Latest 1.0.0
License MIT
Platforms ios 9.0, requires ARC

A developer friendly framework for tracking, storing, and flushing events in iOS apps.

First define an Event to track

class UserImpressionEvent : NSObject, Event {

  let user: String

  init(user: String) {
    self.user = user

  // All objects that conform to Event must implement toString()
  func toString() -> String {
    return "impression:" + self.user

  // All objects that conform to Event must also conform to NSCoding
  func encode(with aCoder: NSCoder) {
    aCoder.encode(self.user, forKey: "user")

  required convenience init?(coder aDecoder: NSCoder) {
    guard let user = aDecoder.decodeObject(forKey: "user") as? String else { return nil }
    self.init(user: user)

Then create an EventTracker

// Create a file store to temporarily cache events before flushing
let store = FileEventStore()

// Create a simple flusher that will just log events to the console
// Could also create a flusher that uploads events for processing
let flusher = LogFlusher()

// Set the flush policy to flush after 100 events are tracked
let flushPolicy = EventFlushPolicy.EventLimit(limit: 100)

// Create the EventTracker
let configuration = EventTrackerConfiguration(store: store, flusher: flusher, flushPolicy: flushPolicy)
let tracker = EventTracker(configuration: configuration)

Then track

override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
  let cell = tableView.dequeueReusableCell(withIdentifier: "cell", for: indexPath)
  let user = self.users[indexPath.row]

  // Track that the user was shown
  tracker.trackEvent(event: UserImpressionEvent(user: user))
  return cell


EventTracker was designed to give developers complete control over how events are defined, stored, and flushed.


public protocol Event: class, NSCoding {
  func toString() -> String

All tracked events must conform to the Event protocol. Event extends NSCoding to ensure that all events can be serialized/deserialized for storage.


public protocol EventStore {
  func storeEvent(event: Event, completion: @escaping EventStoreCompletion)
  func allEvents(completion: @escaping EventStoreReturnCompletion)
  func deleteEvents(completion: @escaping EventStoreCompletion)

Classes that conform to EventStore are used to temporarily cache tracked events before uploading them from the client. Events can be stored in whatever manner best suits the developer. The EventTracker currently comes with two concrete EventStore classes, InMemeoryEventStore and FileEventStore, which store events in memory and files, respectively.


public protocol EventFlusher {
  func flushEvents(events: [Event], completion: @escaping EventFlushCompletion)

Class that conform to EventFlusher are responsible for emitting tracked events. EventFlushers can be used to log all recorded events, write them to a file, or most likely, upload all tracked events to a remote server.

In addition, developers can define when to flush using an EventFlushPolicy. Possible options are:

  • Manually call EventTracker.flushEvents()
  • Flush after a set amount of events have been recorded
  • Flush after a set amount of time


public class EventTracker {
  public func trackEvent(event: Event, completion: EventTrackerCompletion?)
  public func flushEvents(completion: EventTrackerCompletion?)
  public func clearEvents(completion: EventTrackerCompletion?)

The EventTracker is used to drive storage and flushing of events. It is completely thread safe and ensures all operations are done serially.


EventTracker requires Swift 3 and XCode 10


If you are unfamiliar with CocoaPods please read these guides before proceeding:

Add the following to your Podfile:


pod 'EventTracker', '~>0.1.1'


To install SQLite.swift as an Xcode sub-project:

  1. Drag the EventTracker.xcodeproj file into your own project.
    ([Submodule][], clone, or [download][] the project first.)

  2. In your target’s General tab, click the + button under Linked
    Frameworks and Libraries

  3. Select the appropriate EventTracker.framework for your platform.

Contact Info

Email: [email protected]

Twitter: @billy_the_kid


If you want to add functionality please open an issue and/or create a pull request.


EventTracker is available under the MIT license. See the LICENSE file for more information.

Latest podspec

    "name": "EventTracker",
    "version": "1.0.0",
    "summary": "Framework to log events",
    "homepage": "",
    "license": {
        "type": "MIT",
        "file": "LICENSE"
    "authors": {
        "Billy Irwin": "[email protected]"
    "social_media_url": "",
    "platforms": {
        "ios": "9.0"
    "requires_arc": true,
    "source": {
        "git": "",
        "tag": "v1.0.0",
        "submodules": true
    "source_files": "EventTracker/**/*.{h,swift}",
    "pushed_with_swift_version": "3.0"

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