Memlink

Memlink is a high-performance TCP client library for sending and receiving ordered requests for memcached protocol, providing a robust and efficient way to interact with memcached servers. This can also be extended to support any tcp powered protocol.

Features

• Generic TCP client with tls/mtls support as well
• Optimized for memcached protocol implementation
• Connection pooling and management
• High-performance message encoding/decoding
• Comprehensive test coverage

Installation

go get github.com/stripe/memlink

Quickstart

See the example directory for a comprehensive demonstration of how to use the memlink client with memcached instances.

Protocol reference

For detailed information about the memcached protocol, refer to the official documentation.

⚠️ Important disclaimers

Pending TODOs and known limitations

1. Hash key passing: The connection pool currently uses an empty key for key hashing - i.e. it randomly assigns the key to a backend. If this is not desirable, you should consider forwarding the request to the right backend from either the server side or wait for the change to be officially supported.

2. Bulk operation fan-out: Similar to above, all the pipelined bulk requests will land on the same backend. Work is in progress to spread that out over the appropriate backend once #1 is completed.

3. Extra Go routines: Memlink creates 3 new goroutines per backend -- if you have M backends and connection pool size of N, then expect M*N*3 new goroutines created by using memlink, 1 of them being mostly quiet.

4. Safe closing: Memlink doesn't actively monitor health of backends and remove them from rotation, so its users responsibility to safely remove the backend from connection pool if its no longer healthy / going to be replaced.

Memcached protocol considerations

This implementation follows the memcached meta protocol, but there are important considerations:

1. Protocol compliance: The implementation is based on memcached meta protocol specifications, but may not cover all edge cases or newer protocol features.

2. Field ordering: The protocol has specific requirements about field ordering in requests (e.g., TTL must come before BlockTTL in arithmetic operations).

3. Protocol evolution: Memcached protocol may evolve, and this implementation may need updates to support newer features or changes.

Note: Always test thoroughly with your specific memcached version and configuration before using in production.