Edge Functions on Edge Firewall
Edge Functions in JavaScript
Edge Functions are functions that run on the Azion Edge Computing Platform with low latency, bringing the operational power closer to the end user.
Edge Firewall supports edge functions. Through them you can write your own security source code in JavaScript and deploy it to run at the edge of the network.
With edge functions on Edge Firewall, you can:
- Boost your protection.
- Have more dynamism.
- Apply the logic that your business requires.
- Use APIs that provide request and response headers manipulation.
How Edge Functions work with Edge Firewall
Note: the edge functions in JavaScript on the Edge Firewall run in the request phase.
Process
- The rules configured on the Edge Firewall Rules Engine for the function to run are triggered.
- Azion Cells processes the function, returning an outcome.
- Edge Firewall Rules Engine resumes the processing, based on the outcome, from the point the behavior was triggered.
Run Function
Take a look at How to create and configure an edge function on your Edge Firewall for more details on the process.
Note: all edge functions used on Edge Firewall must have a finishing outcome in it, such as:
event.continue()
,event.deny()
, andevent.drop()
.
Possibilities
Add Request Header
You can add new headers to the request that is sent to the origin.
addEventListener("firewall", (event) => {
event.addRequestHeader("X-Custom-Header-1", "1");
event.addRequestHeader("X-Custom-Header-2", "2");
event.continue();
});
Add Response Header
You can add new headers to the response that is sent to users.
addEventListener("firewall", (event) => {
event.addResponseHeader("X-Custom-Header-3", "3");
event.addResponseHeader("X-Custom-Header-4", "4");
event.continue();
});
Deny (403 Forbidden)
Through the event event.deny()
, you can finish a request returning HTTP 403 Forbidden.
addEventListener("firewall", (event) => {
event.deny();
});
Drop (Close Without Response)
Through the event event.drop()
you are able to finish the request without returning an answer to the client.
addEventListener("firewall", (event) => {
event.drop();
});
Respond with
Through the event event.respondWith()
you can intercept requests, return custom responses, and modify the response headers or content.
event.respondWith(new Response('{"my_custom_response": true}', {
status: 599,
headers: { "content-type": "application/json" }
}));
Metadata
The Edge Functions on Edge Firewall have a set of metadata available for manipulation.
By using this metadata you’re able to filter and manage the access to your application and apply the specific logic in different scenarios, such as:
The GeoIP information
You can deny access to your application when the request comes from certain places.
Remote
You’re able to to check the IP address and the TCP port used.
Available metadata list
Name | Description |
---|---|
geoip_asn | GeoIP information |
geoip_city | GeoIP information |
geoip_city_continent_code | GeoIP information |
geoip_city_country_code | GeoIP information |
geoip_city_country_name | GeoIP information |
geoip_continent_code | GeoIP information |
geoip_country_code | GeoIP information |
geoip_country_name | GeoIP information |
geoip_region | GeoIP information |
geoip_region_name | GeoIP information |
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_protocol | Protocol being used in the request. Example: HTTP/1.1 |
ssl_cipher | TLS/SSL cipher used |
ssl_protocol | TLS/SSL protocol used |
Azion Samples repository
Check the Azion Samples repository on GitHub and analyze the code samples that can help you develop your own edge functions.
Related documentation
- Edge Firewall
- How to create and configure an edge function on your Edge Firewall
- Edge Firewall - Edge Functions Instances
- Edge Functions
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