fix(logs): implement SwiftLog event handlers

Package.swift

@@ -431,6 +431,14 @@ let package = Package(
                 .product(name: "SystemPackage", package: "swift-system"),
             ]
         ),
+        .testTarget(
+            name: "ContainerLogTests",
+            dependencies: [
+                .product(name: "Logging", package: "swift-log"),
+                .product(name: "SystemPackage", package: "swift-system"),
+                "ContainerLog",
+            ]
+        ),
         .target(
             name: "ContainerPersistence",
             dependencies: [

Sources/ContainerLog/FileLogHandler.swift

@@ -60,6 +60,14 @@ public struct FileLogHandler: LogHandler {
         self.fileHandle.seekToEndOfFile()
     }
 
+    public func log(event: LogEvent) {
+        self.emit(
+            level: event.level,
+            message: event.message,
+            metadata: event.metadata
+        )
+    }
+
     public func log(
         level: Logger.Level,
         message: Logger.Message,
@@ -68,6 +76,18 @@ public struct FileLogHandler: LogHandler {
         file: String,
         function: String,
         line: UInt
+    ) {
+        self.emit(
+            level: level,
+            message: message,
+            metadata: metadata
+        )
+    }
+
+    private func emit(
+        level: Logger.Level,
+        message: Logger.Message,
+        metadata: Logger.Metadata?
     ) {
         let timestampFormatter: ISO8601DateFormatter = {
             let formatter = ISO8601DateFormatter()

Sources/ContainerLog/OSLogHandler.swift

@@ -47,6 +47,14 @@ public struct OSLogHandler: LogHandler {
 }
 
 extension OSLogHandler {
+    public func log(event: LogEvent) {
+        self.emit(
+            level: event.level,
+            message: event.message,
+            metadata: event.metadata
+        )
+    }
+
     public func log(
         level: Logger.Level,
         message: Logger.Message,
@@ -55,6 +63,18 @@ extension OSLogHandler {
         file: String,
         function: String,
         line: UInt
+    ) {
+        self.emit(
+            level: level,
+            message: message,
+            metadata: metadata
+        )
+    }
+
+    private func emit(
+        level: Logger.Level,
+        message: Logger.Message,
+        metadata: Logger.Metadata?
     ) {
         var formattedMetadata = self.formattedMetadata
         if let metadataOverride = metadata, !metadataOverride.isEmpty {

Sources/ContainerLog/StderrLogHandler.swift

@@ -34,6 +34,14 @@ public struct StderrLogHandler: LogHandler {
 
     public init() {}
 
+    public func log(event: LogEvent) {
+        self.emit(
+            level: event.level,
+            message: event.message,
+            metadata: event.metadata
+        )
+    }
+
     public func log(
         level: Logger.Level,
         message: Logger.Message,
@@ -42,6 +50,18 @@ public struct StderrLogHandler: LogHandler {
         file: String,
         function: String,
         line: UInt
+    ) {
+        self.emit(
+            level: level,
+            message: message,
+            metadata: metadata
+        )
+    }
+
+    private func emit(
+        level: Logger.Level,
+        message: Logger.Message,
+        metadata: Logger.Metadata?
     ) {
         let data: Data
         switch logLevel {

Tests/ContainerLogTests/ContainerLogHandlerTests.swift

@@ -0,0 +1,61 @@
+//===----------------------------------------------------------------------===//
+// Copyright 2026 Apple Inc. and the container project authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//   https://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//===----------------------------------------------------------------------===//
+
+import Foundation
+import Logging
+import SystemPackage
+import Testing
+
+@testable import ContainerLog
+
+@Suite
+struct ContainerLogHandlerTests {
+    @Test
+    func handlersAcceptPrimaryLogEvent() throws {
+        let directory = FileManager.default.temporaryDirectory
+            .appendingPathComponent("container-log-tests-\(UUID().uuidString)", isDirectory: true)
+        defer { try? FileManager.default.removeItem(at: directory) }
+
+        let url = directory.appendingPathComponent("events.log")
+        var fileHandler = try FileLogHandler(
+            label: "container-log-tests",
+            category: "events",
+            path: FilePath(url.path)
+        )
+        fileHandler.metadata = ["scope": "handler"]
+
+        let event = LogEvent(
+            level: .warning,
+            message: "primary event",
+            metadata: ["scope": "event", "request": "123"],
+            source: "ContainerLogTests",
+            file: #fileID,
+            function: #function,
+            line: #line
+        )
+
+        fileHandler.log(event: event)
+        StderrLogHandler().log(event: event)
+        OSLogHandler(label: "container-log-tests", category: "events").log(event: event)
+
+        let output = try String(contentsOf: url, encoding: .utf8)
+        #expect(output.contains("[warning] container-log-tests events"))
+        #expect(output.contains("primary event"))
+        #expect(output.contains("event"))
+        #expect(output.contains("123"))
+        #expect(!output.contains("handler"))
+    }
+}