# BencheeCSV [![Hex Version](https://img.shields.io/hexpm/v/benchee_csv.svg)] (https://hex.pm/packages/benchee_csv) [![docs](https://img.shields.io/badge/docs-hexpm-blue.svg)](https://hexdocs.pm/benchee_csv/) [![Build Status](https://travis-ci.org/PragTob/benchee_csv.svg?branch=master)](https://travis-ci.org/PragTob/benchee_csv)

Formatter for [benchee](https://github.com/PragTob/benchee) to turn the statistics output into a CSV file. This can then be used in the Spreadsheet tool of your choice to generate graphs to your liking.

These might then look like this one (quickly generated with LibreOffice from the output of the sample):

![sample graphs](http://www.pragtob.info/images/benchee_csv.png)

## Installation

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

```elixir
def deps do
  [{:benchee_csv, "~> 0.4", only: :dev}]
end
```

Afterwards, run `mix deps.get` to install it.

## Usage

Simply configure `Benchee.Formatters.CSV.output/1` as one of the formatters for `Benchee.run/2` along with the `%{csv: %{file: "my_file.csv"}}` option as to where to save the csv file:

```elixir
list = Enum.to_list(1..10_000)
map_fun = fn(i) -> [i, i * i] end

Benchee.run(
  %{
    formatters: [
      &Benchee.Formatters.CSV.output/1,
      &Benchee.Formatters.Console.output/1
    ],
    csv: %{file: "my.csv"}
  },
  %{
    "flat_map"    => fn -> Enum.flat_map(list, map_fun) end,
    "map.flatten" => fn -> list |> Enum.map(map_fun) |> List.flatten end
  })
```

The sample defines both the standard console formatter and the CSV formatter, if you don't care about the console output you can also only define the CSV formatter.

You can also use the more verbose and versatile API of Benchee. When it comes to formatting just use `Benchee.Formatters.CSV.format` and then write it to a file. Here is an example:

```elixir
file = File.open!("test.csv", [:write])
list = Enum.to_list(1..10_000)
map_fun = fn(i) -> [i, i * i] end

Benchee.init
|> Benchee.benchmark("flat_map", fn -> Enum.flat_map(list, map_fun) end)
|> Benchee.benchmark("map.flatten",
                     fn -> list |> Enum.map(map_fun) |> List.flatten end)
|> Benchee.measure
|> Benchee.statistics
|> Benchee.Formatters.CSV.format
|> Enum.each(fn(row) -> IO.write(file, row) end)
```

Of course you can also pass in the `%{csv: %{file: "test.csv"}}` option and then use `Benchee.Formatters.CSV.output/1`.