Add method to support flushing log message

CHANGELOG.md

@@ -2,6 +2,7 @@
 
 - Add different error handling behaviors for disk writing errors. [#75](https://github.com/sushichop/Puppy/pull/75)
 - Make `logMessage` method public. [#77](https://github.com/sushichop/Puppy/pull/77)
+- Add method to support flushing log message. [#79](https://github.com/sushichop/Puppy/pull/79)
 
 ## [0.6.0](https://github.com/sushichop/Puppy/releases/tag/0.6.0) (2022-11-29)
 

Sources/Puppy/Loggerable.swift

@@ -9,6 +9,8 @@ public protocol Loggerable: Sendable {
     func pickMessage(_ level: LogLevel, message: String, tag: String, function: String, file: String, line: UInt, swiftLogInfo: [String: String], label: String, date: Date, threadID: UInt64)
 
     func log(_ level: LogLevel, string: String)
+
+    func flush(completion: @escaping @Sendable () -> Void)
 }
 
 extension Loggerable {
@@ -24,4 +26,10 @@ extension Loggerable {
             log(level, string: formattedMessage)
         }
     }
+
+    public func flush(completion: @escaping @Sendable () -> Void) {
+        queue.async {
+            completion()
+        }
+    }
 }

Sources/Puppy/Puppy.swift

@@ -1,3 +1,4 @@
+@preconcurrency import Dispatch
 import Foundation
 #if canImport(Darwin)
 #elseif os(Linux)
@@ -78,6 +79,29 @@ public struct Puppy: Sendable {
         }
     }
 
+    public func flush(_ timeout: Double = 3.0) -> WaitingResult {
+        let date = Date()
+        let threadID = currentThreadID()
+
+        let group = DispatchGroup()
+        for logger in loggers {
+            group.enter()
+            logger.flush {
+                puppyDebug("before group.leave, date: \(date), threadID: \(threadID)")
+                group.leave()
+                puppyDebug("after group.leave, date: \(date), threadID: \(threadID)")
+            }
+        }
+
+        let result = group.wait(timeout: .now() + .seconds(Int(timeout)))
+        switch result {
+        case .success:
+            return .success
+        case .timedOut:
+            return .timeout
+        }
+    }
+
     @usableFromInline
     func currentThreadID() -> UInt64 {
         var threadID: UInt64 = 0
@@ -93,6 +117,11 @@ public struct Puppy: Sendable {
     }
 }
 
+public enum WaitingResult {
+    case success
+    case timeout
+}
+
 @inlinable
 func puppyDebug(_ items: Any) {
     #if DEBUG && PUPPY_DEBUG

Tests/PuppyTests/PuppyTests.swift

@@ -56,4 +56,23 @@ final class PuppyTests: XCTestCase {
               "42".colorize(.colorNumber(42))
         )
     }
+
+    func testFlush() {
+        let consoleLogger: ConsoleLogger = .init("com.example.yourapp.consolelogger.wait", logLevel: .info)
+        var log = Puppy()
+        log.add(consoleLogger)
+
+        log.info("INFO message for testFlush")
+        log.notice("NOTICE message for testFlush")
+        XCTAssertEqual(log.flush(3.0), .success)
+
+        log.warning("WARNING message for testFlush")
+        log.error("ERROR message for testFlush")
+        consoleLogger.flush {
+            Thread.sleep(forTimeInterval: 1.0)
+        }
+        XCTAssertEqual(log.flush(0.5), .timeout)
+
+        log.removeAll()
+    }
 }