I'm trying to build a very small Docker container for a Go program. To do that I'm hoping to use a Docker container to build the Go program then (within the container) build another Docker container to run the program.
Here's my build Dockerfile:
FROM google/golang
WORKDIR /gopath/src/mycompany/mygoprog
# Build the Contributors application
RUN mkdir -p /gopath/src/mycompany/mygoprog
ADD ./src/* /gopath/src/mycompany/mygoprog/
RUN CGO_ENABLED=0 GOOS=linux go build -a -tags rs -ldflags '-w' /gopath/src/mycompany/mygoprog/*.go
RUN cp mygoprog /mygoprog
CMD docker build -t foobar /gopath/src/mycompany/mygoprog
My source directory has my Go program (trivial--compiles/runs) and this Dockerfile for the final product:
FROM scratch
ADD /mygoprog mygoprog
ENTRYPOINT ["/mygoprog"]
EXPOSE 9100
These files are organized thusly:
/myproject
Dockerfile
/src
Dockerfile
mygoprog.go
To launch the build I go to the top directory and run:
docker build .
This runs without errors....and no final image! Output looks like this:
bash-3.2$ docker build .
Sending build context to Docker daemon 6.656 kB
Sending build context to Docker daemon
Step 0 : FROM google/golang
---> 3cc1d7ae0e9c
Step 1 : WORKDIR /gopath/src/mycompany/mygoprog
---> Using cache
---> 49b9686dcbed
Step 2 : RUN mkdir -p /gopath/src/mycompany/mygoprog
---> Using cache
---> 0d0139bb8cae
Step 3 : ADD ./src/* /gopath/src/mycompany/mygoprog/
---> 964ea5ca6afb
Removing intermediate container e57719a417d5
Step 4 : RUN CGO_ENABLED=0 GOOS=linux go build -a -tags rs -ldflags '-w' /gopath/src/mycompany/mygoprog/*.go
---> Running in 608ad65db52c
---> 6e91f06b7654
Removing intermediate container 608ad65db52c
Step 5 : RUN cp mygoprog /mygoprog
---> Running in 196af3db881b
---> 5e90e11ffc7d
Removing intermediate container 196af3db881b
Step 6 : CMD docker build -t foobar /gopath/src/mycompany/mygoprog
---> Running in 4794354abf2b
---> d91a908ee663
Removing intermediate container 4794354abf2b
Successfully built d91a908ee663
What am I missing so I get a final, runnable Docker with my compiled program inside?