Ram is a distributed KV store for Erlang and Elixir. It chooses Consistency over Availability by using the Raft Consensus Algorithm, and is based on Rabbit MQ's implementation Ra.

[Documentation]

Add it to your deps:

defp deps do
  [{:ram, "~> 0.5"}]
end

If you're using rebar3, add ram as a dependency in your project's rebar.config file:

{deps, [
  {ram, {git, "git:https://github.com/ostinelli/ram.git", {tag, "0.5.0"}}}
]}.

Or, if you're using Hex.pm as package manager (with the rebar3_hex plugin):

{deps, [
  {ram, "0.5.0"}
]}.

Note: this example below assumes that you are familiar with Distributed Erlang.

Open 3 shells and start three Erlang nodes:

$ iex --name [email protected] -S mix

$ iex --name [email protected] -S mix

$ iex --name [email protected] -S mix

Choose the main node (for instance [email protected]), and on that node run the following.

First, create an Erlang cluster by connecting all nodes:

iex(ram1@127.0.0.1)1> nodes = [:"[email protected]", :"[email protected]", :"[email protected]"]
[:"[email protected]", :"[email protected]", :"[email protected]"]
iex(ram1@127.0.0.1)2> for node <- nodes, do: Node.connect(node)
[true, true, true]

Now we can create a Ram cluster running on these nodes:

iex(ram1@127.0.0.1)3> :ram.start_cluster(nodes)
13:03:12.902 [info]  RAM[ram1@127.0.0.1] Cluster started on [:"[email protected]", :"[email protected]", :"[email protected]"]
:ok

You can now store and retrieve values from all the nodes:

iex(ram1@127.0.0.1)4> :ram.put("key", "value")
:ok
iex(ram1@127.0.0.1)5> :ram.get("key")
"value"

iex(ram2@127.0.0.1)1> :ram.get("key")
"value"

iex(ram3@127.0.0.1)1> :ram.get("key")
"value"

Open 3 shells and start three Erlang nodes:

$ rebar3 shell --name [email protected]

$ rebar3 shell --name [email protected]

$ rebar3 shell --name [email protected]

Choose the main node (for instance [email protected]), and on that node run the following.

First, create an Erlang cluster by connecting all nodes:

(ram1@127.0.0.1)1> Nodes = ['[email protected]', '[email protected]', '[email protected]'].
['[email protected]','[email protected]','[email protected]']
(ram1@127.0.0.1)2> [net_kernel:connect_node(Node) || Node <- Nodes].
[true,true,true]

Now we can create a Ram cluster running on these nodes:

(ram1@127.0.0.1)3> ram:start_cluster(Nodes).
=INFO REPORT==== 4-Jan-2022::12:46:34.071524 ===
RAM[ram1@127.0.0.1] Cluster started on ['[email protected]','[email protected]',
'[email protected]']
ok

You can now store and retrieve values from all the nodes:

(ram1@127.0.0.1)4> ram:put("key", "value"). 
ok
(ram1@127.0.0.1)5> ram:get("key").
"value"

(ram2@127.0.0.1)1> ram:get("key").
"value"

(ram3@127.0.0.1)1> ram:get("key").
"value"

Specifies after how many logs ram should create a ra snapshot. Defaults to 1000.

config :ram,
  release_cursor_count: 1000

{ram, [
  {release_cursor_count, 1000}
]}

Since Ram uses Ra, please refer to Ra's documentation on available options.

So you want to contribute? That's great! Please follow the guidelines below. It will make it easier to get merged in.

Before implementing a new feature, please submit a ticket to discuss what you intend to do. Your feature might already be in the works, or an alternative implementation might have already been discussed.

Do not commit to master in your fork. Provide a clean branch without merge commits. Every pull request should have its own topic branch. In this way, every additional adjustments to the original pull request might be done easily, and squashed with git rebase -i. The updated branch will be visible in the same pull request, so there will be no need to open new pull requests when there are changes to be applied.

Ensure that proper testing is included. To run Ram tests you simply have to be in the project's root directory and run:

$ make test

Copyright (c) 2021-2022 Roberto Ostinelli.

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The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

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