Merge pull request #166 from WeTransfer/feature/tmob-5115-trimming

[TMOB 5115] Trim using lines instead of bytes

DiagnosticsTests/Reporters/LogsReporterTests.swift

@@ -62,5 +62,4 @@ final class LogsReporterTests: XCTestCase {
         let secondIndex = try XCTUnwrap(diagnostics.range(of: "second")?.lowerBound)
         XCTAssertTrue(firstIndex > secondIndex)
     }
-
 }

DiagnosticsTests/Reporters/LogsTrimmerTests.swift

@@ -0,0 +1,60 @@
+//
+//  LogsTrimmerTests.swift
+//  
+//
+//  Created by Antoine van der Lee on 01/03/2024.
+//
+//  swiftlint:disable line_length
+
+@testable import Diagnostics
+import XCTest
+
+final class LogsTrimmerTests: XCTestCase {
+
+    /// It should trim the oldest line and skip session headers.
+    func testTrimmingSessionsSingleLine() {
+        let expectedOutput = """
+        <summary><div class="session-header"><p><span>Date: </span>2024-02-20 10:33:47</p><p><span>System: </span>iOS 16.3</p><p><span>Locale: </span>en-GB</p><p><span>Version: </span>6.2.8 (17000)</p></div></summary>
+        <p class="system"><span class="log-date">2024-02-20 10:33:47</span><span class="log-separator"> | </span><span class="log-message">SYSTEM: 2024-02-20 10:33:47.086 Collect[32949:1669571] Reachability Flag Status: -R t------ reachabilityStatusForFlags</span></p>
+        """
+
+        var input = expectedOutput
+        input += """
+        <p class="system"><span class="log-date">2024-02-20 10:33:47</span><span class="log-separator"> | </span><span class="log-message">SYSTEM: 2024-02-20 10:33:47.101 Collect[32949:1669571] [Firebase/Crashlytics] Version 8.15.0</span></p>
+        """
+
+        var inputData = Data(input.utf8)
+        let trimmer = LogsTrimmer(
+            numberOfLinesToTrim: 1
+        )
+
+        trimmer.trim(data: &inputData)
+
+        let outputString = String(data: inputData, encoding: .utf8)
+        XCTAssertEqual(outputString, expectedOutput)
+    }
+
+    /// It should trim the oldest lines and skip session headers.
+    func testTrimmingSessionsMultipleLines() {
+        let expectedOutput = """
+        <summary><div class="session-header"><p><span>Date: </span>2024-02-20 10:33:47</p><p><span>System: </span>iOS 16.3</p><p><span>Locale: </span>en-GB</p><p><span>Version: </span>6.2.8 (17000)</p></div></summary>
+        """
+
+        var input = expectedOutput
+        input += """
+        <p class="system"><span class="log-date">2024-02-20 10:33:47</span><span class="log-separator"> | </span><span class="log-message">SYSTEM: 2024-02-20 10:33:47.086 Collect[32949:1669571] Reachability Flag Status: -R t------ reachabilityStatusForFlags</span></p>
+        <p class="system"><span class="log-date">2024-02-20 10:33:47</span><span class="log-separator"> | </span><span class="log-message">SYSTEM: 2024-02-20 10:33:47.101 Collect[32949:1669571] [Firebase/Crashlytics] Version 8.15.0</span></p>
+        """
+
+        var inputData = Data(input.utf8)
+        let trimmer = LogsTrimmer(
+            numberOfLinesToTrim: 10
+        )
+
+        trimmer.trim(data: &inputData)
+
+        let outputString = String(data: inputData, encoding: .utf8)
+        XCTAssertEqual(outputString, expectedOutput)
+    }
+}
+//  swiftlint:enable line_length

Sources/Logging/DiagnosticsLogger.swift

@@ -223,19 +223,14 @@ extension DiagnosticsLogger {
 
         guard
             var data = try? Data(contentsOf: self.logFileLocation, options: .mappedIfSafe),
-            !data.isEmpty,
-            let newline = "\n".data(using: .utf8) else {
-                return assertionFailure("Trimming the current log file failed")
+            !data.isEmpty else {
+            return assertionFailure("Trimming the current log file failed")
         }
 
-        var position: Int = 0
-        while (logSize - Int64(position)) > (maximumSize - trimSize) {
-            guard let range = data.firstRange(of: newline, in: position ..< data.count) else { break }
-            position = range.startIndex.advanced(by: 1)
-        }
+        let trimmer = LogsTrimmer(numberOfLinesToTrim: 10)
+        trimmer.trim(data: &data)
 
-        logSize -= Int64(position)
-        data.removeSubrange(0 ..< position)
+        logSize = Int64(data.count)
 
         guard (try? data.write(to: logFileLocation, options: .atomic)) != nil else {
             return assertionFailure("Could not write trimmed log to target file location: \(logFileLocation)")

Sources/Logging/LogsTrimmer.swift

@@ -0,0 +1,49 @@
+//
+//  LogsTrimmer.swift
+//
+//
+//  Created by Antoine van der Lee on 01/03/2024.
+//
+
+import Foundation
+
+struct LogsTrimmer {
+    let numberOfLinesToTrim: Int
+
+    func trim(data: inout Data) {
+        guard let logs = String(data: data, encoding: .utf8) else {
+            return
+        }
+
+        // Define the regular expression pattern
+        let pattern = "<p class=\"system\"><span class=\"log-date\">(.*?)</span></p>"
+
+        // Create a regular expression object
+        guard let regex = try? NSRegularExpression(pattern: pattern) else {
+            return
+        }
+
+        // Find all matches in the input string
+        let matches = regex
+            .matches(
+                in: logs,
+                range: NSRange(location: 0, length: logs.utf16.count)
+            )
+            .suffix(numberOfLinesToTrim)
+
+        guard let firstMatch = matches.first, let lastMatch = matches.last else {
+            return
+        }
+
+        let range = NSRange(
+            location: firstMatch.range.location,
+            length: lastMatch.range.upperBound - firstMatch.range.location
+        )
+        guard let range = Range(range, in: logs) else {
+            return
+        }
+
+        let trimmedLogs = logs.replacingCharacters(in: range, with: "")
+        data = Data(trimmedLogs.utf8)
+    }
+}