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cluster_stub_test.go
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cluster_stub_test.go
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package radix
import (
"fmt"
"sort"
"strconv"
"strings"
"sync"
. "testing"
errors "golang.org/x/xerrors"
"github.com/mediocregopher/radix/v3/resp/resp2"
"github.com/stretchr/testify/assert"
"github.com/stretchr/testify/require"
)
type clusterSlotStub struct {
kv map[string]string
migrating, importing string // addr migrating to/importing from, if either
}
// clusterDatasetStub describes a dataset hosted by a clusterStub instance. This
// is separated out because different instances can host the same dataset
// (primary and secondaries)
type clusterDatasetStub struct {
sync.Mutex
slots map[uint16]clusterSlotStub
}
func (sd *clusterDatasetStub) slotRanges() [][2]uint16 {
slotIs := make([]uint16, 0, len(sd.slots))
for i := range sd.slots {
slotIs = append(slotIs, i)
}
sort.Slice(slotIs, func(i, j int) bool { return slotIs[i] < slotIs[j] })
ranges := make([][2]uint16, 0, 1)
for _, slot := range slotIs {
if len(ranges) == 0 {
ranges = append(ranges, [2]uint16{slot, slot + 1})
} else if lastRange := &(ranges[len(ranges)-1]); (*lastRange)[1] == slot {
(*lastRange)[1] = slot + 1
} else {
ranges = append(ranges, [2]uint16{slot, slot + 1})
}
}
return ranges
}
////////////////////////////////////////////////////////////////////////////////
// equivalent to a single redis instance
type clusterNodeStub struct {
addr, id string
secondaryOfAddr, secondaryOfID string // set if secondary
*clusterDatasetStub
*clusterStub
}
func (s *clusterNodeStub) addSlot(slot uint16) {
s.clusterDatasetStub.Lock()
defer s.clusterDatasetStub.Unlock()
_, hasSlot := s.clusterDatasetStub.slots[slot]
if hasSlot {
panic(fmt.Sprintf("stub already owns slot %d", slot))
}
s.clusterStub.stubs[s.addr] = s
s.clusterDatasetStub.slots[0] = clusterSlotStub{kv: map[string]string{}}
}
func (s *clusterNodeStub) removeSlot(slot uint16) {
s.clusterDatasetStub.Lock()
defer s.clusterDatasetStub.Unlock()
_, hasSlot := s.clusterDatasetStub.slots[slot]
if !hasSlot {
panic(fmt.Sprintf("stub does not own slot %d", slot))
}
delete(s.clusterStub.stubs, s.addr)
delete(s.clusterDatasetStub.slots, 0)
}
func (s *clusterNodeStub) withKey(key string, asking bool, fn func(clusterSlotStub) interface{}) interface{} {
s.clusterDatasetStub.Lock()
defer s.clusterDatasetStub.Unlock()
return s.withKeyLocked(key, asking, fn)
}
func (s *clusterNodeStub) withKeyLocked(key string, asking bool, fn func(clusterSlotStub) interface{}) interface{} {
slotI := ClusterSlot([]byte(key))
slot, ok := s.clusterDatasetStub.slots[slotI]
if !ok {
movedStub := s.clusterStub.stubForSlotIfSet(slotI)
if movedStub == nil {
return resp2.Error{E: errors.New("CLUSTERDOWN Hash slot not served")}
}
return resp2.Error{E: errors.Errorf("MOVED %d %s", slotI, movedStub.addr)}
} else if _, ok := slot.kv[key]; !ok && slot.migrating != "" {
return resp2.Error{E: errors.Errorf("ASK %d %s", slotI, slot.migrating)}
} else if slot.importing != "" && !asking {
return resp2.Error{E: errors.Errorf("MOVED %d %s", slotI, slot.importing)}
}
return fn(slot)
}
func (s *clusterNodeStub) withKeys(keys []string, asking bool, fn func(clusterSlotStub) interface{}) interface{} {
if err := assertKeysSlot(keys); err != nil {
return err
}
s.clusterDatasetStub.Lock()
defer s.clusterDatasetStub.Unlock()
// this doesn't correctly handle the case were all the given keys are the same,
// in which case a real redis cluster node will handle the command like a single
// key command.
if len(keys) > 1 && asking {
slotI := ClusterSlot([]byte(keys[0]))
slot := s.clusterDatasetStub.slots[slotI]
if slot.importing != "" {
return resp2.Error{E: errors.New("TRYAGAIN Multiple keys request during rehashing of slot")}
}
}
return s.withKeyLocked(keys[0], asking, fn)
}
func (s *clusterNodeStub) newConn() Conn {
asking := false // flag we hold onto in between commands
return Stub("tcp", s.addr, func(args []string) interface{} {
cmd := strings.ToUpper(args[0])
// If the cmd is not ASKING we need to unset the flag at the _end_ of
// this command, if it's set
if cmd != "ASKING" {
defer func() {
asking = false
}()
}
switch cmd {
case "GET":
k := args[1]
return s.withKey(k, asking, func(slot clusterSlotStub) interface{} {
s, ok := slot.kv[k]
if !ok {
return nil
}
return s
})
case "MGET":
ks := args[1:]
return s.withKeys(ks, asking, func(slot clusterSlotStub) interface{} {
ss := make([]string, len(ks))
for i, k := range ks {
ss[i] = slot.kv[k]
}
return ss
})
case "SET":
k := args[1]
return s.withKey(k, asking, func(slot clusterSlotStub) interface{} {
slot.kv[k] = args[2]
return resp2.SimpleString{S: "OK"}
})
case "EVALSHA":
return resp2.Error{E: errors.New("NOSCRIPT: clusterNodeStub does not support EVALSHA")}
case "EVAL":
// see if any keys were sent
if len(args) < 3 {
return resp2.Error{E: errors.New("malformed EVAL command")}
}
numKeys, err := strconv.Atoi(args[2])
if err != nil {
return resp2.Error{E: err}
} else if numKeys == 0 {
return "EVAL: no keys"
}
return s.withKey(args[3], asking, func(slot clusterSlotStub) interface{} {
return "EVAL: success!"
})
case "PING":
return resp2.SimpleString{S: "PONG"}
case "CLUSTER":
switch strings.ToUpper(args[1]) {
case "SLOTS":
return s.clusterStub.topo()
}
case "ASKING":
asking = true
return resp2.SimpleString{S: "OK"}
case "ADDR":
return s.addr
case "SCAN":
if cur := args[1]; cur == "0" {
var keys []string
s.clusterDatasetStub.Lock()
for _, slot := range s.clusterDatasetStub.slots {
for key := range slot.kv {
keys = append(keys, key)
}
}
s.clusterDatasetStub.Unlock()
return []interface{}{"1", keys}
}
return []interface{}{"0", []string{}}
}
return resp2.Error{E: errors.Errorf("unknown command %#v", args)}
})
}
func (s *clusterNodeStub) Close() error {
*s = clusterNodeStub{}
return nil
}
////////////////////////////////////////////////////////////////////////////////
type clusterStub struct {
stubs map[string]*clusterNodeStub // addr -> stub
}
func newStubCluster(tt ClusterTopo) *clusterStub {
// map of addrs to dataset
m := map[string]*clusterDatasetStub{}
sc := &clusterStub{
stubs: make(map[string]*clusterNodeStub, len(tt)),
}
for _, t := range tt {
addr := t.Addr
if t.SecondaryOfAddr != "" {
addr = t.SecondaryOfAddr
}
sd, ok := m[addr]
if !ok {
sd = &clusterDatasetStub{slots: map[uint16]clusterSlotStub{}}
for _, slots := range t.Slots {
for i := slots[0]; i < slots[1]; i++ {
sd.slots[i] = clusterSlotStub{kv: map[string]string{}}
}
}
m[addr] = sd
}
sc.stubs[t.Addr] = &clusterNodeStub{
addr: t.Addr,
id: t.ID,
secondaryOfAddr: t.SecondaryOfAddr,
secondaryOfID: t.SecondaryOfID,
clusterDatasetStub: sd,
clusterStub: sc,
}
}
return sc
}
func (scl *clusterStub) stubForSlot(slot uint16) *clusterNodeStub {
if stub := scl.stubForSlotIfSet(slot); stub != nil {
return stub
}
panic(fmt.Sprintf("couldn't find stub for slot %d", slot))
}
func (scl *clusterStub) stubForSlotIfSet(slot uint16) *clusterNodeStub {
for _, s := range scl.stubs {
if slot, ok := s.clusterDatasetStub.slots[slot]; ok && s.secondaryOfAddr == "" && slot.importing == "" {
return s
}
}
return nil
}
func (scl *clusterStub) topo() ClusterTopo {
var tt ClusterTopo
for _, s := range scl.stubs {
slotRanges := s.clusterDatasetStub.slotRanges()
if len(slotRanges) == 0 {
continue
}
tt = append(tt, ClusterNode{
Addr: s.addr,
ID: s.id,
Slots: slotRanges,
SecondaryOfAddr: s.secondaryOfAddr,
SecondaryOfID: s.secondaryOfID,
})
}
tt.sort()
return tt
}
func (scl *clusterStub) clientFunc() ClientFunc {
return func(network, addr string) (Client, error) {
for _, s := range scl.stubs {
if s.addr == addr {
return s.newConn(), nil
}
}
return nil, errors.Errorf("unknown addr: %q", addr)
}
}
func (scl *clusterStub) addrs() []string {
var res []string
for _, s := range scl.stubs {
res = append(res, s.addr)
}
return res
}
func (scl *clusterStub) newCluster(opts ...ClusterOpt) *Cluster {
opts = append([]ClusterOpt{ClusterPoolFunc(scl.clientFunc())}, opts...)
c, err := NewCluster(scl.addrs(), opts...)
if err != nil {
panic(err)
}
return c
}
func (scl *clusterStub) randStub() *clusterNodeStub {
for _, s := range scl.stubs {
if s.secondaryOfAddr != "" {
return s
}
}
panic("cluster is empty?")
}
// Migration steps:
// * Mark slot as migrating on src and importing on dst
// * Move each key individually
// * Mark slots as migrated, note slot change in datasets
//
// At any point inside those steps we need to be able to run a test
func (scl *clusterStub) migrateInit(dstAddr string, slot uint16) {
src := scl.stubForSlot(slot)
src.clusterDatasetStub.Lock()
defer src.clusterDatasetStub.Unlock()
dst := scl.stubs[dstAddr]
dst.clusterDatasetStub.Lock()
defer dst.clusterDatasetStub.Unlock()
srcSlot := src.clusterDatasetStub.slots[slot]
srcSlot.migrating = dst.addr
src.clusterDatasetStub.slots[slot] = srcSlot
dst.clusterDatasetStub.slots[slot] = clusterSlotStub{
kv: map[string]string{},
importing: src.addr,
}
}
// migrateInit must have been called on the slot this key belongs to
func (scl *clusterStub) migrateKey(key string) {
slot := ClusterSlot([]byte(key))
src := scl.stubForSlot(slot)
src.clusterDatasetStub.Lock()
defer src.clusterDatasetStub.Unlock()
srcSlot := src.clusterDatasetStub.slots[slot]
dst := scl.stubs[srcSlot.migrating]
dst.clusterDatasetStub.Lock()
defer dst.clusterDatasetStub.Unlock()
dst.clusterDatasetStub.slots[slot].kv[key] = srcSlot.kv[key]
delete(srcSlot.kv, key)
}
// migrateInit must have been called on the slot already
func (scl *clusterStub) migrateAllKeys(slot uint16) {
src := scl.stubForSlot(slot)
src.clusterDatasetStub.Lock()
defer src.clusterDatasetStub.Unlock()
srcSlot := src.clusterDatasetStub.slots[slot]
dst := scl.stubs[srcSlot.migrating]
dst.clusterDatasetStub.Lock()
defer dst.clusterDatasetStub.Unlock()
for k, v := range srcSlot.kv {
dst.clusterDatasetStub.slots[slot].kv[k] = v
delete(srcSlot.kv, k)
}
}
// all keys must have been migrated to call this, probably via migrateAllKeys
func (scl *clusterStub) migrateDone(slot uint16) {
src := scl.stubForSlot(slot)
src.clusterDatasetStub.Lock()
defer src.clusterDatasetStub.Unlock()
srcSlot := src.clusterDatasetStub.slots[slot]
dst := scl.stubs[srcSlot.migrating]
dst.clusterDatasetStub.Lock()
defer dst.clusterDatasetStub.Unlock()
delete(src.clusterDatasetStub.slots, slot)
dstSlot := dst.clusterDatasetStub.slots[slot]
dstSlot.importing = ""
dst.clusterDatasetStub.slots[slot] = dstSlot
}
func (scl *clusterStub) migrateSlotRange(dstAddr string, start, end uint16) {
for slot := start; slot < end; slot++ {
scl.migrateInit(dstAddr, slot)
scl.migrateAllKeys(slot)
scl.migrateDone(slot)
}
}
// Who watches the watchmen?
func TestClusterStub(t *T) {
scl := newStubCluster(testTopo)
var outTT ClusterTopo
err := scl.randStub().newConn().Do(Cmd(&outTT, "CLUSTER", "SLOTS"))
require.Nil(t, err)
assert.Equal(t, testTopo, outTT)
// make sure that moving slots works, start by marking the slot 0 as
// migrating to another addr (dst). We choose dst as the node which holds
// some arbitrary high number slot
src := scl.stubForSlot(0)
srcConn := src.newConn()
key := clusterSlotKeys[0]
require.Nil(t, srcConn.Do(Cmd(nil, "SET", key, "foo")))
dst := scl.stubForSlot(10000)
dstConn := dst.newConn()
scl.migrateInit(dst.addr, 0)
// getting a key from that slot from the original should still work
var val string
require.Nil(t, srcConn.Do(Cmd(&val, "GET", key)))
assert.Equal(t, "foo", val)
var vals []string
require.Nil(t, srcConn.Do(Cmd(&vals, "MGET", key)))
assert.Len(t, vals, 1)
assert.Equal(t, "foo", vals[0])
// getting on the new dst should give MOVED
err = dstConn.Do(Cmd(nil, "GET", key))
assert.EqualError(t, err, "MOVED 0 "+src.addr)
// actually migrate that key ...
scl.migrateKey(key)
// ... then doing the GET on the src should give an ASK error ...
err = srcConn.Do(Cmd(nil, "GET", key))
assert.EqualError(t, err, "ASK 0 "+dst.addr)
// ... doing the GET on the dst _without_ asking should give MOVED again ...
err = dstConn.Do(Cmd(nil, "GET", key))
assert.EqualError(t, err, "MOVED 0 "+src.addr)
// ... but doing it with ASKING on dst should work
require.Nil(t, dstConn.Do(Cmd(nil, "ASKING")))
require.Nil(t, dstConn.Do(Cmd(nil, "GET", key)))
assert.Equal(t, "foo", val)
// while migrating a slot
// ... trying to get multiple keys on the dst should give a MOVED ..
err = dstConn.Do(Cmd(nil, "MGET", key, "{"+key+"}.foo"))
assert.EqualError(t, err, "MOVED 0 "+src.addr)
// ... but doing it with ASKING on dst should return a TRYAGAIN ...
require.Nil(t, dstConn.Do(Cmd(nil, "ASKING")))
err = dstConn.Do(Cmd(nil, "MGET", key, "{"+key+"}.foo"))
assert.EqualError(t, err, "TRYAGAIN Multiple keys request during rehashing of slot")
// ... unless we only try to get one key
require.Nil(t, dstConn.Do(Cmd(nil, "ASKING")))
require.Nil(t, dstConn.Do(Cmd(&vals, "MGET", "{"+key+"}.foo")))
assert.Len(t, vals, 1)
assert.Equal(t, "", vals[0])
// finish the migration, then src should always MOVED, dst should always
// work
scl.migrateAllKeys(0)
scl.migrateDone(0)
err = srcConn.Do(Cmd(nil, "GET", key))
assert.EqualError(t, err, "MOVED 0 "+dst.addr)
require.Nil(t, dstConn.Do(Cmd(nil, "GET", key)))
assert.Equal(t, "foo", val)
require.Nil(t, dstConn.Do(Cmd(&vals, "MGET", key, "{"+key+"}.foo")))
assert.Len(t, vals, 2)
assert.Equal(t, vals[0], "foo")
assert.Equal(t, vals[1], "")
}
func TestClusterStubSlotNotBound(t *T) {
scl := newStubCluster(testTopo)
stub0 := scl.stubForSlot(0)
stub0.removeSlot(0)
key := clusterSlotKeys[0]
err := stub0.newConn().Do(Cmd(nil, "GET", key))
assert.EqualError(t, err, "CLUSTERDOWN Hash slot not served")
stub0.addSlot(0)
err = stub0.newConn().Do(Cmd(nil, "GET", key))
assert.Nil(t, err)
}