Feature request: Cloudant package, changes feed: add filtering parameters

[markusthoemmes]

@bseyb commented on Wed Oct 19 2016

Why

I was trying to listen to changes of a cloudant feed and then send an email using sendgrid, when one flag 'process' was set to true.
For this I needed to implement one openwhisk action to filter out whether 'process' was set to true and 'mailsend' set to false.

Suggestion

Looking at the documentation of cloudant I saw that you can add add filter and doc_ids to a changefeed. It would be very awesome to add these parameters, so that filtering can already be taken care of at the change feed instead of the user created action.

Bonus

I also saw that you can pass oldDoc as a parameter. This could be helpful if you want to compare what exactly changed in an action.

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@csantanapr commented on Thu Nov 24 2016

Hi @bseyb I started looking into the design on providing a way to filter changes for the cloudant trigger.

Looking at the spec of the changes API

It looks like a filter and docs_id is doable, a filter will be a filter function on a design document.

What I didn't find was oldDoc during my testing the changes feed only provide the id and deleted=true and the new revision marked as deleted.

I was not able to find a reference to oldDoc in the changes API params.
Could you share a bit more where you saw this reference?

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@bseyb commented on Tue Dec 13 2016

Hi @csantanapr I must have misread it, I cannot find oldDoc in the correct context either.

Having that Filter function available would help a whole lot.

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@rabbah commented on Tue Jan 24 2017

@csantanapr move this to openwhisk-catalog-cloudant? FYI @johnsolm @dubeejw.

[jasonpet]

@csantanapr - this is complete.

[csantanapr]

Thanks @jasonpet for the contribution
@bseyb go ahead and give filter a try