wrap the functions

dgraph/cmd/zero/raft.go

@@ -18,7 +18,6 @@ package zero
 
 import (
 	"context"
-	"crypto/rand"
 	"encoding/binary"
 	"fmt"
 	"log"
@@ -88,16 +87,11 @@ func (n *node) AmLeader() bool {
 // {2 bytes Node ID} {4 bytes for random} {2 bytes zero}
 func (n *node) initProposalKey(id uint64) error {
 	x.AssertTrue(id != 0)
-	random4Bytes := make([]byte, 4)
-	if _, err := rand.Read(random4Bytes); err != nil {
+	var err error
+	proposalKey, err = x.ProposalKey(n.Id)
+	if err != nil {
 		return err
 	}
-	proposalKey = n.Id<<48 | uint64(binary.BigEndian.Uint32(random4Bytes))<<16
-	// We want to avoid spillage to node id in case of overflow. For instance, if the
-	// random bytes end up being [xx,xx, 255, 255, 255, 255, 0 , 0] (xx, xx being the node id)
-	// we would spill to node id after 65535 calls to unique key.
-	// So by setting 48th bit to 0 we ensure that we never spill out to node ids.
-	proposalKey &= ^(uint64(1) << 47)
 	return nil
 }
 

worker/proposal.go

@@ -18,7 +18,6 @@ package worker
 
 import (
 	"context"
-	"crypto/rand"
 	"encoding/binary"
 	"sync"
 	"sync/atomic"
@@ -113,11 +112,11 @@ var proposalKey uint64
 // {2 bytes Node ID} {4 bytes for random} {2 bytes zero}
 func initProposalKey(id uint64) error {
 	x.AssertTrue(id != 0)
-	b := make([]byte, 8)
-	if _, err := rand.Read(b); err != nil {
+	var err error
+	proposalKey, err = x.ProposalKey(groups().Node.Id)
+	if err != nil {
 		return err
 	}
-	proposalKey = groups().Node.Id<<48 | binary.BigEndian.Uint64(b)<<16
 	return nil
 }
 

x/x.go

@@ -21,12 +21,13 @@ import (
 	"bytes"
 	builtinGzip "compress/gzip"
 	"context"
+	"crypto/rand"
 	"crypto/tls"
+	"encoding/binary"
 	"encoding/json"
 	"fmt"
 	"io"
 	"math"
-	"math/rand"
 	"net"
 	"net/http"
 	"os"
@@ -644,6 +645,21 @@ func RetryUntilSuccess(maxRetries int, waitAfterFailure time.Duration,
 	return err
 }
 
+// {2 bytes Node ID} {4 bytes for random} {2 bytes zero}
+func ProposalKey(id uint64) (uint64, error) {
+	random4Bytes := make([]byte, 4)
+	if _, err := rand.Read(random4Bytes); err != nil {
+		return 0, err
+	}
+	proposalKey := id<<48 | uint64(binary.BigEndian.Uint32(random4Bytes))<<16
+	// We want to avoid spillage to node id in case of overflow. For instance, if the
+	// random bytes end up being [xx,xx, 255, 255, 255, 255, 0 , 0] (xx, xx being the node id)
+	// we would spill to node id after 65535 calls to unique key.
+	// So by setting 48th bit to 0 we ensure that we never spill out to node ids.
+	proposalKey &= ^(uint64(1) << 47)
+	return proposalKey, nil
+}
+
 // HasString returns whether the slice contains the given string.
 func HasString(a []string, b string) bool {
 	for _, k := range a {