Build a docker image without staring it - docker

Question

I am trying to create a docker image and tag it at the same time. This way I can create a script that uses the -t option in the "docker build" command. Thus staff members that deploy new images does not need to type docker commands, they simply run the script.
The problem that I have is that the "docker build" command also starts the image. This causes the docker build command to get 'stuck' when it gets to the point where the image runs, because the image is suppose to run indefinitely, it is a service, thus the build command never finishes, and the result is that the tag mentioned in the "-t" part of the build command never gets applied to the new image.
So there is no way to identify new images because none of them have tags. I can fix it by terminating the build command with Ctrl+C and then afterwards using the "docker tag" command. But that means that I cannot put the build and tag commands in a bash script, because I have to tag the image ID and not the name. Which changes every time I run the docker build command.
I have tried the following:
Hitting Ctrl+C to terminate the application running inside the new image. This does end the current running application. But this terminates the docker build command as well. Thus the image tag never gets applied.
I have tried using "docker ps" in another terminal to find the currently running container and stopping it with "docker stop ID". This also stops the application / container but this generates an error on the docker build command and once again doesn't finish and doesn't apply the tag.
This is what I see after I have tried steps 1 or 2 above and run a "docker image list" command, the neither the tag field nor the repository field being set:
REPOSITORY TAG IMAGE ID CREATED SIZE
<none> <none> df355e74685b 6 minutes ago 493MB
openjdk latest e92ef2c3a3dd 12 days ago 470MB
openjdk 8 b84359d0cbce 3 weeks ago 488MB
portainer/portainer latest da2759008147 4 weeks ago 75.4MB
My docker build command :
sudo docker build -t slite/cloud-db-host -f slite/cloud/db/Dockerfile.Host.docker .
And here is my docker file:
FROM openjdk:8
LABEL maintainer="techss.co.za"
LABEL vendor="techss.co.za"
LABEL app="slite-db-host"
LABEL repository="slite"
COPY slite/cloud/db /slite/cloud/db
COPY slite/lib/java /slite/lib/java
EXPOSE 51173
WORKDIR .
RUN javac slite/cloud/db/*.java && javac slite/lib/java/*.java && java slite.cloud.db.SliteDBHost
ENTRYPOINT ["java","slite.cloud.db.SliteDBHost"]
Here is the output from docker build:
Sending build context to Docker daemon 13.43MB
Step 1/11 : FROM openjdk:8
---> b84359d0cbce
Step 2/11 : LABEL maintainer="techss.co.za"
---> Running in 3dc3f0fcea2c
Removing intermediate container 3dc3f0fcea2c
---> 0946737c1386
Step 3/11 : LABEL vendor="techss.co.za"
---> Running in c289dd741158
Removing intermediate container c289dd741158
---> 00d5a7f3d7e5
Step 4/11 : LABEL app="slite-db-host"
---> Running in 1d7e953bdf6f
Removing intermediate container 1d7e953bdf6f
---> 4540390e8bb5
Step 5/11 : LABEL repository="slite"
---> Running in c366a92becb5
Removing intermediate container c366a92becb5
---> c9be0ef5e6da
Step 6/11 : COPY slite/cloud/db /slite/cloud/db
---> f3efeb406aef
Step 7/11 : COPY slite/lib/java /slite/lib/java
---> 797bf7df8335
Step 8/11 : EXPOSE 51173
---> Running in 93389673e9cc
Removing intermediate container 93389673e9cc
---> abfb10413edf
Step 9/11 : WORKDIR .
---> Running in 77a67baa9be6
Removing intermediate container 77a67baa9be6
---> 7d313395f072
Step 10/11 : RUN javac slite/cloud/db/*.java && javac slite/lib/java/*.java && java slite.cloud.db.SliteDBHost
---> Running in 99edcf79d5f4
Sun Jul 07 18:47:02 UTC 2019 Listening on port 51173
It just hangs on the last line, I assume it's waiting for the application running inside the container to end, which will never happen because it's a service. So how do I force docker build to carry on, even though the container is running, thus applying the needed tags. Or force docker build to NOT start the image but simply create it, which would be first prize.

Answer 1

Just replace RUN with CMD and it will not be runned during the build:
CMD ["sh","-c","javac slite/cloud/db/*.java && javac slite/lib/java/*.java && java slite.cloud.db.SliteDBHost"]
Cheers

Answer 2

Any RUN instruction will be executed when the Docker image is built. I suspect your issue will be fixed if you change line 10 of your Dockerfile.
Before:
RUN javac slite/cloud/db/*.java && javac slite/lib/java/*.java && java slite.cloud.db.SliteDBHost
After:
RUN javac slite/cloud/db/*.java && javac slite/lib/java/*.java