Include PassedProviderConfig information in JSON output format.

[nozaq]

Current Terraform Version

Terraform v1.1.5
on linux_amd64

Use-cases

I'm working on a tool to visualize the resource structure by analyzing the JSON output produced from terraform show -json command, and would like to identify which provider to be used for each resource.

Suppose we have the following tf file.

provider "null" {
  alias = "provider_1"
}

provider "null" {
  alias = "provider_2"
}

module "a" {
  providers = {
    null = null.provider_1
  }

  source = "./modules/foo"
}

module "b" {
  providers = {
    null = null.provider_2
  }

  source = "./modules/foo"
}

Running terraform plan -out plan.out and terraform show -json plan.out will produce the JSON output. The resulting JSON contains the following provider configurations in configuration.provider_config.

• null
• null.provider_1
• null.provider_2
• module.a:null
• module.b:null

The issue is that the result does not contain the relations between these providers, so we can't identify that null.provider_1 is assigned to module.a:null as well as null.provider_2 is assigned to module.b:null.

For example, when using AWS provider multiple providers could be defined in one project and each work for a different AWS region. In such case, currently we can not identify in which region the specific resource in a child module would be created from analyzing the JSON output.

Attempted Solutions

I've created a repo containing all sample code and the actual JSON output file.

Proposal

Include PassedProviderConfig defined in ModuleCall struct into configuration.module_calls block of the JSON output so that tools can infer which provider is actually passed to child modules.

{
  ...
  "configuration": {
    ...
    "module_calls": {
      "child": {
        ...
        "passed_provider_config": {
          "in_child": {
            "name": <provider-name-in-child>,
            "alias": <provider-alias-in-child>
          },
          "in_parent": {
            "name": <provider-name-in-parent>.
            "alias": <provider-alias-in-parent>
          }
        }
      }
    }
  }
}

References

[apparentlymart]

Hi @nozaq! Thanks for reporting this.

I think you've reported the same underlying problem as #30113 here, and so I'm going to close this to consolidate the discussion over there. There's already a pending PR to address this issue (albeit in a slightly different way than you proposed) and I believe it's only now pending some coordinated updates in other parts of the Terraform product which consume this JSON output.

Thanks again!

[github-actions]

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