Usage Tips

Index

About Service Restart

Hyperf itself is based on the lifecycle of Swoole. For Custom Processes, Worker Processes, etc., it runs in CLI mode. When the service restarts, if there are tasks (HTTP requests, asynchronous tasks, scheduled tasks, etc.) being processed, unpredictable issues may arise.

Although the framework provides a Signal Handler, it is still not recommended to rely entirely on this component for blind restarts. Here are two solutions regarding service restarts:

1. Use K8S, Docker Swarm, etc., for rolling restarts or switch traffic at the gateway.
2. For tasks like queues and scheduled tasks, it is better to define an external variable that controls whether the message or task should be executed.

Swoole and PHP-FPM

Before understanding coroutines, let's first understand the traditional PHP-FPM working mode. PHP-FPM is essentially a process manager that implements the FastCGI protocol. When a request is sent to Nginx or Apache, Nginx forwards the request to PHP-FPM via the FastCGI protocol, and PHP-FPM forks the corresponding worker process to execute the PHP script. After execution, the process is recycled. The entire process is synchronous and blocking. When there are a large number of concurrent requests, a significant number of processes are created, and the creation and destruction of these processes are resource-intensive. Additionally, under multi-process, a large number of MySQL connections will be generated, leading to database bottlenecks.

To address the pain points of traditional FPM, one might think of using multiple threads within a single process to handle multiple requests or concurrency issues. However, from a code perspective, PHP is not friendly with threads. Moreover, multi-threading introduces additional problems, such as lock contention (CPU scheduling), lock granularity, deadlocks, and thread exceptions that could cause the entire process to crash. In such cases, Coroutines can be used to solve the problem.

Service Usage Categories

When using Hyperf as a pure Http Server, we should ideally use a gateway (e.g., Gateway) or reverse proxies like Nginx to manage traffic. Although Hyperf can be used directly as an Http Server. (╬￣皿￣)=○

When using it as an asynchronous task processing service, special attention should be given to service restart issues.