Tumbleweed

Logs detailed metrics about URLSession tasks to the console, such as DNS lookup durations, request and response times and more. Tumbleweed works by parsing the metrics collected by the URLSessionTaskMetrics introduced in iOS 10.0.

Example output

Task ID: 1 lifetime: 594.9ms redirects: 0
GET https://github.com/ -> 200 text/html, through network-load
protocol: http/1.1 proxy: false reusedconn: false
domain lookup     |#                                                                               |   3.0ms
connect           |###############################################                                 | 330.0ms
secure connection |               ################################                                 | 223.0ms
request           |                                               #                                |   0.2ms
server            |                                               ###################              | 130.9ms
response          |                                                                 ###############| 105.8ms
                                                                                             total   575.0ms

A few notes on the data:

• Task lifetime is the time of the URLSessionTask creation to the response is delivered.
• The "through" key on the second line will tell you whether the response was fetched from cache, delivered by server push or by network load.
• "server" is how long the server spent processing the request

Note that not all responses will deliver complete metrics, such as local cache fetches and other non-network loaded responses.

Usage

In your URLSessionDelegate:

func urlSession(_ session: URLSession, task: URLSessionTask, didFinishCollecting metrics: URLSessionTaskMetrics) {
    let stats = SessionMetrics(source: metrics, task: task)
    let renderer = ConsoleRenderer()
    renderer.render(with: stats)
}

As a convenience Tumbleweed provides the SessionMetricsLogger which can be set as the URLSessionDelegate on URLSession, if you're not using any of the other delegates.

let sessionDelegate: URLSessionDelegate?
if #available(iOS 10.0, *) {
sessionDelegate = SessionMetricsLogger()
} else {
    sessionDelegate = nil
}
let session = URLSession(configuration: .default, delegate: sessionDelegate, delegateQueue: nil)

Installation

Tumbleweed is available as a CocoaPod (pod 'Tumbleweed') and the Swift Package Manager. Framework installation is also available by dragging the Tumbleweed.xcodeproj into your project or via Carthage.

Tumbleweed has no dependencies outside of Foundation.

License

See the LICENSE file