Fix issue 346: Do not require permissions on the controller model to deploy an application.

[hmlanigan]

Description

The controller version can be found via the conn object. We can ignore the boolean as we do have a logged in connection by the time the applicationClient gets one. This is easier, less work and resolves the issue of users not having permissions on the controller for determining the controller version.

Added a channel to the postgresql charm in a test to ensure that ubuntu@18.04 can be used. The current default channel only supports ubuntu@22.04.

Fixes: #346

Type of change

• Change in tests (one or several tests have been changed)
• Bug fix (non-breaking change which fixes an issue)

Environment

• Juju controller version: 2.9.47

• Terraform version: 1.6.5

QA steps

$ juju bootstrap localhost terraform
$ juju add-model tf-test
$ juju add-user tf-test
$ juju grant tf-test write tf-test

#  Set the new user password to "testing".
$ juju change-user-password tf-test

# Set a password for the admin user to be able to use it again.
$ juju change-user-password
$ juju logout

# Now login with the new user.
$ juju login -u tf-test -c terraform

terraform {
  required_version = ">= 1.5"
  required_providers {
    juju = {
      source  = "juju/juju"
      version = ">=0.10.0"
    }
  }
}

provider "juju" {
    username = "tf-test"
    password = "testing"
}

data "juju_model" "tf_test" {
    name       = "tf-test"
}

resource "juju_application" "ubuntu" {
  model = data.juju_model.tf_test.name
  charm {
    name = "ubuntu"
  }
}

To run the plan, supply username and password for the user created above.

terraform init  && terraform plan && terraform apply

Try to deploy the ubuntu charm using base "ubuntu@18.04" against a 3.1.x controller via terraform. Ensure it continues to fail as the controller does not support 18.04.

Additional notes

JUJU-5119

[anvial]

@hmlanigan, I'm failed to run the QA steps:

First, there is a need to add tf-test password change:

...
juju change-user-password tf-test
...

Second, it looks like we need to change the terraform plan:

resource "juju_application" "ubuntu" {
  model = resource.juju_model.tf_test.name
  charm {
    name = "ubuntu"
  }
}

--->

resource "juju_application" "ubuntu" {
  model = data.juju_model.tf_test.name
  charm {
    name = "ubuntu"
  }
}

Finally, I got:

Planning failed. Terraform encountered an error while generating this plan.

╷
│ Error: Username and password must be set
│ 
│   with provider["registry.terraform.io/juju/juju"],
│   on plan1.tf line 11, in provider "juju":
│   11: provider "juju" {
│ 
│ Currently the provider can only authenticate using username and password based authentication, if both are empty the provider will panic
╵

[hmlanigan]

@anvial I updated the plan for testing.

With the plan failing, did you use the env var? Perhaps we need to export them first. The alternative is to add them to the plan:

provider "juju" {
    username = "tf-test"
    password = "testing"
}

[anvial]

I've exported the envvars and it works!

thx for PR.