servant-benchmark: Generate benchamrk files from a Servant API

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Change log
Dependencies aeson, base (>=4.7 && <5), base64-bytestring, bytestring, case-insensitive, http-media, http-types, QuickCheck, servant, text, yaml [details]
License BSD-3-Clause
Copyright 2021 Kyriakos Papachrysanthou
Author Kyriakos Papachrysanthou
Category Web
Home page
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Source repo head: git clone
Uploaded by 3kyro at 2021-04-26T07:52:41Z



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A library for producing random request data from Servant APIs.

Building a Generator

The Generator type must closely follow the structure of the Servant API.

As an example, the following is a valid Generator for a contrived servant API

{-# LANGUAGE OverloadedStrings #-}
{-# LANGUAGE DataKinds #-}
{-# LANGUAGE TypeOperators #-}

type API = 
    "books" :> Get '[JSON] [Book]
    :<|> "view-my-referer" :> Header "from" Referer :> Get '[JSON] Referer
    :<|> "users" :> Capture "userId" Integer :> ReqBody '[JSON] User :> Put '[JSON] User
    :<|> "post" :> QueryParam "segments" Text :> Get '[JSON] Post
    :<|> Raw

generator :: Generator API
let generator =
    ("books", 1)
    :|: arbitrary :>: ("referer", 2)
    :|: pure 1001 :>: arbitrary :>: ("users endpoint", 2)
    :|: elements ["title", "contents", "post"] :>: ("post", 4)
    :|: ("raw", 0)

The first endpoint "books" does not require request data and so only the name / weight tuple is provided.

The "view-my-referer" endpoint requires a "from" header with an accompanying Referer value. Here we assume Referer has an Arbitrary instance to provide a random value. The endpoint generator finishes with the name/weight indication.

The "users" endpoint requires two different request values. An Integer capture representing a user id as well as a User value. We hard-code the user id to 1001 using the monadic pure and assume that User has an Arbitrary instance to produce a random value. We finish with the endpoint's name/weight as necessary.

The "post" endpoint requires a Text query parameter. We provide a fixed set of possible values using the elements function from the QuickCheck package. With a weight of 4, four instances of the "post" endpoint will be produced, each with a random value from the specified set.

Finally our API provides a Raw endpoint for serving static files, but we'd rather not benchmark it. Providing a 0 weight ensures that no request will be generated

Basic Auth

A generator for an endpoint using a BasicAuth combinator requires both a function to convert the requested user data type to BasicAuthData as well as a Gen value for the requested user data.


type privateAPI = "private" :> BasicAuth "foo-realm" User :> PrivateAPI

toBasicAuthData :: User -> BasicAuthData
toBasicAuthData user = ... 

-- assuming `User` has an `Arbitrary` instance
let generator = toBasicAuthData :>: arbitrary :>: ("basicAuth", 1)

The information will be encoded as an Authorization header.

Supported tools

The following benchmarking tools are supported :

If you'd like your favorite tool to be supported, don't hesitate to tell me so in an issue, or better yet submit a PR.

Next steps