pool: Improve payment UUID with random value.

The UUID used for the payment ID was not created with any randomness to
it, leading to occasional test failures due to duplicated values.
Appending a random value to the UUID helps to ensure uniqueness.

The commit also updates the database upgrade code to ensure the old
payment ID format is used when performing the old version upgrade.

pool/hub.go

@@ -6,14 +6,15 @@ package pool
 
 import (
 	"context"
-	"crypto/rand"
+	crand "crypto/rand"
 	"crypto/tls"
 	"crypto/x509"
 	"encoding/binary"
 	"encoding/hex"
 	"errors"
 	"fmt"
 	"math/big"
+	mrand "math/rand"
 	"net/http"
 	"os"
 	"strings"
@@ -95,6 +96,10 @@ var (
 	// high value to reduce the number of round trips to the pool by connected
 	// pool clients since pool shares are a non factor in solo pool mode.
 	soloMaxGenTime = time.Second * 28
+
+	// uuidPRNG is a pseudo-random number generator used as a part of generating
+	// the UUIDs for payments and submitted shares.
+	uuidPRNG = mrand.New(mrand.NewSource(time.Now().UnixNano()))
 )
 
 // WalletConnection defines the functionality needed by a wallet
@@ -766,7 +771,7 @@ func (h *Hub) CSRFSecret() ([]byte, error) {
 			// If the database doesnt contain a CSRF secret, generate one and
 			// persist it.
 			secret = make([]byte, 32)
-			_, err = rand.Read(secret)
+			_, err = crand.Read(secret)
 			if err != nil {
 				return nil, err
 			}

pool/payment.go

@@ -6,6 +6,7 @@ package pool
 
 import (
 	"bytes"
+	"encoding/binary"
 	"encoding/hex"
 	"time"
 
@@ -32,12 +33,16 @@ type Payment struct {
 	Source *PaymentSource `json:"source"`
 }
 
-// paymentID generates a unique id using the provided payment details.
-func paymentID(height uint32, createdOnNano int64, account string) string {
+// paymentID generates a unique id using the provided payment details and a
+// random uint64.
+func paymentID(height uint32, createdOnNano int64, account string, randVal uint64) string {
+	var randValEncoded [8]byte
+	binary.BigEndian.PutUint64(randValEncoded[:], randVal)
 	var buf bytes.Buffer
 	_, _ = buf.WriteString(hex.EncodeToString(heightToBigEndianBytes(height)))
 	_, _ = buf.WriteString(hex.EncodeToString(nanoToBigEndianBytes(createdOnNano)))
 	_, _ = buf.WriteString(account)
+	_, _ = buf.WriteString(hex.EncodeToString(randValEncoded[:]))
 	return buf.String()
 }
 
@@ -46,7 +51,7 @@ func NewPayment(account string, source *PaymentSource, amount dcrutil.Amount,
 	height uint32, estMaturity uint32) *Payment {
 	now := time.Now().UnixNano()
 	return &Payment{
-		UUID:              paymentID(height, now, account),
+		UUID:              paymentID(height, now, account, uuidPRNG.Uint64()),
 		Account:           account,
 		Amount:            amount,
 		Height:            height,

pool/share.go

@@ -9,14 +9,9 @@ import (
 	"encoding/binary"
 	"encoding/hex"
 	"math/big"
-	"math/rand"
 	"time"
 )
 
-// uuidPRNG is a pseudo-random number generator used as a part of generating the
-// UUID for submitted shares.
-var uuidPRNG = rand.New(rand.NewSource(time.Now().UnixNano()))
-
 // ShareWeights reprsents the associated weights for each known DCR miner.
 // With the share weight of the lowest hash DCR miner (LHM) being 1, the
 // rest were calculated as :