Scripted Pipeline - Declare a variable and modify it inside a docker.image directive

[Roberto Fabrizi]

Dear Friends,

I'm trying to accomplish this with my pipeline:

• test a part of my newly produced artifact against some previous artifacts inside a docker base image
  
• if they are the same, launch a docker build using dockerfileA, otherwise using dockerfileB
  

I've arrived at this point:

                        docker.image("mybaseimage").inside {

                                try {

                                        ...

                                        sh 'find tmp_unzip_path/dependencies -type f -exec md5sum {} + | sort -k 2 | awk {\'print $1\'} > dir1.txt'

                                        sh 'find /opt/docker/lib -type f -exec md5sum {} + | sort -k 2 | awk {\'print $1\'} > dir2.txt'

                                        //sh 'printenv'

                                        sh '''if [ $(echo $?) -eq 0 ]; then

                                                echo "No changes to the dependencies!"

                                        else

                                                echo "Dependencies must be updated!"

What I'd like to do is assign the result of if statement to a variable, so I can use it to make another choise later on.

I've tried variables, environment variables, but neither is working. This is one try for example:

withEnv(["DEP_UNCHANGED=0"]) {

...

same code as before

sh '''if [ $(echo $?) -eq 0 ]; then

     DEP_UNCHANGED=0

else 

    DEP_UNCHANGED=1

...

}

This says that DEP_UNCHANGED is not defined. Ironically enough if I do this:

withEnv(["DEP_UNCHANGED=0"]) {

...

same code as before

sh '''if [ $(echo $?) -eq 0 ]; then

     $DEP_UNCHANGED=0

else 

    $DEP_UNCHANGED=1

...

}

it complains that 0 = 0, so it IS defined I guess....

printenv also does print DEP_UNCHANGED=0, so it IS defined?

What is the proper way to accomplish this?

Thank you so much,

Best regards,

Roberto