An example of low level client

es_client.ex

defmodule App.Es.EsClient do

  @config Application.get_env(:app, :es)

  @doc """
  Builds index/type/id|action URL. Like index-prefix/index/id|action
  """
  def build_url(index, id_or_action \\ nil, type \\ nil) do
    host = @config[:host]
    index_prefix = @config[:index_prefix]
    type = case type do
      nil -> "/#{index}"
      false -> ""
      type -> "/#{type}"
    end
    url = "#{host}/#{index_prefix}#{index}#{type}"
    if id_or_action, do: "#{url}/#{id_or_action}", else: url
  end

  @doc """
  Upsert - insert or update document if it exists in db
  """
  def upsert(index, id, body) do    
    url = build_url(index, id)
    result = request!(:put, url, encode!(body))
    result = decode!(result.body)
    {:ok, result}
  end

  @doc """
  Check if index exists
  """
  def index_exists?(index) do
    url = build_url(index)
    result = request!(:head, url)
    case result.status_code do
      404 -> false
      200 -> true
    end
  end

  @doc """
  Delete ES index
  """
  def delete_index(index) do
    result = request!(:delete, build_url(index, nil, false))
    case result.status_code do
      200 -> {:ok, decode!(result.body)}
      _ -> {:error, decode!(result.body)}
    end
  end

  @doc """
  Put mapping for idnex
  """
  def put_mapping(index, mapping) do
     url = build_url(index, nil, false)
     result = request!(:put, url, encode!(%{mappings: mapping}))
     case result.status_code do
       200 -> {:ok, decode!(result.body)}
       _ -> {:error, decode!(result.body)}
     end
  end

  @doc """
  Search in index
  """
  def search(index, payload \\ %{}) do
    url = build_url(index, "_search")
    result = request!(:get, url, encode!(payload))
    case result.status_code do
      200 -> {:ok, decode!(result.body)}
      _ -> {:error, decode!(result.body)}
    end
  end

  defp document_exists?(index, id) do
    url = build_url(index, id)
    result = request!(:head, url)
    case result.status_code do
      404 -> false
      200 -> true
    end
  end


  defp encode!(data), do: Poison.encode!(data)
  defp decode!(data), do: Poison.decode!(data)
  defp requets!(method, url, payload), do: HTTPoison.request!(method, url, payload)

end