Add support for closure based enrichments

Sources/Segment/Plugins.swift

@@ -65,6 +65,22 @@ public protocol VersionedPlugin {
 // For internal platform-specific bits
 internal protocol PlatformPlugin: Plugin { }
 
+public typealias EnrichmentClosure = (_ event: RawEvent?) -> RawEvent?
+public class ClosureEnrichment: Plugin {
+    public var type: PluginType = .enrichment
+    public var analytics: Analytics? = nil
+
+    internal let closure: EnrichmentClosure
+
+    init(closure: @escaping EnrichmentClosure) {
+        self.closure = closure
+    }
+
+    public func execute<T: RawEvent>(event: T?) -> T? {
+        return closure(event) as? T
+    }
+}
+
 
 // MARK: - Plugin instance helpers
 extension Plugin {
@@ -98,7 +114,7 @@ extension DestinationPlugin {
      Adds a new plugin to the currently loaded set.
 
      - Parameter plugin: The plugin to be added.
-     - Returns: Returns the name of the supplied plugin.
+     - Returns: Returns the supplied plugin.
 
      */
     @discardableResult
@@ -110,6 +126,23 @@ extension DestinationPlugin {
         return plugin
     }
 
+    /**
+     Adds a new enrichment to the currently loaded set of plugins.
+
+     - Parameter enrichment: The enrichment closure to be added.
+     - Returns: Returns the the generated plugin.
+
+     */
+    @discardableResult
+    public func add(enrichment: @escaping EnrichmentClosure) -> Plugin {
+        let plugin = ClosureEnrichment(closure: enrichment)
+        if let analytics = self.analytics {
+            plugin.configure(analytics: analytics)
+        }
+        timeline.add(plugin: plugin)
+        return plugin
+    }
+
     /**
      Removes and unloads plugins with a matching name from the system.
 
@@ -147,6 +180,21 @@ extension Analytics {
         return plugin
     }
 
+    /**
+     Adds a new enrichment to the currently loaded set of plugins.
+
+     - Parameter enrichment: The enrichment closure to be added.
+     - Returns: Returns the the generated plugin.
+
+     */
+    @discardableResult
+    public func add(enrichment: @escaping EnrichmentClosure) -> Plugin {
+        let plugin = ClosureEnrichment(closure: enrichment)
+        plugin.configure(analytics: self)
+        timeline.add(plugin: plugin)
+        return plugin
+    }
+
     /**
      Removes and unloads plugins with a matching name from the system.
 

Tests/Segment-Tests/Analytics_Tests.swift

@@ -566,4 +566,43 @@ final class Analytics_Tests: XCTestCase {
 
         RunLoop.main.run(until: Date(timeIntervalSinceNow: 5))
     }
+
+    func testEnrichment() {
+        var sourceHit: Bool = false
+        let sourceEnrichment: EnrichmentClosure = { event in
+            print("source enrichment applied")
+            sourceHit = true
+            return event
+        }
+
+        var destHit: Bool = true
+        let destEnrichment: EnrichmentClosure = { event in
+            print("destination enrichment applied")
+            destHit = true
+            return event
+        }
+
+        let config = Configuration(writeKey: "testEnrichments")
+        let analytics = Analytics(configuration: config)
+        analytics.storage.hardReset(doYouKnowHowToUseThis: true)
+        let outputReader = OutputReaderPlugin()
+        analytics.add(plugin: outputReader)
+
+        analytics.add(enrichment: sourceEnrichment)
+
+        let segment = analytics.find(pluginType: SegmentDestination.self)
+        segment?.add(enrichment: destEnrichment)
+
+        waitUntilStarted(analytics: analytics)
+
+        analytics.track(name: "something")
+
+        analytics.flush()
+
+        RunLoop.main.run(until: Date(timeIntervalSinceNow: 5))
+
+        XCTAssertTrue(sourceHit)
+        XCTAssertTrue(destHit)
+
+    }
 }