#281: added support for DUMP command

[TheRanomial]

#281: Add DUMP and RESTORE Commands

Overview

This pull request introduces the DUMP and RESTORE commands to the DiceDB system, enhancing its capability to serialize and deserialize key-value pairs in a Redis-compatible format. These commands allow users to export the serialized form of a key's value and restore it later.

Changes

1. Implementation of DUMP and RESTORE Commands

• Command Definitions:

  • Added metadata for DUMP and RESTORE commands in internal/eval/commands.go.
  • Defined command names, descriptions, evaluation functions (evalDUMP, evalRestore), arity, and key specifications.

• Command Evaluation Logic:

  • Created internal/eval/dump_restore.go to handle the core logic for both commands.
  • evalDUMP:
    • Serializes the value stored at the specified key into a Redis-specific format.
    • Encodes the serialized data using Base64.
    • Returns the encoded string to the user.
  • evalRestore:
    • Accepts a key, TTL (Time To Live), and a Base64-encoded serialized value.
    • Decodes and deserializes the data.
    • Restores the key with the original value and TTL.

• Serialization/Deserialization Support:

  • Implemented functions for serializing (rdbSerialize) and deserializing (rdbDeserialize) objects.
  • Supported data types include strings and integers.
  • Included CRC64 checksum for data integrity verification.
  • Handled error scenarios such as unsupported types and malformed data.

[apoorvyadav1111]

Hi @TheRanomial , I have doubts regarding the implementation, just for my understanding purposes. I tried running the commands in redis and it was a different output. I understand that we might be using some other algorithm to dump the key. However when I read more about it online, it seems like DUMP and RESTORE go hand in hand. I feel that along with DUMP command, we should be implementing RESTORE such that the behavior can be validated completely. What are your thoughts on this?

[TheRanomial]

I am having problems in running the restore command. I have made a commit which is failing test cases as restore is being timed out . @apoorvyadav1111. Added implementation for restore but it is not working i guess.

[apoorvyadav1111]

Hey @TheRanomial , I tried some changes on my local using your branch and I was able to run following commands.

I share suggestions in the review for what changes I made. Since dump supports all data types, we need to handle all the types including set, hmap and json. We can discuss further on discord if you would prefer. Thanks

[apoorvyadav1111]

Hi @TheRanomial , After making these changes, I was able to run dump and restore. This looks like a good start. Please let me know if you have any suggestions.

[TheRanomial]

@apoorvyadav1111 Thanks a lot for your suggestions. I made the changes you requested and the tests are working fine. Also added the TTL functionality. Open to new changes if any.

[apoorvyadav1111]

I think most of the changes look good, left some minor comments. In addition to them, We still need to support other data types like set, bytearray and json. I feel that this can lead to big PR as tests have to be extensive (like ensuring expire works). Maybe it can be a separate PR. Maybe one of the collaborator and maintainers can provide suggestion here.

[TheRanomial]

@lucifercr07 kindly review it.

[lucifercr07]

@TheRanomial apologies for delay will review by tomorrow, meanwhile can you resolve conflicts?

[TheRanomial]

@lucifercr07 solved the conflicts.

[JyotinderSingh]

Thanks for all the effort in this PR and for addressing all the reviews @TheRanomial! The changes look good, merging.