#general
Title
a
average-breakfast-91545
03/25/2023, 10:56 AMOkay, so assuming I'm dumb enough to jump into building a plugin to build a lambda layer, with a week's "experience" of pants, how do I go about this?
I've gone through the tutorial written by a friendly community member, and I've got a plugin that supports the package rule. I have a fieldset that takes a bunch of dependencies. All I need to do is:
ā¢ Create a temporary directory
ā¢ Copy each dependency to that temporary directory
ā¢ Create a zip of the directory
I can see that there's a
dirutilf
fast-nail-55400
03/25/2023, 6:49 PMAre the dependencies already available as one or more
Digesta
average-breakfast-91545
03/25/2023, 6:51 PMAt the moment I'm just trudging through code becoming increasingly confused. I can create a RequirementsPexRequest from my target, but I'm failing to create a Pex from that digest. Why do you ask?
I'm thinking that if I create a RequirementsPexRequest, then Get a Pex, I should be able to pass that digest to a Process and do the munging.
f
fast-nail-55400
03/25/2023, 7:27 PMI ask because if the dependencies are already available as a
DigestCreateDigestMergeDigestsAddPrefixRemovePrefixDigestEntriesDigestContentsDigesta
average-breakfast-91545
03/25/2023, 7:28 PMThat's my current plan, but f I try to Get(Pex, requirements_pex_request) I get an ast error, which I'm trying to puzzle out. I suspect it's because I'm running 2.15 but reading code from main
f
fast-nail-55400
03/25/2023, 7:28 PMBecause the Pants setup code needs to read the input and output types out of a
GetWhen you have a variable with the input in it, you need to use the three-argument form of
GetGet(OutputType, InputType, my_input)a
average-breakfast-91545
03/25/2023, 7:29 PMAh ha. Excellent, so the places in the code I've seen using the 2 arg form are ... doing what?
I know that's a very stupid question
f
fast-nail-55400
03/25/2023, 7:29 PMyou will note that the two-argument form involves a constructor for the input type
and so the Pants setup code knows what the input type is (and can also just let the constructor call create the input instance)
a
average-breakfast-91545
03/25/2023, 7:30 PMRoger, thank you. I'll give it a whirl
Just fixing a PC with my son š
awesome, I have a pex in my process. Thank you so much for your patience.
f
fast-nail-55400
03/25/2023, 7:59 PMI know that's a very stupid questionNot a stupid question; no software is ever obvious, let alone the Pants plugin API
š 1
h
happy-kitchen-89482
03/25/2023, 9:00 PMYeah, there are no stupid questions here, only incomplete documentation
š 1
a
average-breakfast-91545
03/25/2023, 9:51 PMtbf, the documentation does make the difference between the two and three arg form clear, but I forgot all about that, and then had an inexplicable ast error.
f
fast-nail-55400
03/26/2023, 3:26 PMMaybe the AST error should be improved to suggest the three-argument form in these cases?
for example, if the engine setup code sees the two-argument form but the second argument is a lower-cased identifier and thus likely not a Type, then the error could suggest the three-argument form.
a
average-breakfast-91545
03/26/2023, 4:22 PMIf I get sufficiently bored, I'll open an issue and a PR to make the suggested change. That would definitely have saved me some time.
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