#13: implement Outbound Queue, Retry Backoff Engine & DSN Bounce Generator (RFC 3464)

2026-07-25 10:33:07 -03:00
1 parent 45aaf2a279
commit af35211094
@@ -0,0 +1,40 @@
+package netdns
+
+import (
+	"context"
+	"fmt"
+	"net"
+	"sort"
+	"strings"
+)
+
+type NetMXResolver struct{}
+
+func NewNetMXResolver() *NetMXResolver {
+	return &NetMXResolver{}
+}
+
+func (r *NetMXResolver) LookupMX(ctx context.Context, domain string) ([]string, error) {
+	mxs, err := net.DefaultResolver.LookupMX(ctx, domain)
+	if err != nil {
+		return nil, fmt.Errorf("lookup mx for %s: %w", domain, err)
+	}
+
+	sort.Slice(mxs, func(i, j int) bool {
+		return mxs[i].Pref < mxs[j].Pref
+	})
+
+	var hosts []string
+	for _, mx := range mxs {
+		h := strings.TrimSuffix(mx.Host, ".")
+		if h != "" {
+			hosts = append(hosts, h)
+		}
+	}
+
+	if len(hosts) == 0 {
+		hosts = []string{domain}
+	}
+
+	return hosts, nil
+}
@@ -0,0 +1,106 @@
+package postgres
+
+import (
+	"context"
+	"fmt"
+
+	"github.com/jackc/pgx/v5/pgxpool"
+
+	"lambdamail/protocols/internal/domain/entity"
+)
+
+type OutboundRepository struct {
+	pool *pgxpool.Pool
+}
+
+func NewOutboundRepository(pool *pgxpool.Pool) *OutboundRepository {
+	return &OutboundRepository{pool: pool}
+}
+
+func (r *OutboundRepository) Enqueue(ctx context.Context, job *entity.OutboundJob) error {
+	err := r.pool.QueryRow(ctx, `
+		INSERT INTO outbound_jobs (
+			mailbox_id, blob_id, envelope_from, envelope_to, destination_domain,
+			status, attempt, next_attempt_at, expires_at
+		) VALUES ($1, $2, $3, $4, $5, $6, $7, $8, $9)
+		RETURNING id, created_at
+	`, job.MailboxID, job.BlobID, job.EnvelopeFrom, job.EnvelopeTo, job.DestinationDomain,
+		job.Status, job.Attempt, job.NextAttemptAt, job.ExpiresAt).Scan(&job.ID, &job.CreatedAt)
+
+	if err != nil {
+		return fmt.Errorf("enqueue outbound job: %w", err)
+	}
+	return nil
+}
+
+func (r *OutboundRepository) FetchNextReady(ctx context.Context, workerID string, limit int) ([]*entity.OutboundJob, error) {
+	rows, err := r.pool.Query(ctx, `
+		WITH ready_jobs AS (
+			SELECT id FROM outbound_jobs
+			WHERE status IN ('QUEUED', 'DEFERRED')
+			  AND next_attempt_at <= NOW()
+			ORDER BY next_attempt_at ASC
+			LIMIT $2
+			FOR UPDATE SKIP LOCKED
+		)
+		UPDATE outbound_jobs
+		SET status = 'SENDING', locked_by = $1, locked_until = NOW() + INTERVAL '5 minutes'
+		FROM ready_jobs
+		WHERE outbound_jobs.id = ready_jobs.id
+		RETURNING outbound_jobs.id, outbound_jobs.mailbox_id, outbound_jobs.blob_id,
+		          outbound_jobs.envelope_from, outbound_jobs.envelope_to, outbound_jobs.destination_domain,
+		          outbound_jobs.status, outbound_jobs.attempt, outbound_jobs.next_attempt_at,
+		          outbound_jobs.expires_at, outbound_jobs.last_smtp_code, outbound_jobs.last_error,
+		          outbound_jobs.tls_policy_used, outbound_jobs.delay_dsn_sent, outbound_jobs.created_at
+	`, workerID, limit)
+
+	if err != nil {
+		return nil, fmt.Errorf("fetch ready outbound jobs: %w", err)
+	}
+	defer rows.Close()
+
+	var jobs []*entity.OutboundJob
+	for rows.Next() {
+		j := &entity.OutboundJob{}
+		var statusStr string
+		var lastSmtpCode, lastError, tlsPolicyUsed *string
+
+		if err := rows.Scan(
+			&j.ID, &j.MailboxID, &j.BlobID, &j.EnvelopeFrom, &j.EnvelopeTo, &j.DestinationDomain,
+			&statusStr, &j.Attempt, &j.NextAttemptAt, &j.ExpiresAt, &lastSmtpCode, &lastError,
+			&tlsPolicyUsed, &j.DelayDsnSent, &j.CreatedAt,
+		); err != nil {
+			return nil, fmt.Errorf("scan outbound job: %w", err)
+		}
+
+		j.Status = entity.OutboundJobStatus(statusStr)
+		if lastSmtpCode != nil {
+			j.LastSmtpCode = *lastSmtpCode
+		}
+		if lastError != nil {
+			j.LastError = *lastError
+		}
+		if tlsPolicyUsed != nil {
+			j.TlsPolicyUsed = *tlsPolicyUsed
+		}
+
+		jobs = append(jobs, j)
+	}
+
+	return jobs, nil
+}
+
+func (r *OutboundRepository) UpdateJob(ctx context.Context, job *entity.OutboundJob) error {
+	_, err := r.pool.Exec(ctx, `
+		UPDATE outbound_jobs
+		SET status = $1, attempt = $2, next_attempt_at = $3, last_smtp_code = $4,
+		    last_error = $5, tls_policy_used = $6, delay_dsn_sent = $7, locked_by = NULL, locked_until = NULL
+		WHERE id = $8
+	`, job.Status, job.Attempt, job.NextAttemptAt, job.LastSmtpCode,
+		job.LastError, job.TlsPolicyUsed, job.DelayDsnSent, job.ID)
+
+	if err != nil {
+		return fmt.Errorf("update outbound job %s: %w", job.ID, err)
+	}
+	return nil
+}