Check if Appose is in the Environment

[ian-coccimiglio]

When running Appose for the first time, I was confused.

But briefly, I created a development conda environment with Appose. Then I created a Maven package with Appose as a dependency.

I then set the IntelliJ environment variables to include environment variables, and the first test example ran successfully :). I supposed that this meant that currently-active Appose was enough to build an arbitrary conda environment with Python code in it and run it.

However, I realized later that any built conda environments /also/ need to have Appose on them to work properly. If not, task.outputs.get("result") will return null. There is an indication though: in the task status "CRASHED" however, but it only showed up on the debugger.

So two thoughts:

• Prior to building an environment, check if appose is in the ".yml" file, if not, log a warning?
• Log a warning if a task has a CRASHED status (I think this is supposed to happen, but I do not fully get Java logging yet)

[ctrueden]

My idea for making this nicer is: immediately after starting a service, run an initial "canary" task to validate the service is running properly, blocking till complete. And if not, throw an exception directly in response to the env.service(...) invocation. It will slightly slow down service initialization, but will yield a much friendlier fail-fast behavior in case the environment is not properly configured.

I also thought about automatically installing Appose into the environment upon service startup, but that feels too magical to me, and would complicate the codebase. Better to just have the fail-fast error message be clear that Appose needs to be present in the environment, I think.