In Juju, what command to use for accessing environment settings from within a hook script?

Question

My specific case is for getting the amazon EC2 authentication information stored in the environments.yaml.
I am aware of the get-constraints command available in recent Juju builds. Can this be used to access this information?

Answer 1

Try passing the information you need as config parameters for the charm.

To do this, you'd:

• add parameter names into the charm's config.yaml file

• either pass the keys in as a --config part of the juju deploy command or alternatively using the juju set command

• read the keys from the charm hooks using the config-get command

Answer 2

At this time you can not access Environment varaibables. If your charm requires authentication information you'll need to add it as a configuration option for that Charm (Charms should be designed to deploy on all stacks, so not every provider will have something like an ec2-authentication key). If you require AWS services in your charm consider exposing those in the configuration with something like this:

options:
  aws-public-key:
    type: string
    default: ""
    description: Amazon Public Key for S3
  aws-secret-key:
    type: string
    default: ""
    description: Amazon Secret Key for S3
  s3-bucket:
    type: string
    default: ""
    description: Amazon S3 Bucket

So these would be set using the juju setcommand and would be available in the config_changed hook via config-get

• Service Configuration