Terraform: Conquering the "Unable to Create Multiple azurerm_api_management_api with for_each" Challenge
The Problem: Looping for API Creation
Many developers find themselves needing to create multiple APIs within their Azure API Management instances. Terraform's for_each construct seems like the perfect solution, but sometimes it falls short. You might encounter the frustrating "Unable to create multiple azurerm_api_management_api using for_each loop" error. This article dives into the root cause of this issue and provides clear solutions for successfully creating your APIs.
The Scenario: A Looping Nightmare
Imagine you have a list of API definitions in a file called apis.json. You want to create an API in Azure API Management for each entry in this file. Your Terraform code might look something like this:
resource "azurerm_api_management_api" "api" {
for_each = { for key, value in jsondecode(file("apis.json")) : key => value }
api_management_name = "my-api-management-instance"
api_revision = "1"
api_type = "http"
api_version = "1.0"
description = each.value.description
display_name = each.value.name
path = each.value.path
resource_group_name = "my-resource-group"
service_url = each.value.service_url
# ... other properties ...
}
This code attempts to create an API for each entry in your JSON file using the for_each loop. However, you might get an error like:
Error: Error creating API "api": 1 error(s) occurred:
* api.azurerm_api_management_api.api: The provided value "api" is not a valid name for a new API. The name must be unique within a group.
This error is telling you that Terraform is trying to create multiple APIs with the same name (api) – which violates Azure API Management's naming constraints.
The Solution: Unique Names and Smart Loops
The key to overcoming this issue lies in ensuring unique names for each of your APIs. Here's how you can modify your Terraform code to address this:
resource "azurerm_api_management_api" "api" {
for_each = { for key, value in jsondecode(file("apis.json")) : key => value }
api_management_name = "my-api-management-instance"
api_revision = "1"
api_type = "http"
api_version = "1.0"
description = each.value.description
display_name = each.value.name
path = each.value.path
resource_group_name = "my-resource-group"
service_url = each.value.service_url
name = each.key # Use the key from your JSON as the API name
# ... other properties ...
}
By using each.key for the name property, we leverage the key from your JSON file to automatically generate a unique name for each API. This ensures that your loop creates distinct APIs without conflicts.
Additional Considerations:
- **Data Source: ** If you are using a different data source for your API definitions, you might need to adjust the loop structure accordingly.
- **Validation: ** Before applying your Terraform code, ensure that your JSON file contains valid API definitions and unique keys.
- Resource Ordering: In some cases, you may need to adjust resource ordering within your Terraform code to guarantee dependencies are met.
Conclusion:
While the for_each loop can be a powerful tool, it requires careful consideration and proper implementation to avoid common pitfalls. By understanding the limitations of naming and resource management within Azure API Management, you can effectively create and manage multiple APIs using Terraform, streamlining your deployment process.
