azure-samples/apim-terraform

APIM Terraform Skill

Guide for creating Terraform files for Azure API Management and related Azure services.

Quick Start

Minimum Viable APIM Deployment

terraform {
  required_version = ">=1.0"
  required_providers {
    azurerm = {
      source  = "hashicorp/azurerm"
      version = "~>4.0"
    }
  }
}

provider "azurerm" {
  features {}
}

resource "azurerm_resource_group" "rg" {
  name     = "example-resources"
  location = "westeurope"
}

resource "azurerm_api_management" "apim" {
  name                = "example-apim"
  location            = azurerm_resource_group.rg.location
  resource_group_name = azurerm_resource_group.rg.name
  publisher_name      = "My Company"
  publisher_email     = "[email protected]"
  sku_name            = "Developer_1"
}

Resource Types

Core APIM Resources

| Resource | Description | |----------|-------------| | azurerm_api_management | APIM service instance | | azurerm_api_management_api | API definition | | azurerm_api_management_api_operation | API operation | | azurerm_api_management_backend | Backend service | | azurerm_api_management_subscription | Subscription for API access | | azurerm_api_management_product | Product grouping APIs | | azurerm_api_management_product_api | Link product to API |

Policy Resources

| Resource | Description | |----------|-------------| | azurerm_api_management_policy | Global policy | | azurerm_api_management_api_policy | API-level policy | | azurerm_api_management_api_operation_policy | Operation-level policy | | azurerm_api_management_product_policy | Product-level policy | | azurerm_api_management_policy_fragment | Reusable policy fragment |

Monitoring Resources

| Resource | Description | |----------|-------------| | azurerm_api_management_logger | Logger (App Insights/Event Hub) | | azurerm_api_management_diagnostic | Service-level diagnostics | | azurerm_api_management_api_diagnostic | API-level diagnostics |

Configuration Resources

| Resource | Description | |----------|-------------| | azurerm_api_management_named_value | Named value (property) | | azurerm_api_management_certificate | Certificate | | azurerm_api_management_authorization_server | OAuth server | | azurerm_api_management_openid_connect_provider | OpenID provider |

For complete resource reference, see references/apim-resources.md.

Essential Patterns

APIM Service with Managed Identity

resource "azurerm_api_management" "apim" {
  name                          = "example-apim"
  location                      = azurerm_resource_group.rg.location
  resource_group_name           = azurerm_resource_group.rg.name
  publisher_name                = "My Company"
  publisher_email               = "[email protected]"
  sku_name                      = "BasicV2_1"
  virtual_network_type          = "None"
  public_network_access_enabled = true

  identity {
    type = "SystemAssigned"
  }
}

API with OpenAPI Import

resource "azurerm_api_management_api" "api" {
  name                  = "example-api"
  resource_group_name   = azurerm_resource_group.rg.name
  api_management_name   = azurerm_api_management.apim.name
  revision              = "1"
  display_name          = "Example API"
  path                  = "api"
  protocols             = ["https"]
  subscription_required = false
  api_type              = "http"

  import {
    content_format = "openapi-link"
    content_value  = "https://example.com/openapi.json"
  }

  subscription_key_parameter_names {
    header = "api-key"
    query  = "api-key"
  }
}

Backend with Circuit Breaker (azapi)

For advanced backend features like circuit breakers, use the azapi provider:

resource "azapi_resource" "backend" {
  type      = "Microsoft.ApiManagement/service/backends@2024-06-01-preview"
  parent_id = azurerm_api_management.apim.id
  name      = "example-backend"

  body = {
    properties = {
      url         = "https://backend.example.com/api"
      protocol    = "http"
      description = "Backend service"

      circuitBreaker = {
        rules = [
          {
            failureCondition = {
              count            = 1
              errorReasons     = ["Server errors"]
              interval         = "PT5M"
              statusCodeRanges = [{ min = 429, max = 429 }]
            }
            name             = "BreakerRule"
            tripDuration     = "PT1M"
            acceptRetryAfter = true
          }
        ]
      }
    }
  }
}

Backend Pool for Load Balancing (azapi)

resource "azapi_resource" "backend_pool" {
  type                      = "Microsoft.ApiManagement/service/backends@2024-06-01-preview"
  name                      = "backend-pool"
  parent_id                 = azurerm_api_management.apim.id
  schema_validation_enabled = false

  body = {
    properties = {
      description = "Load balancer for multiple backends"
      type        = "Pool"

      pool = {
        services = [
          { id = azapi_resource.backend1.id, priority = 1, weight = 100 },
          { id = azapi_resource.backend2.id, priority = 2, weight = 50 }
        ]
      }
    }
  }
}

API Policy with XML

resource "azurerm_api_management_api_policy" "policy" {
  api_name            = azurerm_api_management_api.api.name
  api_management_name = azurerm_api_management.apim.name
  resource_group_name = azurerm_resource_group.rg.name

  xml_content = <<XML
<policies>
  <inbound>
    <base />
    <set-backend-service backend-id="backend-pool" />
    <authentication-managed-identity resource="https://cognitiveservices.azure.com" />
  </inbound>
  <backend>
    <base />
  </backend>
  <outbound>
    <base />
  </outbound>
  <on-error>
    <base />
  </on-error>
</policies>
XML
}

Policy from File with Variable Substitution

resource "azurerm_api_management_api_policy" "policy" {
  api_name            = azurerm_api_management_api.api.name
  api_management_name = azurerm_api_management.apim.name
  resource_group_name = azurerm_resource_group.rg.name

  xml_content = replace(file("policy.xml"), "{backend-id}", azapi_resource.backend_pool.name)
}

Subscription

resource "azurerm_api_management_subscription" "subscription" {
  display_name        = "example-subscription"
  api_management_name = azurerm_api_management.apim.name
  resource_group_name = azurerm_resource_group.rg.name
  api_id              = replace(azurerm_api_management_api.api.id, "/;rev=.*/", "")
  allow_tracing       = true
  state               = "active"
}

Product

resource "azurerm_api_management_product" "product" {
  product_id            = "example-product"
  api_management_name   = azurerm_api_management.apim.name
  resource_group_name   = azurerm_resource_group.rg.name
  display_name          = "Example Product"
  subscription_required = true
  approval_required     = true
  published             = true
}

resource "azurerm_api_management_product_api" "product_api" {
  api_name            = azurerm_api_management_api.api.name
  product_id          = azurerm_api_management_product.product.product_id
  api_management_name = azurerm_api_management.apim.name
  resource_group_name = azurerm_resource_group.rg.name
}

Logging with Application Insights

resource "azurerm_application_insights" "appinsights" {
  name                = "example-appinsights"
  location            = azurerm_resource_group.rg.location
  resource_group_name = azurerm_resource_group.rg.name
  application_type    = "web"
}

resource "azurerm_api_management_logger" "logger" {
  name                = "appinsights-logger"
  api_management_name = azurerm_api_management.apim.name
  resource_group_name = azurerm_resource_group.rg.name
  resource_id         = azurerm_application_insights.appinsights.id

  application_insights {
    instrumentation_key = azurerm_application_insights.appinsights.instrumentation_key
  }
}

resource "azurerm_api_management_diagnostic" "diagnostic" {
  identifier               = "applicationinsights"
  resource_group_name      = azurerm_resource_group.rg.name
  api_management_name      = azurerm_api_management.apim.name
  api_management_logger_id = azurerm_api_management_logger.logger.id

  sampling_percentage       = 5.0
  always_log_errors         = true
  log_client_ip             = true
  verbosity                 = "verbose"
  http_correlation_protocol = "W3C"

  frontend_request {
    body_bytes     = 32
    headers_to_log = ["content-type", "accept", "origin"]
  }

  frontend_response {
    body_bytes     = 32
    headers_to_log = ["content-type", "content-length", "origin"]
  }

  backend_request {
    body_bytes     = 32
    headers_to_log = ["content-type", "accept", "origin"]
  }

  backend_response {
    body_bytes     = 32
    headers_to_log = ["content-type", "content-length", "origin"]
  }
}

Named Values

resource "azurerm_api_management_named_value" "value" {
  name                = "example-property"
  resource_group_name = azurerm_resource_group.rg.name
  api_management_name = azurerm_api_management.apim.name
  display_name        = "ExampleProperty"
  value               = "Example Value"
  secret              = false
}

Role Assignment for Cognitive Services

resource "azurerm_role_assignment" "cognitive_services_user" {
  scope                = azurerm_cognitive_account.ai_services.id
  role_definition_name = "Cognitive Services User"
  principal_id         = azurerm_api_management.apim.identity[0].principal_id
}

SKU Reference

| SKU | Format | Notes | |-----|--------|-------| | Consumption | Consumption_0 | Auto-scaling, capacity always 0 | | Developer | Developer_1 | Development/testing | | Basic | Basic_1 or Basic_2 | Entry-level production | | BasicV2 | BasicV2_1 | New v2 tier | | Standard | Standard_1 to Standard_4 | Production workloads | | StandardV2 | StandardV2_1 | New v2 tier | | Premium | Premium_1 to Premium_12 | Enterprise features | | PremiumV2 | PremiumV2_1 | New v2 tier |

Best Practices

1. Use managed identity for secure access to backend services
2. Use azapi provider for features not yet in azurerm (circuit breakers, backend pools)
3. Store policies in separate files and use file() function
4. Use variables for configurable values like locations, SKUs, and names
5. Use for_each for multiple similar resources (backends, deployments)
6. Strip revision suffix from API ID for subscriptions: replace(api.id, "/;rev=.*/", "")
7. Add random suffix to globally unique names using random_string

Provider Requirements

terraform {
  required_version = ">=1.0"
  required_providers {
    azurerm = {
      source  = "hashicorp/azurerm"
      version = "~>4.0"
    }
    azapi = {
      source  = "Azure/azapi"
      version = "~>2.0"
    }
    random = {
      source  = "hashicorp/random"
      version = "~>3.0"
    }
  }
}

provider "azurerm" {
  features {}
}

References

• references/apim-resources.md - Complete APIM resource definitions
• references/ai-gateway-patterns.md - AI Gateway patterns from this repository