A Redis clone for educational purposes, following Codecrafter's "Build Your Own Redis" Challenge.

Scope

• Replication
• Persistence (strings are the only data type persisted and loaded from file at the moment)
• Strings
• Streams
• Fullresync (RDB file over the network)
• Transactions (doesn't mix well with replication at the moment)
• Basic commands: SET, DEL, GET, WAIT, KEYS, XADD, XRANGE, XREAD, INCR, MULTI, EXEC, DISCARD

Usage

# Spawn a first instance
$> ./spawn_redis_server.sh --port 6666 --dir $(pwd) --dbfilename dump.rdb

# Send data
$> redis-cli -p 6666 set mykey myvalue

# Query your data
$> redis-cli -p 6666 get mykey # myvalue

# Save to the disk
$> redis-cli -p 6666 save

# Restart the instance.
# The database should contain previously saved.

# Spawn a second instance
# As soon as it starts, it completes a handshake 
$> ./spawn_redis_server.sh --port 6667 --dir $(pwd) --dbfilename dump.rdb --replicaof "localhost 6666"

# Any further data sent to the first instance will be replicated to the second one.
$> redis-cli -p 6666 set anotherkey anothervalue
$> redis-cli -p 6667 get anotherkey # anothervalue

TODO

• Fix dirty workaround XREAD routine not being canceled in time (we start writing to the map while a read is ongoing in the goroutine)
• Fix flaky ordering of keys when reading multiple streams with XREAD
• Figure out proper logic around returns for XREAD and XRANGE.
• Persist stream to disk (and decode when reading RDB file)
• Replication + Transaction -> multi is never sent, queued commands are only sent once exec is launched