forked from atomix/atomix-go-framework
/
service.go
453 lines (400 loc) · 12.7 KB
/
service.go
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// Copyright 2019-present Open Networking Foundation.
//
// 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 _map //nolint:golint
import (
"bytes"
"github.com/lucasbfernandes/go-framework/pkg/atomix/errors"
"io"
"github.com/lucasbfernandes/go-framework/pkg/atomix/primitive"
"github.com/lucasbfernandes/go-framework/pkg/atomix/stream"
"github.com/lucasbfernandes/go-framework/pkg/atomix/util"
"github.com/golang/protobuf/proto"
)
// Service is a state machine for a map primitive
type Service struct {
primitive.Service
entries map[string]*MapEntryValue
timers map[string]primitive.Timer
listeners map[primitive.SessionID]map[primitive.StreamID]listener
}
// init initializes the map service
func (m *Service) init() {
m.RegisterUnaryOperation(opPut, m.Put)
m.RegisterUnaryOperation(opReplace, m.Replace)
m.RegisterUnaryOperation(opRemove, m.Remove)
m.RegisterUnaryOperation(opGet, m.Get)
m.RegisterUnaryOperation(opExists, m.Exists)
m.RegisterUnaryOperation(opSize, m.Size)
m.RegisterUnaryOperation(opClear, m.Clear)
m.RegisterStreamOperation(opEvents, m.Events)
m.RegisterStreamOperation(opEntries, m.Entries)
}
// Backup takes a snapshot of the service
func (m *Service) Backup(writer io.Writer) error {
listeners := make([]*Listener, 0)
for sessionID, sessionListeners := range m.listeners {
for streamID, sessionListener := range sessionListeners {
listeners = append(listeners, &Listener{
SessionId: uint64(sessionID),
StreamId: uint64(streamID),
Key: sessionListener.key,
})
}
}
if err := util.WriteVarInt(writer, len(listeners)); err != nil {
return err
}
if err := util.WriteSlice(writer, listeners, proto.Marshal); err != nil {
return err
}
return util.WriteMap(writer, m.entries, func(key string, value *MapEntryValue) ([]byte, error) {
return proto.Marshal(&MapEntry{
Key: key,
Value: value,
})
})
}
// Restore restores the service from a snapshot
func (m *Service) Restore(reader io.Reader) error {
length, err := util.ReadVarInt(reader)
if err != nil {
return err
}
listeners := make([]*Listener, length)
err = util.ReadSlice(reader, listeners, func(data []byte) (*Listener, error) {
listener := &Listener{}
if err := proto.Unmarshal(data, listener); err != nil {
return nil, err
}
return listener, nil
})
if err != nil {
return err
}
m.listeners = make(map[primitive.SessionID]map[primitive.StreamID]listener)
for _, snapshotListener := range listeners {
sessionListeners, ok := m.listeners[primitive.SessionID(snapshotListener.SessionId)]
if !ok {
sessionListeners = make(map[primitive.StreamID]listener)
m.listeners[primitive.SessionID(snapshotListener.SessionId)] = sessionListeners
}
sessionListeners[primitive.StreamID(snapshotListener.StreamId)] = listener{
key: snapshotListener.Key,
stream: m.Session(primitive.SessionID(snapshotListener.SessionId)).Stream(primitive.StreamID(snapshotListener.StreamId)),
}
}
entries := make(map[string]*MapEntryValue)
err = util.ReadMap(reader, entries, func(data []byte) (string, *MapEntryValue, error) {
entry := &MapEntry{}
if err := proto.Unmarshal(data, entry); err != nil {
return "", nil, err
}
return entry.Key, entry.Value, nil
})
if err != nil {
return err
}
m.entries = entries
return nil
}
// Put puts a key/value pair in the map
func (m *Service) Put(value []byte) ([]byte, error) {
request := &PutRequest{}
if err := proto.Unmarshal(value, request); err != nil {
return nil, err
}
oldValue := m.entries[request.Key]
if oldValue == nil {
// If the version is positive then reject the request.
if !request.IfEmpty && request.Version > 0 {
return nil, errors.NewAlreadyExists("key %s already exists", request.Key)
}
// Create a new entry value and set it in the map.
newValue := &MapEntryValue{
Value: request.Value,
Version: uint64(m.Index()),
TTL: request.TTL,
Created: m.Timestamp(),
Updated: m.Timestamp(),
}
m.entries[request.Key] = newValue
// Schedule the timeout for the value if necessary.
m.scheduleTTL(request.Key, newValue)
// Publish an event to listener streams.
m.sendEvent(&ListenResponse{
Type: ListenResponse_INSERTED,
Key: request.Key,
Value: newValue.Value,
Version: newValue.Version,
Created: newValue.Created,
Updated: newValue.Updated,
})
return proto.Marshal(&PutResponse{
Status: UpdateStatus_OK,
})
}
// If the version is -1 then reject the request.
// If the version is positive then compare the version to the current version.
if request.IfEmpty {
return nil, errors.NewAlreadyExists("key %s already exists", request.Key)
} else if request.Version > 0 && request.Version != oldValue.Version {
return nil, errors.NewConflict("request version %d does not match stored entry version %d", request.Version, oldValue.Version)
}
// If the value is equal to the current value, return a no-op.
if bytes.Equal(oldValue.Value, request.Value) {
return proto.Marshal(&PutResponse{
Status: UpdateStatus_NOOP,
PreviousValue: oldValue.Value,
PreviousVersion: oldValue.Version,
})
}
// Create a new entry value and set it in the map.
newValue := &MapEntryValue{
Value: request.Value,
Version: uint64(m.Index()),
TTL: request.TTL,
Created: oldValue.Created,
Updated: m.Timestamp(),
}
m.entries[request.Key] = newValue
// Schedule the timeout for the value if necessary.
m.scheduleTTL(request.Key, newValue)
// Publish an event to listener streams.
m.sendEvent(&ListenResponse{
Type: ListenResponse_UPDATED,
Key: request.Key,
Value: newValue.Value,
Version: newValue.Version,
Created: newValue.Created,
Updated: newValue.Updated,
})
return proto.Marshal(&PutResponse{
Status: UpdateStatus_OK,
PreviousValue: oldValue.Value,
PreviousVersion: oldValue.Version,
Created: newValue.Created,
Updated: newValue.Updated,
})
}
// Replace replaces a key/value pair in the map
func (m *Service) Replace(value []byte) ([]byte, error) {
request := &ReplaceRequest{}
if err := proto.Unmarshal(value, request); err != nil {
return nil, err
}
oldValue, ok := m.entries[request.Key]
if !ok {
return nil, errors.NewNotFound("entry for key %s not found", request.Key)
}
// If the version was specified and does not match the entry version, fail the replace.
if request.PreviousVersion != 0 && request.PreviousVersion != oldValue.Version {
return nil, errors.NewConflict("previous version %d does not match stored entry version %d", request.PreviousVersion, oldValue.Version)
}
// If the value was specified and does not match the entry value, fail the replace.
if len(request.PreviousValue) != 0 && bytes.Equal(request.PreviousValue, oldValue.Value) {
return nil, errors.NewConflict("previous value %v does not match stored entry value %v", request.PreviousValue, oldValue.Value)
}
// If we've made it this far, update the entry.
// Create a new entry value and set it in the map.
newValue := &MapEntryValue{
Value: request.NewValue,
Version: uint64(m.Index()),
TTL: request.TTL,
Created: oldValue.Created,
Updated: m.Timestamp(),
}
m.entries[request.Key] = newValue
// Schedule the timeout for the value if necessary.
m.scheduleTTL(request.Key, newValue)
// Publish an event to listener streams.
m.sendEvent(&ListenResponse{
Type: ListenResponse_UPDATED,
Key: request.Key,
Value: newValue.Value,
Version: newValue.Version,
Created: newValue.Created,
Updated: newValue.Updated,
})
return proto.Marshal(&ReplaceResponse{
Status: UpdateStatus_OK,
PreviousValue: oldValue.Value,
PreviousVersion: oldValue.Version,
NewVersion: newValue.Version,
Created: newValue.Created,
Updated: newValue.Updated,
})
}
// Remove removes a key/value pair from the map
func (m *Service) Remove(bytes []byte) ([]byte, error) {
request := &RemoveRequest{}
if err := proto.Unmarshal(bytes, request); err != nil {
return nil, err
}
value, ok := m.entries[request.Key]
if !ok {
return nil, errors.NewNotFound("key %s not found", request.Key)
}
// If the request version is set, verify that the request version matches the entry version.
if request.Version > 0 && request.Version != value.Version {
return nil, errors.NewConflict("request version %s does not match stored entry version %d", request.Version, value.Version)
}
// Delete the entry from the map.
delete(m.entries, request.Key)
// Cancel any TTLs.
m.cancelTTL(request.Key)
// Publish an event to listener streams.
m.sendEvent(&ListenResponse{
Type: ListenResponse_REMOVED,
Key: request.Key,
Value: value.Value,
Version: value.Version,
Created: value.Created,
Updated: value.Updated,
})
return proto.Marshal(&RemoveResponse{
Status: UpdateStatus_OK,
PreviousValue: value.Value,
PreviousVersion: value.Version,
Created: value.Created,
Updated: value.Updated,
})
}
// Get gets a value from the map
func (m *Service) Get(bytes []byte) ([]byte, error) {
request := &GetRequest{}
if err := proto.Unmarshal(bytes, request); err != nil {
return nil, err
}
value, ok := m.entries[request.Key]
if !ok {
return nil, errors.NewNotFound("key %s not found", request.Key)
}
return proto.Marshal(&GetResponse{
Value: value.Value,
Version: value.Version,
Created: value.Created,
Updated: value.Updated,
})
}
// Exists checks if the map contains a key
func (m *Service) Exists(bytes []byte) ([]byte, error) {
request := &ContainsKeyRequest{}
if err := proto.Unmarshal(bytes, request); err != nil {
return nil, err
}
_, ok := m.entries[request.Key]
return proto.Marshal(&ContainsKeyResponse{
ContainsKey: ok,
})
}
// Size returns the size of the map
func (m *Service) Size(bytes []byte) ([]byte, error) {
return proto.Marshal(&SizeResponse{
Size_: uint32(len(m.entries)),
})
}
// Clear removes all entries from the map
func (m *Service) Clear(value []byte) ([]byte, error) {
m.entries = make(map[string]*MapEntryValue)
return proto.Marshal(&ClearResponse{})
}
// Events sends change events to the client
func (m *Service) Events(bytes []byte, stream primitive.Stream) {
request := &ListenRequest{}
if err := proto.Unmarshal(bytes, request); err != nil {
stream.Error(err)
stream.Close()
return
}
// Create and populate the listener
l := listener{
key: request.Key,
stream: stream,
}
listeners, ok := m.listeners[stream.Session().ID()]
if !ok {
listeners = make(map[primitive.StreamID]listener)
m.listeners[stream.Session().ID()] = listeners
}
listeners[stream.ID()] = l
// If replay was requested, send existing entries
if request.Replay {
for key, value := range m.entries {
stream.Result(proto.Marshal(&ListenResponse{
Type: ListenResponse_NONE,
Key: key,
Value: value.Value,
Version: value.Version,
Created: value.Created,
Updated: value.Updated,
}))
}
}
}
// Entries returns a stream of entries to the client
func (m *Service) Entries(value []byte, stream primitive.Stream) {
defer stream.Close()
for key, entry := range m.entries {
stream.Result(proto.Marshal(&EntriesResponse{
Key: key,
Value: entry.Value,
Version: entry.Version,
Created: entry.Created,
Updated: entry.Updated,
}))
}
}
func (m *Service) scheduleTTL(key string, value *MapEntryValue) {
m.cancelTTL(key)
if value.TTL != nil && *value.TTL > 0 {
m.timers[key] = m.ScheduleOnce(value.Created.Add(*value.TTL).Sub(m.Timestamp()), func() {
delete(m.entries, key)
m.sendEvent(&ListenResponse{
Type: ListenResponse_REMOVED,
Key: key,
Value: value.Value,
Version: uint64(value.Version),
Created: value.Created,
Updated: value.Updated,
})
})
}
}
func (m *Service) cancelTTL(key string) {
timer, ok := m.timers[key]
if ok {
timer.Cancel()
}
}
func (m *Service) sendEvent(event *ListenResponse) {
bytes, _ := proto.Marshal(event)
for sessionID, listeners := range m.listeners {
session := m.Session(sessionID)
if session != nil {
for _, listener := range listeners {
if listener.key != "" {
if event.Key == listener.key {
listener.stream.Value(bytes)
}
} else {
listener.stream.Value(bytes)
}
}
}
}
}
type listener struct {
key string
stream stream.WriteStream
}