forked from cocaine/cocaine-framework-go
/
service.go
287 lines (254 loc) · 6.41 KB
/
service.go
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package cocaine
import (
"fmt"
"sync"
"time"
"github.com/ugorji/go/codec"
)
type ServiceResult interface {
Extract(interface{}) error
Err() error
}
type serviceRes struct {
res []byte
err error
}
//Unpacks the result of the called method in the passed structure.
//You can transfer the structure of a particular type that will avoid the type checking. Look at examples.
func (s *serviceRes) Extract(target interface{}) (err error) {
err = codec.NewDecoderBytes(s.res, h).Decode(&target)
return
}
//Error status
func (s *serviceRes) Err() error {
return s.err
}
//
type ServiceError struct {
Code int
Message string
}
func (err *ServiceError) Error() string {
return err.Message
}
func getServiceChanPair(stop <-chan bool) (In chan ServiceResult, Out chan ServiceResult) {
In = make(chan ServiceResult)
Out = make(chan ServiceResult)
finished := false
go func() {
var pending []ServiceResult
for {
var out chan ServiceResult
var first ServiceResult
if len(pending) > 0 {
first = pending[0]
out = Out
} else if finished {
close(Out)
break
}
select {
case incoming, ok := <-In:
if ok {
pending = append(pending, incoming)
} else {
finished = true
In = nil
}
case out <- first:
pending = pending[1:]
case <-stop: // Notification from Close()
return
}
}
}()
return
}
//Allows you to invoke methods of services and send events to other cloud applications.
type Service struct {
sessions *keeperStruct
unpacker *streamUnpacker
stop chan bool
args []interface{}
name string
ResolveResult
socketIO
mutex sync.Mutex
wg sync.WaitGroup
is_reconnecting bool
}
//Creates new service instance with specifed name.
//Optional parameter is a network endpoint of the locator (default ":10053"). Look at Locator.
func serviceResolve(name string, args ...interface{}) (info ResolveResult, err error) {
l, err := NewLocator(args...)
if err != nil {
return
}
defer l.Close()
info = <-l.Resolve(name)
return
}
func serviceCreateIO(endpoint string) (sock socketIO, err error) {
sock, err = newAsyncRWSocket("tcp", endpoint, time.Second*5)
return
}
func NewService(name string, args ...interface{}) (s *Service, err error) {
info, err := serviceResolve(name, args...)
if err != nil {
return
}
if !info.success {
err = fmt.Errorf("Unable to resolve service %s", name)
return
}
sock, err := serviceCreateIO(info.Endpoint.AsString())
if err != nil {
return
}
s = &Service{
sessions: newKeeperStruct(),
unpacker: newStreamUnpacker(),
stop: make(chan bool),
args: args,
name: name,
ResolveResult: info,
socketIO: sock,
mutex: sync.Mutex{},
wg: sync.WaitGroup{},
is_reconnecting: false,
}
go s.loop()
return
}
func (service *Service) loop() {
for data := range service.socketIO.Read() {
for _, item := range service.unpacker.Feed(data) {
switch msg := item.(type) {
case *chunk:
if ch, ok := service.sessions.Get(msg.getSessionID()); ok {
ch <- &serviceRes{msg.Data, nil}
}
case *choke:
if ch, ok := service.sessions.Get(msg.getSessionID()); ok {
close(ch)
service.sessions.Detach(msg.getSessionID())
}
case *errorMsg:
if ch, ok := service.sessions.Get(msg.getSessionID()); ok {
ch <- &serviceRes{nil, &ServiceError{msg.Code, msg.Message}}
}
}
}
}
}
func (service *Service) Reconnect(force bool) error {
if !service.is_reconnecting {
service.mutex.Lock()
defer service.mutex.Unlock()
if service.is_reconnecting {
return fmt.Errorf("%s", "Service is reconnecting now")
}
service.is_reconnecting = true
defer func() { service.is_reconnecting = false }()
if !force {
select {
case <-service.IsClosed():
default:
return fmt.Errorf("%s", "Service is already connected")
}
}
// Send error to all open sessions
for _, key := range service.sessions.Keys() {
service.sessions.RLock()
fmt.Println(key)
if ch, ok := service.sessions.Get(key); ok {
ch <- &serviceRes{nil, &ServiceError{-100, "Disconnected"}}
}
service.sessions.RUnlock()
service.sessions.Detach(key)
}
// Create new socket
info, err := serviceResolve(service.name, service.args...)
if err != nil {
return err
}
sock, err := serviceCreateIO(info.Endpoint.AsString())
if err != nil {
return err
}
// Dispose old IO interface
service.Close()
service.stop = make(chan bool)
service.socketIO = sock
service.unpacker = newStreamUnpacker()
go service.loop()
return nil
}
return fmt.Errorf("%s", "Service is reconnecting now")
}
func (service *Service) call(name string, args ...interface{}) chan ServiceResult {
method, err := service.getMethodNumber(name)
if err != nil {
errorOut := make(chan ServiceResult, 1)
errorOut <- &serviceRes{nil, &ServiceError{-100, "Wrong method name"}}
return errorOut
}
in, out := service.getServiceChanPair()
id := service.sessions.Attach(in)
msg := ServiceMethod{messageInfo{method, id}, args}
service.socketIO.Write() <- packMsg(&msg)
return out
}
//Calls a remote method by name and pass args
func (service *Service) Call(name string, args ...interface{}) chan ServiceResult {
select {
case <-service.IsClosed():
if err := service.Reconnect(false); err != nil {
errorOut := make(chan ServiceResult, 1)
errorOut <- &serviceRes{nil, &ServiceError{-32, "Disconnected"}}
return errorOut
}
default:
}
return service.call(name, args...)
}
//Disposes resources of a service. You must call this method if the service isn't used anymore.
func (service *Service) Close() {
close(service.stop) // Broadcast all related goroutines about disposing
service.socketIO.Close()
}
func (service *Service) getServiceChanPair() (In chan ServiceResult, Out chan ServiceResult) {
In = make(chan ServiceResult)
Out = make(chan ServiceResult)
go func() {
service.wg.Add(1)
defer service.wg.Done()
finished := false
var pending []ServiceResult
for {
var out chan ServiceResult
var first ServiceResult
if len(pending) > 0 {
first = pending[0]
out = Out
} else if finished {
close(Out)
break
}
select {
case incoming, ok := <-In:
if ok {
pending = append(pending, incoming)
} else {
finished = true
In = nil
}
case out <- first:
pending = pending[1:]
case <-service.stop: // Notification from Close()
return
}
}
}()
return
}