README.md

Juju deployment

Local Juju and charm deployment via microk8s and terraform.

Setup a juju environment

Setup an environment to use for any juju deployment.

It is recommended to install the pre-requisites on a VM rather than your host machine. To do so, first install multipass:

sudo snap install multipass

Then launch a new VM instance using (this will take a while):

multipass launch noble --disk 50G --memory 4G --cpus 2 --name test-observer-juju --mount /path/to/test_observer:/home/ubuntu/test_observer --cloud-init /path/to/test_observer/terraform/cloud-init.yaml --timeout 1200

Feel free to increase the storage, memory, cpu limits or change the VM name.

Initialize project's terraform

Now that everything has been set up, you can initialize the project's terraform.

In the terraform directory on your host machine, run:

multipass exec test-observer-juju -- terraform init

Deploy everything

In the terraform directory on your host machine, run:

multipass exec test-observer-juju -- TF_VAR_environment=development TF_VAR_external_ingress_hostname=local terraform apply -auto-approve

Then wait for the deployment to settle and all the statuses to become active. You can watch the statuses via:

multipass exec test-observer-juju -- juju status --storage --relations --watch 5s

Connect to your deployment

Look at the IPv4 addresses of your test-observer-juju vm through:

multipass info test-observer-juju

One of these connect to the ingress enabled inside the VM. To figure out which one try the following command on each IP address until you get response:

curl --connect-to ::<ip-address> http://test-observer-api.local

Once you find the IP address add the following entry to your host machine's /etc/hosts file:

<ip-address>   test-observer.local test-observer-api.local

After that you should be able to get to TO frontend on your host machine's browser through the url http://test-observer.local. You should also be able to access the API through http://test-observer-api.local.

Teardown

To take everything down you can start with terraform:

multipass exec test-observer-juju -- TF_VAR_environment=development TF_VAR_external_ingress_hostname=local terraform destroy -auto-approve

The above step can take a while and may even get stuck with some applications in error state. You can watch it through:

multipass exec test-observer-juju -- juju status --storage --relations --watch 5s

To forcefully remove applications stuck in error state:

multipass exec test-observer-juju -- juju remove-application <application-name> --destroy-storage --force

Once everything is down and the juju model has been deleted you can stop the multipass VM:

multipass stop test-observer-juju

Optionally, delete the VM:

multipass delete --purge test-observer-juju

Developing the charm

To develop and test updates to the backend and frontend charms, you would typically want to first complete the above steps to deploy a working system. Once you have done that, proceed with the following steps.

Build and refresh the backend charm

You can make edits to the backend charm and refresh it in the running system on the fly with:

cd backend/charm
charmcraft pack
juju refresh api --path ./test-observer-api_ubuntu-22.04-amd64.charm

# to update the OCI image that runs the backend
juju attach-resource api api-image=ghcr.io/canonical/test_observer/backend:[tag or sha]

Build and refresh the frontend charm

Same thing with the frontend:

cd frontend/charm
charmcraft pack

juju refresh frontend ./test-observer-frontend_ubuntu-22.04-amd64.charm

# to update the OCI image that runs the backend
juju attach-resource frontend frontend-image=ghcr.io/canonical/test_observer/frontend:[tag or sha]

Note that the frontend app is made aware of the backend URL to connect to using the global window.testObserverAPIBaseURI, which is set at runtime with some nginx config level trickery based on...

• the test-observer-api charm's hostname config value.
• the frontend charm's test-observer-api-scheme config value.

These in turn can be set using the terraform plan (terraform/test-observer.tf and associated variables).

Running tests

To run the unit and integration tests for the frontend charms, do the following:

cd frontend/charm
tox -e unit
tox -e integration

Releasing the charms

Charms are released through GitHub actions on push to main. If however you need to release charms on your branch before merging with main you could always just add your branch as a trigger to those same GitHub actions.

VS Code & charm libraries

VS Code fails to find (for autocompletions and code navigation purposes) the charm libraries under lib in each of backend/charm and frontend/charm. There is a .vscode-settings-default.json found under each of these directories which you can copy to the .gitignored path .vscode/settings.json to make them fly. Taking the backend charm as an example:

mkdir -p backend/charm/.vscode
cp backend/charm/.vscode-settings-default.json backend/charm/.vscode/settings.json

mkdir -p frontend/charm/.vscode
cp frontend/charm/.vscode-settings-default.json frontend/charm/.vscode/settings.json

Now if you use as your project the directory backend/charm and frontend/charm respectively (which you'll want to do also for them to keep their own virtual environments), VS Code should be happy.

Handy documentation pointers about charming

• Integrations (how to provide and require relations)