How can I install Memcached for PHP 5.6 on Alpine?

Installing Memcached for PHP 5.6 on Alpine Linux involves several steps. Since PHP 5.6 is quite old, it might require using the older packages if available or compiling from source.

Here’s a comprehensive guide:

Step 1: Update the package list

First, update your Alpine package list to ensure you have the latest package information:

apk update

Step 2: Install Memcached Server

Install the Memcached server package:

apk add memcached

Step 3: Install PHP 5.6 and required development tools (if not already installed)

Since you're using PHP 5.6 which is no longer actively maintained in standard repositories, you would likely use specific repositories or compile from source. However, if there are any existing PHP 5.6 packages available for Alpine try to install with:

apk add php5 php5-dev

If you can't find those exact packages, you might need to add a specific repository or compile PHP 5.6 from source, which is beyond the scope of this basic answer due to its complexity.

Step 4: Install the Memcached PHP Extension

Now, we will install the PHP extension for Memcached. If the php5-dev is working, you can use pecl to install memcached extension :

pecl install memcached

If PECL is not working for php 5.6, you may need to find an old repository which supports php 5.6 extensions or download extension archive from pecl.php.net

Step 5: Enable the Memcached Extension

After the installation of extension, you need to enable it.

Create a file named `memcached.ini` in `/etc/php5/conf.d/` directory (or equivalent php config directory for your installation). Add the following line:

extension=memcached.so

Step 6: Configure Memcached (if required)

Memcached's main configuration is usually in `/etc/memcached.conf`. You can customize it for memory usage, port, and other settings based on your needs.

You may need to start the Memcached service if it's not started automatically.

rc-service memcached start

Step 7: Verify the Installation

Create a simple PHP file and test the connection to Memcached:

<?php
$memcached = new Memcached();
$memcached->addServer('127.0.0.1', 11211);

$result = $memcached->set('mykey', 'myvalue', 3600);

if($result) {
  echo "Successfully saved data to Memcached!";
} else {
  echo "Could not save data to memcached";
}

$value = $memcached->get('mykey');
if ($value) {
echo "
Data retrieved from Memcached: " . $value;
} else { echo "
No data found"; } ?>

Save the code above as test_memcached.php and run it from your browser.

Important Notes:

- Using PHP 5.6 is highly discouraged due to security risks, but this guide shows how to get memcached installed if needed.

- If php5 packages can’t be found, you may need to find and add a special package repository to `/etc/apk/repositories`, search for php 5.6 packages and install them.

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