Morning all I am converting our build over to Pants I have t

Question

Morning all I am converting our build over to Pants I have tests running and am trying to get our wsgi app packaged We have a Pyramid app that is scanning the package to pick up views registered with a decorator I take it aside from manually listing the views in a BUILD file I would need to create a plugin

hundreds-father-404 · Answer

Yes that is one way to do that Pants allows you to add several dependency inference rules so you can add your custom logic to augment what pants already has

faint-twilight-16124 · Answer

Are there any example plugins that we could leverage that does this

hundreds-father-404 · Answer

One of the projects we want to do this year is to rewrite the example plug in repository to have several examples like this In the meantime this might be a decent example <https github com pantsbuild pants blob main src python pants backend codegen protobuf protobuf dependency inference py> The main idea generally with dependency inference is that you will want to parse out the relevant information from the file and then associate the post information with some mapping that you precomputed Pants already has a module mapping for Python so that it knows imports ports of foo bar gt src py foo bar py for example You will be able to leverage that in your plug in

hundreds-father-404 · Answer

To help me give you better advice can you please explain more about how the dependency inference should work here For example what is the decorator

faint-twilight-16124 · Answer

Basically in pyramid you can decorate your views using view config route name= xyz <https docs pylonsproject org projects pyramid en 2 0 branch narr urldispatch html route configuration>

faint-twilight-16124 · Answer

In some wsgi file you can do a config scan This using something that scans your packages for these decorators and registers them with pyramid

faint-twilight-16124 · Answer

So it seems I need some kind of regex for the decorator and somehow map these files to some other file

hundreds-father-404 · Answer

Either a regex or AST parsing like this <https github com pantsbuild pants blob main src python pants backend python dependency inference scripts dependency parser py>

hundreds-father-404 · Answer

So with the route name how do you determine what that comes from Does that corresponds to a file name

hundreds-father-404 · Answer

By the way in case it is not obvious the reason that dependency inference amp the dependencies field matters is it is what gives you fine grained caching If you depended on everything in your project then we could never safely cache test results for example Fine grained dependencies also make project introspection more useful <https www pantsbuild org v2 11 docs project introspection>

faint-twilight-16124 · Answer

Unfortunately it isn t so simple The app is using pyramid traversals

faint-twilight-16124 · Answer

There is view config context=ResourceClassName ResourceClassName name = the url segment

faint-twilight-16124 · Answer

It seems pants picks up the relationship between the views and the resource I just need a way to link it back to the wsgi class that does the scan

happy-kitchen-89482 · Answer

So you need the wsgi class to depend on anything that has a `view config` in it

faint-twilight-16124 · Answer

Yes that s what I need to achieve

happy-kitchen-89482 · Answer

I think that should be straightforward to implement as a plugin The interesting question would be how to identify the wsgi class to the plugin though

happy-kitchen-89482 · Answer

Does it have any distinguishing content that the plugin can identify

faint-twilight-16124 · Answer

Yes it would do

faint-twilight-16124 · Answer

from pyramid config import Configurator config = Configurator config scan package= xyz

faint-twilight-16124 · Answer

Could I use the decorator like rule desc= Inferring Protobuf dependencies by analyzing imports How would I associate it back to another file that did the import The protobuf one seems to map the current file to the import I would need to somehow associate the file with the found decorator back to another file with the pyramid Configurator

happy-kitchen-89482 · Answer

Yeah this is where your case is interesting I think your plugin would have to gather two kinds of information for files 1 do they contain a `config scan package= xyz ` and 2 do they contain a `view config` And then stitch them together into dependencies in a post processing step

happy-kitchen-89482 · Answer

based on whatever the `package=` says