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Geolix

MaxMind GeoIP2 database reader/decoder.

Note: If you are reading this on GitHub then the information in this file may be out of sync with the Hex package. If you are using this library through Hex please refer to the appropriate documentation on HexDocs (link available on Hex).

Package Setup

To use Geolix with your projects, edit your mix.exs file and add the project as a dependency:

defp deps do
  [
    # ...
    {:geolix, "~> 0.16"},
    # ...
  ]
end

Package Startup (application)

Probably the easiest way to manage startup is by adding :geolix to the list of applications:

def application do
  [
    applications: [
      # ...
      :geolix,
      # ...
    ]
  ]
end

Package Startup (manual supervision)

A second possible approach is to take care of supervision yourself. This means you should add :geolix to your included applications instead:

def application do
  [
    included_applications: [
      # ...
      :geolix,
      # ...
    ]
  ]
end

And also add the appropriate Geolix.Supervisor to your hierarchy:

# in your application/supervisor
children = [
  # ...

  # elixir < 1.5.0
  Supervisor.Spec.supervisor(Geolix.Supervisor, []),
  # elixir >= 1.5.0
  Geolix.Supervisor,

  # ...
]

Application Configuration

To get started you need to define one or more :databases to use for lookups. Each database definition is a map with at least two fields:

  • :id - an identifier for this database, usable to limit lookups to a single database if you have defined more than one
  • :adapter - the adapter module used to handle lookup requests. See the part "Adapter Configuration" in this document for additional information

Depending on the adapter you may need to provide additional values.

Configuration (static)

One option for configuration is using a static configuration, i.e. for two databases handled by the pre-packaged adapter Geolix.Adapter.MMDB2:

config :geolix,
  databases: [
    %{
      id: :city,
      adapter: Geolix.Adapter.MMDB2,
      source: "/absolute/path/to/cities/db"
    },
    %{
      id: :country,
      adapter: Geolix.Adapter.MMDB2,
      source: "/absolute/path/to/countries/db"
    }
  ]

Configuration (dynamic)

If there are any reasons you cannot use a pre-defined configuration you can also configure an initializer module to be called before starting the top-level suprevisor or alternatively for each individual database.

This may be the most suitable configuration if you have the database located in the :priv_dir of your application.

config :geolix,
  init: {MyInitModule, :my_init_fun_toplevel}

config :geolix,
  databases: [
    %{
      id: :dynamic_country,
      adapter: Geolix.Adapter.MMDB2,
      init: {MyInitModule, :my_init_fun_database}
    }
  ]

defmodule MyInitModule do
  @spec my_init_fun_toplevel() :: :ok
  def my_init_fun_toplevel() do
    priv_dir = Application.app_dir(:my_app, "priv")

    databases = [
      %{
        id: :dynamic_city,
        adapter: Geolix.Adapter.MMDB2,
        source: Path.join([priv_dir, "GeoLite2-City.mmdb"])
      }
      | Application.get_env(:geolix, :databases, [])
    ]

    Application.put_env(:geolix, :databases, databases)
  end

  @spec my_init_fun_database(map) :: map
  def my_init_fun_database(%{id: :dynamic_country} = database) do
    priv_dir = Application.app_dir(:my_app, "priv")

    %{database | source: Path.join([priv_dir, "GeoLite2-Country.mmdb"])}
  end
end

Above example illustrates both types of dynamic initialization.

The top-level initializer is called without arguments and expected to always return :ok. At the database level the current database configuration is passed as the first (and only) parameter and the new, complete configuration is expected as the return.

If you choose to use the dynamic database initialization the only requirement for your config file is a plain %{init: {MyInitModule, :my_init_fun}} entry. Every additional field in the example is only used for illustration and only required for the complete return value.

Configuration (system environment)

Each of the static config values can be grabbed upon start (or restart) from your current system environment:

config :geolix,
  databases: [
    %{
      id: :system_city,
      adapter: Geolix.Adapter.MMDB2,
      source: {:system, "SOME_SYSTEM_ENV_VARIABLE"}
    },
    %{
      id: :system_country,
      adapter: Geolix.Adapter.MMDB2,
      source: {:system, "SOME_VARIABLE", "/path/to/fallback.mmdb2"}
    }
  ]

Configuration (runtime)

If you do not want to use a pre-defined or dynamically initialized configuration you can also define adapters at runtime. This may be useful in a testing environment.

iex(1)> Geolix.load_database(%{
...(1)>   id: :runtime_city,
...(1)>   adapter: Geolix.Adapter.MMDB2,
...(1)>   source: "/absolute/path/to/cities/db.mmdb"
...(1)> })
:ok
iex(2)> Geolix.load_database(%{
...(2)>   id: :runtime_country,
...(2)>   adapter: Geolix.Adapter.MMDB2,
...(2)>   source: {:system, "SOME_SYSTEM_ENV_VARIABLE"}
...(2)> })
:ok

Please be aware that these databases will not be reloaded if, for any reason, the supervisor/application is restarted.

Running load_database/1 on an already configured database (matched by :id) will reload/replace it without persisting the configuration. On success a result of :ok will be returned otherwise a tuple in the style of {:error, message}. The individual errors are defined by the adapter.

Adapter Configuration

Geolix.Adapter.MMDB2

This is the default pre-packaged adapter for usage with the databases provided by MaxMind. Depending on the details of your configuration you may need to fetch a suitable distribution of the MaxMind GeoIP2 database (or the free GeoLite2 variant).

The adapter requires the :source configuration field to point to the database to use for lookups:

config :geolix,
  databases: [
    %{
      id: :mmdb2,
      adapter: Geolix.Adapter.MMDB2,
      source: "/absolute/path/to/db.mmdb"
    }
  ]

To avoid any problems with finding the file you should always provide an absolute path to the database file (most likely with the .mmdb extension).

By default it is expected that all databases are provided uncompressed. The only compression directly supported is gzip (not zip!) if the database source configured ends in .gz. If the loader detects a tarball (.tar or .tar.gz) the first file in the archive ending in .mmdb will be loaded.

Floating Point Precision

Please be aware that all values of the type float are rounded to 4 decimal digits and double values to 8 decimal digits.

This might be changed in the future if there are datasets known to return values with a higher precision.

Remote Sources

If you configure a database with a filename starting with "http" (yep, also matches "https"), the application will request it from that location.

Returning a status of 200 and the actual contents of the database then results in the regular loading process. Using this configuration you can load a database during startup from basically any location you can reach.

Note: Please be aware of the drawbacks of remote files! You should take into account the startup times as the file will be requested during GenServer.init/1. Unstable or slow networks could result in nasty timeouts.

Note: Be responsible with the source you configure! Having a public download mirror (or the official MaxMind location) set might flag you as a "not so nice person". Ideally use your own server or online storage.

Database Loading

Loading Errors

Erros occurring during database load are sent to Logger with level :error. The contain an atom with the specific error (like :enoent) and, in some cases, are more readable error message.

The errors are defined by the adapter.

Reloading

To trigger a forceful reload of all databases configured in the application environment you can use Geolix.reload_databases/0 to do so. This uses an internal GenServer.cast/2 so a slight delay will occur.

Unloading

Calling Geolix.unload_database/1 with a database id will unload this database. As this is done in a lazy fashion it will still be kept in memory while not being reloaded or used for lookups. If the database is configured via application environment it will still be reloaded as usual in case of a supervisor or application restart.

Usage

Lookups are done using Geolix.lookup/1,2:

iex(1)> Geolix.lookup("127.0.0.1")
%{
  city: %Geolix.Result.City{...},
  country: %Geolix.Result.Country{...}
}

iex(2)> Geolix.lookup({127, 0, 0, 1}, [as: :raw, where: :city])
%{...}

Using Geolix.lookup/2 with only one parameter (the IP) will lookup the information on all registered databases, returning nil if the IP was not found.

Lookup options:

  • :as - Return the result as a :struct or :raw (plain map)
  • :locale - Language (atom) to fetch information for. Only affects "top level" struct values. Defaults to :en.
  • :timeout - GenServer call timeout for the lookup. Defaults to 5_000.
  • :where - Lookup information in a single registered database

Every non-nil result will include the IP as a tuple either directly in the result field :ip_address or inside %{traits: %{ip_address: ...}} if a city or country (or enterprise) database is used.

Note: Please be aware that all results for enterprise databases are returned using separate structs if the data is not already included in the regular databases. This may change in the future.

Custom Adapters

If you need a different database or have other special needs for lookups you can write your own adapter and configure it.

Each adapter is expected to adhere to the Geolix.Adapter behaviour.

The MMDB2 adapter (Geolix.Adapter.MMDB2) is pre-packaged and usable once you configure it. For testing you can use a fake adapter (Geolix.Adapter.Fake) working on a plain Agent holding your IP lookup responses.

Additional Stuff

Benchmarking (scripted)

A (minimal) benchmark script looking up a predefined ip address is included:

mix bench.lookup

Benchmarking (manual)

If you are curious about how long a lookup of an IP takes, you can measure it using the erlang :timer module:

iex(1)> # display runtime in microseconds and the result
iex(2)> :timer.tc(fn -> Geolix.lookup({108, 168, 255, 243}) end)
{
  1337,
  %{
    city: ... ,
    country: ...
  }
}

iex(3)> # display only runtime in microseconds
iex(4)> (fn ->
...(4)>   {t, _} = :timer.tc(fn -> Geolix.lookup({82, 212, 250, 99}) end)
...(4)>   t
...(4)> end).()
1337

The time returned are the microseconds of the complete lookup including every overhead by for example the process pool. For more details refer to the official erlang documentation.

Result Verification

For (ongoing) verification of the result accuracy a special test environment is configured for each travis run.

This environment performs the following 4 steps:

  • generate a set of random IPs
  • lookup using geolix
  • lookup using python (geoip2)
  • compare the results

To run these tests on a local machine please refer to the travis commands executed on each run (.travis.yml).

License

Apache License, Version 2.0

License information about the supported MaxMind GeoIP2 Country, MaxMind GeoIP2 City and MaxMind GeoLite2 databases can be found on their respective sites.