Bit of a related question about patterns for managing `pulumi.Output`s... several AWS resources, to use an example, are configured by passing a JSON object as a string. Many times, the values in that JSON object are outputs from other resources. Often, you can do this pretty simply, like so:

role.arn.apply(lambda arn: json.dumps({"foo": arn}))

When you have multiple things that need to be interpolated, things get a little more complicated:

pulumi.Output.all(
   foo.arn,
   bar.arn,
   baz.arn
).apply(
    lambda args: json.dumps({
        "foo": args[0],
        "bar": args[1],
        "baz": args[2]
    })
)

While that's awkward, it's doable when you have all the `pulumi.Output`s that you need readily at hand. I'm using `ComponentResource`s to model my domain. In general, I'd like to be able to pass a dictionary of values into my

ComponentResource

, and then have it merge that with another dictionary of default values within the

ComponentResource

itself. Then, this merged dictionary would need to be converted into a JSON string to pass to the low-level Resource.

env = {
   "foo": "my_foo",
   "message": "hello world"
}

pulumi.Output.all(
   foo.arn,
   bar.arn,
   baz.arn
).apply(
    lambda args: json.dumps({
        "foo": args[0],
        "bar": args[1],
        "baz": args[2],
        **env
    })
)

If that inner "default values" dictionary is the one that contains the

pulumi.Output

values, then I can control things with

pulumi.Output.all

, as shown above. If I've got

pulumi.Output

values in that dictionary that I'm merging in, though, it's not clear how I can generically manage things. I'm curious if others have run into similar situations, or if people have some patterns for managing such data (generic, if possible; Python-specific works too). Thanks in advance.

I think the best solution to this that I've seen is Pulumi's own aws.iam.PolicyDocument type. I presume it's used in many places, since the code is fairly generic: https://github.com/pulumi/pulumi-terraform-bridge/blob/ea90ddd011cdf688615b1fae6e705b5449dc4e7f/pkg/tfbridge/transforms.go#L26

I'll look at that Go code for ideas. At the moment, I'm working with an ECS container definition (https://www.pulumi.com/docs/reference/pkg/aws/ecs/taskdefinition/#container_definitions_python)

I’ll admit that I’m not following all the way through, but I’m wondering if passing keyword args to your

Output.all

makes a difference.

If I’ve got

pulumi.Output

values in that dictionary that I’m merging in, though, it’s not clear how I can generically manage things.

Output.all(**dict).apply(lambda args: json.dumps({**args, **env}))

I think I was making some silly mistakes, but using keyword args ultimately helped show me those silly mistakes (and made for more readable code!). I was able to get it working; thanks!