Exporting Unified Logging Data (SwiftUI)

OSLogStore reads back the log entries your app wrote with Logger. Pair it with a share sheet, and users can send their logs to you from a settings screen, without a cable or the Console app.

Fetch Entries With OSLogStore

Open the store scoped to the current process, pick a start position, then fetch and filter. Filter on your own subsystem, or you also get system noise from the process.

import OSLog

@MainActor final class LogStore: ObservableObject {
  @Published private(set) var entries: [String] = []

  func export() {
    do {
      let store = try OSLogStore(scope: .currentProcessIdentifier)
      let position = store.position(timeIntervalSinceLatestBoot: 1)
      entries = try store
        .getEntries(at: position)
        .compactMap { $0 as? OSLogEntryLog }
        .filter { $0.subsystem == Bundle.main.bundleIdentifier! }
        .map { "[\($0.date.formatted())] [\($0.category)] \($0.composedMessage)" }
    } catch {
      // log the failure with your own Logger
    }
  }
}

getEntries(at:) returns generic entries, so cast each one to OSLogEntryLog to reach subsystem, category, and composedMessage.

Choose the Time Window With position

The position function has two useful overloads. timeIntervalSinceLatestBoot: starts at the last boot. position(date:) starts at any date, for example the last 24 hours.

let store = try OSLogStore(scope: .currentProcessIdentifier)
let date = Date.now.addingTimeInterval(-24 * 3600)
let position = store.position(date: date)

Share the Logs From Settings

Join the entries into one string and hand it to a wrapped UIActivityViewController. The user picks Mail, Messages, or Files themselves.

struct SettingsView: View {
  @ObservedObject var logs: LogStore
  @State private var exportShown = false

  var body: some View {
    Form {
      Section(header: Text("debug")) {
        Button("exportLogs") {
          logs.export()
          exportShown = true
        }
        .sheet(isPresented: $exportShown) {
          ShareView(items: [logs.entries.joined(separator: "\n")])
        }
      }
    }
  }
}

struct ShareView: UIViewControllerRepresentable {
  let items: [Any]

  func makeUIViewController(context: Context) -> UIActivityViewController {
    UIActivityViewController(activityItems: items, applicationActivities: nil)
  }

  func updateUIViewController(_ vc: UIActivityViewController, context: Context) {}
}

Only persisted levels come back: notice, warning, and critical survive, while trace messages are never stored, so they cannot be exported.