Dockerfile-dlv-headless

# Compile stage
FROM golang:1.21.1-alpine3.18 AS build-env
#ENV CGO_ENABLED 0
WORKDIR /usr/src/app

# Download and install the Delve debugger.
RUN go install github.com/go-delve/delve/cmd/dlv@v1.21.0

# pre-copy/cache go.mod for pre-downloading dependencies and only redownloading them in subsequent builds if they change
COPY ./sample_app/go.mod ./sample_app/go.sum ./
RUN go mod download && go mod verify

COPY ./sample_app .
## The -gcflags "all=-N -l" flag helps us get a better debug experience
RUN go build -gcflags "all=-N -l" -v -o /usr/local/bin/app ./...

# Final stage
FROM alpine:3.18
# Port 8080 belongs to our application, 40000 belongs to Delve
EXPOSE 8080 40000
WORKDIR /

COPY --from=build-env /go/bin/dlv /bin/dlv
COPY --from=build-env /usr/local/bin/app /

# TODO: use env var and conditional run.sh
# Run delve
CMD ["dlv", "--listen=0.0.0.0:40000", "--headless=true", "--api-version=2", "exec", "/app", "--log"]