Project values and variables

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This page is a reference for all built-in values available for use in your CircleCI projects.

Built-in environment variables

The following built-in environment variables are available for all CircleCI projects. Environment variables are scoped at the job level. They can be used within the context of a job but do not exist at a pipeline level, therefore they cannot be used for any logic at the pipeline or workflow level.

Note: You cannot use a built-in environment variable to define another environment variable. Instead, you must use a run step to export the new environment variables using BASH_ENV. For more details, see Setting an Environment Variable in a Shell Command.

Pipeline values

Pipeline values are available to all pipeline configurations and can be used without previous declaration. Pipeline values are scoped at the pipeline level. They are interpolated at compilation time, not workflow/job runtime.

For example:

version: 2.1

jobs:
  build:
    docker:
      - image: cimg/node:latest
        auth:
          username: mydockerhub-user
          password: $DOCKERHUB_PASSWORD  # context / project UI env-var reference
    environment:
      CIRCLE_COMPARE_URL: << pipeline.project.git_url >>/compare/<< pipeline.git.base_revision >>..<<pipeline.git.revision>>
    working_directory: ~/main
    steps:
      - run: echo "This is pipeline ID << pipeline.id >>"
      - run: echo $CIRCLE_COMPARE_URL

Note: When using the above method to set the variables in the environment key, note that if the pipeline variable is empty it will be set to <nil>. If you need an empty string instead, set the variable in a shell command.

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