Ports
The [ports] section declares which ports Coast manages for forwarding between your Coast instances and the host machine. The optional [egress] section declares ports on the host that Coast instances need to reach outbound.
For how port forwarding works at runtime — canonical vs dynamic ports, checkout swapping, socat — see Ports and Checkout.
[ports]
A flat map of logical_name = port_number. Each entry tells Coast to set up port forwarding for that port when a Coast instance runs.
[ports]
web = 3000
api = 8080
postgres = 5432Every instance gets a dynamic port (high range, always accessible) for each declared port. The checked-out instance also gets the canonical port (the number you declared) forwarded to the host.
Rules:
- Port values must be non-zero unsigned 16-bit integers (1-65535).
- Logical names are freeform strings used as identifiers in
coast ports, Coastguard, andprimary_port.
Minimal example
[coast]
name = "my-app"
compose = "./docker-compose.yml"
[ports]
app = 3000Multi-service example
[ports]
web = 3000
api = 4000
backend = 8080
postgres = 5432
redis = 6379primary_port
Set in the [coast] section (documented in Project and Setup), primary_port names one of your declared ports for quick-links and subdomain routing in Coastguard.
[coast]
name = "my-app"
primary_port = "web"
[ports]
web = 3000
api = 8080The value must match a key in [ports]. See Primary Port and DNS for details.
[egress]
Declares ports on the host that Coast instances need to reach. This is the reverse direction from [ports] — instead of forwarding a port out of the Coast to the host, egress makes a host port reachable from inside the Coast.
[coast]
name = "my-app"
compose = "./docker-compose.yml"
[ports]
app = 48090
[egress]
host-api = 48080This is useful when your compose services inside a Coast need to talk to something running directly on the host machine (outside of Coast's shared services system).
Rules:
- Same as
[ports]: values must be non-zero unsigned 16-bit integers. - Logical names are freeform identifiers.