# Discovery

This plugin can be integrated with Pandora FMS *Discovery*.

To use it, the corresponding `.disco` package must be uploaded from the Pandora FMS plugin library or from the console plugin system.

Once uploaded, Azure Application Gateway resources can be monitored by creating *Discovery* tasks from the Cloud/Application Discovery section.

Each task asks for the following data in the **Azure Base** step:

- **Azure Subscription ID:** Azure subscription identifier where Application Gateways will be discovered.
- **Azure Tenant ID:** Azure Active Directory tenant identifier used by the Service Principal.
- **Azure Client ID:** Service Principal application identifier.
- **Azure Client Secret:** Service Principal secret.
- **Resource group:** optional filter to limit discovery to a specific resource group. If left empty, Application Gateways from the whole subscription are discovered.

The **Application Gateway Options** step contains additional options:

- **Target agent:** target agent where all modules are stored when one agent per Application Gateway is not enabled.
- **Create one agent per Application Gateway:** when enabled, each Application Gateway creates its own agent. When disabled, all modules are sent to the agent configured in **Target agent**.
- **Application Gateway agent prefix:** optional prefix for agents created per Application Gateway. For example, `Azure Application Gateway ` creates agents such as `Azure Application Gateway agw-production`.
- **Modules prefix:** optional prefix for all generated module names.
- **Scan Application Gateways:** enables automatic Application Gateway discovery.
- **Entities file:** temporary file where discovered resource cache is stored.
- **Enable entities file re-scan interval:** enables periodic refresh of the temporary discovered entities file.
- **Entities re-scan interval:** interval used to rebuild the entity cache when re-scan is enabled.
- **Mock Azure API URL:** optional URL for local tests. It must be left empty in production.

The **Metrics** step contains metric and filtering options:

- **Metrics time window:** time window used to query Azure Monitor metrics.
- **Azure metric interval:** Azure Monitor granularity in ISO-8601 format. Default value is `PT1M`.
- **Metric timeout:** timeout in seconds for each Azure call. If set to `0` or a negative value, the plugin uses `30` seconds.
- **Max retries:** maximum number of retries for temporary API errors, including HTTP 429 rate limiting.
- **Output format:** output format generated by the plugin. `JSON` must be used for Discovery.
- **Performance modules:** creates CPU, current connections, throughput and new connections per second modules.
- **Request modules:** creates failed requests, HTTP status and total requests modules.
- **Backend modules:** creates healthy hosts, unhealthy hosts, requests per healthy host and backend HTTP status modules.
- **Latency modules:** creates backend connection time, first byte response time, last byte response time, total time and client RTT modules.
- **Traffic modules:** creates bytes sent and bytes received modules.
- **Security modules:** creates TLS protocol, backend TLS negotiation error and rejected connections modules.
- **Capacity modules:** creates compute units, capacity units, estimated billed capacity units and fixed billable capacity units modules. These metrics apply to v2 SKUs.
- **WAF modules:** creates WAF matched, blocked, request, rule, bot protection, challenge and penalty box modules. These metrics apply to WAF SKUs.
- **WebSocket modules:** creates WebSocket active connections and WebSocket close status code modules.
- **Application Gateway count module:** creates the discovered Application Gateway count module.
- **Modules allow regexp:** allows defining allowed module regular expressions, one per line. If configured, only modules whose final name matches one expression are created.
- **Modules deny regexp:** allows defining denied module regular expressions, one per line. If a module matches this list, it is not created.

Successful tasks include an execution summary similar to:

- **application_gateways_discovered:** number of Application Gateways discovered in the current execution.
- **application_gateways_vanished:** number of previously stored Application Gateways that no longer appear in the current discovery.
- **modules:** total number of generated modules.
- **errors:** number of errors detected during execution.
- **scan_source:** scan origin, `azure` when Azure is queried or `entities_cache` when the cache is reused.