Dynamic Paramters in the circleci config.yml

Hi,
I set the below sample environment variables in my project:

dev_key=xxxx
prod_key=yyyy
test_key=zzzz

Then I want to insert those variables to the parameters configuration so, if the CIRCLE_BRANCH=dev then:
my_key=${CIRCLE_BRANCH}_key
and same for the other branches:

So the configuration would be:

parameters:
    my_key:
        type: string
        default: ${CIRCLE_BRANCH}_key

For example, if circle CI branch is dev, then my_key must be xxxx (From environmental variables). But it doesn’t work and it only sends back the key (my_key = dev_key)

Do you have any idea how to solve the issue?

Br,
Meraj

Hi @meraj-kashi,

Thank you for sharing your question on our forum!

Environment variables such as CIRCLE_BRANCH are not available when your config.yml file is compiled, and as such you won’t be able to use them directly as a parameter. You can however use pipeline values directly in parameters as described on the following page:

Pipeline Variables - CircleCI

This means it wouldn’t be possible to filter jobs or workflows for example based on a parameter using an environment variable.

If you are looking to store a command as a parameter and later evaluate it inside of a job (after the job starts), then something like this should work:

Assume there is a project environment variable DEV_KEY set to equal test12345.
I then push a commit to the dev branch, triggering a new build.

Here is a sample config:

version: 2.1

jobs:
  build:
    parameters:
      my_key:
        type: string
        default: "echo $<< pipeline.git.branch >>_KEY"
    docker:
      - image: cimg/node:17.3.1
    steps:
      - checkout
      - run: << parameters.my_key >>

workflows: 
  workflow1:
    jobs:
      - build

In the above, I am using a pipeline value pipeline.git.branch which is made available to use in your config.yml file.

Let me know if you have any further questions!

1 Like

Hi again @aaronclark,

Thanks for your solution, it works fine!

parameters:
    my_key:
        type: string
        default: "echo  $KEY_<< pipeline.git.branch >>"

Just a quick question, is there any built-in function that can capitalize (to uppercase) the value? I mean in the above example, the default value of my_key is equal to KEY_dev , then is there any solution to change it to KEY_DEV ?

Br,
Meraj

Hi @meraj-kashi,

Glad to hear it was useful!

There is no built in feature within CircleCI to capitalize the characters in a string, but I believe you can do something like the following with bash:

echo $KEY_<< pipeline.git.branch >> | tr a-z A-Z
1 Like