init push

internal/service/email_job_handler.go

@@ -0,0 +1,119 @@
+package service
+
+import (
+	"context"
+	"errors"
+	"log/slog"
+	"net"
+	"strings"
+
+	"github.com/aws/smithy-go"
+
+	"wucher/internal/queue"
+)
+
+type EmailDeliveryHandler struct {
+	sender EmailSender
+	logger *slog.Logger
+}
+
+func NewEmailDeliveryHandler(sender EmailSender, logger *slog.Logger) *EmailDeliveryHandler {
+	if logger == nil {
+		logger = slog.Default()
+	}
+	return &EmailDeliveryHandler{
+		sender: sender,
+		logger: logger,
+	}
+}
+
+func (h *EmailDeliveryHandler) Handle(ctx context.Context, envelope *queue.Envelope) error {
+	if h.sender == nil {
+		return queue.Permanent(errors.New("email sender is required"))
+	}
+	if envelope == nil {
+		return queue.Permanent(errors.New("email envelope is required"))
+	}
+	if err := envelope.Payload.Validate(); err != nil {
+		return queue.Permanent(err)
+	}
+
+	job := envelope.Payload
+	shouldSkipSend := strings.EqualFold(strings.TrimSpace(job.Metadata["skip_send"]), "true")
+	// Defense-in-depth: register verification emails should never be delivered.
+	if !shouldSkipSend &&
+		strings.EqualFold(strings.TrimSpace(job.MessageType), "email_verify") &&
+		strings.EqualFold(strings.TrimSpace(job.Tags["source"]), "register") {
+		shouldSkipSend = true
+	}
+	if shouldSkipSend {
+		h.logger.Info("email delivery skipped",
+			slog.String("message_id", envelope.MessageID),
+			slog.String("job_type", job.NormalizedType()),
+			slog.String("recipient_hash", job.RecipientHash()),
+			slog.String("correlation_id", envelope.CorrelationID),
+		)
+		return nil
+	}
+	result, err := h.sender.Send(ctx, job)
+	if err != nil {
+		classified := classifyDeliveryError(err)
+		h.logger.Error("email delivery failed",
+			slog.String("message_id", envelope.MessageID),
+			slog.String("job_type", job.NormalizedType()),
+			slog.String("recipient_hash", job.RecipientHash()),
+			slog.String("correlation_id", envelope.CorrelationID),
+			slog.Any("error", err),
+		)
+		return classified
+	}
+
+	h.logger.Info("email delivered",
+		slog.String("message_id", envelope.MessageID),
+		slog.String("job_type", job.NormalizedType()),
+		slog.String("recipient_hash", job.RecipientHash()),
+		slog.String("correlation_id", envelope.CorrelationID),
+		slog.String("provider", result.Provider),
+		slog.String("provider_message_id", result.ProviderMessageID),
+		slog.String("provider_request_id", result.RequestID),
+	)
+	return nil
+}
+
+func classifyDeliveryError(err error) error {
+	if err == nil {
+		return nil
+	}
+	if errors.Is(err, context.Canceled) || errors.Is(err, context.DeadlineExceeded) {
+		return queue.Transient(err)
+	}
+	var netErr net.Error
+	if errors.As(err, &netErr) {
+		return queue.Transient(err)
+	}
+	var apiErr smithy.APIError
+	if errors.As(err, &apiErr) {
+		code := strings.ToLower(strings.TrimSpace(apiErr.ErrorCode()))
+		switch code {
+		case "throttling", "throttlingexception", "toomanyrequestsexception", "serviceunavailableexception", "internalserviceerror", "sendingpausedexception":
+			return queue.Transient(err)
+		case "message_rejected", "messagerejected", "badrequestexception", "mailfromdomainnotverifiedexception", "configurationsetdoesnotexistexception", "notfoundexception":
+			return queue.Permanent(err)
+		}
+	}
+	message := strings.ToLower(strings.TrimSpace(err.Error()))
+	switch {
+	case strings.Contains(message, "recipient is required"):
+		return queue.Permanent(err)
+	case strings.Contains(message, "subject is required"):
+		return queue.Permanent(err)
+	case strings.Contains(message, "body is required"):
+		return queue.Permanent(err)
+	case strings.Contains(message, "invalid email job"):
+		return queue.Permanent(err)
+	case strings.Contains(message, "ses is not configured"):
+		return queue.Permanent(err)
+	default:
+		return queue.Transient(err)
+	}
+}