InfluxEx

Hex.pm

Library for working with the v2.X InfluxDB API.

installation

Installation

def deps do
  [
    {:influx_ex, "~> 0.2.1"},
    # below are optional deps but InfluxEx will try to use them as defaults so
    # if you are okay with these defaults ensure they are added in your deps as
    # well.
    {:req, "~> 0.2.0"},
    {:jason, "~> 1.0"},
    {:nimble_csv, "~> 1.0"}
  ]
end

setup

Setup

To get started quickly you need to add these optional dependencies to your deps:

{:req, "~> 0.2.0"},
{:jason, "~> 1.0"},
{:nimble_csv, "~> 1.0"}

After adding these to your dependencies run mix deps.get

Then run docker-compose up -d to start a InfluxDB container which will be reachable at http://localhost:8086.

Next lets check the current user but running iex -S mix and typing:

client = InfluxEx.Client.new("devtoken")

InfluxEx.me(client)
{:ok, %InfluxEx.Me{}}

If you don't want to use the default libraries for HTTP, JSON, and CSV see the configuration section below for more information.

If you're using docker-compose, the development token is "devtoken" and during tests the token is "testtoken".

client

Client

InfluxEx does not provide a process based client. This provided the most flexibility to consuming applications to decide if a process is needed or not for managing state.

If you want the client to be in a process here's a stub of what that might look like to get you started:

defmodule MyApp.InfluxClient do
  use GenServer

  alias InfluxEx.{Client, Orgs}

  @type arg() ::
          {:token, InfluxEx.token()}
          | {:org, Orgs.name()}
          | {:org_id, Orgs.id()}
          | {:port, :inet.port_number()}
          | {:host, :inet.hostname()}

  @doc """
  Start the client
  """
  @spec start_link([arg()]) :: GenServer.on_start()
  def start_link(args) do
    GenServer.start_link(__MODULE__, args, name: __MODULE__)
  end

  @impl GenServer
  def init(args) do
    # required args
    token = Keyword.fetch!(args, :token)
    org = Keyword.fetch!(args, :org)
    org_id = Keyword.fetch!(args, :org_id)

    # optional args
    port = Keyword.get(args, :port) || 8086
    host = Keyword.get(args, :host) || "http://localhost"

    client = Client.new(token, port: port, host: host, org: org, org_id: org_id)

    {:ok, %{client: client}}
  end
end

configuration

Configuration

http-client

HTTP Client

The InfluxDB API uses the HTTP protocol. By default InfluxEx will try to use Req to make HTTP request. If you want to use Req you will need to add it to your deps in your mix.exs file.

{:req, "~> 0.2.0"}

If you use a different HTTP library you can provide the client with a module that implements the InfluxEx.HTTP behaviour that wraps your preferred HTTP library.

my_client = InfluxEx.Client.new("mytoken", http_client: MyHTTPClient)

json-library

JSON Library

The InfluxDB API using JSON format to communicate data between the client and server. InfluxEx needs away to encode and decode the JSON payloads to and from Elixir data types. By default InfluxEx will try to use the Jason library. To use this default you need to add :jason to you deps in your mix.exs:

{:jason, "~> 1.0"}

If you want to use a different JSON library pass a module name into the :json_library option when creating a client. Ensure that the module implements the InfluxEx.JSONLibrary behaviour.

InfluxEx.Client.new("mytoken", json_library: MyJSONLibrary)

csv-library

CSV Library

For some API calls the InfluxDB API requires working with the CSV content type. By default InfluxEx will try to use the :nimble_csv library. If you are okay with default you need to add this to your mix.exs file:

{:nimble_csv, "~> 1.0"}

If you want to use a different decoder you can supply that to InfluxEx.Client.new/2.

If you want to use a different library you can supply a module that implements InfluxEx.CSVLibrary to your client using the :csv_library option:

InfluxEx.Client.new("mytoken", csv_library: MyCSVLibrary)

One important note about using a custom CSV library is the parse_string/1 callback implementation needs to keep the CSV headers as InfluxEx needs them to ensure it handles tag names and values correctly.