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https://github.com/hamiltop/rethinkdb-elixir

Rethinkdb client in pure elixir (JSON protocol)
https://github.com/hamiltop/rethinkdb-elixir

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Rethinkdb client in pure elixir (JSON protocol)

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RethinkDB [![Build Status](https://travis-ci.org/hamiltop/rethinkdb-elixir.svg?branch=master)](https://travis-ci.org/hamiltop/rethinkdb-elixir)

===========

UPDATE: I am not actively developing this.



Multiplexed RethinkDB client in pure Elixir.



If you are coming here from elixir-rethinkdb, welcome!

If you were expecting `Exrethinkdb` you are in the right place. We decided to change the name to just `RethinkDB` and the repo to `rethinkdb-elixir`. Sorry if it has caused confusion. Better now in the early stages than later!



I just set up a channel on the Elixir slack, so if you are on there join #rethinkdb.



### Recent changes



#### 0.4.0



* Extract Changefeed out into separate [package](https://github.com/hamiltop/rethinkdb_changefeed)

* Accept keyword options with queries



## Getting Started



See [API documentation](http://hexdocs.pm/rethinkdb/) for more details.



### Connection



Connections are managed by a process. Start the process by calling `start_link/1`. See [documentation for `Connection.start_link/1`](http://hexdocs.pm/rethinkdb/RethinkDB.Connection.html#start_link/1) for supported options.



#### Basic Remote Connection



```elixir

{:ok, conn} = RethinkDB.Connection.start_link([host: "10.0.0.17", port: 28015])

```



#### Named Connection



```elixir

{:ok, conn} = RethinkDB.Connection.start_link([name: :foo])

```



#### Supervised Connection



Start the supervisor with:



```elixir

worker(RethinkDB.Connection, [[name: :foo]])

worker(RethinkDB.Connection, [[name: :bar, host: 'localhost', port: 28015]])

```



#### Default Connection



An `RethinkDB.Connection` does parallel queries via pipelining. It can and should be shared among multiple processes. Because of this, it is common to have one connection shared in your application. To create a default connection, we create a new module and `use RethinkDB.Connection`.



```elixir

defmodule FooDatabase do

  use RethinkDB.Connection

end

```



This connection can be supervised without a name (it will assume the module as the name).



```elixir

worker(FooDatabase, [])

```



Queries can be run without providing a connection (it will use the name connection).



```elixir

import RethinkDB.Query

table("people") |> FooDatabase.run

```



#### Connection Pooling



To use a connection pool, add Poolboy to your dependencies:



```elixir

{:poolboy, "~> 1.5"}

```



Then, in your supervision tree, add:



```elixir

worker(:poolboy, [[name: {:local, :rethinkdb_pool}, worker_module: RethinkDB.Connection, size: 10, max_overflow: 0], [])

```



NOTE: If you want to use changefeeds or any persistent queries, `max_overflow: 0` is required.



Then use it in your code:



```elixir

db = :poolboy.checkout(:rethinkdb_pool)

table("people") |> db

:poolboy.checkin(:rethinkdb_pool, db)

```



### Query



`RethinkDB.run/2` accepts a process as the second argument (to facilitate piping).



#### Insert



```elixir



q = Query.table("people")

  |> Query.insert(%{first_name: "John", last_name: "Smith"})

  |> RethinkDB.run conn

```



#### Filter



```elixir

q = Query.table("people")

  |> Query.filter(%{last_name: "Smith"})

  |> RethinkDB.run conn

```



#### Functions



RethinkDB supports RethinkDB functions in queries. There are two approaches you can take:



Use RethinkDB operators



```elixir

import RethinkDB.Query



make_array([1,2,3]) |> map(fn (x) -> add(x, 1) end)

```



Use Elixir operators via the lambda macro



```elixir

require RethinkDB.Lambda

import RethinkDB.Lambda



make_array([1,2,3]) |> map(lambda fn (x) -> x + 1 end)

```



#### Map



```elixir

require RethinkDB.Lambda

import Query

import RethinkDB.Lambda



conn = RethinkDB.connect



table("people")

  |> has_fields(["first_name", "last_name"])

  |> map(lambda fn (person) ->

    person[:first_name] + " " + person[:last_name]

  end) |> RethinkDB.run conn

```



See [query.ex](lib/rethinkdb/query.ex) for more basic queries. If you don't see something supported, please open an issue. We're moving fast and any guidance on desired features is helpful.



#### Indexes



```elixir

# Simple indexes

# create

result = Query.table("people")

  |> Query.index_create("first_name", Lambda.lambda fn(row) -> row["first_name"] end)

  |> RethinkDB.run conn



# retrieve

result = Query.table("people")

  |> Query.get_all(["Will"], index: "first_name")

  |> RethinkDB.run conn



# Compound indexes

# create

result = Query.table("people")

  |> Query.index_create("full_name", Lambda.lambda fn(row) -> [row["first_name"], row["last_name"]] end)

  |> RethinkDB.run conn



# retrieve

result = Query.table("people")

  |> Query.get_all([["Will", "Smith"], ["James", "Bond"]], index: "full_name")

  |> RethinkDB.run conn

```



One limitation we have in Elixir is that we don't support varargs. So in JavaScript you would do `getAll(key1, key2, {index: "uniqueness"})`. In Elixir we have to do `get_all([key1, key2], index: "uniqueness")`. With a single key it becomes `get_all([key1], index: "uniqueness")` and when `key1` is `[partA, partB]` you have to do `get_all([[partA, partB]], index: "uniqueness")`



### Changes



Change feeds can be consumed either incrementally (by calling `RethinkDB.next/1`) or via the Enumerable Protocol.



```elixir

results = Query.table("people")

  |> Query.filter(%{last_name: "Smith"})

  |> Query.changes

  |> RethinkDB.run conn

# get one result

first_change = RethinkDB.next results

# get stream, chunked in groups of 5, Inspect

results |> Stream.chunk(5) |> Enum.each &IO.inspect/1

```



### Supervised Changefeeds



Supervised Changefeeds (an OTP behavior for running a changefeed as a process) have been moved to their own repo to enable independent release cycles. See https://github.com/hamiltop/rethinkdb_changefeed



### Roadmap



Version 1.0.0 will be limited to individual connections and implement the entire documented ReQL (as of rethinkdb 2.0)



While not provided by this library, we will also include example code for:



* Connection Pooling



The goal for 1.0.0 is to be stable. Issues have been filed for work that needs to be completed before 1.0.0 and tagged with the 1.0.0 milestone.



### Example Apps



Checkout the wiki page for various [example apps](https://github.com/hamiltop/rethinkdb-elixir/wiki/Example-Apps)



### Contributing



Contributions are welcome. Take a look at the Issues. Anything that is tagged `Help Wanted` or `Feedback Wanted` is a good candidate for contributions. Even if you don't know where to start, respond to an interesting issue and you will be pointed in the right direction.



#### Testing



Be intentional. Whether you are writing production code or tests, make sure there is value in the test being written.