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FastCGI Proxy

Description

A proxy for distributing (a)sync requests to multiple fastCGI servers.

Installation

Usage

Request distribution

The proxy can distribute requests to multiple fastCGI servers in the following ways:

1. Randomly
2. Via round robin

Random distribution

To set up random distribution use the following example code:

When sending requests now the proxy will randomly choose one of the fastCGI servers to process the request.

Round robin distribution

To set up round robin distribution use the following example code:

The proxy will send your requests to the next fastCGI server in the same order they were added to the RoundRobin instance. In this example it will send to:

1. 127.0.0.1:9001
2. 10.100.10.42:9001,
3. /var/run/php7.1-fpm.sock
4. 127.0.0.1:9001 (start from the beginning again)
5. and so on...

Sending requests

The Proxy class has the same methods as the underlying Client class for sending (a)sync requests and retrieving responses (reactively). So please consult the documentation of hollodotme/fast-cgi-client for further information.

Here is just a short list of available methods:

• $proxy->sendRequest(ProvidesRequestData $request) : ProvidesResponseData
  Sends a synchronous request and returns the response. (blocking)

• $proxy->sendAsyncRequest(ProvidesRequestData $request) : int
  Sends an asynchronous request and returns the request ID. (non-blocking)

• $proxy->readResponse(int $requestId, ?int $timeoutMs = null) : ProvidesResponseData
  Reads and returns the response of a previously obtained request ID.
  (blocking until response was read or read timed out)

• $proxy->readResponses(?int $timeoutMs = null, int ...$requestIds) : \Generator|ProvidesResponseData[]
  Reads and yields the responses of previously obtained request IDs in the order of the given request IDs.
  (blocking until all responses were read or read timed out)

• $proxy->readReadyResponses(?int $timeoutMs = null) : \Generator|ProvidesResponseData[]
  Reads and yields the responses of all finished requests.
  (non-blocking, meant to be used in a loop)

• $proxy->waitForResponse(int $requestId, ?int $timeoutMs = null) : void
  Waits for the response of a previously obtained request ID and calls the request's response callback.
  (blocking until response was read or read timed out)

• $proxy->waitForResponses(?int $timeoutMs = null) : void
  Waits for the responses of the previously obtained request IDs in the order of finished requests and calls the corresponding response callbacks.
  (blocking until all responses were read or read timed out)

• $proxy->hasResponse(int $requestId) : bool
  Returns whether the given request ID has a response or not. (non-blocking)

• $proxy->handleResponse(int $requestId, ?int $timeoutMs = null) : void
  Calls the corresponding response callback of an already finished request.
  (If request ID has a response must be checked before calling this method, see $proxy->hasResponse(int $requestId)).

• $proxy->hasUnhandledResponses() : bool
  Returns TRUE if there are unhandles responses left, otherwise FALSE.

• $proxy->getRequestIdsHavingResponse() : array
  Returns all request IDs that have responses. (non-blocking)

• $proxy->handleResponses(?int $timeoutMs = null, int ...$requestIds) : void
  Calls the corresponding response callbacks of already finished requests in the order of the given request Ids.
  (If request IDs have a response must be checked before calling this method, see $proxy->hasResponse(int $requestId) or $proxy->getRequestIdsHavingResponse() : array.)

• $proxy->handleReadyResponses(?int $timeoutMs = null) : void
  Calls the corresponding response callbacks in the order of finished requests.
  (non-blocking, short for $proxy->handleResponses($timeoutMs, int ...$proxy->getRequestIdsHavingResponse()))

Cluster requests

This feature is available since v0.2.0 of this library.

In order to process a single request on a multitude of fastCGI servers, the ClusterProxy class was introduced. So in order to distribute the request to one of the configured fastCGI servers, the cluster proxy will send the same request to ALL configured fastCGI servers and allows you to read/handle their responses (reactively).

As per concept of cluster requests, there is always a one-to-many relation for request & responses. That's why the ClusterProxy class does not offer synchronous requests and reading of single responses based on a request ID.

To set up a cluster proxy, use the following example code:

The following reduced set of methods to send requests and handle responses are available in the cluster proxy class:

• $clusterProxy->sendAsyncRequest(ProvidesRequestData $request) : void
  Sends an asynchronous request to all connections in the cluster. (non-blocking)

• $clusterProxy->readReadyResponses(?int $timeoutMs = null) : \Generator|ProvidesResponseData[]
  Reads and yields the responses of all finished requests.
  (non-blocking, meant to be used in a loop)

• $clusterProxy->waitForResponses(?int $timeoutMs = null) : void
  Waits for the responses of the previously obtained request IDs in the order of finished requests and calls the corresponding response callbacks.
  (blocking until all responses were read or read timed out)

• $clusterProxy->hasUnhandledResponses() : bool
  Returns TRUE if there are unhandles responses left, otherwise FALSE.

• $clusterProxy->handleReadyResponses(?int $timeoutMs = null) : void
  Calls the corresponding response callbacks in the order of finished requests.
  (non-blocking, meant to be used in a loop in combination with $clusterProxy->hasUnhandledResponses())

Cluster status

This feature is available since v0.2.0 of this library.

In order to retrieve the status of all fastCGI servers in a cluster, the method ClusterProxy#getStatus() was introduced.

Currently this method solely supports status response implementation for PHP-FPM, but can easily be extended for other fastCGI servers by implementing the interface hollodotme\FastCGI\Interfaces\ProvidesServerStatus.

Cluster status example

The following code reads the status of all 3 php-fpm containers that are part of the docker-compose setup of this library.

Please note: If the status endpoint is not enabled in the server's config (pm.status_path for PHP-FPM), the ClusterProxy#getStatus() method will throw a RuntimeException.

examples/cluster_status.php

This script produces for example the following output

Contributing

Contributions are welcome and will be fully credited. Please see the contribution guide for details.