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pubsub_stub.go
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pubsub_stub.go
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package radix
import (
"errors"
"fmt"
"io"
"strings"
"sync"
"github.com/vikram-suki/radix/v3/resp"
"github.com/vikram-suki/radix/v3/resp/resp2"
)
var errPubSubMode = resp2.Error{
E: errors.New("ERR only (P)SUBSCRIBE / (P)UNSUBSCRIBE / PING / QUIT allowed in this context"),
}
type multiMarshal []resp.Marshaler
func (mm multiMarshal) MarshalRESP(w io.Writer) error {
for _, m := range mm {
if err := m.MarshalRESP(w); err != nil {
return err
}
}
return nil
}
type pubSubStub struct {
Conn
fn func([]string) interface{}
inCh <-chan PubSubMessage
closeOnce sync.Once
closeCh chan struct{}
closeErr error
l sync.Mutex
pubsubMode bool
subbed, psubbed map[string]bool
// this is only used for tests
mDoneCh chan struct{}
}
// PubSubStub returns a (fake) Conn, much like Stub does, which pretends it is a
// Conn to a real redis instance, but is instead using the given callback to
// service requests. It is primarily useful for writing tests.
//
// PubSubStub differes from Stub in that Encode calls for (P)SUBSCRIBE,
// (P)UNSUBSCRIBE, MESSAGE, and PING will be intercepted and handled as per
// redis' expected pubsub functionality. A PubSubMessage may be written to the
// returned channel at any time, and if the PubSubStub has had (P)SUBSCRIBE
// called matching that PubSubMessage it will be written to the PubSubStub's
// internal buffer as expected.
//
// This is intended to be used so that it can mock services which can perform
// both normal redis commands and pubsub (e.g. a real redis instance, redis
// sentinel). Once created this stub can be passed into PubSub and treated like
// a real connection.
func PubSubStub(remoteNetwork, remoteAddr string, fn func([]string) interface{}) (Conn, chan<- PubSubMessage) {
ch := make(chan PubSubMessage)
s := &pubSubStub{
fn: fn,
inCh: ch,
closeCh: make(chan struct{}),
subbed: map[string]bool{},
psubbed: map[string]bool{},
mDoneCh: make(chan struct{}, 1),
}
s.Conn = Stub(remoteNetwork, remoteAddr, s.innerFn)
go s.spin()
return s, ch
}
func (s *pubSubStub) innerFn(ss []string) interface{} {
s.l.Lock()
defer s.l.Unlock()
writeRes := func(mm multiMarshal, cmd, subj string) multiMarshal {
c := len(s.subbed) + len(s.psubbed)
s.pubsubMode = c > 0
return append(mm, resp2.Any{I: []interface{}{cmd, subj, c}})
}
switch strings.ToUpper(ss[0]) {
case "PING":
if !s.pubsubMode {
return s.fn(ss)
}
return []string{"pong", ""}
case "SUBSCRIBE":
var mm multiMarshal
for _, channel := range ss[1:] {
s.subbed[channel] = true
mm = writeRes(mm, "subscribe", channel)
}
return mm
case "UNSUBSCRIBE":
var mm multiMarshal
for _, channel := range ss[1:] {
delete(s.subbed, channel)
mm = writeRes(mm, "unsubscribe", channel)
}
return mm
case "PSUBSCRIBE":
var mm multiMarshal
for _, pattern := range ss[1:] {
s.psubbed[pattern] = true
mm = writeRes(mm, "psubscribe", pattern)
}
return mm
case "PUNSUBSCRIBE":
var mm multiMarshal
for _, pattern := range ss[1:] {
delete(s.psubbed, pattern)
mm = writeRes(mm, "punsubscribe", pattern)
}
return mm
case "MESSAGE":
m := PubSubMessage{
Type: "message",
Channel: ss[1],
Message: []byte(ss[2]),
}
var mm multiMarshal
if s.subbed[m.Channel] {
mm = append(mm, m)
}
return mm
case "PMESSAGE":
m := PubSubMessage{
Type: "pmessage",
Pattern: ss[1],
Channel: ss[2],
Message: []byte(ss[3]),
}
var mm multiMarshal
if s.psubbed[m.Pattern] {
mm = append(mm, m)
}
return mm
default:
if s.pubsubMode {
return errPubSubMode
}
return s.fn(ss)
}
}
func (s *pubSubStub) Close() error {
s.closeOnce.Do(func() {
close(s.closeCh)
s.closeErr = s.Conn.Close()
})
return s.closeErr
}
func (s *pubSubStub) spin() {
for {
select {
case m, ok := <-s.inCh:
if !ok {
panic("PubSubStub message channel was closed")
}
if m.Type == "" {
if m.Pattern == "" {
m.Type = "message"
} else {
m.Type = "pmessage"
}
}
if err := s.Conn.Encode(m); err != nil {
panic(fmt.Sprintf("error encoding message in PubSubStub: %s", err))
}
select {
case s.mDoneCh <- struct{}{}:
default:
}
case <-s.closeCh:
return
}
}
}