Bolt-Sips, the Neo4j driver for Elixir wrapped around the Bolt protocol.

Documentation: http://hexdocs.pm/bolt_sips/

Disclaimer

This is a new generation of Bolt.Sips: v1.0.nn - transitioning to a new driver design

It is implementing the db_connection database connection behavior.

Features

It is using: Bolt. The Neo4j's newest network protocol, designed for high-performance
Supported bolt version: 1, 2
Supports transactions, simple and complex Cypher queries with or w/o parameters
Supports Neo4j versions: 3.0.x/3.1.x/3.2.x/3.4.x/3.5.x

Note

It works with Neo4j 3.5.x but not with the new bolt v3 but with bolt v2. However, as bolt v3 only introduces alternative message for initialization and transaction, all neo4j's features can be used.

Breaking changes introduced in version 1.x

non-closure based transactions are not supported anymore. This is a change introduced in DBConnection 2.x. Bolt.Sips version tagged v0.5.10 is the last version supporting open transactions.
the support for ETLS was dropped. It was mostly used for development or hand-crafted deployments

Installation

Available in Hex, the package can be installed as:

1. Add bolt_sips to your list of dependencies in `mix.exs`:

def deps do
  [{:bolt_sips, "~> 1.0"}]
end

2. Ensure bolt_sips is started before your application:

def application do
  [applications: [:bolt_sips], mod: {Bolt.Sips.Application, []}]
end

You can also specify custom configuration settings in you app's mix config file. These may overwrite your config file:

def application do
  [extra_applications: [:logger], mod:
    {Bolt.Sips.Application, [url: 'localhost', pool_size: 15]}
  ]
end

Usage

Edit your config/config.exs and set Bolt connection, for example:

config :bolt_sips, Bolt,
  hostname: 'localhost',
  basic_auth: [username: "neo4j", password: "*********"],
  port: 7687,
  pool_size: 5,
  max_overflow: 1

A new parameter: url, can be used for reducing the verbosity of the config files; available starting with version 0.1.5. For example:

config :bolt_sips, Bolt,
  url: 'localhost:7687',
  pool_size: 5,
  max_overflow: 1

And if you are using any remote instances of hosted Neo4j servers, such as the ones available (also for free) at Neo4j/Sandbox configuring the driver is a matter of a simple copy and paste:

config :bolt_sips, Bolt,
  url: "bolt://<ip_address>:<bolt_port>",
  basic_auth: [username: "neo4j", password: "#######"]
  ssl: true

We’re also retrying sending the requests to the Neo4j server, with a linear backoff, and try them a couple of times before giving up - all these as part of the existing pool management, of course. Example

config :bolt_sips, Bolt,
  url: "bolt://<ip_address>:<bolt_port>",
  basic_auth: [username: "neo4j", password: "#######"]
  ssl: true
  timeout: 15_000,
  retry_linear_backoff: [delay: 150, factor: 2, tries: 3]

In the configuration above, the retry will linearly increase the delay from 150ms following a Fibonacci pattern, cap the delay at 15 seconds (the value defined by the :timeout parameter) and giving up after 3 attempts.

But you can reduce the configuration even further, and rely on the driver's default values. For example: given you're running a Neo4j server on your local machine and Bolt is enabled on 7687, this is the simplest configuration you need, in order to get you started:

config :bolt_sips, Bolt,
  url: "localhost:7687"

With a minimalist setup configured as above, and the Neo4j 3.x server running, you can connect to the server and run some queries using Elixir’s interactive shell (IEx). Example:

$ MIX_ENV=test iex -S mix
Erlang/OTP 21 [erts-10.0.5] [source] [64-bit] [smp:8:8] [ds:8:8:10] [async-threads:1] [hipe]

Interactive Elixir (1.7.3) - press Ctrl+C to exit (type h() ENTER for help)
iex> {:ok, pid} = Bolt.Sips.start_link(url: "localhost")
{:ok, #PID<0.191.0>}

iex> conn = Bolt.Sips.conn
:bolt_sips_pool

iex> Bolt.Sips.query!(conn, "CREATE (a:Person {name:'Bob'})")
%{
  stats: %{"labels-added" => 1, "nodes-created" => 1, "properties-set" => 1},
  type: "w"
}

iex> Bolt.Sips.query!(conn, "MATCH (a:Person {name: 'Bob'}) RETURN a.name AS name") |> Enum.map(&(&1["name"]))

["Bob"]

iex> Bolt.Sips.query!(conn, "MATCH (a:Person {name:'Bob'}) DELETE a")
%{stats: %{"nodes-deleted" => 1}, type: "w"}

iex> Bolt.Sips.query!(conn, "MATCH (a:Person {name: 'Bob'}) RETURN a.name AS name") |> Enum.map(&(&1["name"]))
[]

Using temporal and spatial types

Temporal and spatial types are supported since Neo4J 3.4. You can used the elixir structs: Time, NaiveDateTime, DateTime, as well as the Bolt Sips structs: DateTimeWithTZOffset, TimeWithTZOffset, Duration, Point.

$ MIX_ENV=test iex -S mix
Erlang/OTP 21 [erts-10.0.5] [source] [64-bit] [smp:8:8] [ds:8:8:10] [async-threads:1] [hipe]

Interactive Elixir (1.7.3) - press Ctrl+C to exit (type h() ENTER for help)
iex> alias Bolt.Sips.Types.{Duration, DateTimeWithTZOffset, Point, TimeWithTZOffset}
[Bolt.Sips.Types.Duration, Bolt.Sips.Types.DateTimeWithTZOffset,
 Bolt.Sips.Types.Point, Bolt.Sips.Types.TimeWithTZOffset]

iex> alias Bolt.Sips.TypesHelper
Bolt.Sips.TypesHelper

iex> {:ok, pid} = Bolt.Sips.start_link(url: "localhost", basic_auth: [username: "neo4j", password: "test"])
{:ok, #PID<0.236.0>}

iex> conn = Bolt.Sips.conn
:bolt_sips_pool

# Date without timezone with Date
iex(8)> Bolt.Sips.query!(conn, "RETURN date({d}) AS d", %{d: ~D[2019-02-04]})
[%{"d" => ~D[2019-02-04]}]

# Time without timezone with Time
iex> Bolt.Sips.query!(conn, "RETURN localtime({t}) AS t", %{t: ~T[13:26:08.543440]})
[%{"t" => ~T[13:26:08.543440]}]

# Datetime without timezone with Naive DateTime
iex> Bolt.Sips.query!(conn, "RETURN localdatetime({ldt}) AS ldt", %{ldt: ~N[2016-05-24 13:26:08.543]})
[%{"ldt" => ~N[2016-05-24 13:26:08.543]}]

# Datetime with timezone ID with DateTime (through Calendar)
iex> date_time_with_tz_id = TypesHelper.datetime_with_micro(~N[2016-05-24 13:26:08.543], "Europe/Paris")
#DateTime<2016-05-24 13:26:08.543+02:00 CEST Europe/Paris>
iex> Bolt.Sips.query!(conn, "RETURN datetime({dt}) AS dt", %{dt: date_time_with_tz_id})
[%{"dt" => #DateTime<2016-05-24 13:26:08.543+02:00 CEST Europe/Paris>}]

# Datetime with timezone offset (seconds) with DateTimeWithTZOffset
iex(17)> date_time_with_tz = DateTimeWithTZOffset.create(~N[2016-05-24 13:26:08.543], 7200)
%Bolt.Sips.Types.DateTimeWithTZOffset{
  naive_datetime: ~N[2016-05-24 13:26:08.543],
  timezone_offset: 7200
}
iex(18)> Bolt.Sips.query!(conn, "RETURN datetime({dt}) AS dt", %{dt: date_time_with_tz})
[
  %{
    "dt" => %Bolt.Sips.Types.DateTimeWithTZOffset{
      naive_datetime: ~N[2016-05-24 13:26:08.543],
      timezone_offset: 7200
    }
  }
]


# Datetime with timezone offset (seconds) with TimeWithTZOffset
iex> time_with_tz = TimeWithTZOffset.create(~T[12:45:30.250000], 3600)
%Bolt.Sips.Types.TimeWithTZOffset{
  time: ~T[12:45:30.250000],
  timezone_offset: 3600
}
iex> Bolt.Sips.query!(conn, "RETURN time({t}) AS t", %{t: time_with_tz})
[
  %{
    "t" => %Bolt.Sips.Types.TimeWithTZOffset{
      time: ~T[12:45:30.250000],
      timezone_offset: 3600
    }
  }
]

# Cartesian 2D point with Point
iex> point_cartesian_2D = Point.create(:cartesian, 50, 60.5)
%Bolt.Sips.Types.Point{
  crs: "cartesian",
  height: nil,
  latitude: nil,
  longitude: nil,
  srid: 7203,
  x: 50.0,
  y: 60.5,
  z: nil
}
iex> Bolt.Sips.query!(conn, "RETURN point({pt}) AS pt", %{pt: point_cartesian_2D})
[
  %{
    "pt" => %Bolt.Sips.Types.Point{
      crs: "cartesian",
      height: nil,
      latitude: nil,
      longitude: nil,
      srid: 7203,
      x: 50.0,
      y: 60.5,
      z: nil
    }
  }
]

# Geographic 2D point with Point
iex> point_geo_2D = Point.create(:wgs_84, 50, 60.5)
%Bolt.Sips.Types.Point{
  crs: "wgs-84",
  height: nil,
  latitude: 60.5,
  longitude: 50.0,
  srid: 4326,
  x: 50.0,
  y: 60.5,
  z: nil
}
iex> Bolt.Sips.query!(conn, "RETURN point({pt}) AS pt", %{pt: point_geo_2D})
[
  %{
    "pt" => %Bolt.Sips.Types.Point{
      crs: "wgs-84",
      height: nil,
      latitude: 60.5,
      longitude: 50.0,
      srid: 4326,
      x: 50.0,
      y: 60.5,
      z: nil
    }
  }
]

# Cartesian 3D point with Point
iex> point_cartesian_3D = Point.create(:cartesian, 50, 60.5, 12.34)
%Bolt.Sips.Types.Point{
  crs: "cartesian-3d",
  height: nil,
  latitude: nil,
  longitude: nil,
  srid: 9157,
  x: 50.0,
  y: 60.5,
  z: 12.34
}
iex> Bolt.Sips.query!(conn, "RETURN point({pt}) AS pt", %{pt: point_cartesian_3D})
[
  %{
    "pt" => %Bolt.Sips.Types.Point{
      crs: "cartesian-3d",
      height: nil,
      latitude: nil,
      longitude: nil,
      srid: 9157,
      x: 50.0,
      y: 60.5,
      z: 12.34
    }
  }
]

# Geographic 2D point with Point
iex> point_geo_3D = Point.create(:wgs_84, 50, 60.5, 12.34)
%Bolt.Sips.Types.Point{
  crs: "wgs-84-3d",
  height: 12.34,
  latitude: 60.5,
  longitude: 50.0,
  srid: 4979,
  x: 50.0,
  y: 60.5,
  z: 12.34
}
iex> Bolt.Sips.query!(conn, "RETURN point({pt}) AS pt", %{pt: point_geo_2D})
[
  %{
    "pt" => %Bolt.Sips.Types.Point{
      crs: "wgs-84",
      height: nil,
      latitude: 60.5,
      longitude: 50.0,
      srid: 4326,
      x: 50.0,
      y: 60.5,
      z: nil
    }
  }
]

Using Bolt.Sips with Phoenix, or similar

Don't forget to start the Bolt.Sips driver in your supervision tree. Example:

defmodule MoviesElixirPhoenix do
  use Application

  # See https://hexdocs.pm/elixir/Application.html
  # for more information on OTP Applications
  def start(_type, _args) do
    # Define workers and child supervisors to be supervised
    children = [
      # Start the endpoint when the application starts
      {Bolt.Sips, Application.get_env(:bolt_sips, Bolt)},
      %{
        id: MoviesElixirPhoenix.Endpoint,
        start: {MoviesElixirPhoenix.Endpoint, :start_link, []}
      }
    ]

    # See https://hexdocs.pm/elixir/Supervisor.html
    # for other strategies and supported options
    opts = [strategy: :one_for_one, name: MoviesElixirPhoenix.Supervisor]
    Supervisor.start_link(children, opts)
  end

  # Tell Phoenix to update the endpoint configuration
  # whenever the application is updated.
  def config_change(changed, _new, removed) do
    MoviesElixirPhoenix.Endpoint.config_change(changed, removed)
    :ok
  end
end

The code above was extracted from the Neo4j Movies Demo, a Phoenix web application using this driver and the well known Dataset - Movie Database.

Note: as explained below, you don't need to convert your query result before having it encoded in JSON. BoltSips provides Jason and Poison implementation to tackle this problem automatically.

About encoding

Bolt.Sips povides solution for encoding your query result in different format.
For now, only JSON is supported.

There is two way of encoding data to json:

By using the helpers provided by the module Bolt.Sips.ResponseEncoder
Using your usual JSON encoding library. Bolt.Sips have implementation for: Jason and Poison. With this the query results can be automatically encoded by one of the libraries available: Jason or Poison. No further work is required when using a framework like: Phoenix, for example.

Examples

iex> query_result = [
   %{
     "t" => %Bolt.Sips.Types.Node{
       id: 26,
       labels: ["Test"],
       properties: %{
         "created_at" => "2019-08-03T12:34:56+01:00",
         "name" => "A test node",
         "uid" => 12345
       }
     }
   }
 ]

# Using Bolt.Sips.ResponseEncoder
 iex> Bolt.Sips.ResponseEncoder.encode(query_result, :json)
{:ok,
 "[{\"t\":{\"id\":26,\"labels\":[\"Test\"],\"properties\":{\"created_at\":\"2019-08-03T12:34:56+01:00\",\"name\":\"A test node\",\"uid\":12345}}}]"}
iex(11)> Bolt.Sips.ResponseEncoder.encode!(query_result, :json)
"[{\"t\":{\"id\":26,\"labels\":[\"Test\"],\"properties\":{\"created_at\":\"2019-08-03T12:34:56+01:00\",\"name\":\"A test node\",\"uid\":12345}}}]"

# Using Jason
iex(14)> Jason.encode!(query_result) 
"[{\"t\":{\"id\":26,\"labels\":[\"Test\"],\"properties\":{\"created_at\":\"2019-08-03T12:34:56+01:00\",\"name\":\"A test node\",\"uid\":12345}}}]"

# Using Poison
iex(13)> Poison.encode!(query_result)
"[{\"t\":{\"properties\":{\"uid\":12345,\"name\":\"A test node\",\"created_at\":\"2019-08-03T12:34:56+01:00\"},\"labels\":[\"Test\"],\"id\":26}}]"

Both solutions rely on protocols, then they can be easily overriden if needed.
More info in the modules Bolt.Sips.ResponseEncoder.Json, Bolt.Sips.ResponseEncoder.Json.Jason, Bolt.Sips.ResponseEncoder.Json.Poison

Command line

Run simple Cypher commands from a mix task, for quick testing Cypher results or the connection with your server:

MIX_ENV=test mix bolt.cypher "MATCH (people:Person) RETURN people.name LIMIT 5"

Output sample:

"MATCH (people:Person) RETURN people.name LIMIT 5"

[
  %{"people.name" => "Keanu Reeves"},
  %{"people.name" => "Carrie-Anne Moss"},
  %{"people.name" => "Laurence Fishburne"},
  %{"people.name" => "Hugo Weaving"},
  %{"people.name" => "Lilly Wachowski"}
]

Available command line options:

--url, -u - server host
--ssl, -s - use ssl

For example, if your server requires authentication:

MIX_ENV=test mix bolt.cypher --ssl true --url "bolt://<user>:<password>@happy-warlocks.dbs.graphenedb.com:24786"\

"MATCH (people:Person) RETURN people.name LIMIT 5"

Testing

Tests run against a running instance of Neo4j. Please verify that you do not store critical data on this server!

If you have docker available on your system, you can start an instance before running the test suite:

docker run --rm -p 7687:7687 -e 'NEO4J_AUTH=neo4j/test' neo4j:3.0.6

Neo4j versions used for test: 3.0, 3.1, 3.4, 3.5

mix test

Special thanks

Michael Schaefermeyer (@mschae), for implementing the Bolt protocol in Elixir: mschae/boltex

Contributors

As reported by Github: contributions to master, excluding merge commits

Contributing

Fork it
Create your feature branch (git checkout -b my-new-feature)
Test (mix test)
Commit your changes (git commit -am 'Add some feature')
Push to the branch (git push origin my-new-feature)
Create new Pull Request

License

Copyright 2016-2019 the original author or authors

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

   http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.

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