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input_pubsub.go
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input_pubsub.go
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package redis
import (
"context"
"sync"
"time"
"github.com/go-redis/redis/v7"
"github.com/benthosdev/benthos/v4/internal/bundle"
"github.com/benthosdev/benthos/v4/internal/component"
"github.com/benthosdev/benthos/v4/internal/component/input"
"github.com/benthosdev/benthos/v4/internal/component/input/processors"
"github.com/benthosdev/benthos/v4/internal/docs"
"github.com/benthosdev/benthos/v4/internal/impl/redis/old"
"github.com/benthosdev/benthos/v4/internal/log"
"github.com/benthosdev/benthos/v4/internal/message"
)
func init() {
err := bundle.AllInputs.Add(processors.WrapConstructor(newRedisPubSubInput), docs.ComponentSpec{
Name: "redis_pubsub",
Summary: `
Consume from a Redis publish/subscribe channel using either the SUBSCRIBE or
PSUBSCRIBE commands.`,
Description: `
In order to subscribe to channels using the ` + "`PSUBSCRIBE`" + ` command set
the field ` + "`use_patterns` to `true`" + `, then you can include glob-style
patterns in your channel names. For example:
- ` + "`h?llo`" + ` subscribes to hello, hallo and hxllo
- ` + "`h*llo`" + ` subscribes to hllo and heeeello
- ` + "`h[ae]llo`" + ` subscribes to hello and hallo, but not hillo
Use ` + "`\\`" + ` to escape special characters if you want to match them
verbatim.`,
Config: docs.FieldComponent().WithChildren(old.ConfigDocs()...).WithChildren(
docs.FieldString("channels", "A list of channels to consume from.").Array(),
docs.FieldBool("use_patterns", "Whether to use the PSUBSCRIBE command."),
).ChildDefaultAndTypesFromStruct(input.NewRedisPubSubConfig()),
Categories: []string{
"Services",
},
})
if err != nil {
panic(err)
}
}
func newRedisPubSubInput(conf input.Config, mgr bundle.NewManagement) (input.Streamed, error) {
r, err := newRedisPubSubReader(conf.RedisPubSub, mgr.Logger())
if err != nil {
return nil, err
}
return input.NewAsyncReader("redis_pubsub", true, input.NewAsyncPreserver(r), mgr)
}
type redisPubSubReader struct {
client redis.UniversalClient
pubsub *redis.PubSub
cMut sync.Mutex
conf input.RedisPubSubConfig
log log.Modular
}
func newRedisPubSubReader(conf input.RedisPubSubConfig, log log.Modular) (*redisPubSubReader, error) {
r := &redisPubSubReader{
conf: conf,
log: log,
}
_, err := clientFromConfig(r.conf.Config)
if err != nil {
return nil, err
}
return r, nil
}
func (r *redisPubSubReader) ConnectWithContext(ctx context.Context) error {
r.cMut.Lock()
defer r.cMut.Unlock()
if r.client != nil {
return nil
}
client, err := clientFromConfig(r.conf.Config)
if err != nil {
return err
}
if _, err := client.Ping().Result(); err != nil {
return err
}
r.log.Infof("Receiving Redis pub/sub messages from channels: %v\n", r.conf.Channels)
r.client = client
if r.conf.UsePatterns {
r.pubsub = r.client.PSubscribe(r.conf.Channels...)
} else {
r.pubsub = r.client.Subscribe(r.conf.Channels...)
}
return nil
}
func (r *redisPubSubReader) ReadWithContext(ctx context.Context) (*message.Batch, input.AsyncAckFn, error) {
var pubsub *redis.PubSub
r.cMut.Lock()
pubsub = r.pubsub
r.cMut.Unlock()
if pubsub == nil {
return nil, nil, component.ErrNotConnected
}
select {
case rMsg, open := <-pubsub.Channel():
if !open {
_ = r.disconnect()
return nil, nil, component.ErrTypeClosed
}
return message.QuickBatch([][]byte{[]byte(rMsg.Payload)}), func(ctx context.Context, err error) error {
return nil
}, nil
case <-ctx.Done():
}
return nil, nil, component.ErrTimeout
}
func (r *redisPubSubReader) disconnect() error {
r.cMut.Lock()
defer r.cMut.Unlock()
var err error
if r.pubsub != nil {
err = r.pubsub.Close()
r.pubsub = nil
}
if r.client != nil {
err = r.client.Close()
r.client = nil
}
return err
}
func (r *redisPubSubReader) CloseAsync() {
_ = r.disconnect()
}
func (r *redisPubSubReader) WaitForClose(timeout time.Duration) error {
return nil
}