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matterbridge/vendor/github.com/gopackage/ddp/client.go
Wim 4dd8bae5c9
Update dependencies (#1610)
* Update dependencies

* Update module to go 1.17
2021-10-17 00:47:22 +02:00

635 lines
18 KiB
Go

package ddp
import (
"encoding/json"
"errors"
"fmt"
"io"
"sync"
"time"
"github.com/apex/log"
"golang.org/x/net/websocket"
)
const (
DISCONNECTED = iota
DIALING
CONNECTING
CONNECTED
)
type ConnectionListener interface {
Connected()
}
type ConnectionNotifier interface {
AddConnectionListener(listener ConnectionListener)
}
type StatusListener interface {
Status(status int)
}
type StatusNotifier interface {
AddStatusListener(listener StatusListener)
}
// Client represents a DDP client connection. The DDP client establish a DDP
// session and acts as a message pump for other tools.
type Client struct {
// HeartbeatInterval is the time between heartbeats to send
HeartbeatInterval time.Duration
// HeartbeatTimeout is the time for a heartbeat ping to timeout
HeartbeatTimeout time.Duration
// ReconnectInterval is the time between reconnections on bad connections
ReconnectInterval time.Duration
// writeSocketStats controls statistics gathering for current websocket writes.
writeSocketStats *WriterStats
// writeStats controls statistics gathering for overall client writes.
writeStats *WriterStats
// readSocketStats controls statistics gathering for current websocket reads.
readSocketStats *ReaderStats
// readStats controls statistics gathering for overall client reads.
readStats *ReaderStats
// reconnects in the number of reconnections the client has made
reconnects int64
// pingsIn is the number of pings received from the server
pingsIn int64
// pingsOut is te number of pings sent by the client
pingsOut int64
// session contains the DDP session token (can be used for reconnects and debugging).
session string
// version contains the negotiated DDP protocol version in use.
version string
// serverID the cluster node ID for the server we connected to
serverID string
// ws is the underlying websocket being used.
ws *websocket.Conn
// encoder is a JSON encoder to send outgoing packets to the websocket.
encoder *json.Encoder
// url the websocket is connected to
url string
// origin is the origin for the websocket connection
origin string
// inbox is an incoming message channel
inbox chan map[string]interface{}
// errors is an incoming errors channel
errors chan error
// pingTimer is a timer for sending regular pings to the server
pingTimer *time.Timer
// pings tracks inflight pings based on each ping ID.
pings map[string][]*PingTracker
// calls tracks method invocations that are still in flight
calls map[string]*Call
// subs tracks active subscriptions. Map contains name->args
subs map[string]*Call
// collections contains all the collections currently subscribed
collections map[string]Collection
// connectionStatus is the current connection status of the client
connectionStatus int
// reconnectTimer is the timer tracking reconnections
reconnectTimer *time.Timer
// reconnectLock protects access to reconnection
reconnectLock *sync.Mutex
// statusListeners will be informed when the connection status of the client changes
statusListeners []StatusListener
// connectionListeners will be informed when a connection to the server is established
connectionListeners []ConnectionListener
// KeyManager tracks IDs for ddp messages
KeyManager
}
// NewClient creates a default client (using an internal websocket) to the
// provided URL using the origin for the connection. The client will
// automatically connect, upgrade to a websocket, and establish a DDP
// connection session before returning the client. The client will
// automatically and internally handle heartbeats and reconnects.
//
// TBD create an option to use an external websocket (aka htt.Transport)
// TBD create an option to substitute heartbeat and reconnect behavior (aka http.Transport)
// TBD create an option to hijack the connection (aka http.Hijacker)
// TBD create profiling features (aka net/http/pprof)
func NewClient(url, origin string) *Client {
c := &Client{
HeartbeatInterval: time.Minute, // Meteor impl default + 10 (we ping last)
HeartbeatTimeout: 15 * time.Second, // Meteor impl default
ReconnectInterval: 5 * time.Second,
collections: map[string]Collection{},
url: url,
origin: origin,
inbox: make(chan map[string]interface{}, 100),
errors: make(chan error, 100),
pings: map[string][]*PingTracker{},
calls: map[string]*Call{},
subs: map[string]*Call{},
connectionStatus: DISCONNECTED,
reconnectLock: &sync.Mutex{},
// Stats
writeSocketStats: NewWriterStats(nil),
writeStats: NewWriterStats(nil),
readSocketStats: NewReaderStats(nil),
readStats: NewReaderStats(nil),
KeyManager: *NewKeyManager(),
}
c.encoder = json.NewEncoder(c.writeStats)
// We spin off an inbox processing goroutine
go c.inboxManager()
return c
}
// Session returns the negotiated session token for the connection.
func (c *Client) Session() string {
return c.session
}
// Version returns the negotiated protocol version in use by the client.
func (c *Client) Version() string {
return c.version
}
// AddStatusListener in order to receive status change updates.
func (c *Client) AddStatusListener(listener StatusListener) {
c.statusListeners = append(c.statusListeners, listener)
}
// AddConnectionListener in order to receive connection updates.
func (c *Client) AddConnectionListener(listener ConnectionListener) {
c.connectionListeners = append(c.connectionListeners, listener)
}
// status updates all status listeners with the new client status.
func (c *Client) status(status int) {
if c.connectionStatus == status {
return
}
c.connectionStatus = status
for _, listener := range c.statusListeners {
listener.Status(status)
}
}
// Connect attempts to connect the client to the server.
func (c *Client) Connect() error {
c.status(DIALING)
ws, err := websocket.Dial(c.url, "", c.origin)
if err != nil {
c.Close()
log.WithError(err).Debug("dial error")
c.reconnectLater()
return err
}
log.Debug("dialed")
// Start DDP connection
c.start(ws, NewConnect())
return nil
}
// Reconnect attempts to reconnect the client to the server on the existing
// DDP session.
//
// TODO needs a reconnect backoff so we don't trash a down server
// TODO reconnect should not allow more reconnects while a reconnection is already in progress.
func (c *Client) Reconnect() {
func() {
c.reconnectLock.Lock()
defer c.reconnectLock.Unlock()
if c.reconnectTimer != nil {
c.reconnectTimer.Stop()
c.reconnectTimer = nil
}
}()
c.Close()
c.reconnects++
// Reconnect
c.status(DIALING)
ws, err := websocket.Dial(c.url, "", c.origin)
if err != nil {
c.Close()
log.WithError(err).Debug("Dial error")
c.reconnectLater()
return
}
c.start(ws, NewReconnect(c.session))
// --------------------------------------------------------------------
// We resume inflight or ongoing subscriptions - we don't have to wait
// for connection confirmation (messages can be pipelined).
// --------------------------------------------------------------------
// Send calls that haven't been confirmed - may not have been sent
// and effects should be idempotent
for _, call := range c.calls {
IgnoreErr(c.Send(NewMethod(call.ID, call.ServiceMethod, call.Args.([]interface{}))), "resend method")
}
// Resend subscriptions and patch up collections
for _, sub := range c.subs {
IgnoreErr(c.Send(NewSub(sub.ID, sub.ServiceMethod, sub.Args.([]interface{}))), "resend sub")
}
}
// Subscribe to data updates.
func (c *Client) Subscribe(subName string, done chan *Call, args ...interface{}) *Call {
if args == nil {
args = []interface{}{}
}
call := new(Call)
call.ID = c.Next()
call.ServiceMethod = subName
call.Args = args
call.Owner = c
if done == nil {
done = make(chan *Call, 10) // buffered.
} else {
// If caller passes done != nil, it must arrange that
// done has enough buffer for the number of simultaneous
// RPCs that will be using that channel. If the channel
// is totally unbuffered, it's best not to run at all.
if cap(done) == 0 {
log.Fatal("ddp.rpc: done channel is unbuffered")
}
}
call.Done = done
c.subs[call.ID] = call
// Save this subscription to the client so we can reconnect
subArgs := make([]interface{}, len(args))
copy(subArgs, args)
IgnoreErr(c.Send(NewSub(call.ID, subName, args)), "send sub")
return call
}
// Sub sends a synchronous subscription request to the server.
func (c *Client) Sub(subName string, args ...interface{}) error {
call := <-c.Subscribe(subName, make(chan *Call, 1), args...).Done
return call.Error
}
// Go invokes the function asynchronously. It returns the Call structure representing
// the invocation. The done channel will signal when the call is complete by returning
// the same Call object. If done is nil, Go will allocate a new channel.
// If non-nil, done must be buffered or Go will deliberately crash.
//
// Go and Call are modeled after the standard `net/rpc` package versions.
func (c *Client) Go(serviceMethod string, done chan *Call, args ...interface{}) *Call {
if args == nil {
args = []interface{}{}
}
call := new(Call)
call.ID = c.Next()
call.ServiceMethod = serviceMethod
call.Args = args
call.Owner = c
if done == nil {
done = make(chan *Call, 10) // buffered.
} else {
// If caller passes done != nil, it must arrange that
// done has enough buffer for the number of simultaneous
// RPCs that will be using that channel. If the channel
// is totally unbuffered, it's best not to run at all.
if cap(done) == 0 {
log.Fatal("ddp.rpc: done channel is unbuffered")
}
}
call.Done = done
c.calls[call.ID] = call
IgnoreErr(c.Send(NewMethod(call.ID, serviceMethod, args)), "send method")
return call
}
// Call invokes the named function, waits for it to complete, and returns its error status.
func (c *Client) Call(serviceMethod string, args ...interface{}) (interface{}, error) {
call := <-c.Go(serviceMethod, make(chan *Call, 1), args...).Done
return call.Reply, call.Error
}
// Ping sends a heartbeat signal to the server. The Ping doesn't look for
// a response but may trigger the connection to reconnect if the ping times out.
// This is primarily useful for reviving an unresponsive Client connection.
func (c *Client) Ping() {
c.PingPong(c.Next(), c.HeartbeatTimeout, func(err error) {
if err != nil {
// Is there anything else we should or can do?
c.reconnectLater()
}
})
}
// PingPong sends a heartbeat signal to the server and calls the provided
// function when a pong is received. An optional id can be sent to help
// track the responses - or an empty string can be used. It is the
// responsibility of the caller to respond to any errors that may occur.
func (c *Client) PingPong(id string, timeout time.Duration, handler func(error)) {
err := c.Send(NewPing(id))
if err != nil {
handler(err)
return
}
c.pingsOut++
pings, ok := c.pings[id]
if !ok {
pings = make([]*PingTracker, 0, 5)
}
tracker := &PingTracker{handler: handler, timeout: timeout, timer: time.AfterFunc(timeout, func() {
handler(fmt.Errorf("ping timeout"))
})}
c.pings[id] = append(pings, tracker)
}
// Send transmits messages to the server. The msg parameter must be json
// encoder compatible.
func (c *Client) Send(msg interface{}) error {
return c.encoder.Encode(msg)
}
// Close implements the io.Closer interface.
func (c *Client) Close() {
// Shutdown out all outstanding pings
if c.pingTimer != nil {
c.pingTimer.Stop()
c.pingTimer = nil
}
// Close websocket
if c.ws != nil {
IgnoreErr(c.ws.Close(), "close ws")
c.ws = nil
}
for _, collection := range c.collections {
collection.reset()
}
c.status(DISCONNECTED)
}
// ResetStats resets the statistics for the client.
func (c *Client) ResetStats() {
c.readSocketStats.Reset()
c.readStats.Reset()
c.writeSocketStats.Reset()
c.writeStats.Reset()
c.reconnects = 0
c.pingsIn = 0
c.pingsOut = 0
}
// Stats returns the read and write statistics of the client.
func (c *Client) Stats() *ClientStats {
return &ClientStats{
Reads: c.readSocketStats.Snapshot(),
TotalReads: c.readStats.Snapshot(),
Writes: c.writeSocketStats.Snapshot(),
TotalWrites: c.writeStats.Snapshot(),
Reconnects: c.reconnects,
PingsSent: c.pingsOut,
PingsRecv: c.pingsIn,
}
}
// CollectionByName retrieves a collection by its name.
func (c *Client) CollectionByName(name string) Collection {
collection, ok := c.collections[name]
if !ok {
collection = NewCollection(name)
c.collections[name] = collection
}
return collection
}
// CollectionStats returns a snapshot of statistics for the currently known collections.
func (c *Client) CollectionStats() []CollectionStats {
stats := make([]CollectionStats, 0, len(c.collections))
for name, collection := range c.collections {
stats = append(stats, CollectionStats{Name: name, Count: len(collection.FindAll())})
}
return stats
}
// start a new client connection on the provided websocket
func (c *Client) start(ws *websocket.Conn, connect *Connect) {
c.status(CONNECTING)
c.ws = ws
c.writeSocketStats = NewWriterStats(c.ws)
c.writeStats.Writer = c.writeSocketStats
c.readSocketStats = NewReaderStats(c.ws)
c.readStats.Reader = c.readSocketStats
// We spin off an inbox stuffing goroutine
go c.inboxWorker(c.readStats)
IgnoreErr(c.Send(connect), "send connect")
}
// inboxManager pulls messages from the inbox and routes them to appropriate
// handlers.
func (c *Client) inboxManager() {
for {
select {
case msg := <-c.inbox:
// Message!
//log.Println("Got message", msg)
msgType, ok := msg["msg"]
if ok {
log.WithField("msg", msgType).Debug("recv")
switch msgType.(string) {
// Connection management
case "connected":
c.status(CONNECTED)
for _, collection := range c.collections {
collection.init()
}
c.version = "1" // "1" is the only version we support
c.session = msg["session"].(string)
// Start automatic heartbeats
c.pingTimer = time.AfterFunc(c.HeartbeatInterval, func() {
c.Ping()
c.pingTimer.Reset(c.HeartbeatInterval)
})
// Notify connection listeners
for _, listener := range c.connectionListeners {
go listener.Connected()
}
case "failed":
log.Fatalf("IM Failed to connect, we support version 1 but server supports %s", msg["version"])
// Heartbeats
case "ping":
// We received a ping - need to respond with a pong
id, ok := msg["id"]
if ok {
IgnoreErr(c.Send(NewPong(id.(string))), "send id ping")
} else {
IgnoreErr(c.Send(NewPong("")), "send empty ping")
}
c.pingsIn++
case "pong":
// We received a pong - we can clear the ping tracker and call its handler
id, ok := msg["id"]
var key string
if ok {
key = id.(string)
}
pings, ok := c.pings[key]
if ok && len(pings) > 0 {
ping := pings[0]
pings = pings[1:]
if len(key) == 0 || len(pings) > 0 {
c.pings[key] = pings
}
ping.timer.Stop()
ping.handler(nil)
}
// Live Data
case "nosub":
log.WithField("msg", msg).Debug("sub returned a nosub error")
// Clear related subscriptions
sub, ok := msg["id"]
if ok {
id := sub.(string)
runningSub := c.subs[id]
if runningSub != nil {
runningSub.Error = errors.New("sub returned a nosub error")
runningSub.done()
delete(c.subs, id)
}
}
case "ready":
// Run 'done' callbacks on all ready subscriptions
subs, ok := msg["subs"]
if ok {
for _, sub := range subs.([]interface{}) {
call, ok := c.subs[sub.(string)]
if ok {
call.done()
}
}
}
case "added":
c.collectionBy(msg).added(msg)
case "changed":
c.collectionBy(msg).changed(msg)
case "removed":
c.collectionBy(msg).removed(msg)
case "addedBefore":
c.collectionBy(msg).addedBefore(msg)
case "movedBefore":
c.collectionBy(msg).movedBefore(msg)
// RPC
case "result":
id, ok := msg["id"]
if ok {
call := c.calls[id.(string)]
delete(c.calls, id.(string))
e, ok := msg["error"]
if ok {
txt, _ := json.Marshal(e)
call.Error = fmt.Errorf(string(txt))
call.Reply = e
} else {
call.Reply = msg["result"]
}
call.done()
}
case "updated":
// We currently don't do anything with updated status
default:
// Ignore?
log.WithField("msg", msg).Debug("Server sent unexpected message")
}
} else {
// Current Meteor server sends an undocumented DDP message
// (looks like clustering "hint"). We will register and
// ignore rather than log an error.
serverID, ok := msg["server_id"]
if ok {
switch ID := serverID.(type) {
case string:
c.serverID = ID
default:
log.WithField("id", serverID).Debug("Server cluster node")
}
} else {
log.WithField("msg", msg).Debug("Server sent message with no `msg` field")
}
}
case err := <-c.errors:
log.WithError(err).Warn("Websocket error")
}
}
}
func (c *Client) collectionBy(msg map[string]interface{}) Collection {
n, ok := msg["collection"]
if !ok {
return NewMockCollection()
}
switch name := n.(type) {
case string:
return c.CollectionByName(name)
default:
return NewMockCollection()
}
}
// inboxWorker pulls messages from a websocket, decodes JSON packets, and
// stuffs them into a message channel.
func (c *Client) inboxWorker(ws io.Reader) {
dec := json.NewDecoder(ws)
for {
var event interface{}
if err := dec.Decode(&event); err == io.EOF {
break
} else if err != nil {
c.errors <- err
}
if c.pingTimer != nil {
c.pingTimer.Reset(c.HeartbeatInterval)
}
if event == nil {
log.Debug("Inbox worker found nil event. May be due to broken websocket. Reconnecting.")
break
} else {
c.inbox <- event.(map[string]interface{})
}
}
c.reconnectLater()
}
// reconnectLater schedules a reconnect action for later. We need to make sure that we don't
// block, and that we don't reconnect more frequently than once every c.ReconnectInterval
func (c *Client) reconnectLater() {
c.Close()
c.reconnectLock.Lock()
defer c.reconnectLock.Unlock()
if c.reconnectTimer == nil {
c.reconnectTimer = time.AfterFunc(c.ReconnectInterval, c.Reconnect)
}
}