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Cache Systems

Health checks for caching systems including Redis, KeyDB, and Memcached.

Redis

Redis is an in-memory data structure store used as a database, cache, and message broker.

Basic Usage

from healthcheckx import Health

health = Health()
health.redis_check("redis://localhost:6379")

results = health.run()

With Authentication

health.redis_check("redis://username:password@localhost:6379/0")

Custom Timeout

health.redis_check("redis://localhost:6379", timeout=3)

Custom Name

# Monitor multiple Redis instances
health.redis_check("redis://primary:6379", name="redis-primary")
health.redis_check("redis://cache:6379", name="redis-cache")
health.redis_check("redis://sessions:6379", name="redis-sessions")

Connection Formats

# Basic
health.redis_check("redis://localhost:6379")

# With database number
health.redis_check("redis://localhost:6379/1")

# With authentication
health.redis_check("redis://user:pass@localhost:6379")

# Redis Sentinel
health.redis_check("redis://sentinel1:26379,sentinel2:26379/mymaster")

# Unix socket
health.redis_check("redis:///var/run/redis.sock")

Installation

pip install healthcheckx[redis]

How It Works

The Redis health check: 1. Connects to the Redis server using the provided URL 2. Executes a PING command 3. Returns healthy if ping succeeds 4. Returns unhealthy if connection fails or times out

KeyDB

KeyDB is a Redis-compatible in-memory database with enhanced performance features.

Basic Usage

from healthcheckx import Health

health = Health()
health.keydb_check("keydb://localhost:6379")

results = health.run()

Connection Formats

# Using keydb:// scheme
health.keydb_check("keydb://localhost:6379")

# Using redis:// scheme (also works)
health.keydb_check("redis://localhost:6379")

# With authentication
health.keydb_check("keydb://user:password@localhost:6379/0")

Multiple KeyDB Instances

health.keydb_check("keydb://node1:6379", name="keydb-node1")
health.keydb_check("keydb://node2:6379", name="keydb-node2")
health.keydb_check("keydb://node3:6379", name="keydb-node3")

Installation

# KeyDB uses the same client as Redis
pip install healthcheckx[redis]

Notes

  • KeyDB is 100% Redis-compatible
  • Uses the same redis Python library
  • Supports all Redis connection features
  • Can use either keydb:// or redis:// URL schemes

Memcached

Memcached is a high-performance, distributed memory object caching system.

Basic Usage

from healthcheckx import Health

health = Health()
health.memcached_check()  # Defaults to localhost:11211

results = health.run()

Custom Host and Port

health.memcached_check(host="cache.example.com", port=11211)

With Timeout

health.memcached_check(
    host="localhost",
    port=11211,
    timeout=3
)

Multiple Memcached Servers

health.memcached_check(host="cache1.local", port=11211, name="memcached-1")
health.memcached_check(host="cache2.local", port=11211, name="memcached-2")
health.memcached_check(host="cache3.local", port=11211, name="memcached-3")

Complete Example

from healthcheckx import Health

health = Health()

# Single instance
health.memcached_check()

# Multiple instances with custom configuration
health.memcached_check(
    host="cache-primary.example.com",
    port=11211,
    timeout=2,
    name="cache-primary"
)

health.memcached_check(
    host="cache-secondary.example.com",
    port=11211,
    timeout=2,
    name="cache-secondary"
)

results = health.run()

for result in results:
    print(f"{result.name}: {result.status} ({result.duration_ms:.2f}ms)")

Installation

pip install healthcheckx[memcached]

How It Works

The Memcached health check: 1. Connects to the Memcached server 2. Executes a stats command 3. Returns healthy if stats are retrieved successfully 4. Returns unhealthy if connection fails or times out

Comparison

Feature Redis KeyDB Memcached
URL-based config ✅ Yes ✅ Yes ❌ No (host/port)
Authentication ✅ Yes ✅ Yes ❌ No
Default port 6379 6379 11211
Check method PING PING stats
Installation [redis] [redis] [memcached]

Best Practices

  1. Set appropriate timeouts - Cache checks should be fast (1-3 seconds)
  2. Use named checks - When monitoring multiple instances, always use the name parameter
  3. Monitor read replicas - Check both primary and replica instances
  4. Connection pooling - healthcheckx creates new connections for each check
  5. Production monitoring - Combine with metrics to track check duration over time

Common Issues

Connection Refused

# Error: Connection refused
# Solution: Verify service is running and accessible
health.redis_check("redis://localhost:6379", timeout=1)

Authentication Failed

# Error: Authentication required / Invalid password
# Solution: Check credentials in connection string
health.redis_check("redis://user:correct_password@localhost:6379")

Timeout

# Error: Connection timeout
# Solution: Increase timeout or check network connectivity
health.redis_check("redis://slow-server:6379", timeout=5)

Next Steps