Cloudflared SSE test

This repository is created to test the behavior of a PHP-based Server-Sent Events stream with the Cloudflare Argo tunnel.

The problem

At the time of writing the cloudflared Argo tunnel does not seem to disconnect a SSE stream connection when the browser disconnects and the proxy keeps the connection alive. This causes a PHP-FPM child process to be locked to a disconnected stream as the PHP script never receives a disconnection through connection_aborted().

When enough Server-Sent event stream requests are made to the PHP-FPM container, it will eventually only be processing (disconnected) streams, causing a denial of service.

Server-Sent event stream requests sent directly to the Nginx container will stop processing properly when they are disconnected. Freeing up the PHP-FPM process.

Installation

Prerequisites

To install this project you require the following tooling:

• Git
• Docker CE
• Docker Compose

Also, port 8090 is currently required to access the project through: http://localhost:8090

Get the source

Clone this repository to be able to use/test this project:

git clone https://github.com/niels-nijens/cloudflared-sse-test.git

Usage

Start the project by executing the following command:

docker-compose up

This command will build and start an Nginx, PHP-FPM and Cloudflared container and show the container logs. The cloudflared container will create a free Argo tunnel and display output similar to the following:

cloudflared_1_977caf5e35f8 | time="2020-01-22T13:12:27Z" level=info msg="Each HA connection's tunnel IDs: map[0:0765dtv5hkb3dle6bgtlb9hi0zl3vcv7367ydb4uga7f9i692kzg]" connectionID=0
cloudflared_1_977caf5e35f8 | time="2020-01-22T13:12:27Z" level=info msg=+-------------------------------------------------------------+ connectionID=0
cloudflared_1_977caf5e35f8 | time="2020-01-22T13:12:27Z" level=info msg="|  Your free tunnel has started! Visit it:                    |" connectionID=0
cloudflared_1_977caf5e35f8 | time="2020-01-22T13:12:27Z" level=info msg="|    https://elite-bread-accessible-rabbit.trycloudflare.com  |" connectionID=0
cloudflared_1_977caf5e35f8 | time="2020-01-22T13:12:27Z" level=info msg=+-------------------------------------------------------------+ connectionID=0
cloudflared_1_977caf5e35f8 | time="2020-01-22T13:12:27Z" level=info msg="Route propagating, it may take up to 1 minute for your new route to become functional" connectionID=0

This project will be accessible through the Visit it: Cloudflare URL.

PHP-FPM status

To see the status of the (locked) PHP-FPM processes go to: http://localhost:8090/status?html&full

Resources

• Server-Sent Events on MDN
• Cloudflare Argo tunnel documentation
• Cloudflared repository on GitHub