PANIC: interface conversion: interface {} is nil, not map[string]interface {} in aws_cloudfront_cache_policy

[zaitsevpavel]

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Terraform CLI and Terraform AWS Provider Version

Terraform v1.0.8
on linux_amd64

• provider registry.terraform.io/hashicorp/aws v3.63.0

Affected Resource(s)

• aws_cloudfront_cache_policy

Terraform Configuration Files

Please include all Terraform configurations required to reproduce the bug. Bug reports without a functional reproduction may be closed without investigation.

resource "aws_cloudfront_cache_policy" "some-cache-policy" {
  name        = "some-cache-policy"
  comment     = "To disable CF caching for some-cf-distribution"
  default_ttl = 0
  max_ttl     = 0
  min_ttl     = 0

  parameters_in_cache_key_and_forwarded_to_origin {
    enable_accept_encoding_brotli = false
    enable_accept_encoding_gzip   = false

    cookies_config {
      cookie_behavior = "none"
      cookies {}
    }
    headers_config {
      header_behavior = "none"
      headers {}
    }
    query_strings_config {
      query_string_behavior = "none"
      query_strings {}
    }
  }
}

Debug Output

https://gist.github.com/zaitsevpavel/9fbcb72c43fab7140bbe699582128228

Panic Output

There is no crash.log, just:

PANIC: interface conversion: interface {} is nil, not map[string]interface {}

Expected Behavior

Resource is created.

Actual Behavior

Panic, resource is not created

Steps to Reproduce

1. terraform apply

Important Factoids

We use a new resource instead of a managed data-source, because TF always tries to reach AWS even if the flag -refresh=false set.
I've tried different versions of aws provider, and the bug has been reproduced in the latest provider version.

[ewbankkit]

Stack trace from the terraform-provider-aws_v3.63.0_x5 plugin:

panic: interface conversion: interface {} is nil, not map[string]interface {}

goroutine 78 [running]:
github.com/terraform-providers/terraform-provider-aws/aws.expandCloudFrontCachePolicyCookiesConfig(0xc001c05aa0, 0xc001c05a40)
        /opt/teamcity-agent/work/5d79fe75d4460a2f/src/github.com/hashicorp/terraform-provider-aws/aws/cloudfront_cache_policy_structure.go:34 +0x1e5
github.com/terraform-providers/terraform-provider-aws/aws.expandCloudFrontCachePolicyParametersConfig(0xc001c05a40, 0x77f17ec)
        /opt/teamcity-agent/work/5d79fe75d4460a2f/src/github.com/hashicorp/terraform-provider-aws/aws/cloudfront_cache_policy_structure.go:112 +0xb2
github.com/terraform-providers/terraform-provider-aws/aws.expandCloudFrontCachePolicyConfig(0xc001979500, 0xc001b27718)
        /opt/teamcity-agent/work/5d79fe75d4460a2f/src/github.com/hashicorp/terraform-provider-aws/aws/cloudfront_cache_policy_structure.go:138 +0xb9
github.com/terraform-providers/terraform-provider-aws/aws.resourceAwsCloudFrontCachePolicyCreate(0xc001979500, 0x6856740, 0xc001ae6000, 0x3, 0xffffffffffffffff)
        /opt/teamcity-agent/work/5d79fe75d4460a2f/src/github.com/hashicorp/terraform-provider-aws/aws/resource_aws_cloudfront_cache_policy.go:161 +0x55
github.com/hashicorp/terraform-plugin-sdk/v2/helper/schema.(*Resource).create(0xc0007fb5e0, 0x83169a8, 0xc00196e1c0, 0xc001979500, 0x6856740, 0xc001ae6000, 0x0, 0x0, 0x0)
        /opt/teamcity-agent/work/5d79fe75d4460a2f/pkg/mod/github.com/gdavison/terraform-plugin-sdk/v2@v2.7.1-0.20210913224932-c7c2dbd9e010/helper/schema/resource.go:318 +0x1ee
github.com/hashicorp/terraform-plugin-sdk/v2/helper/schema.(*Resource).Apply(0xc0007fb5e0, 0x83169a8, 0xc00196e1c0, 0xc001904cb0, 0xc0009492e0, 0x6856740, 0xc001ae6000, 0x0, 0x0, 0x0, ...)
        /opt/teamcity-agent/work/5d79fe75d4460a2f/pkg/mod/github.com/gdavison/terraform-plugin-sdk/v2@v2.7.1-0.20210913224932-c7c2dbd9e010/helper/schema/resource.go:456 +0x67b
github.com/hashicorp/terraform-plugin-sdk/v2/helper/schema.(*GRPCProviderServer).ApplyResourceChange(0xc00000cfc0, 0x83169a8, 0xc00196e1c0, 0xc001925810, 0xc00196e1c0, 0x74d4b80, 0xc001933800)
        /opt/teamcity-agent/work/5d79fe75d4460a2f/pkg/mod/github.com/gdavison/terraform-plugin-sdk/v2@v2.7.1-0.20210913224932-c7c2dbd9e010/helper/schema/grpc_provider.go:955 +0x8ef
github.com/hashicorp/terraform-plugin-go/tfprotov5/server.(*server).ApplyResourceChange(0xc00222d600, 0x8316a50, 0xc00196e1c0, 0xc001904a80, 0xc00222d600, 0xc001933830, 0xc001898ba0)
        /opt/teamcity-agent/work/5d79fe75d4460a2f/pkg/mod/github.com/hashicorp/terraform-plugin-go@v0.3.0/tfprotov5/server/server.go:332 +0xb5
github.com/hashicorp/terraform-plugin-go/tfprotov5/internal/tfplugin5._Provider_ApplyResourceChange_Handler(0x74d4b80, 0xc00222d600, 0x8316a50, 0xc001933830, 0xc001964fc0, 0x0, 0x8316a50, 0xc001933830, 0xc001934800, 0x3d3)
        /opt/teamcity-agent/work/5d79fe75d4460a2f/pkg/mod/github.com/hashicorp/terraform-plugin-go@v0.3.0/tfprotov5/internal/tfplugin5/tfplugin5_grpc.pb.go:380 +0x214
google.golang.org/grpc.(*Server).processUnaryRPC(0xc0000cb880, 0x833a6d8, 0xc000e1e300, 0xc002270f00, 0xc001547500, 0xbdc3000, 0x0, 0x0, 0x0)
        /opt/teamcity-agent/work/5d79fe75d4460a2f/pkg/mod/google.golang.org/grpc@v1.32.0/server.go:1194 +0x52b
google.golang.org/grpc.(*Server).handleStream(0xc0000cb880, 0x833a6d8, 0xc000e1e300, 0xc002270f00, 0x0)
        /opt/teamcity-agent/work/5d79fe75d4460a2f/pkg/mod/google.golang.org/grpc@v1.32.0/server.go:1517 +0xd0c
google.golang.org/grpc.(*Server).serveStreams.func1.2(0xc001556200, 0xc0000cb880, 0x833a6d8, 0xc000e1e300, 0xc002270f00)
        /opt/teamcity-agent/work/5d79fe75d4460a2f/pkg/mod/google.golang.org/grpc@v1.32.0/server.go:859 +0xab
created by google.golang.org/grpc.(*Server).serveStreams.func1
        /opt/teamcity-agent/work/5d79fe75d4460a2f/pkg/mod/google.golang.org/grpc@v1.32.0/server.go:857 +0x1fd

Error: The terraform-provider-aws_v3.63.0_x5 plugin crashed!

[ewbankkit]

Relates: #20870.

[yhakbar]

I ran into this issue while trying to setup a TF module for aws_cloudfront_cache_policy.

The following is a workaround that prevents this error from popping up when the length of the items field under cookies, headers or query_strings is unknown:

cookies_config {
      cookie_behavior = var.cookie_behavior
      # Workaround due to provider bug
      # https://github.com/hashicorp/terraform-provider-aws/issues/21397

      # cookies {
      #   items = var.cookies
      # }

      dynamic "cookies" {
        for_each = length(var.cookies) == 0 ? [] : [var.cookies]
        content {
          items = var.cookies
        }
      }
    }
    headers_config {
      header_behavior = var.header_behavior

      # Workaround due to provider bug
      # https://github.com/hashicorp/terraform-provider-aws/issues/21397

      # headers {
      #   items = var.headers
      # }

      dynamic "headers" {
        for_each = length(var.headers) == 0 ? [] : [var.headers]
        content {
          items = var.headers
        }
      }
    }
    query_strings_config {
      query_string_behavior = var.query_string_behavior

      # Workaround due to provider bug
      # https://github.com/hashicorp/terraform-provider-aws/issues/21397

      # query_strings {
      #   items = var.query_strings
      # }

      dynamic "query_strings" {
        for_each = length(var.query_strings) == 0 ? [] : [var.query_strings]
        content {
          items = var.query_strings
        }
      }
    }

I'm guessing what this does is bypass the attempted cast here, that will fail if items is not populated with a valid list of strings, but I'm not sure

terraform-provider-aws/internal/service/cloudfront/cache_policy_structure.go

Line 35 in de17e73

apiObject.Cookies = expandCloudFrontCachePolicyCookieNames(items[0].(map[string]interface{}))

.

[github-actions]

This functionality has been released in v3.65.0 of the Terraform AWS Provider. Please see the Terraform documentation on provider versioning or reach out if you need any assistance upgrading.

For further feature requests or bug reports with this functionality, please create a new GitHub issue following the template. Thank you!

[github-actions]

I'm going to lock this issue because it has been closed for 30 days ⏳. This helps our maintainers find and focus on the active issues.
If you have found a problem that seems similar to this, please open a new issue and complete the issue template so we can capture all the details necessary to investigate further.