EmailCodeDispatchConsumer

Info

RabbitMQ consumer that dispatches verification code emails via Resend with retry and dead-letter queue support.

Overview

Listens on the main dispatch queue and DLQ. The main listener validates the message scene, calls ResendEmailService to send the email, and routes failures to the retry queue or DLQ based on retry count. The DLQ listener persists permanently failed messages to MySQL via EmailVerificationService.logDispatchDlq().

Main Queue Processing (onMessage)

1. Validation -- Rejects messages with null/invalid scene (ack and drop)
2. Email Dispatch -- Calls ResendEmailService.sendVerificationCode()
3. On Success -- Logs dispatch completion
4. On Failure -- Routes to retry or DLQ via routeToRetryOrDlq()

DLQ Processing (onDeadLetter)

• Persists a EmailDispatchDlqLog record with trace ID, email, scene, retry count, and last error
• Logs the DLQ entry

Retry Routing

Condition	Action
retryCount < emailNotifyMaxRetries	Route to retry queue (TTL-based delay)
retryCount >= emailNotifyMaxRetries	Route to DLQ

Retry Message

On failure, the consumer creates a new EmailCodeDispatchMessage with the error message appended as lastError and sets the x-email-retry-count header to nextRetry.

Configuration

Property	Default	Description
email.notify-max-retries	3	Maximum retry attempts before DLQ

Dependencies

• ResendEmailService -- actual email sending
• EmailVerificationService -- DLQ log persistence
• RabbitTemplate -- retry/DLQ message routing

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EmailCodeDispatchMessage

Info

Java record representing an email verification code dispatch message in the RabbitMQ queue.

Fields

Field	Type	Description
traceId	String	Unique trace identifier
email	String	Target email address
scene	String	Verification scene (e.g. REGISTER, LOGIN)
code	String	Plain-text verification code
createdAtEpochSeconds	long	Message creation timestamp (seconds)
lastError	String	Last error message (null on first attempt)

Constructors

Constructor	Description
EmailCodeDispatchMessage(traceId, email, scene, code, createdAtEpochSeconds)	Initial dispatch (lastError = null)
EmailCodeDispatchMessage(traceId, email, scene, code, createdAtEpochSeconds, lastError)	Retry dispatch with error info