Is there a hook for the event that Pulumi creates a resource? I would like to print a message if and only if a resource of a particular type was created by Pulumi in the current

pulumi up

call.

I don't think there's a hook as such - the easiest way to achieve this is to use a dynamic resource which depends on the first. There's an example of making this happen for Provisioners here: https://github.com/pulumi/examples/blob/master/aws-py-ec2-provisioners/__main__.py

You could do this with a CrossGuard

ResourceValidationPolicy

- e.g. https://github.com/pulumi/templates-policy/blob/master/aws-python/__main__.py#L10-L15 and run pulumi with

pulumi up --policy-pack path-to-policy-code/

.

Thanks @stocky-spoon-28903, seems to be exactly what I want. A bit more involved than I would have liked for this specific purpose, but I might as well learn about this now as I might need the concept later.

James's suggestion is good if you explicitly know the resource being created as you have to "link" it into the dynamic resource that James mentioned. A policy will let you run code for any resource of that type that's defined, JFWIW.

I came up with

from typing import Optional, Any
from uuid import uuid4

import pulumi
from pulumi import dynamic


class OnCreateWarningProvider(dynamic.ResourceProvider):

    warning_printed = False

    def print_warning(self, message):
        if not self.warning_printed:
            pulumi.warn(message)
            OnCreateWarningProvider.warning_printed = True

    def create(self, inputs: Any):
        self.print_warning(inputs['message'])
        return dynamic.CreateResult(id_=uuid4().hex, outs={})


class OnCreateWarning(dynamic.Resource):
    def __init__(self, name: str, message: str, opts: Optional[pulumi.ResourceOptions] = None):

        super().__init__(
            OnCreateWarningProvider(),
            name,
            {'message': message},
            opts=opts
        )

that I would call with something like

messaging.OnCreateWarning(
    name=f"on-create-warning-{resource_name}",
    message="Resource was created!",
    opts=pulumi.ResourceOptions(depends_on=[resource]),
)

How does this look, @stocky-spoon-28903, @gentle-diamond-70147? Any ideas on simplyfing or improving this further? Do I need to set the CreateResult id_, for example? Thanks!