Adding an Action
Adding an action to a charm that currently does not have any actions requires two things, the new action to be written and an
actions.yaml be added to the charm’s root directory to describe the new action as well as any options that it takes.
An action can be as sinple as a bash one liner or as complex as a compiled binary, just like a standard Juju hook. I went about adding my two hooks, pause and resume, as simple bash files that tell ceph to pause and resume the Ceph cluster’s health monitoring.
After adding in my two actions’ executables, I created
At this point, I could deploy the Ceph charm as well as run these actions on the cluster. My work was done, right? Wrong! I needed to have tests validating that these actions work; I’d hate to have somebody accidentally break these features at a later date and not be alerted to the break by their tests!
Adding a new test to an Open Stack charm seems pretty reasonable, add a function into the right place and it’ll run:
Now I’ve got a running test but how do I actually run and verify the actions? After a lot of digging around, I found another Open Stack charm that does test their actions, Swift-proxy, that I could model my test on.
First, a bit of background. The Open Stack charms tend to test a lot of the Open Stack deployment to verify each service. They each define
u = OpenStackAmuletUtils(DEBUG) in the setup of the tests.
u gives a lot of support methods for the Open Stack charms, including logging and authenticating to the various Open Stack services.
Another thing that the
u offers is the ability to run actions :smile: The code I needed was:
After doing this, the action had been run on the first Ceph unit in the cluster. After running the hook, I could add:
ceph -s on the node and check for the expected flags. Testing the resume action is nearly the same, and the whole function is posted below for clarity: