Deploying

A Preá app is a single binary, plus its configuration and migrations. This page shows what to build, what to ship and how to run it in production.

What you'll learn

• How to build the binary
• What travels with it
• How to configure and run it in production
• How migrations fit into a release

Build

prea build

The binary goes to bin/<project name>. Go's build flags pass through, and so do GOOS and GOARCH for another platform:

GOOS=linux GOARCH=amd64 prea build -trimpath -ldflags="-s -w"

What to ship

release/
├── shop            the binary
├── config/         the YAML files
└── migrations/     the SQL files

The app reads config/ and migrations/ from the folder it runs in, so keep the three together.

Configure production

The prod profile of a new project switches the server to release mode and the logs to JSON:

# config/application-prod.yaml
server:
  mode: release
logging:
  format: json

Everything secret comes from the environment:

PREA_PROFILE=prod
DATABASE_URL=postgres://...
JWT_SECRET=...          # if the app uses tokens

A checklist for application-prod.yaml:

• database.schema: validate, so the app never runs against tables it doesn't expect;
• database.migrations.from_models: false, so production never writes migration files;
• server.trusted_proxies, if a load balancer sits in front of the app (HTTP security);
• the server timeouts, if you stream or serve large downloads.

Migrations in a release

Pick one of the two:

• At startup: database.migrations.on_start: true. Every instance tries, and a lock lets only one of them migrate.
• As a deploy step: run prea migrate --profile prod up before starting the new version, and leave on_start off.

Either way, schema: validate checks the result before the app serves.

Run

PREA_PROFILE=prod ./shop

The app stops gracefully on SIGTERM, which is what deploy platforms and orchestrators send. It finishes the requests in flight, up to server.shutdown_timeout, before it exits. Set your platform's grace period a bit longer than that.

A container image needs nothing more than the binary and the two folders:

FROM golang:1.26 AS build
WORKDIR /src
COPY . .
RUN go install github.com/prea-framework/prea/cmd/prea@latest && prea build -trimpath

FROM gcr.io/distroless/base-debian12
WORKDIR /app
COPY --from=build /src/bin/shop ./
COPY --from=build /src/config ./config
COPY --from=build /src/migrations ./migrations
ENV PREA_PROFILE=prod
CMD ["./shop"]

Next steps

• Configuration keys
• CLI reference