#63: added the reader example

Author: zookzook

README.md

@@ -1,14 +1,13 @@
 # An Alternative Elixir Driver for MongoDB
 [![Build Status](https://travis-ci.org/zookzook/elixir-mongodb-driver.svg?branch=master)](https://travis-ci.org/zookzook/elixir-mongodb-driver)
-[![Coverage Status](https://coveralls.io/repos/github/zookzook/elixir-mongodb-driver/badge.svg?branch=master)](https://coveralls.io/github/zookzook/elixir-mongodb-driver?branch=master)
 [![Hex.pm](https://img.shields.io/hexpm/v/mongodb_driver.svg)](https://hex.pm/packages/mongodb_driver)
 [![Hex.pm](https://img.shields.io/hexpm/dt/mongodb_driver.svg)](https://hex.pm/packages/mongodb_driver)
 [![Hex.pm](https://img.shields.io/hexpm/dw/mongodb_driver.svg)](https://hex.pm/packages/mongodb_driver)
 [![Hex.pm](https://img.shields.io/hexpm/dd/mongodb_driver.svg)](https://hex.pm/packages/mongodb_driver)
 
 ## Features
 
-  * Supports MongoDB versions 3.2, 3.4, 3.6, 4.0, 4.2, 4.4
+  * Supports MongoDB versions 3.2, 3.4, 3.6, 4.x, 5.x
   * Connection pooling ([through DBConnection 2.x](https://github.com/elixir-ecto/db_connection))
   * Streaming cursors
   * Performant ObjectID generation

examples/reader.ex

@@ -0,0 +1,48 @@
+defmodule Reader do
+
+  require Logger
+
+  ##
+  # see https://github.com/zookzook/elixir-mongodb-driver/issues/63 for more information
+  #
+  # 1. start a replica set and call the Reader.test()
+  # 2. go to the primary db and call db.adminCommand({replSetStepDown: 30})
+  # 3. check the log to see the error message only one time
+  ##
+  def start_link(conn) do
+    Logger.info("starting reader")
+
+    Task.start_link(fn -> read(conn, false) end)
+  end
+
+  defp read(conn, error) do
+
+    if error do
+      Logger.info("Called with error")
+    end
+
+    # Gets an enumerable cursor for the results
+    cursor = Mongo.find(conn, "data", %{})
+
+    error = case cursor do
+      {:error, error} ->
+        Logger.info("Error: #{inspect error}")
+        true
+
+      _ ->
+        cursor
+        |> Enum.to_list()
+        |> Enum.count()
+        false
+    end
+
+    read(conn, error)
+  end
+
+  def test() do
+    {:ok, conn} = Mongo.start_link(url: "mongodb://localhost:27017,localhost:27018,localhost:27019/load?replicaSet=rs_1")
+
+    Enum.map(1..10_000, fn counter -> Mongo.insert_one(conn, "data", %{counter: counter}) end)
+    Reader.start_link(conn)
+  end
+end