Crate Map

Mailman is organized as a Cargo workspace with 9 crates.

mailman/
├── crates/
│   ├── core/               # Domain logic (no I/O)
│   ├── adapters-postgres/  # PostgreSQL repository
│   ├── adapters-aws/       # S3, SES, SQS adapters
│   ├── adapters-scan/      # ClamAV malware scanner
│   ├── http/               # Axum router & handlers
│   ├── config/             # Configuration loading
│   ├── bin-api/            # API service entrypoint
│   ├── bin-worker/         # Worker service entrypoint
│   └── test-utils/         # Shared test helpers

Dependency Graph

bin-api ──► http ──► core
                 ──► config
                 ──► adapters-postgres ──► core
                 ──► adapters-aws ──► core
                 ──► adapters-scan ──► core

bin-worker ──► core
           ──► config
           ──► adapters-postgres
           ──► adapters-aws
           ──► adapters-scan

test-utils ──► core
           ──► http
           ──► adapters-postgres
           ──► adapters-aws

core

Pure domain logic with zero I/O dependencies.

Key modules:

• lib.rs — Domain entities: Domain, Inbox, EmailMessage, Thread, AuthKey, DeliveryStatus, etc.
• repository.rs — Repository traits: ThreadRepository, MessageRepository, DomainRepository, InboxRepository, WebhookRepository, AttachmentRepository, DeliveryEventRepository, SuppressionRepository, HealthRepository, AuthKeyRepository
• threading.rs — Thread resolution algorithm (In-Reply-To → References → Subject fallback → New thread)
• parser.rs — RFC 5322 MIME email parsing
• mime.rs — MIME message builder for outbound email
• webhooks.rs — HMAC-SHA256 signature generation for webhook payloads

adapters-postgres

Single PostgresRepository struct implementing all repository traits from core against a PgPool.

Migrations: Embedded via SQLx, run automatically on startup. Located in migrations/ directory.

adapters-aws

AWS SDK adapters implementing traits from core:

• s3.rs — S3Storage for raw email and attachment storage (presigned URLs)
• ses.rs — SesEmailSender for outbound delivery and domain identity management
• sqs.rs — SqsPublisher for queue publishing

adapters-scan

ClamAV malware scanner connecting via TCP socket (INSTREAM protocol).

• ClamAvScanner — connects to a ClamAV daemon, scans buffers for malware
• NoopScanner — pass-through when ClamAV is not configured

http

Axum router with all REST endpoint handlers.

Route modules: send, messages, threads, attachments, webhooks, domains, inboxes, auth_keys, reports

Middleware: auth (JWT + API key), rate_limit (governor), volume_limit (Redis), trace (request logging), pagination

config

Figment-based configuration loading with layered sources: defaults → config file (JSON/TOML) → environment variables.

bin-api / bin-worker

Thin binary entrypoints that wire together adapters and start the respective service.

test-utils

Shared test infrastructure: TestApp, E2EClient, fixtures, and mock adapter implementations.