Metadata API

Explore how Functions and Firewall utilize metadata for enhanced security, including GeoIP, TLS, and remote client details to manage and secure access.

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The Functions on Firewall have access to a set of metadata that can be manipulated to:

Filter and manage access to your application.
Apply specific logic in different scenarios.

This reference documentation describes the available metadata and their usage.

GeoIP

The GeoIP metadata provides information on the geographical location of the client based on IP data.

Name	Description
geoip_asn	Autonomous system number
geoip_city	City code
geoip_city_continent_code	City continent code information
geoip_city_country_code	City country code
geoip_city_country_name	City country name
geoip_continent_code	Continent code
geoip_country_code	Country code
geoip_country_name	Country name
geoip_region	Region code
geoip_region_name	Region name

Remote

The Remote metadata provides details about the remote client’s IP address and TCP port.

Name	Description
remote_addr	Remote (client) IP address
remote_port	Remote (client) TCP port
remote_user	User informed in the URL. Example: user in http://user@site.com/

Server

The Server metadata provides details about the protocol being used in the request.

Name	Description
server_protocol	Protocol being used in the request. Example: HTTP/1.1

TLS

The TLS metadata provides details about TLS certificates.

Name	Description
ssl_cipher	TLS cipher used
ssl_protocol	TLS protocol used

Server Fingerprints

The Server Fingerprints metadata provides TLS fingerprinting information for enhanced security analysis.

Name	Description
server_fingerprint	Server TLS fingerprint
server_fingerprint_ja4h	Server JA4H fingerprint

Identifiers

Name	Description
solution_id	Internal identifier of the Solution (bundle of products) handling the request.
client_id	Identifier of the Azion account (client) that owns the workload.
function_id	Identifier of the Function instance executed for this request.
configuration_id	Identifier of the Function configuration (version / revision) applied.
virtualhost_id	Identifier of the Virtual Host (Applications domain) that received the request.
edge_connector_id	Identifier of the Edge Connector used when the request is routed through a connector. A dash (-) is returned when none is involved.
request_id	Globally-unique ID automatically attached to every request; useful for end-to-end tracing.

Usage

You can access the metadata through event.request.metadata["remote_addr"], as in:

let ip = event.request.metadata["remote_addr"] // Accessing the remote address

Implementation

In the code sample below:

The remote address is accessed.
It’s verified if this address is in a network list.
If it’s in the network list, the request is denied.

addEventListener("firewall", (event) => {

let ip = event.request.metadata["remote_addr"] // Accessing the remote address

try {

let found = Azion.networkList.contains(String(networkListId), ip); // Checking if the ip is in the list

if (found) {

event.deny(); // If it's in the list, deny the request

}

} catch (err) {

event.console.error(`Error: `, err.stack);

}

});