NectarDB

Description

An in-memory distributed key-value store implemented in Elixir prioritizing availability and partition-tolerance over consistency Not meant to be a serious implementation of a full-fledged database, but instead a learning experience to get practice with Agents, Tasks, Genservers, Supervisors, and Nodes in Elixir

Note: NectarDB only works on OSX (Macs)

Installation

1. Execute brew install erlang to install the erlang dependencies
2. Execute brew install openssl to install OpenSSL
3. Clone the repository by executing git clone https://github.com/KontosTwo/NectarDB.git
4. Navigate to NectarDB/bin
5. Execute chmod +x nectar_node.sh and chmod +x nectar_api.sh

Usage

Starting the API

1. Open a terminal session and navigate to NectarDB/bin
2. Execute ./nectar_api.sh <PORT NUMBER> and wait for a message in the format of "NectarAPI started at node <name of the api node>"
3. You may have to allow beam.smp and other apps to allow connections

Starting a node

1. Open a terminal session and navigate to NectarDB/bin
2. Execute ./nectar_node.sh <unique name> <name of the api node> and wait for a message in the format of "NectarNode started at node "
3. You may have to allow beam.smp and other apps to allow connections

Querying through REST API

1. Write data with the following POST request to localhost:<PORT NUMBER>/write, Content-Type set to application/json. You may have as many writes and deletes as you want.

{
	"writes" : [
		{
			"type": "write",
			"key": 1,
			"value": 2
		},
    {
			"type": "delete",
			"key": 1
		},
	]
}

If the write is successful you will get a message

{
  "message": "Successful write!"
}

2. Read data with the following POST request to localhost:<PORT NUMBER>/read, Content-Type set to application/json. You may have as many reads as you want

{
	"reads" : [
		{
			"type": "read",
			"key": 1
		},
    {
			"type": "read",
			"key": 2
		}
	]
}

Depending on if an individual read succeeds, it will appear in either the "successes" or "failures" category

{
  "successes": [
    {
      "key": 1,
      "result": 2
    }
  ],
  "failures": [
    {
      "key": 2,
      "result": "nodes_unresponsive"
    }
  ]
}

Fault Tolerance

Kill, restart, and add nodes as you please.

Future features

• Nodes can be added even after data has begun flowing in
• API nodes can be restarted after crashing

Closing words

If there are any problems running NectarDB, please shoot me an email