feat: add Nagios provider via webhook notifications

docs/providers/documentation/nagios-provider.mdx

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+---
+title: "Nagios Provider"
+sidebarTitle: "Nagios"
+description: "Nagios provider allows you to receive host and service alerts from Nagios in Keep."
+---
+
+import AutoGeneratedSnippet from '/snippets/providers/nagios-snippet-autogenerated.mdx';
+
+<AutoGeneratedSnippet />
+
+# Nagios Provider
+
+The Nagios provider allows you to forward host and service notifications from
+Nagios into Keep using a webhook-based integration.
+
+This provider is intentionally lightweight and focuses on the most common
+integration path for Nagios Core: custom notification commands that POST a JSON
+payload to Keep.
+
+## Overview
+
+The provider supports:
+
+- Host notifications
+- Service notifications
+- Problem and recovery flows through `notification_type`
+- State/severity normalization into Keep alerts
+
+## Webhook Configuration
+
+To configure Nagios to send alerts to Keep:
+
+1. Create a custom notification command that sends an HTTP POST request.
+2. Set the target URL to your Keep webhook endpoint:
+
+```text
+{keep_webhook_api_url}
+```
+
+3. Add an `X-API-KEY` header using a Keep API key with webhook permissions.
+4. Build the request body from standard Nagios macros.
+
+Example payload for a **service** notification:
+
+```json
+{
+  "alert_type": "service",
+  "notification_type": "$NOTIFICATIONTYPE$",
+  "timestamp": "$LONGDATETIME$",
+  "host_name": "$HOSTNAME$",
+  "host_display_name": "$HOSTDISPLAYNAME$",
+  "host_address": "$HOSTADDRESS$",
+  "service_name": "$SERVICEDESC$",
+  "service_display_name": "$SERVICEDESC$",
+  "service_state": "$SERVICESTATE$",
+  "service_state_type": "$SERVICESTATETYPE$",
+  "service_attempt": "$SERVICEATTEMPT$",
+  "service_output": "$SERVICEOUTPUT$",
+  "service_perfdata": "$SERVICEPERFDATA$",
+  "service_check_command": "$SERVICECHECKCOMMAND$"
+}
+```
+
+Example payload for a **host** notification:
+
+```json
+{
+  "alert_type": "host",
+  "notification_type": "$NOTIFICATIONTYPE$",
+  "timestamp": "$LONGDATETIME$",
+  "host_name": "$HOSTNAME$",
+  "host_display_name": "$HOSTDISPLAYNAME$",
+  "host_address": "$HOSTADDRESS$",
+  "host_state": "$HOSTSTATE$",
+  "host_output": "$HOSTOUTPUT$"
+}
+```
+
+## Suggested Command Example
+
+One practical approach is to use `curl` from a custom Nagios notification
+command:
+
+```bash
+/usr/bin/curl -X POST \
+  -H "Content-Type: application/json" \
+  -H "X-API-KEY: <KEEP_API_KEY>" \
+  -d '<JSON_PAYLOAD_FROM_MACROS>' \
+  '<KEEP_WEBHOOK_URL>'
+```
+
+You can then attach that command to `host_notification_commands` and
+`service_notification_commands` in your Nagios object definitions.
+
+## State Mapping
+
+### Host States
+
+| Nagios State | Keep Status | Keep Severity |
+|:-------------|:------------|:--------------|
+| UP           | RESOLVED    | INFO          |
+| DOWN         | FIRING      | CRITICAL      |
+| UNREACHABLE  | FIRING      | CRITICAL      |
+
+### Service States
+
+| Nagios State | Keep Status | Keep Severity |
+|:-------------|:------------|:--------------|
+| OK           | RESOLVED    | INFO          |
+| WARNING      | FIRING      | WARNING       |
+| CRITICAL     | FIRING      | CRITICAL      |
+| UNKNOWN      | FIRING      | INFO          |
+
+## Useful Links
+
+- [Nagios Standard Macros](https://assets.nagios.com/downloads/nagioscore/docs/nagioscore/4/en/macrolist.html)
+- [Nagios Notifications](https://assets.nagios.com/downloads/nagioscore/docs/nagioscore/4/en/notifications.html)

docs/snippets/providers/nagios-snippet-autogenerated.mdx

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+{/* This snippet is automatically generated using scripts/docs_render_provider_snippets.py 
+Do not edit it manually, as it will be overwritten */}
+
+
+## In workflows
+
+This provider can't be used as a "step" or "action" in workflows. If you want to use it, please let us know by creating an issue in the [GitHub repository](https://github.com/keephq/keep/issues).

keep/providers/nagios_provider/__init__.py

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+from keep.providers.nagios_provider.nagios_provider import NagiosProvider
+
+__all__ = ["NagiosProvider"]

keep/providers/nagios_provider/nagios_provider.py

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+"""
+Nagios Provider is a class that provides a way to receive alerts from Nagios
+using webhook notifications.
+"""
+
+from keep.api.models.alert import AlertDto, AlertSeverity, AlertStatus
+from keep.contextmanager.contextmanager import ContextManager
+from keep.providers.base.base_provider import BaseProvider
+from keep.providers.models.provider_config import ProviderConfig
+
+
+class NagiosProvider(BaseProvider):
+    """
+    Receive Nagios host and service notifications into Keep via webhooks.
+    """
+
+    webhook_documentation_here_differs_from_general_documentation = True
+    webhook_description = ""
+    webhook_template = ""
+    webhook_markdown = """
+To send alerts from Nagios to Keep, configure a custom notification command:
+
+1. Create a notification command that POSTs JSON to `{keep_webhook_api_url}`.
+2. Add header `X-API-KEY` with your Keep API key (webhook role).
+3. Use Nagios macros such as `$NOTIFICATIONTYPE$`, `$HOSTNAME$`, `$HOSTSTATE$`,
+   `$HOSTOUTPUT$`, `$SERVICEDESC$`, `$SERVICESTATE$`, and `$SERVICEOUTPUT$` to
+   build the JSON payload.
+4. Attach the command to your host and/or service notification definitions.
+5. For a complete example, see the [Keep documentation](https://docs.keephq.dev/providers/documentation/nagios-provider).
+    """
+
+    PROVIDER_DISPLAY_NAME = "Nagios"
+    PROVIDER_TAGS = ["alert"]
+    PROVIDER_CATEGORY = ["Monitoring"]
+    WEBHOOK_INSTALLATION_REQUIRED = True
+
+    HOST_STATUS_MAP = {
+        "UP": AlertStatus.RESOLVED,
+        "DOWN": AlertStatus.FIRING,
+        "UNREACHABLE": AlertStatus.FIRING,
+    }
+
+    HOST_SEVERITY_MAP = {
+        "UP": AlertSeverity.INFO,
+        "DOWN": AlertSeverity.CRITICAL,
+        "UNREACHABLE": AlertSeverity.CRITICAL,
+    }
+
+    SERVICE_STATUS_MAP = {
+        "OK": AlertStatus.RESOLVED,
+        "WARNING": AlertStatus.FIRING,
+        "CRITICAL": AlertStatus.FIRING,
+        "UNKNOWN": AlertStatus.FIRING,
+    }
+
+    SERVICE_SEVERITY_MAP = {
+        "OK": AlertSeverity.INFO,
+        "WARNING": AlertSeverity.WARNING,
+        "CRITICAL": AlertSeverity.CRITICAL,
+        "UNKNOWN": AlertSeverity.INFO,
+    }
+
+    def __init__(
+        self, context_manager: ContextManager, provider_id: str, config: ProviderConfig
+    ):
+        super().__init__(context_manager, provider_id, config)
+
+    def dispose(self):
+        """
+        Dispose of the provider.
+        """
+        pass
+
+    def validate_config(self):
+        """
+        Nagios webhook integration does not require provider-side configuration.
+        """
+        pass
+
+    @staticmethod
+    def _format_alert(
+        event: dict, provider_instance: "BaseProvider" = None
+    ) -> AlertDto | list[AlertDto]:
+        """
+        Format Nagios notification payload into Keep alert format.
+
+        Supported payloads are intentionally simple and map closely to Nagios
+        host/service notification macros configured in the webhook command.
+        """
+        alert_type = (event.get("alert_type") or "service").lower()
+
+        if alert_type == "host":
+            state = event.get("host_state", "DOWN")
+            output = event.get("host_output", "No output provided")
+            return AlertDto(
+                id=event.get("host_name"),
+                name=event.get("host_display_name") or event.get("host_name"),
+                status=NagiosProvider.HOST_STATUS_MAP.get(state, AlertStatus.FIRING),
+                severity=NagiosProvider.HOST_SEVERITY_MAP.get(
+                    state, AlertSeverity.CRITICAL
+                ),
+                description=output,
+                source=["nagios"],
+                hostname=event.get("host_name"),
+                state=state,
+                lastReceived=event.get("timestamp"),
+                timestamp=event.get("timestamp"),
+                notification_type=event.get("notification_type"),
+                raw_output=output,
+                host_address=event.get("host_address"),
+            )
+
+        state = event.get("service_state", "CRITICAL")
+        output = event.get("service_output", "No output provided")
+        return AlertDto(
+            id=event.get("service_name") or event.get("host_name"),
+            name=event.get("service_display_name") or event.get("service_name"),
+            status=NagiosProvider.SERVICE_STATUS_MAP.get(state, AlertStatus.FIRING),
+            severity=NagiosProvider.SERVICE_SEVERITY_MAP.get(
+                state, AlertSeverity.CRITICAL
+            ),
+            description=output,
+            source=["nagios"],
+            hostname=event.get("host_name"),
+            host_address=event.get("host_address"),
+            service_name=event.get("service_name"),
+            check_command=event.get("service_check_command"),
+            state=state,
+            lastReceived=event.get("timestamp"),
+            timestamp=event.get("timestamp"),
+            notification_type=event.get("notification_type"),
+            raw_output=output,
+            current_attempt=event.get("service_attempt"),
+            state_type=event.get("service_state_type"),
+            performance_data=event.get("service_perfdata"),
+        )
+
+
+if __name__ == "__main__":
+    pass