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rpc_server.go
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rpc_server.go
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package server
import (
"context"
"io"
"net"
"runtime/debug"
"sort"
"strconv"
"strings"
"sync"
"time"
"github.com/pkg/errors"
"go-micro.dev/v4/broker"
"go-micro.dev/v4/codec"
log "go-micro.dev/v4/logger"
"go-micro.dev/v4/metadata"
"go-micro.dev/v4/registry"
"go-micro.dev/v4/transport"
"go-micro.dev/v4/transport/headers"
"go-micro.dev/v4/util/addr"
"go-micro.dev/v4/util/backoff"
mnet "go-micro.dev/v4/util/net"
"go-micro.dev/v4/util/socket"
)
type rpcServer struct {
opts Options
// Subscribe to service name
subscriber broker.Subscriber
// Goal:
// router Router
router *router
exit chan chan error
handlers map[string]Handler
subscribers map[Subscriber][]broker.Subscriber
// Graceful exit
wg *sync.WaitGroup
// Cached service
rsvc *registry.Service
sync.RWMutex
// Marks the serve as started
started bool
// Used for first registration
registered bool
}
// NewRPCServer will create a new default RPC server.
func NewRPCServer(opts ...Option) Server {
options := NewOptions(opts...)
router := newRpcRouter()
router.hdlrWrappers = options.HdlrWrappers
router.subWrappers = options.SubWrappers
return &rpcServer{
opts: options,
router: router,
handlers: make(map[string]Handler),
subscribers: make(map[Subscriber][]broker.Subscriber),
exit: make(chan chan error),
wg: wait(options.Context),
}
}
func (s *rpcServer) Init(opts ...Option) error {
s.Lock()
defer s.Unlock()
for _, opt := range opts {
opt(&s.opts)
}
// update router if its the default
if s.opts.Router == nil {
r := newRpcRouter()
r.hdlrWrappers = s.opts.HdlrWrappers
r.serviceMap = s.router.serviceMap
r.subWrappers = s.opts.SubWrappers
s.router = r
}
s.rsvc = nil
return nil
}
// ServeConn serves a single connection.
func (s *rpcServer) ServeConn(sock transport.Socket) {
logger := s.opts.Logger
// Global error tracking
var gerr error
// Keep track of Connection: close header
var closeConn bool
// Streams are multiplexed on Micro-Stream or Micro-Id header
pool := socket.NewPool()
// Waitgroup to wait for processing to finish
// A double waitgroup is used to block the global waitgroup incase it is
// empty, but only wait for the local routines to finish with the local waitgroup.
wg := NewWaitGroup(s.getWg())
defer func() {
// Only wait if there's no error
if gerr != nil {
select {
case <-s.exit:
default:
// EOF is expected if the client closes the connection
if !errors.Is(gerr, io.EOF) {
logger.Logf(log.ErrorLevel, "error while serving connection: %v", gerr)
}
}
} else {
wg.Wait()
}
// Close all the sockets for this connection
pool.Close()
// Close underlying socket
if err := sock.Close(); err != nil {
logger.Logf(log.ErrorLevel, "failed to close socket: %v", err)
}
// recover any panics
if r := recover(); r != nil {
logger.Log(log.ErrorLevel, "panic recovered: ", r)
logger.Log(log.ErrorLevel, string(debug.Stack()))
}
}()
for {
msg := transport.Message{
Header: make(map[string]string),
}
// Close connection if Connection: close header was set
if closeConn {
return
}
// Process inbound messages one at a time
if err := sock.Recv(&msg); err != nil {
// Set a global error and return.
// We're saying we essentially can't
// use the socket anymore
gerr = errors.Wrapf(err, "%s-%s | %s", s.opts.Name, s.opts.Id, sock.Remote())
return
}
// Keep track of when to close the connection
if c := msg.Header["Connection"]; c == "close" {
closeConn = true
}
// Check the message header for micro message header, if so handle
// as micro event
if t := msg.Header[headers.Message]; len(t) > 0 {
// Process the event
ev := newEvent(msg)
if err := s.HandleEvent(ev); err != nil {
msg.Header[headers.Error] = err.Error()
logger.Logf(log.ErrorLevel, "failed to handle event: %v", err)
}
// Write back some 200
if err := sock.Send(&transport.Message{Header: msg.Header}); err != nil {
gerr = err
break
}
continue
}
// business as usual
// use Micro-Stream as the stream identifier
// in the event its blank we'll always process
// on the same socket
var (
stream bool
id string
)
if s := getHeader(headers.Stream, msg.Header); len(s) > 0 {
id = s
stream = true
} else {
// If there's no stream id then its a standard request
// use the Micro-Id
id = msg.Header[headers.ID]
}
// Check if we have an existing socket
psock, ok := pool.Get(id)
// If we don't have a socket and its a stream
// Check if its a last stream EOS error
if !ok && stream && msg.Header[headers.Error] == errLastStreamResponse.Error() {
pool.Release(psock)
continue
}
// Got an existing socket already
if ok {
// we're starting processing
wg.Add(1)
// Pass the message to that existing socket
if err := psock.Accept(&msg); err != nil {
// Release the socket if there's an error
pool.Release(psock)
}
wg.Done()
continue
}
// No socket was found so its new
// Set the local and remote values
psock.SetLocal(sock.Local())
psock.SetRemote(sock.Remote())
// Load the socket with the current message
if err := psock.Accept(&msg); err != nil {
logger.Logf(log.ErrorLevel, "Socket failed to accept message: %v", err)
}
// Now walk the usual path
// We use this Timeout header to set a server deadline
to := msg.Header["Timeout"]
// We use this Content-Type header to identify the codec needed
contentType := msg.Header["Content-Type"]
// Copy the message headers
header := make(map[string]string, len(msg.Header))
for k, v := range msg.Header {
header[k] = v
}
// Set local/remote ips
header["Local"] = sock.Local()
header["Remote"] = sock.Remote()
// Create new context with the metadata
ctx := metadata.NewContext(context.Background(), header)
// Set the timeout from the header if we have it
if len(to) > 0 {
if n, err := strconv.ParseUint(to, 10, 64); err == nil {
var cancel context.CancelFunc
ctx, cancel = context.WithTimeout(ctx, time.Duration(n))
defer cancel()
}
}
// If there's no content type default it
if len(contentType) == 0 {
msg.Header["Content-Type"] = DefaultContentType
contentType = DefaultContentType
}
// Setup old protocol
cf := setupProtocol(&msg)
// No legacy codec needed
if cf == nil {
var err error
// Try get a new codec
if cf, err = s.newCodec(contentType); err != nil {
// No codec found so send back an error
if err = sock.Send(&transport.Message{
Header: map[string]string{
"Content-Type": "text/plain",
},
Body: []byte(err.Error()),
}); err != nil {
gerr = err
}
pool.Release(psock)
continue
}
}
// Create a new rpc codec based on the pseudo socket and codec
rcodec := newRPCCodec(&msg, psock, cf)
// Check the protocol as well
protocol := rcodec.String()
// Internal request
request := rpcRequest{
service: getHeader(headers.Request, msg.Header),
method: getHeader(headers.Method, msg.Header),
endpoint: getHeader(headers.Endpoint, msg.Header),
contentType: contentType,
codec: rcodec,
header: msg.Header,
body: msg.Body,
socket: psock,
stream: stream,
}
// Internal response
response := rpcResponse{
header: make(map[string]string),
socket: psock,
codec: rcodec,
}
// Wait for two coroutines to exit
// Serve the request and process the outbound messages
wg.Add(2)
// Process the outbound messages from the socket
go func(psock *socket.Socket) {
defer func() {
// TODO: don't hack this but if its grpc just break out of the stream
// We do this because the underlying connection is h2 and its a stream
if protocol == "grpc" {
if err := sock.Close(); err != nil {
logger.Logf(log.ErrorLevel, "Failed to close socket: %v", err)
}
}
s.deferer(pool, psock, wg)
}()
for {
// Get the message from our internal handler/stream
m := new(transport.Message)
if err := psock.Process(m); err != nil {
return
}
// Send the message back over the socket
if err := sock.Send(m); err != nil {
return
}
}
}(psock)
// Serve the request in a go routine as this may be a stream
go func(psock *socket.Socket) {
defer s.deferer(pool, psock, wg)
s.serveReq(ctx, msg, &request, &response, rcodec)
}(psock)
}
}
func (s *rpcServer) NewHandler(h interface{}, opts ...HandlerOption) Handler {
return s.router.NewHandler(h, opts...)
}
func (s *rpcServer) Handle(h Handler) error {
s.Lock()
defer s.Unlock()
if err := s.router.Handle(h); err != nil {
return err
}
s.handlers[h.Name()] = h
return nil
}
func (s *rpcServer) Register() error {
config := s.Options()
logger := config.Logger
// Registry function used to register the service
regFunc := s.newRegFuc(config)
// Directly register if service was cached
rsvc := s.getCachedService()
if rsvc != nil {
if err := regFunc(rsvc); err != nil {
return errors.Wrap(err, "failed to register service")
}
return nil
}
// Only cache service if host IP valid
addr, cacheService, err := s.getAddr(config)
if err != nil {
return err
}
node := ®istry.Node{
// TODO: node id should be set better. Add native option to specify
// host id through either config or ENV. Also look at logging of name.
Id: config.Name + "-" + config.Id,
Address: addr,
Metadata: s.newNodeMetedata(config),
}
service := ®istry.Service{
Name: config.Name,
Version: config.Version,
Nodes: []*registry.Node{node},
Endpoints: s.getEndpoints(),
}
registered := s.isRegistered()
if !registered {
logger.Logf(log.InfoLevel, "Registry [%s] Registering node: %s", config.Registry.String(), node.Id)
}
// Register the service
if err := regFunc(service); err != nil {
return errors.Wrap(err, "failed to register service")
}
// Already registered? don't need to register subscribers
if registered {
return nil
}
s.Lock()
defer s.Unlock()
s.registered = true
// Cache service
if cacheService {
s.rsvc = service
}
// Set what we're advertising
s.opts.Advertise = addr
// Router can exchange messages on broker
// Subscribe to the topic with its own name
if err := s.subscribeServer(config); err != nil {
return errors.Wrap(err, "failed to subscribe to service name topic")
}
// Subscribe for all of the subscribers
if err := s.reSubscribe(config); err != nil {
return errors.Wrap(err, "failed to resubscribe")
}
return nil
}
func (s *rpcServer) Deregister() error {
config := s.Options()
logger := config.Logger
addr, _, err := s.getAddr(config)
if err != nil {
return err
}
// TODO: there should be a better way to do this than reconstruct the service
// Edge case is that if service is not cached
node := ®istry.Node{
// TODO: also update node id naming
Id: config.Name + "-" + config.Id,
Address: addr,
}
service := ®istry.Service{
Name: config.Name,
Version: config.Version,
Nodes: []*registry.Node{node},
}
logger.Logf(log.InfoLevel, "Registry [%s] Deregistering node: %s", config.Registry.String(), node.Id)
if err := config.Registry.Deregister(service); err != nil {
return err
}
s.Lock()
defer s.Unlock()
s.rsvc = nil
if !s.registered {
return nil
}
s.registered = false
// close the subscriber
if s.subscriber != nil {
if err := s.subscriber.Unsubscribe(); err != nil {
logger.Logf(log.ErrorLevel, "Failed to unsubscribe service from service name topic: %v", err)
}
s.subscriber = nil
}
for sb, subs := range s.subscribers {
for i, sub := range subs {
logger.Logf(log.InfoLevel, "Unsubscribing %s from topic: %s", node.Id, sub.Topic())
if err := sub.Unsubscribe(); err != nil {
logger.Logf(log.ErrorLevel, "Failed to unsubscribe subscriber nr. %d from topic %s: %v", i+1, sub.Topic(), err)
}
}
s.subscribers[sb] = nil
}
return nil
}
func (s *rpcServer) Start() error {
if s.isStarted() {
return nil
}
config := s.Options()
logger := config.Logger
// start listening on the listener
listener, err := config.Transport.Listen(config.Address, config.ListenOptions...)
if err != nil {
return err
}
logger.Logf(log.InfoLevel, "Transport [%s] Listening on %s", config.Transport.String(), listener.Addr())
// swap address
addr := s.swapAddr(config, listener.Addr())
// connect to the broker
brokerName := config.Broker.String()
if err = config.Broker.Connect(); err != nil {
logger.Logf(log.ErrorLevel, "Broker [%s] connect error: %v", brokerName, err)
return err
}
logger.Logf(log.InfoLevel, "Broker [%s] Connected to %s", brokerName, config.Broker.Address())
// Use RegisterCheck func before register
if err = s.opts.RegisterCheck(s.opts.Context); err != nil {
logger.Logf(log.ErrorLevel, "Server %s-%s register check error: %s", config.Name, config.Id, err)
} else if err = s.Register(); err != nil {
// Perform initial registration
logger.Logf(log.ErrorLevel, "Server %s-%s register error: %s", config.Name, config.Id, err)
}
exit := make(chan bool)
// Listen for connections
go s.listen(listener, exit)
// Keep the service registered to registry
go s.registrar(listener, addr, config, exit)
s.setStarted(true)
return nil
}
func (s *rpcServer) Stop() error {
if !s.isStarted() {
return nil
}
ch := make(chan error)
s.exit <- ch
err := <-ch
s.setStarted(false)
return err
}
func (s *rpcServer) String() string {
return "mucp"
}
// newRegFuc will create a new registry function used to register the service.
func (s *rpcServer) newRegFuc(config Options) func(service *registry.Service) error {
return func(service *registry.Service) error {
rOpts := []registry.RegisterOption{registry.RegisterTTL(config.RegisterTTL)}
var regErr error
// Attempt to register. If registration fails, back off and try again.
// TODO: see if we can improve the retry mechanism. Maybe retry lib, maybe config values
for i := 0; i < 3; i++ {
if err := config.Registry.Register(service, rOpts...); err != nil {
regErr = err
time.Sleep(backoff.Do(i + 1))
continue
}
return nil
}
return regErr
}
}
// getAddr will take the advertise or service address, and return it.
func (s *rpcServer) getAddr(config Options) (string, bool, error) {
// Use advertise address if provided, else use service address
advt := config.Address
if len(config.Advertise) > 0 {
advt = config.Advertise
}
// Use explicit host and port if possible
host, port := advt, ""
if cnt := strings.Count(advt, ":"); cnt >= 1 {
// ipv6 address in format [host]:port or ipv4 host:port
h, p, err := net.SplitHostPort(advt)
if err != nil {
return "", false, err
}
host, port = h, p
}
validHost := net.ParseIP(host) != nil
addr, err := addr.Extract(host)
if err != nil {
return "", false, err
}
// mq-rpc(eg. nats) doesn't need the port. its addr is queue name.
if port != "" {
addr = mnet.HostPort(addr, port)
}
return addr, validHost, nil
}
// newNodeMetedata creates a new metadata map with default values.
func (s *rpcServer) newNodeMetedata(config Options) metadata.Metadata {
md := metadata.Copy(config.Metadata)
// TODO: revisit this for v5
md["transport"] = config.Transport.String()
md["broker"] = config.Broker.String()
md["server"] = s.String()
md["registry"] = config.Registry.String()
md["protocol"] = "mucp"
return md
}
// getEndpoints takes the list of handlers and subscribers and adds them to
// a single endpoints list.
func (s *rpcServer) getEndpoints() []*registry.Endpoint {
s.RLock()
defer s.RUnlock()
var handlerList []string
for n, e := range s.handlers {
// Only advertise non internal handlers
if !e.Options().Internal {
handlerList = append(handlerList, n)
}
}
// Maps are ordered randomly, sort the keys for consistency
// TODO: replace with generic version
sort.Strings(handlerList)
var subscriberList []Subscriber
for e := range s.subscribers {
// Only advertise non internal subscribers
if !e.Options().Internal {
subscriberList = append(subscriberList, e)
}
}
sort.Slice(subscriberList, func(i, j int) bool {
return subscriberList[i].Topic() > subscriberList[j].Topic()
})
endpoints := make([]*registry.Endpoint, 0, len(handlerList)+len(subscriberList))
for _, n := range handlerList {
endpoints = append(endpoints, s.handlers[n].Endpoints()...)
}
for _, e := range subscriberList {
endpoints = append(endpoints, e.Endpoints()...)
}
return endpoints
}
func (s *rpcServer) listen(listener transport.Listener, exit chan bool) {
for {
// Start listening for connections
// This will block until either exit signal given or error occurred
err := listener.Accept(s.ServeConn)
// TODO: listen for messages
// msg := broker.Exchange(service).Consume()
select {
// check if we're supposed to exit
case <-exit:
return
// check the error and backoff
default:
if err != nil {
s.opts.Logger.Logf(log.ErrorLevel, "Accept error: %v", err)
time.Sleep(time.Second)
continue
}
}
return
}
}
// registrar is responsible for keeping the service registered to the registry.
func (s *rpcServer) registrar(listener transport.Listener, addr string, config Options, exit chan bool) {
logger := config.Logger
// Only process if it exists
ticker := new(time.Ticker)
if s.opts.RegisterInterval > time.Duration(0) {
ticker = time.NewTicker(s.opts.RegisterInterval)
}
// Return error chan
var ch chan error
Loop:
for {
select {
// Register self on interval
case <-ticker.C:
registered := s.isRegistered()
rerr := s.opts.RegisterCheck(s.opts.Context)
if rerr != nil && registered {
logger.Logf(log.ErrorLevel, "Server %s-%s register check error: %s, deregister it", config.Name, config.Id, rerr)
// deregister self in case of error
if err := s.Deregister(); err != nil {
logger.Logf(log.ErrorLevel, "Server %s-%s deregister error: %s", config.Name, config.Id, err)
}
} else if rerr != nil && !registered {
logger.Logf(log.ErrorLevel, "Server %s-%s register check error: %s", config.Name, config.Id, rerr)
continue
}
if err := s.Register(); err != nil {
logger.Logf(log.ErrorLevel, "Server %s-%s register error: %s", config.Name, config.Id, err)
}
// Wait for exit signal
case ch = <-s.exit:
ticker.Stop()
close(exit)
break Loop
}
}
// Shutting down, deregister
if s.isRegistered() {
if err := s.Deregister(); err != nil {
logger.Logf(log.ErrorLevel, "Server %s-%s deregister error: %s", config.Name, config.Id, err)
}
}
// Wait for requests to finish
if swg := s.getWg(); swg != nil {
swg.Wait()
}
// Close transport listener
ch <- listener.Close()
brokerName := config.Broker.String()
logger.Logf(log.InfoLevel, "Broker [%s] Disconnected from %s", brokerName, config.Broker.Address())
// Disconnect the broker
if err := config.Broker.Disconnect(); err != nil {
logger.Logf(log.ErrorLevel, "Broker [%s] Disconnect error: %v", brokerName, err)
}
// Swap back address
s.setOptsAddr(addr)
}
func (s *rpcServer) serveReq(ctx context.Context, msg transport.Message, req *rpcRequest, resp *rpcResponse, rcodec codec.Codec) {
logger := s.opts.Logger
router := s.getRouter()
// serve the actual request using the request router
if serveRequestError := router.ServeRequest(ctx, req, resp); serveRequestError != nil {
// write an error response
writeError := rcodec.Write(&codec.Message{
Header: msg.Header,
Error: serveRequestError.Error(),
Type: codec.Error,
}, nil)
// if the server request is an EOS error we let the socket know
// sometimes the socket is already closed on the other side, so we can ignore that error
alreadyClosed := errors.Is(serveRequestError, errLastStreamResponse) && errors.Is(writeError, io.EOF)
// could not write error response
if writeError != nil && !alreadyClosed {
logger.Logf(log.DebugLevel, "rpc: unable to write error response: %v", writeError)
}
}
}
func (s *rpcServer) deferer(pool *socket.Pool, psock *socket.Socket, wg *waitGroup) {
pool.Release(psock)
wg.Done()
logger := s.opts.Logger
if r := recover(); r != nil {
logger.Log(log.ErrorLevel, "panic recovered: ", r)
logger.Log(log.ErrorLevel, string(debug.Stack()))
}
}
func (s *rpcServer) getRouter() Router {
router := Router(s.router)
// if not nil use the router specified
if s.opts.Router != nil {
// create a wrapped function
handler := func(ctx context.Context, req Request, rsp interface{}) error {
return s.opts.Router.ServeRequest(ctx, req, rsp.(Response))
}
// execute the wrapper for it
for i := len(s.opts.HdlrWrappers); i > 0; i-- {
handler = s.opts.HdlrWrappers[i-1](handler)
}
// set the router
router = rpcRouter{h: handler}
}
return router
}