Dockerfile

FROM golang:1.18-alpine as base
ENV CGO_ENABLED=0
WORKDIR /opt/app
COPY go.mod .
COPY go.sum .
RUN go mod download

FROM base as build
RUN --mount=target=. \
    --mount=type=cache,target=/root/.cache/go-build \
    go build -o /out/app src/cmd/main.go

FROM base AS unit-test
RUN --mount=target=. \
    --mount=type=cache,target=/root/.cache/go-build \
    go test -v ./...

FROM golangci/golangci-lint:v1.46.2-alpine as lint-base

FROM base as lint
COPY --from=lint-base /usr/bin/golangci-lint /usr/bin/golangci-lint
RUN --mount=target=. \
    --mount=type=cache,target=/root/.cache/go-build \
    --mount=type=cache,target=/root/.cache/golangci-lint \
      golangci-lint run --timeout 10m0s ./...

FROM base as build-dev
RUN apk add git
RUN go install github.com/go-delve/delve/cmd/dlv@latest
RUN go install github.com/cweill/gotests/gotests@latest
RUN go install github.com/fatih/gomodifytags@latest
RUN go install github.com/josharian/impl@latest
RUN go install github.com/haya14busa/goplay/cmd/goplay@latest
RUN go install honnef.co/go/tools/cmd/staticcheck@latest
RUN go install golang.org/x/tools/gopls@latest
RUN --mount=target=. \
    --mount=type=cache,target=/root/.cache/go-build \
    go build -gcflags="all=-N -l" -o /bin/app src/cmd/main.go
EXPOSE 3000 40000
CMD ["/dlv", "--listen=:40000", "--headless=true", "--api-version=2", "--accept-multiclient", "exec", "/bin/app"]

FROM build-dev as webservice-watch
RUN go install github.com/cosmtrek/air@latest
EXPOSE 3000
CMD ["air"]

FROM scratch as webservice
EXPOSE 3000
COPY --from=build /out/app .
CMD ["./app"]