Add a go example to the sawtooth material

LFS171x/sawtooth-material/sawtooth-tuna/go-processor/README.md

@@ -0,0 +1,21 @@
+### Setting up the project
+
+You are going to have to download a few packages:
+
+* `go get -u github.com/golang/protobuf/proto`
+* `go get -u github.com/satori/go.uuid`
+* `go get -u github.com/pebbe/zmq4`
+
+Now since the golang sawtooth_sdk has been commited to this repo (given https://jira.hyperledger.org/browse/STL-974 ), you are ready to go.
+
+### Launch the project
+
+* First start the docker with `docker-compose -f sawtooth-default.yaml up` in the folder `sawtooth-material`
+* Now go to the folder `sawtooth-material/sawtooth-tuna/go-processor` and in your shell run: `export GOPATH=$PWD`
+* Finally run `go run src/processor/main.go`
+
+The transaction processor should start, and you should see at the end
+
+```
+2018/01/08 21:49:30.017209 processor.go:351: [INFO] Successfully registered handler (transfer-chain, 0x525b60, application/json, [19d832])
+```

LFS171x/sawtooth-material/sawtooth-tuna/go-processor/sawtooth_sdk/client/encoder.go

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+/**
+ * Copyright 2017 Intel Corporation
+ *
+ * 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 client
+
+import (
+	"encoding/hex"
+	"fmt"
+	"github.com/golang/protobuf/proto"
+	"sawtooth_sdk/protobuf/batch_pb2"
+	"sawtooth_sdk/protobuf/transaction_pb2"
+	"time"
+)
+
+type TransactionParams struct {
+	FamilyName      string
+	FamilyVersion   string
+	PayloadEncoding string
+	Nonce           string
+	BatcherPubkey   string
+	Dependencies    []string
+	Inputs          []string
+	Outputs         []string
+}
+
+type Encoder struct {
+	privkey  []byte
+	pubkey   string
+	defaults TransactionParams
+}
+
+// NewTransactionEncoder constructs a new encoder which can be used to generate
+// transactions and batches, and to serialize batches for submitting to the
+// REST API.
+func NewEncoder(privkey []byte, defaults TransactionParams) *Encoder {
+	return &Encoder{
+		privkey:  privkey,
+		pubkey:   hex.EncodeToString(GenPubKey(privkey)),
+		defaults: defaults,
+	}
+}
+
+// -- Transactions --
+
+// NewTransaction Creates a new transaction and handles the construction and
+// signing of the transaction header.
+func (self *Encoder) NewTransaction(payload []byte, p TransactionParams) *Transaction {
+	h := &transaction_pb2.TransactionHeader{
+		// Load defaults
+		FamilyName:      self.defaults.FamilyName,
+		FamilyVersion:   self.defaults.FamilyVersion,
+		PayloadEncoding: self.defaults.PayloadEncoding,
+		Nonce:           self.defaults.Nonce,
+		BatcherPubkey:   self.defaults.BatcherPubkey,
+
+		Inputs:       self.defaults.Inputs,
+		Outputs:      self.defaults.Outputs,
+		Dependencies: self.defaults.Dependencies,
+
+		// Set unique fields
+		PayloadSha512: hex.EncodeToString(SHA512(payload)),
+		SignerPubkey:  self.pubkey,
+	}
+
+	// Override defaults if set
+	if p.FamilyName != "" {
+		h.FamilyName = p.FamilyName
+	}
+	if p.FamilyVersion != "" {
+		h.FamilyVersion = p.FamilyVersion
+	}
+	if p.PayloadEncoding != "" {
+		h.PayloadEncoding = p.PayloadEncoding
+	}
+	if p.Nonce != "" {
+		h.Nonce = p.Nonce
+	}
+	if p.BatcherPubkey != "" {
+		h.BatcherPubkey = p.BatcherPubkey
+	}
+
+	if p.Inputs != nil {
+		h.Inputs = p.Inputs[:]
+	}
+	if p.Outputs != nil {
+		h.Outputs = p.Outputs[:]
+	}
+	if p.Dependencies != nil {
+		h.Dependencies = p.Dependencies[:]
+	}
+
+	// Generate a nonce if none has been set yet
+	if h.Nonce == "" {
+		h.Nonce = fmt.Sprintf("%x", time.Now().UTC().UnixNano())
+	}
+
+	// If a BatcherPubkey hasn't been set yet, assume its our key
+	if h.BatcherPubkey == "" {
+		h.BatcherPubkey = self.pubkey
+	}
+
+	hb, err := proto.Marshal(h)
+	if err != nil {
+		panic(err)
+	}
+	hs := hex.EncodeToString(Sign(hb, self.privkey))
+
+	transaction := &transaction_pb2.Transaction{
+		Header:          hb,
+		HeaderSignature: hs,
+		Payload:         payload,
+	}
+
+	return (*Transaction)(transaction)
+}
+
+// SerializeTransactions serializes the given transactions to bytes for
+// transmission to a separate batcher.
+func SerializeTransactions(transactions []*Transaction) []byte {
+	txns := make([]*transaction_pb2.Transaction, 0, len(transactions))
+	for _, tx := range transactions {
+		txns = append(txns, tx.ToPb())
+	}
+
+	tl := &transaction_pb2.TransactionList{
+		Transactions: txns,
+	}
+
+	tlb, err := proto.Marshal(tl)
+	if err != nil {
+		panic(err)
+	}
+
+	return tlb
+}
+
+// ParseTransactions deserializes the given bytes into a list of transactions.
+// The bytes are assumed to be in the format returned by SerializeTransactions.
+func ParseTransactions(b []byte) ([]*Transaction, error) {
+	tl := &transaction_pb2.TransactionList{}
+	err := proto.Unmarshal(b, tl)
+	if err != nil {
+		return nil, err
+	}
+
+	txns := tl.GetTransactions()
+
+	transactions := make([]*Transaction, 0, len(txns))
+	for _, tx := range txns {
+		transactions = append(transactions, (*Transaction)(tx))
+	}
+
+	return transactions, nil
+}
+
+// -- Batches --
+
+// NewBatch creates a new batch from the given transactions created by
+// NewTransaction. It handles the construction and signing of the batch header.
+func (self *Encoder) NewBatch(transactions []*Transaction) *Batch {
+	txnIds := make([]string, 0, len(transactions))
+	txns := make([]*transaction_pb2.Transaction, 0, len(transactions))
+	for _, tx := range transactions {
+		txnIds = append(txnIds, tx.Id())
+		txns = append(txns, tx.ToPb())
+	}
+
+	h := &batch_pb2.BatchHeader{
+		SignerPubkey:   self.pubkey,
+		TransactionIds: txnIds,
+	}
+
+	hb, err := proto.Marshal(h)
+	if err != nil {
+		panic(err)
+	}
+
+	hs := hex.EncodeToString(Sign(hb, self.privkey))
+
+	batch := &batch_pb2.Batch{
+		Header:          hb,
+		HeaderSignature: hs,
+		Transactions:    txns,
+	}
+
+	return (*Batch)(batch)
+}
+
+// SerializeBatches serializes the given batches to bytes in the form expected
+// by the REST API.
+func SerializeBatches(batches []*Batch) []byte {
+	bs := make([]*batch_pb2.Batch, 0, len(batches))
+	for _, b := range batches {
+		bs = append(bs, b.ToPb())
+	}
+	bl := &batch_pb2.BatchList{
+		Batches: bs,
+	}
+
+	blb, err := proto.Marshal(bl)
+	if err != nil {
+		panic(err)
+	}
+
+	return blb
+}
+
+// ParseBatches deserializes the given bytes into a list of batches. The bytes
+// are assumed to be in the format returned by SerializeBatches.
+func ParseBatches(b []byte) ([]*Batch, error) {
+	bl := &batch_pb2.BatchList{}
+	err := proto.Unmarshal(b, bl)
+	if err != nil {
+		return nil, err
+	}
+
+	bs := bl.GetBatches()
+
+	batches := make([]*Batch, 0, len(bs))
+	for _, b := range bs {
+		batches = append(batches, (*Batch)(b))
+	}
+
+	return batches, nil
+}
+
+// -- Wrap Protobuf --
+
+// Wrap the protobuf types so that they do not need to be imported separately.
+type Transaction transaction_pb2.Transaction
+
+func (t *Transaction) ToPb() *transaction_pb2.Transaction {
+	return (*transaction_pb2.Transaction)(t)
+}
+
+// GetId Returns the Transaction ID which can be used to specify this
+// transaction as a dependency for other transactions.
+func (t *Transaction) Id() string {
+	return t.ToPb().GetHeaderSignature()
+}
+
+type Batch batch_pb2.Batch
+
+func (b *Batch) ToPb() *batch_pb2.Batch {
+	return (*batch_pb2.Batch)(b)
+}

LFS171x/sawtooth-material/sawtooth-tuna/go-processor/sawtooth_sdk/client/pem_loader.go

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+/**
+ * Copyright 2017 Intel Corporation
+ *
+ * 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 client
+
+// #cgo LDFLAGS: -lcrypto
+// #include "../../../../c/loader.c"
+import "C"
+
+import "fmt"
+
+func loadPemKey(pemstr string, pemstrLen int, password string) (priv_key string, pub_key string, err error) {
+	cPemstr := C.CString(pemstr)
+	cPemstrLen := C.size_t(pemstrLen)
+	cPassword := C.CString(password)
+	cOutPrivKey := C.CString("-----------------------------------------------------------------")
+	cOutPubKey := C.CString("-----------------------------------------------------------------------------------------------------------------------------------")
+	errnum := C.load_pem_key(cPemstr, cPemstrLen, cPassword, cOutPrivKey, cOutPubKey)
+	if errnum < 0 {
+		var errstr string
+		switch errnum {
+		case -1:
+			errstr = "Failed to decrypt or decode private key"
+		case -2:
+			errstr = "Failed to create new big number context"
+		case -3:
+			errstr = "Failed to load group"
+		case -4:
+			errstr = "Failed to load private key"
+		case -5:
+			errstr = "Failed to load public key point"
+		case -6:
+			errstr = "Failed to construct public key from point"
+		}
+		return "", "", fmt.Errorf(errstr)
+	}
+	return C.GoString(cOutPrivKey), C.GoString(cOutPubKey), nil
+}