| 1 | import Foundation |
| 2 | #if canImport(MetricKit) |
| 3 | import MetricKit |
| 4 | #endif |
| 5 | |
| 6 | // 🤖 MetricKit intake: the OS's own APM. Payloads arrive about once a day |
| 7 | // (metrics: launch-time histograms, hang totals, memory peaks; diagnostics: |
| 8 | // hang call trees — the gold for chasing "little cuts" on devices nobody is |
| 9 | // profiling). Each arrival is filed verbatim as JSON under |
| 10 | // Library/Logs/perf-diagnostics/ plus one compact ledger line, so the |
| 11 | // Settings report carries both the summary and the raw material. Started and |
| 12 | // stopped by Perf.setRecording — no consent, no collection. |
| 13 | #if canImport(MetricKit) |
| 14 | final class MetricKitCollector: NSObject, MXMetricManagerSubscriber { |
| 15 | private var started = false |
| 16 | |
| 17 | func start() { |
| 18 | guard !started else { return } |
| 19 | started = true |
| 20 | MXMetricManager.shared.add(self) |
| 21 | } |
| 22 | |
| 23 | func stop() { |
| 24 | guard started else { return } |
| 25 | started = false |
| 26 | MXMetricManager.shared.remove(self) |
| 27 | } |
| 28 | |
| 29 | func didReceive(_ payloads: [MXMetricPayload]) { |
| 30 | for p in payloads { |
| 31 | file(json: p.jsonRepresentation(), prefix: "metrics") |
| 32 | Perf.record(kind: "metric", name: "metrickit.daily", ms: nil, detail: summarize(p)) |
| 33 | } |
| 34 | } |
| 35 | |
| 36 | func didReceive(_ payloads: [MXDiagnosticPayload]) { |
| 37 | for p in payloads { |
| 38 | file(json: p.jsonRepresentation(), prefix: "diagnostics") |
| 39 | let hangs = p.hangDiagnostics ?? [] |
| 40 | guard !hangs.isEmpty else { continue } |
| 41 | let total = hangs.reduce(0.0) { |
| 42 | $0 + $1.hangDuration.converted(to: .milliseconds).value |
| 43 | } |
| 44 | Perf.record(kind: "diag", name: "metrickit.hangs", ms: total, |
| 45 | detail: "\(hangs.count) \(hangs.count == 1 ? "hang" : "hangs") with call trees") |
| 46 | } |
| 47 | } |
| 48 | |
| 49 | /// "launch avg 812ms · hang 3.2s/day" — enough for the ledger to show |
| 50 | /// trend; the filed payload holds the full histograms. |
| 51 | private func summarize(_ p: MXMetricPayload) -> String { |
| 52 | var parts: [String] = [] |
| 53 | if let avg = Self.histogramAverageMs(p.applicationLaunchMetrics?.histogrammedTimeToFirstDraw) { |
| 54 | parts.append("launch avg \(Int(avg))ms") |
| 55 | } |
| 56 | if let hang = Self.histogramTotalMs(p.applicationResponsivenessMetrics?.histogrammedApplicationHangTime) { |
| 57 | parts.append("hang total \((hang / 1000).formatted(.number.precision(.fractionLength(1))))s") |
| 58 | } |
| 59 | return parts.isEmpty ? "payload filed" : parts.joined(separator: " · ") |
| 60 | } |
| 61 | |
| 62 | // MXHistogram walks: buckets carry (start, end, count); average uses the |
| 63 | // bucket midpoint, total sums midpoint×count — the standard reduction. |
| 64 | private static func histogramAverageMs(_ h: MXHistogram<UnitDuration>?) -> Double? { |
| 65 | var weighted = 0.0, count = 0.0 |
| 66 | forEachBucket(h) { midMs, n in |
| 67 | weighted += midMs * n |
| 68 | count += n |
| 69 | } |
| 70 | return count > 0 ? weighted / count : nil |
| 71 | } |
| 72 | |
| 73 | private static func histogramTotalMs(_ h: MXHistogram<UnitDuration>?) -> Double? { |
| 74 | var total = 0.0, any = false |
| 75 | forEachBucket(h) { midMs, n in |
| 76 | total += midMs * n |
| 77 | any = true |
| 78 | } |
| 79 | return any ? total : nil |
| 80 | } |
| 81 | |
| 82 | private static func forEachBucket(_ h: MXHistogram<UnitDuration>?, |
| 83 | _ body: (_ midMs: Double, _ count: Double) -> Void) { |
| 84 | guard let h else { return } |
| 85 | let e = h.bucketEnumerator |
| 86 | while let b = e.nextObject() as? MXHistogramBucket<UnitDuration> { |
| 87 | let mid = (b.bucketStart.converted(to: .milliseconds).value |
| 88 | + b.bucketEnd.converted(to: .milliseconds).value) / 2 |
| 89 | body(mid, Double(b.bucketCount)) |
| 90 | } |
| 91 | } |
| 92 | |
| 93 | /// One file per arrival, ISO-stamped so a directory sort is |
| 94 | /// chronological; keep the newest 24 (a few weeks of dailies). The stamp |
| 95 | /// alone isn't unique — a batch (first subscribe delivers the accumulated |
| 96 | /// backlog in one call) lands within a second — so a random suffix keeps |
| 97 | /// same-second payloads from overwriting each other. |
| 98 | private func file(json: Data, prefix: String) { |
| 99 | guard Perf.isRecording else { return } |
| 100 | let stamp = ISO8601DateFormatter().string(from: Date()) |
| 101 | let unique = UUID().uuidString.prefix(8) |
| 102 | let url = Perf.diagnosticsDir.appendingPathComponent("\(stamp)-\(prefix)-\(unique).json") |
| 103 | try? json.write(to: url, options: .atomic) |
| 104 | let fm = FileManager.default |
| 105 | guard let names = try? fm.contentsOfDirectory(atPath: Perf.diagnosticsDir.path), |
| 106 | names.count > 24 else { return } |
| 107 | for name in names.sorted().dropLast(24) { |
| 108 | try? fm.removeItem(at: Perf.diagnosticsDir.appendingPathComponent(name)) |
| 109 | } |
| 110 | } |
| 111 | } |
| 112 | #else |
| 113 | final class MetricKitCollector: NSObject { |
| 114 | func start() {} |
| 115 | func stop() {} |
| 116 | } |
| 117 | #endif |
| 118 | |
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