Events: Add placeholder to subqueries

[ghost]

see Intevation/intelmq-fody#70

[bernhardreiter]

Hi @wagner-certat,
thanks for the pull request.

I've had a first look,

• To me it looks sensible to also add an example of a placeholder to the config file.
• An example for using % as post and prefix for substring search would be illustrative.
• The change introduces a dependency to intelmq which wasn't there before. Probably fine, maybe listed in setup.py so this gets an automatic check. (Before in principle, someone could run the module without having a full intelmq installed, e.g. on a pure database machine.)

What do you think?

[ghost]

* To me it looks sensible to also add an example of a placeholder to the config file.

Good idea, done

* An example for using `%` as post and prefix for substring search would be illustrative.

Also added

* The change introduces a dependency to `intelmq`  which wasn't there before. Probably fine, maybe listed in setup.py so this gets an automatic check. (Before in principle, someone could run the module without having a full intelmq installed, e.g. on a pure database machine.)

It actually does only require the installed library, not the full (running) application. I didn't even check if the requirement is already there because I assumed it is. Thanks for the hint, I added it.

[ghost]

Resolved the conflicts with master

[ghost]

Is there interest in this feature?

[bernhardreiter]

@wagner-certat yes so far I think it is a useful feature. (We currently lack contracted time to properly review it.)

BTW: I wonder if the intelmq dependency could be made optional with little effort.