gob: type mismatch: no fields matched compiling decoder - Golang

Question

I'm using PubSub on two different streams where we receive messages from one stream, run some logic, and if it fits certain criteria, we publish it to the second stream. The second stream is also being received from in a goroutine.

Now, I have two main functions HandleMessage and HandleRetry where the former is from the first stream, and the second is for the second stream.

The relevant code for HandleMessage is as follows:

    if c.handler.ShouldProcess(tx) {
        err := c.handler.Process(tx)
        if err != nil {
            c.log.
                WithError(err).
                WithField("tx_hash", tx.TxHash.String()).
                Error("failed to process")

            retryMsg := RetryMessage{
                Transaction:                 tx,
                RemainingProcessingAttempts: c.config.MaxProcessingAttempts,
                LastAttempt:                 time.Now(),
            }

            data, err := pubsub.EncodeMessage(retryMsg)
            if err != nil {
                c.log.WithError(err).Error("failed to convert retry msg to byte slice")
            }

            id, err := c.retryQueue.Publish(context.Background(), &pubsub.Message{Data: data})
            if err != nil {
                c.log.WithError(err).
                    WithField("id", id).
                    Error("failed to publish message to retry queue")
            }
        }
    }

and in HandleRetry , the function opens with

    retryTx := new(RetryMessage)
    err := pubsub.DecodeMessage(msg.Data, retryTx)
    if err != nil {
        c.log.WithError(err).
            Error("failed to decode message: not a retry tx")
        msg.Ack()
        return
    }

For the RetryQueue which is handled by HandleRetry -- there is no other input except the messages being published from HandleMessage

But, I keep getting a gob decoding error saying

level=error msg="failed to decode message: not a retry tx" env=LOCAL error="gob: type mismatch: no fields matched compiling decoder for RetryMessage"

RetryMessage looks like this

type RetryMessage struct {
    Transaction                 *firehose.Transaction
    RemainingProcessingAttempts int
    LastAttempt                 time.Time
}

The encoding and decoding functions are as follows

// EncodeMessage convert an arbitrary interface into a byte slice.
func EncodeMessage(data interface{}) ([]byte, error) {
    var buf bytes.Buffer

    enc := gob.NewEncoder(&buf)

    err := enc.Encode(data)
    if err != nil {
        return nil, err
    }

    return buf.Bytes(), nil
}

// DecodeMessage decodes message data into the provided interface.
func DecodeMessage(data []byte, dest interface{}) error {
    buf := bytes.NewBuffer(data)
    dec := gob.NewDecoder(buf)
    return dec.Decode(dest)
}

Answer 1

In this code in HandleMessage :

        data, err := pubsub.EncodeMessage(retryMsg)
        if err != nil {
            c.log.WithError(err).Error("failed to convert retry msg to byte slice")
        }

The error is ignored and the published message's data field is populated with a potentially bad value. Check whether you are seeing “failed to convert retry msg to byte slice” in the logs.