Benchmark extension for IBM Swift HeliumLogger

LoggerAPI.swift

//
//  LoggerAPI.swift
//  Collection
//
//  Created by Maxim Veksler on 05/02/2017.
//
//
import Foundation
import LoggerAPI

import Darwin

extension Log {
    // Thanks
    // http://stackoverflow.com/questions/25006235/how-to-benchmark-swift-code-execution
    // https://developer.apple.com/library/content/qa/qa1398/_index.html
    // https://gist.github.com/jstn/d93c86f7bd2b6f22f0bf
    // https://gist.github.com/dsheets/f316b6f7d0edbdedaa4007e2f04471df
    
    private static func duration(_ tick: UInt64, _ tock: UInt64) -> UInt64 {
        var info = mach_timebase_info(numer: 0, denom: 0)
        mach_timebase_info(&info)
        let numer = UInt64(info.numer)
        let denom = UInt64(info.denom)
        return ((tock-tick) * numer) / denom // nanoseconds
    }
    
    private static func log(nanoseconds: UInt64,
                            functionName: String, lineNum: Int, fileName: String) {
        let milliseconds = nanoseconds / 1_000_000
        let seconds = Double(nanoseconds) / 1_000_000_000
        
        Log.info("Operation time: \(milliseconds)ms [\(String(format: "%.2f", seconds)) seconds]",
            functionName: functionName,
            lineNum: lineNum,
            fileName: fileName)
    }
    
    static func benchmark<T>(functionName: String = #function, lineNum: Int = #line, fileName: String = #file,
                          operation: () throws -> T) rethrows -> T {
        let tick = mach_absolute_time()
        let t = try operation()
        let tock = mach_absolute_time()
        
        log(nanoseconds: duration(tick, tock), functionName: functionName, lineNum: lineNum, fileName: fileName)
        
        return t
    }
}

usage.swift

// Hello World
        Log.benchmark {
            print("Hello World")
        }
// [2017-02-05T07:05:03.569+02:00] [INFO] [Scaphold.swift:23 query(graph:variables:)] Operation time: 0ms [0.00 seconds]
// GraphQL
    private static func query(graph: String, variables: String) throws -> JSON {
        return try Log.benchmark {
            let client = try! Client(url: "https://us-west-2.api.scaphold.io")
            let body = "{\"query\": \"\(graph)\", \"variables\": \(variables)}"
            let contentNegotiation = ContentNegotiationMiddleware(mediaTypes: [.json, .urlEncodedForm], mode: .client)
            let response = try! client.post("/graphql/trustme-im-from-the-internet", headers: headers, body: Buffer(Array(body.utf8)), middleware: [contentNegotiation])
            
            guard let description = response.content?.description else {
                Log.error("Did not receive network reply from server")
                throw ParsingError.RuntimeError("Did not receive network reply from server")
            }
            
            let json = try! Jay.jsonFromString(description)
            
            guard json.dictionary?["errors"] == nil else {
                Log.error("Scaphold operation failed \(json)")
                throw ParsingError.RuntimeError("Scaphold operation failed")
            }
            
            guard let data = json.dictionary?["data"] else {
                Log.error("Scaphold operation failed graph:\n\(graph)\nvariables: \(variables)\nresult: \(json)")
                throw ParsingError.RuntimeError("Scaphold operation failed")
            }
            
            Log.debug("Scaphold, for graph:\n\(graph)\nvariables: \(variables)\nsaid: \(json)")
            
            return data
        }
    }
// [2017-02-05T07:05:04.997+02:00] [INFO] [Scaphold.swift:27 query(graph:variables:)] Operation time: 1428ms [1.43 seconds]