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Support configuration_aliases argument #40

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takumin opened this issue May 2, 2021 · 3 comments · Fixed by #43
Closed

Support configuration_aliases argument #40

takumin opened this issue May 2, 2021 · 3 comments · Fixed by #43

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@takumin
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takumin commented May 2, 2021

Starting with Terraform 0.15, configuration_aliases is available.

See also 1: https://www.terraform.io/upgrade-guides/0-15.html#alternative-provider-configurations-within-modules
See also 2: https://www.terraform.io/docs/language/modules/develop/providers.html#provider-aliases-within-modules

For example, the following declaration.

terraform {
  required_providers {
    aws = {
      version = "2.65.0"
      source  = "hashicorp/aws"

      configuration_aliases = [
        aws.primary,
        aws.secondary,
      ]
    }
  }
}

Are you planning to support this syntax?
@minamijoyo
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minamijoyo commented May 2, 2021 •
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@takumin Thank you for reporting this!

I confirmed that if we have the configuration_aliases key in the required_providers block, the tfupdate fails to parse and silently ignores the block.

I found the root cause of this problem is a dirty hack in the tfupdate implementation due to limitations of the hcl library. We expect a literal expression here:
https://github.com/minamijoyo/tfupdate/blob/v0.4.3/tfupdate/hclwrite.go#L48-L71

If my understanding is correct, the configuration_aliases contains provider references, that is, variables in hcl and it requires a EvalContext to parse.

I think it should be fixed, but it may be quite difficult under the current technical constraints. I'm not sure how to fix it for now 🤔

@minamijoyo
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I found the terraform-config-inspect seems to parse the required_providers block without an EvalContext using hcl.ExprMap. It's worth investigating.
hashicorp/terraform-config-inspect#59

minamijoyo added a commit that referenced this issue May 26, 2021
@minamijoyo
[WIP] Allow to parse the configuration_aliases syntax in Terraform v0.15
ea94578 
Fixes #40
@minamijoyo minamijoyo mentioned this issue May 26, 2021
Merged
minamijoyo added a commit that referenced this issue May 27, 2021
@minamijoyo
Allow to parse the configuration_aliases syntax in Terraform v0.15
9157bc5 
Fixes #40

The tfupdate mainly uses the hclwrite parser to preserve comments, but
the hclwrite doesn't have enough AST for an object type, as a
compromise, the tfupdate also uses the hclsyntax parser to detect old
version.

Terraform v0.15 introduced a new configuration_aliases syntax.
https://www.terraform.io/upgrade-guides/0-15.html#alternative-provider-configurations-within-modules

It's not directly related version updating but it contains provider
references and it causes a parse error without an EvalContext.

The ideal solution would be extending the hclwrite to be able to parse
such a complicated object, but it's not realistic to expect it to be
possible in the short term. So I decided to add a new hack on top of the
existing hack to achieve the short term goal.

After seeking a temporary solution, I found that the
terraform-config-inspect parses the configuration_aliases by using a
hcl.ExprMap which doesn't require to decode fully references.

I feel the implementation is messy and fragile. It's probably better not
to re-implement by ourselves and depend on the terraform-config-inspect.
However the terraform-config-inspect loads a root module not a file, and
the current implementation of tfupdate detects and updates version in a
single file. It's hard to use it for now. Using the
terraform-config-inspect would require additional refactors for
splitting the implementation to detecting and updating. To minimize the
patch, I fixed only how to parse the required_providers block.
minamijoyo added a commit that referenced this issue May 27, 2021
@minamijoyo
Allow to parse the configuration_aliases syntax in Terraform v0.15
ccef41a 
Fixes #40

The tfupdate mainly uses the hclwrite parser to preserve comments, but
the hclwrite doesn't have enough AST for an object type, as a
compromise, the tfupdate also uses the hclsyntax parser to detect old
version.

Terraform v0.15 introduced a new configuration_aliases syntax.
https://www.terraform.io/upgrade-guides/0-15.html#alternative-provider-configurations-within-modules

It's not directly related version updating but it contains provider
references and it causes a parse error without an EvalContext.

The ideal solution would be extending the hclwrite to be able to parse
such a complicated object, but it's not realistic to expect it to be
possible in the short term. So I decided to add a new hack on top of the
existing hack to achieve the short term goal.

After seeking a temporary solution, I found that the
terraform-config-inspect parses the configuration_aliases by using a
hcl.ExprMap which doesn't require to decode fully references.

I feel the implementation is messy and fragile. It's probably better not
to re-implement by ourselves and depend on the terraform-config-inspect.
However the terraform-config-inspect loads a root module not a file, and
the current implementation of tfupdate detects and updates version in a
single file. It's hard to use it for now. Using the
terraform-config-inspect would require additional refactors for
splitting the implementation to detecting and updating. To minimize the
patch, I fixed only how to parse the required_providers block.
minamijoyo added a commit that referenced this issue May 27, 2021
@minamijoyo
Allow to parse the configuration_aliases syntax in Terraform v0.15
f5a46c4 
Fixes #40

The tfupdate mainly uses the hclwrite parser to preserve comments, but
the hclwrite doesn't have enough AST for an object type, as a
compromise, the tfupdate also uses the hclsyntax parser to detect old
version.

Terraform v0.15 introduced a new configuration_aliases syntax.
https://www.terraform.io/upgrade-guides/0-15.html#alternative-provider-configurations-within-modules

It's not directly related version updating but it contains provider
references and it causes a parse error without an EvalContext.

The ideal solution would be extending the hclwrite to be able to parse
such a complicated object, but it's not realistic to expect it to be
possible in the short term. So I decided to add a new hack on top of the
existing hack to achieve the short term goal.

After seeking a temporary solution, I found that the
terraform-config-inspect parses the configuration_aliases by using a
hcl.ExprMap which doesn't require to decode fully references.

I feel the implementation is messy and fragile. It's probably better not
to re-implement by ourselves and depend on the terraform-config-inspect.
However the terraform-config-inspect loads a root module not a file, and
the current implementation of tfupdate detects and updates version in a
single file. It's hard to use it for now. Using the
terraform-config-inspect would require additional refactors for
splitting the implementation to detecting and updating. To minimize the
patch, I fixed only how to parse the required_providers block.
@minamijoyo
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@takumin Fixed in v0.5.1 🚀

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Allow to parse the configuration_aliases syntax in Terraform v0.15 minamijoyo/tfupdate
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@takumin @minamijoyo