IAM resources fail with RegionNotSupport when provider region is not cn-beijing

[cofyc]

Bug Report

Description

IAM resources (user, group, role, policy, accesskey, project) fail with RegionNotSupport error when the provider is configured with any region other than cn-beijing (e.g. cn-shanghai, ap-southeast-1).

IAM is a global service in Volcengine, anchored to cn-beijing. The Cloud Control API at cloudcontrol.<region>.volcengineapi.com rejects IAM requests for non-cn-beijing regions.

Provider Version

• volcengine/volcenginecc v0.0.33
• Terraform >= 1.5

Steps to Reproduce

Save the following as main.tf:

terraform {
  required_providers {
    volcenginecc = {
      source  = "volcengine/volcenginecc"
      version = "0.0.33"
    }
  }
  required_version = ">= 1.5"
}

variable "volcengine_access_key" {
  type = string
}
variable "volcengine_secret_key" {
  type = string
}

provider "volcenginecc" {
  region     = "cn-shanghai"
  access_key = var.volcengine_access_key
  secret_key = var.volcengine_secret_key
}

# Import existing IAM user — triggers GetResource read during plan
import {
  to = volcenginecc_iam_user.bot_terraform
  id = "bot-terraform"
}
resource "volcenginecc_iam_user" "bot_terraform" {
  user_name    = "bot-terraform"
  description  = ""
  display_name = ""
  email        = ""
}

# Import existing IAM project — also triggers read during plan
import {
  to = volcenginecc_iam_project.default
  id = "default"
}
resource "volcenginecc_iam_project" "default" {
  project_name = "default"
  display_name = "默认项目"
  description  = ""
}

Then run:

export TF_VAR_volcengine_access_key="your-ak"
export TF_VAR_volcengine_secret_key="your-sk"
terraform init
terraform plan

Error Output

volcenginecc_iam_project.default: Preparing import... [id=default]
volcenginecc_iam_user.bot_terraform: Preparing import... [id=bot-terraform]
volcenginecc_iam_project.default: Refreshing state... [id=default]
volcenginecc_iam_user.bot_terraform: Refreshing state... [id=bot-terraform]

Planning failed. Terraform encountered an error while generating this plan.

╷
│ Error: SDK Go Service Operation Unsuccessful
│
│ Calling Cloud Control API service GetResource operation returned: RegionNotSupport: service
│ [iam] not support region [cn-shanghai]
│       status code: 400, request id: 20260323160830DA2EF76E27138A9334D9
╵
╷
│ Error: SDK Go Service Operation Unsuccessful
│
│ Calling Cloud Control API service GetResource operation returned: RegionNotSupport: service
│ [iam] not support region [cn-shanghai]
│       status code: 400, request id: 2026032316083001814B54A8814394340F
╵

Expected Behavior

IAM resources should work regardless of the provider-configured region, since IAM is a global service.

[cofyc]

https://github.com/volcengine/terraform-provider-volcengine v.0.0.194 also has the same issue.