Add JSONMarshal to go sdk

[Frassle]

Description

This is not as useful for Go as it is for other languages, but it's consistent and it saves an Apply call.

Ideally we would handle nested Output types during marshalling, but to do that correctly we need some way to get access to per-call-to-JSONMarshal flags to note if we see any unknowns, or secrets.

Go just doesn't (AFAIK) have any way to support doing that.

So we do the next best thing which is we at least error that nested Outputs can't be marshalled. Note that the Output interface doesn't embed the Marshal interface because there may be users who have wrote their own Output types and that would be a breaking change.

Checklist

• I have added tests that prove my fix is effective or that my feature works

• I have run make changelog and committed the changelog/pending/<file> documenting my change

• Yes, there are changes in this PR that warrants bumping the Pulumi Service API version

[pulumi-bot]

Changelog

[uncommitted] (2022-12-09)

Features

• [sdk/go] Add JSONMarshal to go sdk.
  #11609

[iwahbe]

Ideally we would handle nested Output types during marshalling, but to do that correctly we need some way to get access to per-call-to-JSONMarshal flags to note if we see any unknowns, or secrets.

Can you provide an example here? I have other issues with the encoding/json custom marshaler interface, but I don't understand how it relates to unknowns or secrets.

[Frassle]

Can you provide an example here? I have other issues with the encoding/json custom marshaler interface, but I don't understand how it relates to unknowns or secrets.

Yup firstly how would you make TestJSONMarshalNested work but with a successful json result of "[0, 1]" rather than the current code where it errors.

Secondly how would you make that work if one of the nested secrets was unknown? The overall json parse should then be unknown. Likewise for secrets.

[iwahbe]

Can you provide an example here? I have other issues with the encoding/json custom marshaler interface, but I don't understand how it relates to unknowns or secrets.

Yup firstly how would you make TestJSONMarshalNested work but with a successful json result of "[0, 1]" rather than the current code where it errors.

Taking another look, I think this would require leaving encoding/json framework. 😒 You would need to manually marshal into map[string]any and []any, then call json.Marshal. Never mind then.

Secondly how would you make that work if one of the nested secrets was unknown? The overall json parse should then be unknown. Likewise for secrets.

If the value is secret, I would mark the whole thing as secret. If its unknown, I would abort, and mark the returned value as unknown.

[Frassle]

If the value is secret, I would mark the whole thing as secret. If its unknown, I would abort, and mark the returned value as unknown.

Yup that's what this method does in dotnet and python. The fun is how you track that in Go where you don't have any async context to grab inside the marshal methods.

I think your right we could do better here if we didn't use encoding/json. That might be worth doing.

[iwahbe]

We could replicate the encoding/json interface, observing json tags and json.Marshaller. We would just allow ourselves a better internal API to handle outputs. We can consider that later. Improving JSONMarshal internal API will be a backward compatible change, allowing strictly more values to be serialized.

[Frassle]

bors merge

[bors]

Build succeeded:

• bors-ok