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

[keereets]

Terraform Version

Terraform v1.10.5
on linux_amd64

Terraform Configuration Files

terraform {
  required_providers {
    google = {
      source = "hashicorp/google"
      version = "6.17.0"
    }
  }
  backend "gcs" {
    # the bucket is configured through the config file, and the
    # command `terraform init --migrate-state --backend-config=config/gcp-pilot-us.config`
    prefix = "terraform/state"
  }
}

provider "google" {
  # Configuration options
  region = var.region
}

# FIXME: rename "db_name_suffix" to "rnd_name_suffix", needs to be done after a `destroy`, otherwise everything gets destroyed anyway
resource "random_id" "db_name_suffix" {
  byte_length = 4
}

data "google_compute_global_address" "global_ip_k8s" {
  name = var.app_lb_global_ip_name
  project = var.project_id
}

# Create LB backend buckets

resource "google_storage_bucket" "ng-frontend" {
  name                        = "${var.specific_name}ng-frontend-site"
  project                     = var.project_id
  location                    = var.bucket_location
  uniform_bucket_level_access = true
  storage_class               = "STANDARD"
  // delete bucket and contents on destroy.
  force_destroy = true

  website {
    main_page_suffix = "index.html"
    not_found_page   = "index.html"
  }
  cors {
    origin          = ["*"]
    method          = ["GET", "HEAD", "PUT", "POST", "PATCH", "DELETE", "OPTIONS"]
    response_header = ["Content-Type"]
    max_age_seconds = 3600
  }
}

resource "google_storage_bucket" "web-engine" {
  name                        = "${var.specific_name}web-engine-site"
  project                     = var.project_id
  location                    = var.bucket_location
  uniform_bucket_level_access = true
  storage_class               = "STANDARD"
  // delete bucket and contents on destroy.
  force_destroy = true

  website {
    main_page_suffix = "index.html"
    not_found_page   = "index.html"
  }
  cors {
    origin          = ["*"]
    method          = ["GET", "HEAD", "PUT", "POST", "PATCH", "DELETE", "OPTIONS"]
    response_header = ["Content-Type"]
    max_age_seconds = 3600
  }
}

resource "google_compute_backend_bucket" "ng-frontend" {
  name        = "ngfrontend"
  description = "Main application angular for ng-frontend"
  bucket_name = google_storage_bucket.ng-frontend.name
  project = var.project_id
  enable_cdn  = true
  cdn_policy {
    cache_key_policy {
        include_http_headers = ["X-Header-Field"] # FIXME: which ones do we need?
    }
  }
}

resource "google_compute_backend_bucket" "web-engine" {
  name        = "webengine"
  description = "Main application vue for web-engine"
  bucket_name = google_storage_bucket.web-engine.name
  project = var.project_id
  enable_cdn  = true
  cdn_policy {
    cache_key_policy {
        include_http_headers = ["X-Header-Field"] # FIXME: which ones do we need?
    }
  }
}

data "google_compute_global_address" "global-lb-address" {
  name = var.admin_bucket_lb_global_ip_name
  project = var.project_id
}

# Policy to make buckets public
data "google_iam_policy" "storage_object_viewer" {
  binding {
    role = "roles/storage.objectViewer"
    members = [
      "allUsers",
    ]
  }
}

resource "google_storage_bucket_iam_policy" "policy-ng-1" {
  bucket = google_storage_bucket.ng-frontend.name
  policy_data = data.google_iam_policy.storage_object_admin.policy_data
}

resource "google_storage_bucket_iam_policy" "policy-we-1" {
  bucket = google_storage_bucket.web-engine.name
  policy_data = data.google_iam_policy.storage_object_admin.policy_data
}

resource "google_storage_bucket_iam_policy" "policy-we-3" {
  bucket = google_storage_bucket.web-engine.name
  policy_data = data.google_iam_policy.storage_object_viewer.policy_data
}

resource "google_storage_bucket_iam_policy" "policy-ng-3" {
  bucket = google_storage_bucket.ng-frontend.name
  policy_data = data.google_iam_policy.storage_object_viewer.policy_data
}

# Create url map
resource "google_compute_url_map" "default" {
  name    = "http-lb"
  project = var.project_id

  default_service = google_compute_backend_bucket.ng-frontend.id

  host_rule {
    hosts        = [
        "ng-frontend.${var.dns_domain_name}",
        "admin.${var.dns_domain_name}",
    ]
    path_matcher = "path-matcher-ng-frontend"
  }

  host_rule {
    hosts        = ["web-engine.${var.dns_domain_name}"]
    path_matcher = "path-matcher-web-engine"
  }

  path_matcher {
    name            = "path-matcher-ng-frontend"
    default_service = google_compute_backend_bucket.ng-frontend.id
  }

  path_matcher {
    name            = "path-matcher-web-engine"
    default_service = google_compute_backend_bucket.web-engine.id
  }
}

resource "google_compute_managed_ssl_certificate" "default" {
  project = var.project_id
  name    = "global-lb-buckets-certificate"
  type    = "MANAGED"
  managed {
    # Note: these hostnames should appear as "NONE" in the DNS zone definitions in the other file
    domains = [
      "ng-frontend.${var.dns_domain_name}",
      "web-engine.${var.dns_domain_name}",
      "admin.${var.dns_domain_name}",
    ]
  }
}

# Create HTTPS target proxy
resource "google_compute_target_https_proxy" "default" {
  project  = var.project_id
  name     = "global-lb-buckets-proxy"
  url_map  = google_compute_url_map.default.id
  ssl_certificates = [
    google_compute_managed_ssl_certificate.default.id,
  ]
}

# Create forwarding rule
resource "google_compute_global_forwarding_rule" "default" {
  project               = var.project_id
  name                  = "http-lb-buckets-forwarding-rule"
  ip_protocol           = "TCP"
  load_balancing_scheme = "EXTERNAL_MANAGED"  # this makes it a global load-balancer
  port_range            = "443"
  target                = google_compute_target_https_proxy.default.id
  ip_address            = data.google_compute_global_address.global-lb-address.address
}

resource "google_storage_bucket" "files-site" {
  name          = "infra-tf-${var.specific_name}files-site"
  location      = var.bucket_location
  force_destroy = true
  project = var.project_id

  uniform_bucket_level_access = true

  hierarchical_namespace {
    enabled = true
  }
  versioning {
    enabled = false
  }
}

data "google_iam_policy" "storage_object_admin" {
  binding {
    role = "roles/storage.objectAdmin"
    members = [
      "serviceAccount:...",
      "serviceAccount:...",
    ]
  }
}

resource "google_storage_bucket_iam_policy" "policy-files-1" {
  bucket = google_storage_bucket.files-site.name
  policy_data = data.google_iam_policy.storage_object_admin.policy_data
}

Vars:

project_id = "qa-lotus"
terraform_state_bucket = "bucket-flower-1"
specific_name = "lotus-"
region     = "europe-west3"
dual_region = "eur8"
bucket_location = "EU"
dns_host_part = "lotus"
bucket_lb_name = "app-buckets-lb"
dns_zone_name = "gcp-lotus"
dns_domain_name = "example.com"
app_lb_global_ip_name = "app-lb-lotus"
admin_bucket_lb_global_ip_name = "admin-bucket-lb-lotus"
outputs_k8s_config_dir = "outputs-gcp-config-lotus"

Debug Output

...debug output, or link to a gist...

Expected Behavior

I ran terraform init and then CTRL-C on the first request for an input. I expected no crash.

Actual Behavior

$ terraform init
Initializing the backend...
bucket
  The name of the Google Cloud Storage bucket

  Enter a value: ^C

!!!!!!!!!!!!!!!!!!!!!!!!!!! TERRAFORM CRASH !!!!!!!!!!!!!!!!!!!!!!!!!!!!

Terraform crashed! This is always indicative of a bug within Terraform.
Please report the crash with Terraform[1] so that we can fix this.

When reporting bugs, please include your terraform version, the stack trace
shown below, and any additional information which may help replicate the issue.

[1]: https://github.com/hashicorp/terraform/issues

!!!!!!!!!!!!!!!!!!!!!!!!!!! TERRAFORM CRASH !!!!!!!!!!!!!!!!!!!!!!!!!!!!

panic: interface conversion: interface {} is nil, not map[string]interface {}
goroutine 1 [running]:
runtime/debug.Stack()
	runtime/debug/stack.go:26 +0x5e
github.com/hashicorp/terraform/internal/logging.PanicHandler()
	github.com/hashicorp/terraform/internal/logging/panic.go:84 +0x16a
panic({0x321ee80?, 0xc000bb86c0?})
	runtime/panic.go:785 +0x132
github.com/zclconf/go-cty/cty.Value.GetAttr({{{0x3e21210?, 0xc0009e3160?}}, {0x0?, 0x0?}}, {0x3791b4b, 0x1b})
	github.com/zclconf/go-cty@v1.16.2/cty/value_ops.go:819 +0x2d7
github.com/hashicorp/terraform/internal/backend/backendbase.SDKLikeDefaults.ApplyTo(0xc000a21e90, {{{0x3e21210?, 0xc0009e3160?}}, {0x0?, 0x0?}})
	github.com/hashicorp/terraform/internal/backend/backendbase/sdklike.go:195 +0x25a
github.com/hashicorp/terraform/internal/backend/backendbase.Base.PrepareConfig({0xc000a21ec0?, 0xc000a21e90?}, {{{0x3e21210?, 0xc0009e30c0?}}, {0x0?, 0x0?}})
	github.com/hashicorp/terraform/internal/backend/backendbase/base.go:109 +0x38f
github.com/hashicorp/terraform/internal/command.(*Meta).backendInitFromConfig(0xc000704700, 0xc0009f7d60)
	github.com/hashicorp/terraform/internal/command/meta_backend.go:1415 +0x537
github.com/hashicorp/terraform/internal/command.(*Meta).backend_C_r_s(0xc000704700, 0xc0009f7d60, 0x852e28c6, 0xc000a24780, 0xc00088d4d0)
	github.com/hashicorp/terraform/internal/command/meta_backend.go:989 +0x979
github.com/hashicorp/terraform/internal/command.(*Meta).backendFromConfig(0xc000704700, 0xc00088d4d0)
	github.com/hashicorp/terraform/internal/command/meta_backend.go:638 +0x1865
github.com/hashicorp/terraform/internal/command.(*Meta).Backend(0xc000704700, 0x0?)
	github.com/hashicorp/terraform/internal/command/meta_backend.go:105 +0x6a
github.com/hashicorp/terraform/internal/command.(*InitCommand).initBackend(0xc000704700, {0x3e20c30?, 0xc00071a730?}, 0xc0005822d0, {{0x37631a7?, 0xc0007220a0?}, 0xc00087b9e0?}, 0x48, {0x3e26120, 0xc000714a30})
	github.com/hashicorp/terraform/internal/command/init.go:499 +0x730
github.com/hashicorp/terraform/internal/command.(*InitCommand).Run(0xc000704700, {0xc000072050?, 0x0?, 0x0?})
	github.com/hashicorp/terraform/internal/command/init.go:187 +0xf65
github.com/hashicorp/cli.(*CLI).Run(0xc0002ee3c0)
	github.com/hashicorp/cli@v1.1.6/cli.go:265 +0x55f
main.realMain()
	github.com/hashicorp/terraform/main.go:339 +0x1deb
main.main()
	github.com/hashicorp/terraform/main.go:64 +0x13

Steps to Reproduce

1. terraform init
2. it expects an input, because I forgot to add the var file on the command line
3. I pressed CTRL-C
4. it crashed.

Additional Context

No response

References

No response

Generative AI / LLM assisted development?

No response

[dbanck]

Hi @keereets,

Thanks for filing the issue and the detailed report! I'm able to reproduce the crash with this configuration:

terraform {
  required_providers {
    google = {
      source = "hashicorp/google"
      version = "6.17.0"
    }
  }
  backend "gcs" {
  }
}

We'll take a look

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