new feature: Memcached In Transit Encryption (TLS) support

[elichai]

Feature Description

AWS Elasticache Memcached serverless instances require using TLS,
meaning that instead of doing telnet ....cache.amazonaws.com 1211 you do openssl s_client -quiet -crlf -connect ....cache.amazonaws.com:11211, supporting this TLS mode here would be great :)

Problem and Solution

Adding TLS support, See: https://docs.aws.amazon.com/AmazonElastiCache/latest/dg/in-transit-encryption.html

Additional Context

No response

Are you willing to contribute to the development of this feature?

• Yes, I am willing to contribute to the development of this feature.

[ozewr]

Hello, I would like to contribute to the development of this feature. Could you tell me which part of the code I should read , or provide some other relevant information? @Xuanwo

[Xuanwo]

Hi, @ozewr, thank you for your interest!

Memcached currently interacts directly with TcpStream:

opendal/core/src/services/memcached/binary.rs

Lines 104 to 109 in f0ace56

	impl Connection {
	pub fn new(io: TcpStream) -> Self {
	Self {
	io: BufReader::new(io),
	}
	}

We need to add support for using a TLS library like tokio_rustls to establish a TLS connection. For example: https://github.com/rustls/tokio-rustls/blob/main/examples/client.rs

[ozewr]

Hi, @ozewr, thank you for your interest!

Memcached currently interacts directly with TcpStream:

opendal/core/src/services/memcached/binary.rs

Lines 104 to 109 in f0ace56

	impl Connection {
	pub fn new(io: TcpStream) -> Self {
	Self {
	io: BufReader::new(io),
	}
	}

We need to add support for using a TLS library like tokio_rustls to establish a TLS connection. For example: https://github.com/rustls/tokio-rustls/blob/main/examples/client.rs

Hello, I'm a new programmer, so I want to share my thoughts and see if they are correct. It seems that here we need a new struct implementing bb8::ManageConnection, similar to MemcacheConnectionManager. However,

impl bb8::ManageConnection for MemcacheConnectionManager {
    type Connection = TlsConnection { io: BufReader<TlsStream<TcpStream>> };
    type Error = Error;
...

Or directly modify the implementation of bb8::ManageConnection for MemcacheConnectionManager to make it only support TLS connections. @Xuanwo

[Xuanwo]

Maybe we can make binary::Connection an enum that have TcpConnection and TlsConnection.