print-env

print-env

CLI to print environment variables from supported sources.

This is derived from projects that:

• Use environment variables as the main interface for configuration
• Use source-control ignored files to store environment variables for scenarios such as local development

Install

$ pipenv install print-env
# or
$ pip install print-env

Usage

Assume a .env file that contains the following content:

# .env
FLASK_APP=app.py
FLASK_DEBUG=1
SQL_URI=<SQL connection string that may contain credentials>
# and more...

Then simply

$ print-env
FLASK_APP=app.py FLASK_DEBUG=1 SQL_URI=<redacted> # and more...

The above would print out environment variables stored in .env, or env.yml, or env.json (roughly attempted in this order). You can also exclusively specify the file:

$ print-env /path/to/env/file.yml

and the script would attempt to parse the file based on its extension given. Note that any file extension that is not of YAML or JSON type is attempted as a dotenv file.

In fact, you can specify a series of files. Note that in case of duplicates, the last files take precedence, for example:

# content of base.env
LOG_LVL=warning
API_TOKEN=aabbcc

# content of dev.env
LOG_LVL=debug

$ print-env base.env dev.env
LOG_LVL=debug API_TOKEN=aabbcc

Another common case is when an external file is used to supply environment variables at deploy-time, for example, when used with the serverless framework with a serverless.yml that may look like:

service: env-vars

package:
  exclude:
    - node_modules/**
    - '*env.yml'
    - Pipefile
    - Pipfile.lock

functions:
  test:
    # test.py - handler()
    handler: test.handler
    # sourcing env vars from ./env.yml
    environment: ${file(./env.yml):}

and for local test runs you can utilize print-env to reuse the same env.yml:

$ env $(print-env) python test.py  # omitted file path since env.yml is on the default try-list

Similarly, print-env can be used for build-time configuration. For example, with an imaginary client-side project with a package.json that may look like:

{
  "name": "TestApp",
  "version": "1.0.1",
  "scripts": {
    "build": "env $(print-env local-env.json) parcel build index.html",
    "build:dev": "env $(print-env dev-env.json) parcel build index.html",
    "build:prod": "env $(print-env prod-env.json) parcel build index.html"
  }
}