Extensions

What varies between marinas and depends on external vendors sits behind public Go interfaces in the pkg/ext package. The package imports nothing from internal/: an extension is written against these interfaces and registered in the binary, by passing the implementations in ext.Extensions where cmd/porto builds the application.

Interface	For	In the core
PaymentProvider	payment gateways and methods	manual (always on) and stripe drivers
FiscalDriver	fiscal cash registers and commercial documents	none, export and the desktop app bridge
ChargeExporter	sending charges to invoicing software and receiving invoice number and date back	none
SignatureProvider	advanced or qualified e-signature	none (paper, OTP and on-screen signature are in the core)
BookingChannel	berth booking portals	none
SensorSource	polled reading sources (vendor API, MQTT broker)	none (sensors can also push directly, protocol)
Notifier	extra notification channels (SMS, WhatsApp)	none (email is in the core)
EventSink	receiving every outbox event, at least once	webhooks and SSE
TenantResolver	custom domains for the public pages	—
AuthProvider, BotProtection	external identity providers, protection of public forms	—
HTTPRoutes	extra routes on the router	—

Rules for extensions

• No personal data in logs, in metadata sent to providers and in events: only ids and enumerated values.
• Outgoing HTTP only through the client Porto gives the driver: https, no private or metadata addresses, redirects rechecked.
• Money in integer cents with an explicit ISO 4217 currency; no decimal numbers.
• Provider calls happen outside database transactions; the outcome usually arrives through a signed webhook.
• Events may arrive more than once: EventSink.Handle must be idempotent.
• A booking channel cannot create overlaps: incoming bookings go through the same transit service and occupy a concrete berth.

Before writing a driver

Open a new driver issue on the repository to agree on the interface and on whether the driver belongs in the core or in a separate extension. See Contributing and, for payments, Payment drivers.