		return hash, 0
 	}
 }
 
-func (appC *CounterAppContext) Commit() types.RetCode {
-	appC.commitCount += 1
-
-	appC.app.mtx.Lock()
-	appC.app.hashCount = appC.hashCount
-	appC.app.txCount = appC.txCount
-	appC.app.commitCount = appC.commitCount
-	appC.app.mtx.Unlock()
-	return 0
-}
-
-func (appC *CounterAppContext) Rollback() types.RetCode {
-	appC.app.mtx.Lock()
-	appC.hashCount = appC.app.hashCount
-	appC.txCount = appC.app.txCount
-	appC.commitCount = appC.app.commitCount
-	appC.app.mtx.Unlock()
-	return 0
-}
-
-func (appC *CounterAppContext) AddListener(key string) types.RetCode {
+func (app *CounterApplication) AddListener(key string) types.RetCode {
 	return 0
 }
 
-func (appC *CounterAppContext) RemListener(key string) types.RetCode {
+func (app *CounterApplication) RemListener(key string) types.RetCode {
 	return 0
 }
-
-func (appC *CounterAppContext) Close() error {
-	return nil
-}

example/golang/dummy.go

@@ -1,8 +1,6 @@
 package example
 
 import (
-	"sync"
-
 	. "github.com/tendermint/go-common"
 	"github.com/tendermint/go-merkle"
 	"github.com/tendermint/go-wire"
@@ -10,7 +8,6 @@ import (
 )
 
 type DummyApplication struct {
-	mtx   sync.Mutex
 	state merkle.Tree
 }
 
@@ -24,74 +21,36 @@ func NewDummyApplication() *DummyApplication {
 	return &DummyApplication{state: state}
 }
 
-func (dapp *DummyApplication) Open() types.AppContext {
-	dapp.mtx.Lock()
-	defer dapp.mtx.Unlock()
-	return &DummyAppContext{
-		app:   dapp,
-		state: dapp.state.Copy(),
-	}
-}
-
-func (dapp *DummyApplication) commitState(state merkle.Tree) {
-	dapp.mtx.Lock()
-	defer dapp.mtx.Unlock()
-	dapp.state = state.Copy()
-}
-
-func (dapp *DummyApplication) getState() merkle.Tree {
-	dapp.mtx.Lock()
-	defer dapp.mtx.Unlock()
-	return dapp.state.Copy()
-}
-
-//--------------------------------------------------------------------------------
-
-type DummyAppContext struct {
-	app   *DummyApplication
-	state merkle.Tree
-}
-
-func (dac *DummyAppContext) Echo(message string) string {
+func (app *DummyApplication) Echo(message string) string {
 	return message
 }
 
-func (dac *DummyAppContext) Info() []string {
-	return []string{Fmt("size:%v", dac.state.Size())}
+func (app *DummyApplication) Info() []string {
+	return []string{Fmt("size:%v", app.state.Size())}
 }
 
-func (dac *DummyAppContext) SetOption(key string, value string) types.RetCode {
+func (app *DummyApplication) SetOption(key string, value string) types.RetCode {
 	return 0
 }
 
-func (dac *DummyAppContext) AppendTx(tx []byte) ([]types.Event, types.RetCode) {
-	dac.state.Set(tx, tx)
+func (app *DummyApplication) AppendTx(tx []byte) ([]types.Event, types.RetCode) {
+	app.state.Set(tx, tx)
 	return nil, 0
 }
 
-func (dac *DummyAppContext) GetHash() ([]byte, types.RetCode) {
-	hash := dac.state.Hash()
-	return hash, 0
-}
-
-func (dac *DummyAppContext) Commit() types.RetCode {
-	dac.app.commitState(dac.state)
-	return 0
+func (app *DummyApplication) CheckTx(tx []byte) types.RetCode {
+	return 0 // all txs are valid
 }
 
-func (dac *DummyAppContext) Rollback() types.RetCode {
-	dac.state = dac.app.getState()
-	return 0
+func (app *DummyApplication) GetHash() ([]byte, types.RetCode) {
+	hash := app.state.Hash()
+	return hash, 0
 }
 
-func (dac *DummyAppContext) AddListener(key string) types.RetCode {
+func (app *DummyApplication) AddListener(key string) types.RetCode {
 	return 0
 }
 
-func (dac *DummyAppContext) RemListener(key string) types.RetCode {
+func (app *DummyApplication) RemListener(key string) types.RetCode {
 	return 0
 }
-
-func (dac *DummyAppContext) Close() error {
-	return nil
-}

example/js/app.js

@@ -5,36 +5,25 @@ util = require("util")
 function CounterApp(){
 	this.hashCount = 0;
 	this.txCount = 0;
-	this.commitCount = 0;
+  this.serial = false;
 };
 
-CounterApp.prototype.open = function(){
-	return new CounterAppContext(this);
-}
-
-function CounterAppContext(app) {
-	this.hashCount = app.hashCount;
-	this.txCount = app.txCount;
-	this.commitCount = app.commitCount;
-	this.serial = false;
-}
-
-CounterAppContext.prototype.echo = function(msg){
+CounterApp.prototype.echo = function(msg){
 	return {"response": msg, "ret_code":0}
 }
 
-CounterAppContext.prototype.info = function(){
-	return {"response": [util.format("hash, tx, commit counts: %d, %d, %d", this.hashCount, this.txCount, this.commitCount)]}
+CounterApp.prototype.info = function(){
+	return {"response": [util.format("hashes:%d, txs:%d", this.hashCount, this.txCount)]}
 }
 
-CounterAppContext.prototype.set_option = function(key, value){
+CounterApp.prototype.set_option = function(key, value){
 	if (key == "serial" && value == "on"){
 		this.serial = true;
 	}
 	return {"ret_code":0}
 }
 
-CounterAppContext.prototype.append_tx = function(txBytes){
+CounterApp.prototype.append_tx = function(txBytes){
 	if (this.serial) {
 		txByteArray = new Buffer(txBytes)
 		if (txBytes.length >= 2 && txBytes.slice(0, 2) == "0x") {
@@ -50,7 +39,22 @@ CounterAppContext.prototype.append_tx = function(txBytes){
 	return {"ret_code":0} // TODO: return events
 }
 
-CounterAppContext.prototype.get_hash = function(){
+CounterApp.prototype.check_tx = function(txBytes){
+	if (this.serial) {
+		txByteArray = new Buffer(txBytes)
+		if (txBytes.length >= 2 && txBytes.slice(0, 2) == "0x") {
+			txByteArray = wire.hex2bytes(txBytes.slice(2));
+		}	
+		r = new msg.buffer(txByteArray)
+		txValue = wire.decode_big_endian(r, txBytes.length)
+		if (txValue < this.txCount){
+			return {"ret_code":1}
+		}
+	}
+	return {"ret_code":0}
+}
+
+CounterApp.prototype.get_hash = function(){
 	this.hashCount += 1;
 	if (this.txCount == 0){
 		return {"response": "", "ret_code":0}
@@ -60,24 +64,15 @@ CounterAppContext.prototype.get_hash = function(){
 	return {"response": h.toString(), "ret_code":0}
 }
 
-CounterAppContext.prototype.commit = function(){
-	this.commitCount += 1;
-	return {"ret_code":0}
-}
-
-CounterAppContext.prototype.rollback = function(){
-	return {"ret_code":0}
-}
-
-CounterAppContext.prototype.add_listener = function(){
+CounterApp.prototype.add_listener = function(){
 	return {"ret_code":0}
 }
 
-CounterAppContext.prototype.rm_listener = function(){
+CounterApp.prototype.rm_listener = function(){
 	return {"ret_code":0}
 }
 
-CounterAppContext.prototype.event = function(){
+CounterApp.prototype.event = function(){
 }
 
 console.log("Counter app in Javascript")

example/js/msgs.js

@@ -7,17 +7,13 @@ module.exports = {
 		0x03 : "info",
 		0x04 : "set_option",
 		0x21 : "append_tx",
-		0x22 : "get_hash",
-		0x23 : "commit",
-		0x24 : "rollback",
-		0x25 : "add_listener",
-		0x26 : "rm_listener",
+		0x22 : "check_tx",
+		0x23 : "get_hash",
+		0x24 : "add_listener",
+		0x25 : "rm_listener",
 	},
-
 	decoder : RequestDecoder,
-
 	buffer: BytesBuffer
-
 }
 
 function RequestDecoder(buf){
@@ -32,9 +28,8 @@ RequestDecoder.prototype.flush = function(){};
 RequestDecoder.prototype.info = function(){};
 RequestDecoder.prototype.set_option = function(){ return [decode_string(this.buf), decode_string(this.buf)] };
 RequestDecoder.prototype.append_tx = function(){ return decode_string(this.buf)};
+RequestDecoder.prototype.check_tx = function(){ return decode_string(this.buf)};
 RequestDecoder.prototype.get_hash = function(){ };
-RequestDecoder.prototype.commit = function(){ };
-RequestDecoder.prototype.rollback = function(){ };
 RequestDecoder.prototype.add_listener = function(){ }; // TODO
 RequestDecoder.prototype.rm_listener = function(){ }; // TODO
 

example/js/server.js

@@ -27,8 +27,6 @@ AppServer.prototype.createServer = function(){
 		  socket.name = socket.remoteAddress + ":" + socket.remotePort 
 		  console.log("new connection from", socket.name)
 
-		  appCtx = app.open()
-
 		  var conn = { 
 			  recBuf: new msg.buffer(new Buffer(0)),
 			  resBuf: new msg.buffer(new Buffer(0)),
@@ -90,11 +88,11 @@ AppServer.prototype.createServer = function(){
 
 			var res = function(){
 				if (args == null){
-					return appCtx[reqType]();
+					return app[reqType]();
 				} else if (Array.isArray(args)){
-					return appCtx[reqType].apply(appCtx, args);
+					return app[reqType].apply(app, args);
 				} else {
-					return appCtx[reqType](args)
+					return app[reqType](args)
 				}
 			}()
 

example/python/app.py

@@ -10,28 +10,13 @@ class CounterApplication():
     def __init__(self):
         self.hashCount = 0
         self.txCount = 0
-        self.commitCount = 0
-
-    def open(self):
-        return CounterAppContext(self)
-
-
-class CounterAppContext():
-
-    def __init__(self, app):
-        self.app = app
-        self.hashCount = app.hashCount
-        self.txCount = app.txCount
-        self.commitCount = app.commitCount
         self.serial = False
 
     def echo(self, msg):
         return msg, 0
 
     def info(self):
-        return ["hash, tx, commit counts:%d, %d, %d" % (self.hashCount,
-                                                        self.txCount,
-                                                        self.commitCount)], 0
+        return ["hashes:%d, txs:%d" % (self.hashCount, self.txCount)], 0
 
     def set_option(self, key, value):
         if key == "serial" and value == "on":
@@ -50,6 +35,17 @@ class CounterAppContext():
         self.txCount += 1
         return None, 0
 
+    def check_tx(self, txBytes):
+        if self.serial:
+            txByteArray = bytearray(txBytes)
+            if len(txBytes) >= 2 and txBytes[:2] == "0x":
+                txByteArray = hex2bytes(txBytes[2:])
+            txValue = decode_big_endian(
+                BytesBuffer(txByteArray), len(txBytes))
+            if txValue < self.txCount:
+                return 1
+        return 0
+
     def get_hash(self):
         self.hashCount += 1
         if self.txCount == 0:
@@ -58,13 +54,6 @@ class CounterAppContext():
         h.reverse()
         return str(h), 0
 
-    def commit(self):
-        self.commitCount += 1
-        return 0
-
-    def rollback(self):
-        return 0
-
     def add_listener(self):
         return 0
 

example/python/tmsp/msg.py

@@ -7,16 +7,14 @@ message_types = {
     0x03: "info",
     0x04: "set_option",
     0x21: "append_tx",
-    0x22: "get_hash",
-    0x23: "commit",
-    0x24: "rollback",
-    0x25: "add_listener",
-    0x26: "rm_listener",
+    0x22: "check_tx",
+    0x23: "get_hash",
+    0x24: "add_listener",
+    0x25: "rm_listener",
 }
 
 # return the decoded arguments of tmsp messages
 
-
 class RequestDecoder():
 
     def __init__(self, reader):
@@ -37,13 +35,10 @@ class RequestDecoder():
     def append_tx(self):
         return decode_string(self.reader)
 
-    def get_hash(self):
-        return
-
-    def commit(self):
-        return
+    def check_tx(self):
+        return decode_string(self.reader)
 
-    def rollback(self):
+    def get_hash(self):
         return
 
     def add_listener(self):

example/python/tmsp/server.py

@@ -2,7 +2,6 @@ import socket
 import select
 import sys
 
-
 from wire import decode_varint, encode
 from reader import BytesBuffer
 from msg import RequestDecoder, message_types
@@ -10,12 +9,11 @@ from msg import RequestDecoder, message_types
 # hold the asyncronous state of a connection
 # ie. we may not get enough bytes on one read to decode the message
 
-
 class Connection():
 
-    def __init__(self, fd, appCtx):
+    def __init__(self, fd, app):
         self.fd = fd
-        self.appCtx = appCtx
+        self.app = app
         self.recBuf = BytesBuffer(bytearray())
         self.resBuf = BytesBuffer(bytearray())
         self.msgLength = 0
@@ -30,12 +28,11 @@ class Connection():
 
 # TMSP server responds to messges by calling methods on the app
 
-
 class TMSPServer():
 
     def __init__(self, app, port=5410):
         self.app = app
-        # map conn file descriptors to (appContext, reqBuf, resBuf, msgDecoder)
+        # map conn file descriptors to (app, reqBuf, resBuf, msgDecoder)
         self.appMap = {}
 
         self.port = port
@@ -60,8 +57,7 @@ class TMSPServer():
         self.write_list.append(new_fd)
         print 'new connection to', new_addr
 
-        appContext = self.app.open()
-        self.appMap[new_fd] = Connection(new_fd, appContext)
+        self.appMap[new_fd] = Connection(new_fd, self.app)
 
     def handle_conn_closed(self, r):
         self.read_list.remove(r)
@@ -70,7 +66,7 @@ class TMSPServer():
         print "connection closed"
 
     def handle_recv(self, r):
-        #  appCtx, recBuf, resBuf, conn
+        #  app, recBuf, resBuf, conn
         conn = self.appMap[r]
         while True:
             try:
@@ -127,7 +123,7 @@ class TMSPServer():
                 conn.msgLength = 0
                 conn.inProgress = False
 
-                req_f = getattr(conn.appCtx, req_type)
+                req_f = getattr(conn.app, req_type)
                 if req_args is None:
                     res = req_f()
                 elif isinstance(req_args, tuple):

example/python3/app.py

@@ -10,28 +10,13 @@ class CounterApplication():
     def __init__(self):
         self.hashCount = 0
         self.txCount = 0
-        self.commitCount = 0
-
-    def open(self):
-        return CounterAppContext(self)
-
-
-class CounterAppContext():
-
-    def __init__(self, app):
-        self.app = app
-        self.hashCount = app.hashCount
-        self.txCount = app.txCount
-        self.commitCount = app.commitCount
         self.serial = False
 
     def echo(self, msg):
         return msg, 0
 
     def info(self):
-        return ["hash, tx, commit counts:%d, %d, %d" % (self.hashCount,
-                                                        self.txCount,
-                                                        self.commitCount)], 0
+        return ["hashes:%d, txs:%d" % (self.hashCount, self.txCount)], 0
 
     def set_option(self, key, value):
         if key == "serial" and value == "on":
@@ -50,6 +35,17 @@ class CounterAppContext():
         self.txCount += 1
         return None, 0
 
+    def check_tx(self, txBytes):
+        if self.serial:
+            txByteArray = bytearray(txBytes)
+            if len(txBytes) >= 2 and txBytes[:2] == "0x":
+                txByteArray = hex2bytes(txBytes[2:])
+            txValue = decode_big_endian(
+                BytesBuffer(txByteArray), len(txBytes))
+            if txValue < self.txCount:
+                return 1
+        return 0
+
     def get_hash(self):
         self.hashCount += 1
         if self.txCount == 0:
@@ -58,13 +54,6 @@ class CounterAppContext():
         h.reverse()
         return h.decode(), 0
 
-    def commit(self):
-        self.commitCount += 1
-        return 0
-
-    def rollback(self):
-        return 0
-
     def add_listener(self):
         return 0
 

example/python3/tmsp/msg.py

@@ -7,16 +7,14 @@ message_types = {
     0x03: "info",
     0x04: "set_option",
     0x21: "append_tx",
-    0x22: "get_hash",
-    0x23: "commit",
-    0x24: "rollback",
-    0x25: "add_listener",
-    0x26: "rm_listener",
+    0x22: "check_tx",
+    0x23: "get_hash",
+    0x24: "add_listener",
+    0x25: "rm_listener",
 }
 
 # return the decoded arguments of tmsp messages
 
-
 class RequestDecoder():
 
     def __init__(self, reader):
@@ -37,13 +35,10 @@ class RequestDecoder():
     def append_tx(self):
         return decode_string(self.reader)
 
-    def get_hash(self):
-        return
-
-    def commit(self):
-        return
+    def check_tx(self):
+        return decode_string(self.reader)
 
-    def rollback(self):
+    def get_hash(self):
         return
 
     def add_listener(self):

example/python3/tmsp/server.py

@@ -12,12 +12,11 @@ from .msg import RequestDecoder, message_types
 
 logger = logging.getLogger(__name__)
 
-
 class Connection():
 
-    def __init__(self, fd, appCtx):
+    def __init__(self, fd, app):
         self.fd = fd
-        self.appCtx = appCtx
+        self.app = app
         self.recBuf = BytesBuffer(bytearray())
         self.resBuf = BytesBuffer(bytearray())
         self.msgLength = 0
@@ -32,12 +31,11 @@ class Connection():
 
 # TMSP server responds to messges by calling methods on the app
 
-
 class TMSPServer():
 
     def __init__(self, app, port=5410):
         self.app = app
-        # map conn file descriptors to (appContext, reqBuf, resBuf, msgDecoder)
+        # map conn file descriptors to (app, reqBuf, resBuf, msgDecoder)
         self.appMap = {}
 
         self.port = port
@@ -62,8 +60,7 @@ class TMSPServer():
         self.write_list.append(new_fd)
         print('new connection to', new_addr)
 
-        appContext = self.app.open()
-        self.appMap[new_fd] = Connection(new_fd, appContext)
+        self.appMap[new_fd] = Connection(new_fd, self.app)
 
     def handle_conn_closed(self, r):
         self.read_list.remove(r)
@@ -72,7 +69,7 @@ class TMSPServer():
         print("connection closed")
 
     def handle_recv(self, r):
-        #  appCtx, recBuf, resBuf, conn
+        #  app, recBuf, resBuf, conn
         conn = self.appMap[r]
         while True:
             try:
@@ -129,7 +126,7 @@ class TMSPServer():
                 conn.msgLength = 0
                 conn.inProgress = False
 
-                req_f = getattr(conn.appCtx, req_type)
+                req_f = getattr(conn.app, req_type)
                 if req_args is None:
                     res = req_f()
                 elif isinstance(req_args, tuple):

server/server.go

@@ -6,6 +6,7 @@ import (
 	"io"
 	"net"
 	"strings"
+	"sync"
 
 	. "github.com/tendermint/go-common"
 	"github.com/tendermint/go-wire"
@@ -15,6 +16,7 @@ import (
 // var maxNumberConnections = 2
 
 func StartListener(protoAddr string, app types.Application) (net.Listener, error) {
+	var mtx sync.Mutex // global mutex
 	parts := strings.SplitN(protoAddr, "://", 2)
 	proto, addr := parts[0], parts[1]
 	ln, err := net.Listen(proto, addr)
@@ -38,12 +40,11 @@ func StartListener(protoAddr string, app types.Application) (net.Listener, error
 				fmt.Println("Accepted a new connection")
 			}
 
-			appContext := app.Open()
 			closeConn := make(chan error, 2)             // Push to signal connection closed
 			responses := make(chan types.Response, 1000) // A channel to buffer responses
 
 			// Read requests from conn and deal with them
-			go handleRequests(appContext, closeConn, conn, responses)
+			go handleRequests(&mtx, app, closeConn, conn, responses)
 			// Pull responses from 'responses' and write them to conn.
 			go handleResponses(closeConn, responses, conn)
 
@@ -62,12 +63,6 @@ func StartListener(protoAddr string, app types.Application) (net.Listener, error
 					fmt.Printf("Error in closing connection: %v\n", err)
 				}
 
-				// Close the AppContext
-				err = appContext.Close()
-				if err != nil {
-					fmt.Printf("Error in closing app context: %v\n", err)
-				}
-
 				// <-semaphore
 			}()
 		}
@@ -78,7 +73,7 @@ func StartListener(protoAddr string, app types.Application) (net.Listener, error
 }
 
 // Read requests from conn and deal with them
-func handleRequests(appC types.AppContext, closeConn chan error, conn net.Conn, responses chan<- types.Response) {
+func handleRequests(mtx *sync.Mutex, app types.Application, closeConn chan error, conn net.Conn, responses chan<- types.Response) {
 	var count int
 	var bufReader = bufio.NewReader(conn)
 	for {
@@ -94,44 +89,43 @@ func handleRequests(appC types.AppContext, closeConn chan error, conn net.Conn,
 			}
 			return
 		}
+		mtx.Lock()
 		count++
-		handleRequest(appC, req, responses)
+		handleRequest(app, req, responses)
+		mtx.Unlock()
 	}
 }
 
-func handleRequest(appC types.AppContext, req types.Request, responses chan<- types.Response) {
+func handleRequest(app types.Application, req types.Request, responses chan<- types.Response) {
 	switch req := req.(type) {
 	case types.RequestEcho:
-		msg := appC.Echo(req.Message)
+		msg := app.Echo(req.Message)
 		responses <- types.ResponseEcho{msg}
 	case types.RequestFlush:
 		responses <- types.ResponseFlush{}
 	case types.RequestInfo:
-		data := appC.Info()
+		data := app.Info()
 		responses <- types.ResponseInfo{data}
 	case types.RequestSetOption:
-		retCode := appC.SetOption(req.Key, req.Value)
+		retCode := app.SetOption(req.Key, req.Value)
 		responses <- types.ResponseSetOption{retCode}
 	case types.RequestAppendTx:
-		events, retCode := appC.AppendTx(req.TxBytes)
+		events, retCode := app.AppendTx(req.TxBytes)
 		responses <- types.ResponseAppendTx{retCode}
 		for _, event := range events {
 			responses <- types.ResponseEvent{event}
 		}
+	case types.RequestCheckTx:
+		retCode := app.CheckTx(req.TxBytes)
+		responses <- types.ResponseCheckTx{retCode}
 	case types.RequestGetHash:
-		hash, retCode := appC.GetHash()
+		hash, retCode := app.GetHash()
 		responses <- types.ResponseGetHash{retCode, hash}
-	case types.RequestCommit:
-		retCode := appC.Commit()
-		responses <- types.ResponseCommit{retCode}
-	case types.RequestRollback:
-		retCode := appC.Rollback()
-		responses <- types.ResponseRollback{retCode}
 	case types.RequestAddListener:
-		retCode := appC.AddListener(req.EventKey)
+		retCode := app.AddListener(req.EventKey)
 		responses <- types.ResponseAddListener{retCode}
 	case types.RequestRemListener:
-		retCode := appC.RemListener(req.EventKey)
+		retCode := app.RemListener(req.EventKey)
 		responses <- types.ResponseRemListener{retCode}
 	default:
 		responses <- types.ResponseException{"Unknown request"}

tests/test_dummy.sh

@@ -13,17 +13,16 @@ fi
 echo "... Pass!"
 echo ""
 
-# Add a tx, get hash, commit, get hash
+# Add a tx, get hash, get hash
 # hashes should be non-empty and identical
 echo "Dummy batch test ..."
 OUTPUT=`(tmsp-cli batch) <<STDIN 
 append_tx abc
 get_hash
-commit
 get_hash
 STDIN`
 
-HASH1=`echo "$OUTPUT" | tail -n 3 | head -n 1`
+HASH1=`echo "$OUTPUT" | tail -n 2 | head -n 1`
 HASH2=`echo "$OUTPUT" | tail -n 1`
 
 if [[ "$HASH1" == "" ]]; then
@@ -37,7 +36,7 @@ if [[ "$HASH1" == "EOF" ]]; then
 fi
 
 if [[ "$HASH1" != "$HASH2" ]]; then
-	echo "Expected hashes before and after commit to match: $HASH1, $HASH2"
+	echo "Expected first and second hashes to match: $HASH1, $HASH2"
 	exit 1
 fi
 echo "... Pass!"

types/application.go

@@ -2,12 +2,6 @@ package types
 
 type Application interface {
 
-	// For new socket connections
-	Open() AppContext
-}
-
-type AppContext interface {
-
 	// Echo a message
 	Echo(message string) string
 
@@ -17,24 +11,18 @@ type AppContext interface {
 	// Set application option (e.g. mode=mempool, mode=consensus)
 	SetOption(key string, value string) RetCode
 
-	// Append a tx, which may or may not get committed
+	// Append a tx
 	AppendTx(tx []byte) ([]Event, RetCode)
 
+	// Validate a tx for the mempool
+	CheckTx(tx []byte) RetCode
+
 	// Return the application Merkle root hash
 	GetHash() ([]byte, RetCode)
 
-	// Set commit checkpoint
-	Commit() RetCode
-
-	// Rollback to the latest commit
-	Rollback() RetCode
-
 	// Add event listener
 	AddListener(key string) RetCode
 
 	// Remove event listener
 	RemListener(key string) RetCode
-
-	// Close this AppContext
-	Close() error
 }

types/messages.go

@@ -17,20 +17,18 @@ const (
 	// reserved for GetOption = byte(0x15)
 
 	requestTypeAppendTx    = byte(0x21)
-	requestTypeGetHash     = byte(0x22)
-	requestTypeCommit      = byte(0x23)
-	requestTypeRollback    = byte(0x24)
-	requestTypeAddListener = byte(0x25)
-	requestTypeRemListener = byte(0x26)
-	// reserved for responseTypeEvent 0x27
+	requestTypeCheckTx     = byte(0x22)
+	requestTypeGetHash     = byte(0x23)
+	requestTypeAddListener = byte(0x24)
+	requestTypeRemListener = byte(0x25)
+	// reserved for responseTypeEvent 0x26
 
 	responseTypeAppendTx    = byte(0x31)
-	responseTypeGetHash     = byte(0x32)
-	responseTypeCommit      = byte(0x33)
-	responseTypeRollback    = byte(0x34)
-	responseTypeAddListener = byte(0x35)
-	responseTypeRemListener = byte(0x36)
-	responseTypeEvent       = byte(0x37)
+	responseTypeCheckTx     = byte(0x32)
+	responseTypeGetHash     = byte(0x33)
+	responseTypeAddListener = byte(0x34)
+	responseTypeRemListener = byte(0x35)
+	responseTypeEvent       = byte(0x36)
 )
 
 //----------------------------------------
@@ -54,13 +52,11 @@ type RequestAppendTx struct {
 	TxBytes []byte
 }
 
-type RequestGetHash struct {
-}
-
-type RequestCommit struct {
+type RequestCheckTx struct {
+	TxBytes []byte
 }
 
-type RequestRollback struct {
+type RequestGetHash struct {
 }
 
 type RequestAddListener struct {
@@ -80,9 +76,8 @@ func (_ RequestFlush) AssertRequestType()       {}
 func (_ RequestInfo) AssertRequestType()        {}
 func (_ RequestSetOption) AssertRequestType()   {}
 func (_ RequestAppendTx) AssertRequestType()    {}
+func (_ RequestCheckTx) AssertRequestType()     {}
 func (_ RequestGetHash) AssertRequestType()     {}
-func (_ RequestCommit) AssertRequestType()      {}
-func (_ RequestRollback) AssertRequestType()    {}
 func (_ RequestAddListener) AssertRequestType() {}
 func (_ RequestRemListener) AssertRequestType() {}
 
@@ -93,9 +88,8 @@ var _ = wire.RegisterInterface(
 	wire.ConcreteType{RequestInfo{}, requestTypeInfo},
 	wire.ConcreteType{RequestSetOption{}, requestTypeSetOption},
 	wire.ConcreteType{RequestAppendTx{}, requestTypeAppendTx},
+	wire.ConcreteType{RequestCheckTx{}, requestTypeCheckTx},
 	wire.ConcreteType{RequestGetHash{}, requestTypeGetHash},
-	wire.ConcreteType{RequestCommit{}, requestTypeCommit},
-	wire.ConcreteType{RequestRollback{}, requestTypeRollback},
 	wire.ConcreteType{RequestAddListener{}, requestTypeAddListener},
 	wire.ConcreteType{RequestRemListener{}, requestTypeRemListener},
 )
@@ -121,17 +115,13 @@ type ResponseAppendTx struct {
 	RetCode
 }
 
-type ResponseGetHash struct {
-	RetCode
-	Hash []byte
-}
-
-type ResponseCommit struct {
+type ResponseCheckTx struct {
 	RetCode
 }
 
-type ResponseRollback struct {
+type ResponseGetHash struct {
 	RetCode
+	Hash []byte
 }
 
 type ResponseAddListener struct {
@@ -159,9 +149,8 @@ func (_ ResponseFlush) AssertResponseType()       {}
 func (_ ResponseInfo) AssertResponseType()        {}
 func (_ ResponseSetOption) AssertResponseType()   {}
 func (_ ResponseAppendTx) AssertResponseType()    {}
+func (_ ResponseCheckTx) AssertResponseType()     {}
 func (_ ResponseGetHash) AssertResponseType()     {}
-func (_ ResponseCommit) AssertResponseType()      {}
-func (_ ResponseRollback) AssertResponseType()    {}
 func (_ ResponseAddListener) AssertResponseType() {}
 func (_ ResponseRemListener) AssertResponseType() {}
 func (_ ResponseException) AssertResponseType()   {}
@@ -174,9 +163,8 @@ var _ = wire.RegisterInterface(
 	wire.ConcreteType{ResponseInfo{}, responseTypeInfo},
 	wire.ConcreteType{ResponseSetOption{}, responseTypeSetOption},
 	wire.ConcreteType{ResponseAppendTx{}, responseTypeAppendTx},
+	wire.ConcreteType{ResponseCheckTx{}, responseTypeCheckTx},
 	wire.ConcreteType{ResponseGetHash{}, responseTypeGetHash},
-	wire.ConcreteType{ResponseCommit{}, responseTypeCommit},
-	wire.ConcreteType{ResponseRollback{}, responseTypeRollback},
 	wire.ConcreteType{ResponseAddListener{}, responseTypeAddListener},
 	wire.ConcreteType{ResponseRemListener{}, responseTypeRemListener},
 	wire.ConcreteType{ResponseException{}, responseTypeException},