Variable substitution

Build Environment
1

I’ve worked with Octopus Deploy and Azure DevOps, where it’s straight forward to do variable substitution, but I find nothing about it for CircleCI. Googling “CircleCI variable substitution” gives no hints.

I basically want to do something like this Variable substitutions - Octopus Deploy, i.e. pinpoint a file that should be affected (a json file in my case) and change all properties that match any of the environment variables declared in Circle CI.

A concrete example:
In the json file that I want to modify, there is a property named mongodbURI.

In the config.yml file I’d like to do something like:

version: 2.1

orbs:
  heroku: circleci/heroku@1.2.6

jobs:
  stage:
    executor: heroku/default
    steps:
      - checkout
      - variable-substitution
        path: "config/*json"
        variables:
          - mongodbURI: $MONGODB_STAGING_URI
      - heroku/install
      - heroku/deploy-via-git:
          app-name: $HEROKU_STAGING_APP_NAME

...

Is this doable with CircleCI?

2

I’m somewhat new to circleci, so can not say for certain that there is no such built-in feature, but I have not yet come across such a feature in the docs and this old discussion exchange indicates that there was no built-in feature about 2 years ago.

The easiest way to emulate this would be to have a run step defined that just executes a shell script to do the same task.

3

Thanks for your reply.

This seems strange to me as variable substitution has been essential in the previous pipelines that I’ve built.

If the option is to implement it myself, I think I’ll go with Github Actions instead, that support variable substitution out of the box.