Investigate on codec reconfiguration for a active connection

[mp911de]

Using different codecs requires to run multiple connections as each connection is typed with a specific codec. We should investigate whether it's possible to retype a connection to create a new connection facade that provides its functionality with a different codec:

StatefulRedisConnection<String, String> connection  = …

StatefulRedisConnection<byte[], byte[]> binary = connection.withCodec(ByteArrayCodec.INSTANCE);

[TheSpiritXIII]

I agree with this suggestion. My use case is this: I want to reuse a connection pool but serialize differently depending on the data structure, e.g. single Redis database but with maps and lists used for different purposes.

While I agree this depends largely on the serialization strategy (deserializing between different key types may be tricky and lead to ill effects), the user should decide whether they want to. In most cases, e.g. when my serialization strategy is JSON/XML/etc, it is valid.

I could do this in Spring Data Redis via RedisTemplate<K, V>. There, I could have different templates with different serialization strategies utilizing the same connection factory. We could look through what Spring has done, because they have a slightly better API for this (however, I opted to use Lettuce because they have an asynchronous API, while Spring does not).

[mp911de]

Looking at the API, we could introduce StatefulRedisConnection.withCodec(…) to create a new object that exposes sync/async/reactive API objects that are associated with the new RedisCodec. The thing here is that StatefulRedisConnection isn't the right type to return as we would have two connection object instances whereas we have only a single connection. Finding a good name for the type seems the actual challenge here.

@TheSpiritXIII You could create RedisAsyncCommandsImpl instances passing in the connection object and a RedisCodec to create multiple async API facades for a single connection.

Another caveat is that RedisAsyncCommandsImpl and other command API types return StatefulRedisConnection.

[osoriano]

I'm migrating from Jedis and hitting this issue as well. Jedis supports byte[]/String methods out of the box (edit: on the same connection), but for Lettuce, I'm planning to use a RedisCodec<ByteBuffer,ByteBuffer> and manually encode/decode the Lettuce calls.

[mp911de]

Lettuce supports binary and String types out of the box (ByteArrayCodec.INSTANCE, StringCodec.UTF8, StringCodec.ASCII).

[little-fish]

Hello.
Is there any progress related to this feature?
Thank you.

[mp911de]

Right now, there's no proper way how to achieve this functionality.

We either get hold of another connection object that doesn't represent the actual connection or we get a back-reference to a connection that isn't using the reconfigured codec (RedisCommands.getStatefulConnection()).

That being said, if you have another proposal, we're happy to discuss it here.