How to Send a Script as Variable to the Meilix ISO with Travis and Meilix Generator

We wanted to add more features to Melix Generator web app to be able to customize Meilix ISO with more features so we thought of sending every customization we want to apply as a different variable and then use the scripts from Meilix Generator repo to generate ISO but that idea was bad as many variables are to be made and need to be maintained on both Heroku and Travis CI and keep growing with addition of features to web app.

So we thought of a better idea of creating a combined script with web app for each feature to be applied to ISO and send it as a variable to Travis CI.

Now another problem was how to send script as a variable after generating it as json do not support special characters inside the script. We tried escaping the special characters and the data was successfully sent to Travis CI and was shown in config but when setting that variable as an environment variable in Travis CI the whole value of variable was not taken as we had spaces in the script.

So to eliminate that problem we encoded the variable in the app as base64 and sent it to Travis CI and used it using following code.

To generate the variable from script.

with open('travis_script_1.sh','rb') as f:
    os.environ["TRAVIS_SCRIPT"] = str(base64.b64encode(f.read()))[1:]

 

For this we have to import base64 module and open the script generated in binary mode and using base64 we encode the script and using Travis CI API we send variable as script to the Travis CI to build the ISO with script in chroot we were also required to make changes in Meilix to be able to decode the script and then copy it into chroot during the ISO build.

sudo su <<EOF
echo "$TRAVIS_SCRIPT" > edit/meilix-generator.sh
mv browser.sh edit/browser.sh
EOF 

 

Using script inside chroot.

chmod +x meilix-generator.sh browser.sh
echo "$(<meilix-generator.sh)" #to test the file
./browser.sh
rm browser.sh

Resources

Base64 python documentation from docs.python.org

Base64 bash tutorial from scottlinux.com by Scott Miller

su in a script from unix.stackexchange.com answered by Ankit