Memcache Bundle Laravel Package

## Getting Started

### Minimal Setup
1. **Installation**:
   ```bash
   composer require leaseweb/memcache-bundle

Add to AppKernel.php:

new Lsw\MemcacheBundle\LswMemcacheBundle(),

2. Basic Configuration (config.yml):

   lsw_memcache:
       pools:
           default:
               servers:
                   - { host: localhost, tcp_port: 11211 }
   

3. First Use Case: Inject the Memcache client in a controller/service:

   use Lsw\MemcacheBundle\Client\MemcacheClientInterface;
   
   public function __construct(MemcacheClientInterface $memcache)
   {
       $this->memcache = $memcache;
   }
   
   public function cacheExample()
   {
       $this->memcache->set('key', 'value', 0, 3600); // 1 hour TTL
       $value = $this->memcache->get('key');
   }
   

Key Starting Points

• Debug Toolbar: Memcache stats appear under the "Memcache" tab in Symfony Profiler.
• Session Storage: Enable via session.pool in config (see Session Support).
• Doctrine Caching: Configure doctrine.metadata_cache, doctrine.result_cache, or doctrine.query_cache.

Implementation Patterns

1. Memcache Client Usage

Basic CRUD Operations

// Set with TTL (0 = no expiration)
$this->memcache->set('user:123:profile', $profileData, 0, 3600);

// Get with fallback
$profileData = $this->memcache->get('user:123:profile') ?: $this->loadFromDb();

// Delete
$this->memcache->delete('user:123:profile');

// Increment/Decrement (e.g., for counters)
$this->memcache->increment('hit_counter', 1);

Anti-Dog-Pile (ADP) Pattern

// Atomic read-modify-write to prevent stampedes
$oldValue = $this->memcache->getAdp('expensive:calc:123');
if ($oldValue === false) {
    $newValue = $this->expensiveCalculation();
    $this->memcache->setAdp('expensive:calc:123', $newValue, 0, 3600);
} else {
    // Use stale data if available
}

2. Session Management

Load Balancer Compatibility

# config.yml
lsw_memcache:
    session:
        pool: sessions
        locking: true  # Critical for multi-server setups
        spin_lock_wait: 150000  # 150ms lock retry interval

Custom Session Handler (Advanced)

# services.yml
my.session.handler:
    class: Lsw\MemcacheBundle\Session\Storage\LockingSessionHandler
    arguments:
        - "@memcache.sessions"  # Your configured pool service
        - { prefix: "app_sess_", expiretime: 7200 }

3. Doctrine Caching

Configure Caching Layers

# config.yml
lsw_memcache:
    doctrine:
        metadata_cache:
            pool: default
            entity_manager: default
        result_cache:
            pool: default
            entity_manager: [default, read_replica]
            prefix: "result:"
        query_cache:
            pool: default
            entity_manager: default

Query-Specific Caching

// Enable result caching for a query
$query->useResultCache(true);
$query->setCacheLifetime(300); // 5 minutes

4. Firewall/Throttling

# config.yml
lsw_memcache:
    firewall:
        pool: firewall
        concurrency: 50  # Max 50 concurrent requests per IP
        reverse_proxies: [10.0.0.1, 10.0.0.2]  # Trusted proxies

Check Throttle Status

$this->get('lsw_memcache.firewall')->isAllowed($request->getClientIp());

5. Multi-Pool Strategies

# config.yml
lsw_memcache:
    pools:
        primary:
            servers: [{ host: memcache1, port: 11211 }]
        secondary:
            servers: [{ host: memcache2, port: 11211 }]
            options:
                redundancy: true
                session_redundancy: 2

Dynamic Pool Selection

$pool = $this->get('memcache.primary'); // Inject via DI
if ($pool->isDown()) {
    $pool = $this->get('memcache.secondary');
}

Gotchas and Tips

1. Common Pitfalls

2. Debugging Tips

• Profiler Tab: Inspect Memcache tab for hit/miss ratios, latency, and memory usage.
• CLI Stats:

  php app/console lsw:memcache:stats
  

• Log Failures:

  # config.yml
  lsw_memcache:
      pools:
          default:
              options:
                  log_errors: true
  

3. Performance Tuning

4. Extension Points

Custom Memcache Client

// services.yml
my.custom.memcache:
    class: MyApp\CustomMemcacheClient
    arguments:
        - "@memcache.default"
    tags:
        - { name: lsw_memcache.client, alias: custom }

Event Listeners

// Subscribe to cache events
use Lsw\MemcacheBundle\Event\MemcacheEvents;

public function onCacheMiss(MemcacheMissEvent $event) {
    if ($event->getKey() === 'expensive:calc') {
        $event->setValue($this->fallbackCalculation());
    }
}

5. Migration Notes

• From memcached extension: This bundle requires the memcache extension (not memcached).
• Symfony 4+: Use config/packages/lsw_memcache.yaml instead of config.yml.
• Doctrine 2.7+: Ensure entity_manager names match your Doctrine config.

6. Anti-Patterns to Avoid

• Ignoring TTLs: Always set ttl (even if 0 for "no expiration").
• Blocking Calls: Avoid long-running get()/set() in request paths.
• Overusing ADP: ADP adds overhead; reserve for truly expensive operations.
• Hardcoded Keys: Use namespacing (e.g., user:123:profile) to avoid collisions.

7. Legacy Quirks

• YAML Deprecation: Symfony 3.2+ may warn about YAML config; use !tagged for complex structures.
• Windows Support: Tested in v2.0+, but some features (e.g., session locking) may behave differently.
• PHP 5.3: Avoid if possible; upgrade to PHP 7+ for better performance.

8. When to Fork

• Critical Bugs: If the bundle breaks due to unmaintained dependencies (e.g., Symfony 5+).
• Feature Gaps: Add missing features (e.g., Memcached SASL auth) and submit PRs upstream.
• Security Patches: Backport fixes if the original repo is abandoned.

9. Alternatives