Add a -max_executions flag and config option to limit evaluations

[chrisberkhout]

When many pages are available it's handy to be able to set a limit, especially for wrapper scripts.

[efd6]

Sorry, this didn't send a review request. Is there a reason not to reflect the behaviour of the filebeat input and add a max_executions field to the config? Is this purely to simulate a head?

[chrisberkhout]

The idea was to be able to run a single evaluation from the command line.

So needing to supply extra config in a file isn't as good, but having a flag do it just once rather than N times would be just as good.

I did think it was nice to be able to specify -max 0 and have it do all the checks and setup without actually running it, but that's not so important either.

[efd6]

I'm fine with a flag, but since we are doing this, let's also have the config field, with the flag taking precedence.

[chrisberkhout]

Sounds good. Named -max_executions?

[efd6]

Yes, to match the existing filebeat config field.

[efd6]

Commit message:

mito: add max_executions flag and config option to limit evaluations