Include If else statement in docker file

Question

I want to create docker file with conditional statements. i get parameters from outside ( BUILD_TOOL) . This is the code but i got error while building docker image.

i got this error = dockerfile parse error line 23: unknown instruction: ELSE

RUN if [ "$BUILD_TOOL" = "maven" ] ; then 
    RUN mvn clean install;

#if build tool is gradle
else 
    RUN gradle clean;
fi

Dockerfiles don't have conditionals. As @anemyte suggests and the linked question shows, you can `RUN if ...; then ...; else ...; fi` within a single RUN statement, and that's enough for what you show. — David Maze, Jan 13 '21 at 14:37

anemyte · Answer 1 · 2021-01-13T14:24:09.243

8

Dokerfile itself does not have conditional statements. However you can implement them in shell:

RUN if [ "$BUILD_TOOL" = "maven" ] ; then \
       echo do something; \
    else \
       echo do something else; \
    fi

Just remember to add \ at the end of each line when you have a multi-line command.

edited Jan 13 '21 at 14:24

answered Jan 13 '21 at 14:13

anemyte

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run command is not getting recognized if i put '\' – Tarang Rathod Sep 28 '21 at 10:17
@TarangRathod you probably added one at the last line of the command. The last line should not end with `\ `, just as `fi` in the example. – anemyte Sep 28 '21 at 10:22
I am doing something like this `RUN if [ "$zxbild" = "demo" ] ; then \ RUN npm run zxDemo; fi` may be run wont work as you said it is shell way not docker way – Tarang Rathod Sep 28 '21 at 10:23
Remove second `RUN` after backslash – anemyte Sep 28 '21 at 10:24

Include If else statement in docker file

1 Answers1