feat: add Nagios XI Provider - fixes #3960

keep/providers/nagiosxi_provider/README.md

@@ -0,0 +1,67 @@
+## Nagios XI Provider
+
+Nagios XI provider for Keep pulls host and service status from the Nagios XI REST API using API key authentication.
+
+### Supported Features
+
+- **Polling**: Periodically fetches host and service status from Nagios XI and maps them to Keep alerts.
+- **Host Status**: Maps Nagios host states (UP/DOWN/UNREACHABLE) to Keep alert statuses and severities.
+- **Service Status**: Maps Nagios service states (OK/WARNING/CRITICAL/UNKNOWN) to Keep alert statuses and severities.
+
+### State Mapping
+
+| Nagios Host State | Keep Status | Keep Severity |
+|-------------------|-------------|----------------|
+| 0 (UP)            | RESOLVED    | LOW            |
+| 1 (DOWN)          | FIRING      | CRITICAL       |
+| 2 (UNREACHABLE)   | FIRING      | WARNING        |
+
+| Nagios Service State | Keep Status | Keep Severity |
+|-----------------------|-------------|----------------|
+| 0 (OK)                | RESOLVED    | LOW            |
+| 1 (WARNING)           | FIRING      | WARNING        |
+| 2 (CRITICAL)          | FIRING      | CRITICAL       |
+| 3 (UNKNOWN)           | FIRING      | INFO           |
+
+### Configuration
+
+| Parameter | Description | Required |
+|-----------|-------------|----------|
+| `host_url` | Nagios XI base URL (e.g. `https://nagios.example.com/nagios`) | Yes |
+| `api_key`  | Nagios XI API key | Yes |
+
+### How to get the API Key
+
+1. Log in to your Nagios XI web interface.
+2. Navigate to **Admin** > **Backends** > **API Keys** (or **Configure** > **API Keys** in older versions).
+3. Click **Add New API Key**, provide a description, and save.
+4. Copy the generated API key for use in Keep.
+
+### How to debug with local Nagios XI
+
+Start a Nagios XI Docker instance:
+
+```bash
+docker run -d \
+  --name=nagiosxi \
+  -p 8080:80 \
+  -p 8443:443 \
+  ghcr.io/nagiosenterprises/nagiosxi:latest
+```
+
+Wait 2-3 minutes for initialization, then access the web UI at `https://localhost:8443/nagiosxi/`.
+
+Default login credentials: `nagiosadmin` / `nagiosadmin` (you will be prompted to change the password on first login).
+
+After logging in, generate an API key from the Admin panel and configure Keep with:
+
+- **host_url**: `https://localhost:8443/nagios`
+- **api_key**: Your generated API key
+
+### Troubleshooting
+
+- **Connection refused**: Ensure Nagios XI is running and the host URL is correct. The URL should end with `/nagios` (not `/nagiosxi`).
+- **401 Unauthorized**: Verify your API key is valid and has not expired. Regenerate the key if needed.
+- **Empty results**: Make sure hosts and services are configured in Nagios XI. A fresh installation may not have any monitored objects.
+- **SSL certificate errors**: If using a self-signed certificate, the provider will fail TLS verification. Consider using a valid certificate or testing with HTTP instead of HTTPS.
+- **Timeout errors**: Increase the polling interval or check network connectivity between Keep and the Nagios XI server.