# Terraform Datadog Synthetics Module

## Overview

This Terraform module creates synthetic API tests and associated monitors for endpoint health checking in Datadog.

## Features

- **HTTP API Health Checks**: Automated endpoint monitoring
- **Multi-Region Testing**: Tests from AWS regions globally
- **Pod Health Monitoring**: Kubernetes container monitoring
- **15-Minute Intervals**: Regular health check execution
- **Live Status**: Tests are active immediately upon creation

## Resources Created

- `datadog_synthetics_test` (beacon): HTTP API health check
- `datadog_monitor` (beacon): Kubernetes Pod Health metric alert

## Requirements

| Name | Version |
|------|---------|
| terraform | >= 0.12 |
| datadog | >= 2.0 |

## Usage

```hcl
module "synthetics" {
  source = "./terraform-datadog-synthetics"

  datadog_api_key = var.datadog_api_key
  datadog_app_key = var.datadog_app_key
  region          = "eu-west-1"
  url             = "https://api.example.com/health"
  
  dd_synthetics = {
    name = "API Health Check"
    tags = ["env:production", "service:api"]
  }
  
  notify = {
    alert_recipients = ["team@example.com"]
  }
}
```

## Inputs

| Name | Description | Type | Required | Default |
|------|-------------|------|----------|---------|
| `datadog_api_key` | Datadog API key | `string` | yes | - |
| `datadog_app_key` | Datadog APP key | `string` | yes | - |
| `dd_synthetics` | Synthetics configuration | `any` | yes | - |
| `notify` | Notification configuration | `any` | yes | - |
| `region` | AWS region | `string` | no | `"eu-west-1"` |
| `url` | URL to monitor | `string` | yes | - |

## Synthetic Test Configuration

### HTTP API Test

- **Type**: API test (HTTP subtype)
- **Method**: GET
- **Interval**: Every 15 minutes (900 seconds)
- **Assertion**: HTTP status code equals 200
- **Locations**: AWS regions (EU and US)
- **Failure Threshold**: 1 location
- **Status**: Live (active immediately)

### Test Locations

The synthetic test runs from multiple AWS regions:
- EU regions for European coverage
- US regions for American coverage

## Pod Health Monitor

### Configuration

- **Query**: `docker.containers.running <= 1`
- **Type**: Metric alert
- **Thresholds**:
  - OK: 3 containers running
  - Warning: 2 containers running
  - Critical: 1 or fewer containers running
- **Evaluation**: Last 5 minutes average

## Outputs

Currently, this module does not export any outputs.

## Synthetic Test Features

### Assertions

- Validates HTTP response status code is 200
- Can be extended with additional assertions:
  - Response time checks
  - Response body validation
  - Header validation

### Locations

Tests execute from AWS-based synthetic locations for:
- Low latency testing
- Geographic distribution
- Realistic user perspective

### Timing

- **Tick Interval**: 900 seconds (15 minutes)
- **Min Failure**: 1 location must fail to trigger alert
- **Min Location Success**: Not specified (uses default)

## Notifications

Configure notifications through the `notify` variable:
```hcl
notify = {
  alert_recipients   = ["critical@example.com"]
  warning_recipients = ["warnings@example.com"]
  message           = "Custom alert message"
}
```

## Use Cases

- **API Health Monitoring**: Ensure endpoints are responding
- **SLA Compliance**: Track uptime and availability
- **Geographic Testing**: Validate performance from multiple regions
- **Container Health**: Monitor Kubernetes pod availability

## Notes

- Tests start in "live" status immediately
- Minimum 1 location failure required to trigger alert
- Pod health monitor uses 5-minute evaluation window
- Synthetic tests count towards Datadog billing
- Configure appropriate tick intervals to balance cost and monitoring frequency

## Extension Ideas

Add additional assertions:
```hcl
assertion {
  type     = "responseTime"
  operator = "lessThan"
  target   = 2000
}

assertion {
  type     = "body"
  operator = "contains"
  target   = "healthy"
}
```

## License

Internal use only - Sanoma/WeBuildYourCloud

## Authors

Created and maintained by the Platform Engineering team.