Go Redis

A simple implementation of Redis server in Go programming lanugage.

Motivation

I built this Redis server in Go as a personal project and a learning experience. It helped me better understand in-memory databases and how to handle network connections in Go efficiently.

🚀 Quick Start

Ensure you have either Docker or Go environments set up. Additionally, make sure Redis is installed on your local machine.

Clone the project:

git clone https://github.com/danilovict2/go-redis.git
cd go-redis

Run with Docker:

docker build .
docker container run -p "6379:6379" <IMAGE ID>

Run locally:

./your_program.sh

Interact with Go Redis:

Open a new terminal and run the following command to start the Redis client:

redis-cli

📖 Usage

Available commands

• PING
• ECHO
• SET
• GET
• CONFIG GET
• KEYS
• INFO REPLICATION
• REPLCONF GETACK
• WAIT
• TYPE
• XADD
• XRANGE
• XREAD
• INCR

Examples

Creating a replica

A replica is a clone of a Redis instance that listens to all write commands and executes them.

Creating a replica with Docker

1. Create a network:

docker network create my-network

2. Run the main program:

docker container run -p "6379:6379" --network my-network --name leader <IMAGE ID>

3. Start the replica in a new terminal window:

docker container run -p "<PORT>:<PORT>" --network my-network --name replica <IMAGE ID> --port <PORT> --replicaof "leader 6379"

4. Connect to the replica:

redis-cli -p <PORT>

Creating a replica locally

1. Run the main program:

./your_program.sh

2. Start the replica in a new terminal window:

./your_program.sh --port <PORT> --replicaof "localhost 6379"

3. Connect to the replica:

redis-cli -p <PORT>

Reading Data from an RDB File

To load data from an RDB file into the program, you can either:

1. Place the file in the project's root directory and name it dump.rdb.
2. Or, run the following command to specify the file's location and name:

./your_program --dir "/path/to/your/file" --dbfilename "file.rdb"

For example, if you have file.rdb in the home directory, run:

./your_program.sh --dir "/home" --dbfilename "file.rdb"

Streams

Creating a Stream

To create a stream and add an entry to it, use the following command:

redis-cli XADD some_key 1526985054069-0 temperature 36 humidity 95

The output will be the ID of the first added entry:

"1526985054069-0"

Querying Entries from a Stream

Once you've added a few entries to the stream, you can query them using the XRANGE command.

1. Querying a Specific Range:

$ redis-cli XADD some_key 1526985054069-0 temperature 36 humidity 95
"1526985054069-0"
$ redis-cli XADD some_key 1526985054079-0 temperature 37 humidity 94
"1526985054079-0"
$ redis-cli XRANGE some_key 1526985054069 1526985054079
1) 1) 1526985054069-0
   2) 1) temperature
      2) 36
      3) humidity
      4) 95
2) 1) 1526985054079-0
   2) 1) temperature
      2) 37
      3) humidity
      4) 94

2. Querying Until the End of the Stream:

Use the + symbol to query entries up to the end of the stream:

$ redis-cli XRANGE some_key 1526985054069 +
1) 1) 1526985054069-0
   2) 1) temperature
      2) 36
      3) humidity
      4) 95
2) 1) 1526985054079-0
   2) 1) temperature
      2) 37
      3) humidity
      4) 94

3. Querying from the Beginning of the Stream:

Use the - symbol to query entries from the beginning of the stream:

$ redis-cli XRANGE some_key - 1526985054079
1) 1) 1526985054069-0
   2) 1) temperature
      2) 36
      3) humidity
      4) 95
2) 1) 1526985054079-0
   2) 1) temperature
      2) 37
      3) humidity
      4) 94

Reading Data from Streams with XREAD

The XREAD command is used to read data from one or more streams, starting from a specified entry ID:

$ redis-cli XADD some_key 1526985054069-0 temperature 36 humidity 95
"1526985054069-0"
$ redis-cli XADD some_key 1526985054079-0 temperature 37 humidity 94
"1526985054079-0"
$ redis-cli XREAD streams some_key 1526985054069-0
1) 1) "some_key"
   2) 1) 1) 1526985054079-0
         2) 1) temperature
            2) 37
            3) humidity
            4) 94

Blocking Reads Using $

You can block reads until a new entry is added to the stream or the specified timeout is reached. Use the $ symbol for this:

$ redis-cli XADD some_key 1526985054069-0 temperature 36 humidity 95
"1526985054069-0"
$ redis-cli XREAD block 1000 streams some_key $

This command will block reads until either 1000ms has passed or another Redis client adds a new entry to the stream:

$ redis-cli -p <PORT> XADD some_key 1526985054079-0 temperature 37 humidity 94
"1526985054079-0"

Lists

Creating a list and appending elements

> RPUSH list "bar" "baz"
> LPUSH list_key "a" "b" "c"

List elements

> RPUSH list_key "a" "b" "c" "d" "e"
(integer) 5

# List first 2 items 
> LRANGE list_key 0 1
1) "a"
2) "b"

# List last 2 items 
> LRANGE list_key -2 -1
1) "d"
2) "e"

Query list length

> RPUSH list_key "a" "b" "c" "d"
(integer) 4

> LLEN list_key
(integer) 4

Remove elements

> RPUSH list_key "a" "b" "c" "d"
(integer) 4
> LPOP list_key 2
1) "a"
2) "b"
> LRANGE list_key 0 -1
1) "c"
2) "d"

Blocking retrieval

> BLPOP list_key 0

# ... this blocks until an element is added to the list

# As soon as an element is added, it responds with a resp array:
1) "list_key"
2) "foobar"

$ redis-cli BLPOP list_key 0.1
# (Blocks for 0.1 seconds)

🤝 Contributing

Build the project

go build -o redis app/*.go

Run the project

./redis

Submit a pull request

If you'd like to contribute, please fork the repository and open a pull request to the master branch.