LONO_ENV

Lono’s behavior is controlled by the LONO_ENV environment variable. For example, the LONO_ENV variable is used to layer different lono files together to make it easy to define multiple environments like production and development. This is covered thoroughly in the Layering docs. LONO_ENV defaults to development when not set.

Setting LONO_ENV

The LONO_ENV can be set in several ways:

1. At the CLI command invocation - This takes the highest precedence.
2. Exported as an environment variable to your shell - This takes the second highest precedence.
3. As a aws_profile value in your lono settings.yml file - This takes the lowest precedence.

At the CLI Command

LONO_ENV=production lono generate

As an environment variable

export LONO_ENV=production
lono generate

If you do not want to remember to type LONO_ENV=production, you can set it in your ~/.profile.

Settings: aws_profile

The most interesting way to set LONO_ENV is with aws_profile in settings.yml. This setting tightly binds the two environment variables: LONO_ENV and AWS_PROFILE. Let’s say you have a settings.yml with the following:

development:
  aws_profile: dev_profile
production:
  aws_profile: prod_profile

In this case, when you set AWS_PROFILE to switch AWS profiles, lono picks this up and maps aws_profile to the containing LONO_ENV config. This prevents you from switching AWS_PROFILE, forgetting to also switch LONO_ENV, and accidentally deploying to the wrong environment. Example:

The binding is two-way. So:

LONO_ENV=production lono cfn deploy # will deploy to the AWS_PROFILE=prod_profile
AWS_PROFILE=prod_profile lono cfn deploy # will deploy to the LONO_ENV=production

More info on settings is available at the Settings docs.

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