Hello, given this note from the docs:

During some program executions,

apply

doesn’t run. For example, it won’t run during a preview, when resource output values may be unknown. Therefore, you should avoid side-effects within the callbacks. For this reason, you should not allocate new resources inside of your callbacks either, as it could lead to

pulumi preview

being wrong.

can anyone let me know the preferred way to create a resource that depends on an output value? Me and my teammates have been trying for days to create resources without this, and always end up with various errors relating to things being an Output instance (we’re using python if it matters)

Can you give an example of the error and what you are trying to do? It'll be a lot easier to point you in the right direction that way.

i’d have to do a bunch of re-rework to get it producing the errors again, we’d just refit everything to use an apply callback any time an output is used

we’d just refit everything to use an apply callback any time an output is used

that's probably not necessary TBH

i was hoping so, but we’ve not gotten it fully working without that

Are you creating the resources inside the apply?

Yeah currently all the resources that depend on the value of any output are being created in an apply

FWIW, you should just be able to do this:

res1 = MyResource("my_resource", property="blah")

res2 = OtherResource("foo", dependent_property=res1.property)

If you need to transform the output (like add something to the string)

res1 = MyResource("my_resource", property="blah")

res2 = OtherResource("foo", dependent_property=res1.property.apply(lambda x: f"new-string-{x}")

yeah i knew it was the cause of the wrong previews, thanks for the datapoint though

awesome!