If conditional in docker file

Question

RUN if [ "$AUTH_MS_PROFILE" = "test" ]; then RUN ["mvn", "verify"]; fi

I'm trying to to have two images for production and testing environments. Now, because I don't need integration test for production env, I'm using build-arg to set dev and test profiles, therefore I require if conditional if the input is test it should test otherwise it should not.

Answer 1

First of all, create a build_internal.sh file and paste all such conditionals to it

if [ "$AUTH_MS_PROFILE" = "test" ]; then 
   mvn verify
fi

Copy this file inside and then run it inside the dockerfile. I you want to try what you were trying then do:

RUN if [ "$AUTH_MS_PROFILE" = "test" ]; then mvn verify ; fi

Answer 2

Try this:

FROM centos:7
ARG arg
RUN if [ "x$arg" = "x" ] ; then echo Argument not provided ; else echo Argument is $arg ; fi

and then build the image as:

docker build -t my_docker .

Answer 3

You can build it this way:

docker build --build-arg HTTP_PROXY=http://10.20.30.2:1234 .

Answer 4

Create a bash script:

#!/bin/bash -x

if test -z $1 ; then 
    echo "argument empty"
    ........
else 
    echo "Arg not empty: $1"
    ........
fi

Dockerfile:

FROM ...
....
ARG arg
COPY bash.sh /tmp/  
RUN chmod u+x /tmp/bash.sh && /tmp/bash.sh $arg

Answer 5

you can do this inside the Dockerfile

ARG argname=false   #default argument when not provided in the --build-arg
RUN if [ "$argname" = "false" ] ; then echo 'false'; else echo 'true'; fi

and in the docker build:

docker build --pull -f "Dockerfile" --label "service_name=${SERVICE_NAME}" -t $SERVICE_NAME --build-arg argname=true .

Comments

RUN if [ "$argname" = "false" ] ; then echo 'false'; else echo 'true'; fi

Can we split this into mutiple line like :

RUN if [ "$argname" = "false" ] ; 

then 

RUN something

RUN something2

;

else 

RUN something3

RUN something4

; fi

Answer 6

You can use the test command

RUN test -z "$VAR" || echo "arg is set" && echo "var is not set"
RUN test -z "$VAR" && echo "arg is not set" || :
RUN test -z "$VAR" || echo "arg is set" && :

Answer 7

Hi,

Sometimes when running a Dockerfile you need to run some conditional logic based upon an ARG variable. This can be handy in the instance you want to run a production build or development build or need to run an extra step for production, etc.

ARG ENV
RUN if [ "$ENV" = "production" ] ; then yarn client:build:prod ; else yarn client:build ; fi