How to detect if the current script is running in a docker build?-CodePudding

Suppose I have a Dockerfile which runs a script,

RUN ./myscript.sh

How could I write the myscript.sh so that it could detect if itself is launched by the RUN command during a docker build?

#! /bin/bash

# myscript.sh

if <What should I do here?>
then
  echo "I am in a docker build"
else
  echo "I am not in a docker build"
fi

Ideally, it should not require any changes in the Dockerfile, so that the caller of myscript.sh does not need specialized knowledge about myscript.sh.

CodePudding user response：

Try this :

#!/bin/bash

# myscript.sh

isDocker(){
    local cgroup=/proc/1/cgroup
    test -f $cgroup && [[ "$(<$cgroup)" = *:cpuset:/docker/* ]]
}

isDockerBuildkit(){
    local cgroup=/proc/1/cgroup
    test -f $cgroup && [[ "$(<$cgroup)" = *:cpuset:/docker/buildkit/* ]]
}

isDockerContainer(){
    [ -e ./dockerenv ]
}

if isDockerBuildkit || (isDocker && ! isDockerContainer)
then
  echo "I am in a docker build"
else
  echo "I am not in a docker build"
fi

CodePudding user response：

In your Dockerfile, you can try this to run the script

ADD myscript.sh .

RUN chmod  x myscript.sh

ENTRYPOINT ["myscript.sh"]