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Merge pull request #14902 from serathius/linearizability-issue14685 

Refactor etcd model
dependabot/go_modules/go.uber.org/atomic-1.10.0
Marek Siarkowicz 2022-12-08 23:32:18 +01:00 committed by GitHub
parent bb528a6bf4 60200b37d3
commit dc9e422e28
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GPG Key ID: 4AEE18F83AFDEB23
2 changed files with 67 additions and 107 deletions
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163
tests/linearizability/model.go
View File

@ -43,10 +43,13 @@ type EtcdResponse struct {
}
type EtcdState struct {
Key string
Value string
LastRevision int64
FailedWrite *EtcdRequest
Key string
PossibleValues []ValueRevision
}
type ValueRevision struct {
Value string
Revision int64
}
var etcdModel = porcupine.Model{
@ -93,121 +96,77 @@ var etcdModel = porcupine.Model{
}
func step(state EtcdState, request EtcdRequest, response EtcdResponse) (bool, EtcdState) {
if request.Key == "" {
panic("invalid request")
}
if state.Key == "" {
return true, initState(request, response)
if len(state.PossibleValues) == 0 {
state.Key = request.Key
if ok, v := initValueRevision(request, response); ok {
state.PossibleValues = append(state.PossibleValues, v)
}
return true, state
}
if state.Key != request.Key {
panic("Multiple keys not supported")
panic("multiple keys not supported")
}
if response.Err != nil {
for _, v := range state.PossibleValues {
newV, _ := stepValue(v, request)
state.PossibleValues = append(state.PossibleValues, newV)
}
} else {
var i = 0
for _, v := range state.PossibleValues {
newV, expectedResponse := stepValue(v, request)
if expectedResponse == response {
state.PossibleValues[i] = newV
i++
}
}
state.PossibleValues = state.PossibleValues[:i]
}
return len(state.PossibleValues) > 0, state
}
func initValueRevision(request EtcdRequest, response EtcdResponse) (ok bool, v ValueRevision) {
if response.Err != nil {
return false, ValueRevision{}
}
switch request.Op {
case Get:
return stepGet(state, request, response)
return true, ValueRevision{
Value: response.GetData,
Revision: response.Revision,
}
case Put:
return stepPut(state, request, response)
return true, ValueRevision{
Value: request.PutData,
Revision: response.Revision,
}
case Delete:
return stepDelete(state, request, response)
return true, ValueRevision{
Value: "",
Revision: response.Revision,
}
default:
panic("Unknown operation")
}
}
func initState(request EtcdRequest, response EtcdResponse) EtcdState {
state := EtcdState{
Key: request.Key,
LastRevision: response.Revision,
}
func stepValue(v ValueRevision, request EtcdRequest) (ValueRevision, EtcdResponse) {
resp := EtcdResponse{}
switch request.Op {
case Get:
state.Value = response.GetData
resp.GetData = v.Value
case Put:
if response.Err == nil {
state.Value = request.PutData
} else {
state.FailedWrite = &request
}
v.Value = request.PutData
v.Revision += 1
case Delete:
if response.Err != nil {
state.FailedWrite = &request
if v.Value != "" {
v.Value = ""
v.Revision += 1
resp.Deleted = 1
}
default:
panic("Unknown operation")
panic("unsupported operation")
}
return state
}
func stepGet(state EtcdState, request EtcdRequest, response EtcdResponse) (bool, EtcdState) {
if state.Value == response.GetData && state.LastRevision == response.Revision {
state.FailedWrite = nil
return true, state
}
if state.FailedWrite != nil && state.LastRevision < response.Revision {
var ok bool
switch state.FailedWrite.Op {
case Get:
panic("Expected write")
case Put:
ok = response.GetData == state.FailedWrite.PutData
case Delete:
ok = response.GetData == ""
default:
panic("Unknown operation")
}
if ok {
state.Value = response.GetData
state.LastRevision = response.Revision
state.FailedWrite = nil
return true, state
}
}
return false, state
}
func stepPut(state EtcdState, request EtcdRequest, response EtcdResponse) (bool, EtcdState) {
if response.Err != nil {
state.FailedWrite = &request
return true, state
}
if response.Revision <= state.LastRevision {
return false, state
}
if response.Revision != state.LastRevision+1 && state.FailedWrite == nil {
return false, state
}
state.Value = request.PutData
state.LastRevision = response.Revision
state.FailedWrite = nil
return true, state
}
func stepDelete(state EtcdState, request EtcdRequest, response EtcdResponse) (bool, EtcdState) {
if response.Err != nil {
state.FailedWrite = &request
return true, state
}
// revision should never decrease
if response.Revision < state.LastRevision {
return false, state
}
deleteSucceeded := response.Deleted != 0
keySet := state.Value != ""
// non-existent key cannot be deleted.
if deleteSucceeded != keySet && state.FailedWrite == nil {
return false, state
}
//if key was deleted, response revision should increase
if deleteSucceeded && (response.Revision != state.LastRevision+1 || !keySet) && (state.FailedWrite == nil || response.Revision < state.LastRevision+2) {
return false, state
}
//if key was not deleted, response revision should not change
if !deleteSucceeded && state.LastRevision != response.Revision && state.FailedWrite == nil {
return false, state
}
state.Value = ""
state.LastRevision = response.Revision
return true, state
resp.Revision = v.Revision
return v, resp
}

11
tests/linearizability/model_test.go
View File

@ -105,8 +105,6 @@ func TestModel(t *testing.T) {
// Two failed request, two persisted.
{req: EtcdRequest{Op: Put, Key: "key", PutData: "3"}, resp: EtcdResponse{Err: errors.New("failed")}},
{req: EtcdRequest{Op: Put, Key: "key", PutData: "4"}, resp: EtcdResponse{Err: errors.New("failed")}},
{req: EtcdRequest{Op: Get, Key: "key"}, resp: EtcdResponse{GetData: "3", Revision: 3}, failure: true},
{req: EtcdRequest{Op: Get, Key: "key"}, resp: EtcdResponse{GetData: "3", Revision: 4}, failure: true},
{req: EtcdRequest{Op: Get, Key: "key"}, resp: EtcdResponse{GetData: "4", Revision: 4}},
},
},
@ -220,15 +218,18 @@ func TestModel(t *testing.T) {
},
}
for _, tc := range tcs {
var ok bool
t.Run(tc.name, func(t *testing.T) {
state := etcdModel.Init()
for _, op := range tc.operations {
t.Logf("state: %v", state)
ok, state = etcdModel.Step(state, op.req, op.resp)
ok, newState := etcdModel.Step(state, op.req, op.resp)
if ok != !op.failure {
t.Logf("state: %v", state)
t.Errorf("Unexpected operation result, expect: %v, got: %v, operation: %s", !op.failure, ok, etcdModel.DescribeOperation(op.req, op.resp))
}
if ok {
state = newState
t.Logf("state: %v", state)
}
}
})
}