feat(telemetry): implement real-time disk I/O throughput and IOPS provider (fixes #10)

Sources/Bridging/MacMonitor-Bridging-Header.h

@@ -21,5 +21,6 @@
 #import "MMPowerTelemetryProvider.h"
 #import "MMKernelTelemetryProvider.h"
 #import "MMLoadAverageProvider.h"
+#import "MMDiskIOProvider.h"
 
 #endif /* MacMonitor_Bridging_Header_h */

Sources/Telemetry/Storage/MMDiskIOProvider.h

@@ -0,0 +1,29 @@
+#ifndef MMDiskIOProvider_h
+#define MMDiskIOProvider_h
+
+#import <Foundation/Foundation.h>
+#import "MMTelemetryProvider.h"
+
+NS_ASSUME_NONNULL_BEGIN
+
+/**
+ * MMDiskIOProvider
+ * Samples real-time storage disk transfer rates (read/write bytes per second)
+ * and transaction rates (read/write IOPS) across internal and external block storage devices.
+ */
+@interface MMDiskIOProvider : NSObject <MMTelemetryProvider>
+
+- (instancetype)init;
+
+/**
+ * Pure calculator method for deterministic unit testing.
+ */
++ (NSDictionary<NSString *, id> *)calculateDiskIOMetricsWithCurrentSnapshots:(NSDictionary<NSString *, NSDictionary<NSString *, NSNumber *> *> *)current
+                                                           previousSnapshots:(nullable NSDictionary<NSString *, NSDictionary<NSString *, NSNumber *> *> *)previous
+                                                                   timeDelta:(NSTimeInterval)timeDelta;
+
+@end
+
+NS_ASSUME_NONNULL_END
+
+#endif /* MMDiskIOProvider_h */

Sources/Telemetry/Storage/MMDiskIOProvider.m

@@ -0,0 +1,170 @@
+#import "MMDiskIOProvider.h"
+#import <IOKit/IOKitLib.h>
+#import <IOKit/storage/IOBlockStorageDriver.h>
+#import <mach/mach_time.h>
+#import <os/lock.h>
+
+@interface MMDiskIOProvider () {
+    os_unfair_lock _lock;
+    NSDictionary<NSString *, NSDictionary<NSString *, NSNumber *> *> *_previousSnapshots;
+    uint64_t _previousTimestamp;
+    mach_timebase_info_data_t _timebase;
+}
+@end
+
+@implementation MMDiskIOProvider
+
+- (instancetype)init {
+    self = [super init];
+    if (self) {
+        _lock = OS_UNFAIR_LOCK_INIT;
+        _previousSnapshots = nil;
+        _previousTimestamp = 0;
+        mach_timebase_info(&_timebase);
+    }
+    return self;
+}
+
+- (MMTelemetryDomain)domain {
+    return MMTelemetryDomainStorage;
+}
+
+- (NSString *)providerIdentifier {
+    return @"com.i3omb.macmonitor.telemetry.storage.io";
+}
+
+- (BOOL)isAvailable {
+    return YES;
+}
+
++ (NSDictionary<NSString *, id> *)calculateDiskIOMetricsWithCurrentSnapshots:(NSDictionary<NSString *, NSDictionary<NSString *, NSNumber *> *> *)current
+                                                           previousSnapshots:(nullable NSDictionary<NSString *, NSDictionary<NSString *, NSNumber *> *> *)previous
+                                                                   timeDelta:(NSTimeInterval)timeDelta {
+    double totalReadBps = 0.0;
+    double totalWriteBps = 0.0;
+    double totalReadIOPS = 0.0;
+    double totalWriteIOPS = 0.0;
+    
+    NSMutableArray<NSDictionary<NSString *, id> *> *disks = [NSMutableArray arrayWithCapacity:current.count];
+    NSArray<NSString *> *sortedBsdNames = [current.allKeys sortedArrayUsingSelector:@selector(compare:)];
+    
+    for (NSString *bsdName in sortedBsdNames) {
+        NSDictionary<NSString *, NSNumber *> *curr = current[bsdName];
+        NSDictionary<NSString *, NSNumber *> *prev = previous ? previous[bsdName] : nil;
+        
+        uint64_t currReadBytes = [curr[@"readBytes"] unsignedLongLongValue];
+        uint64_t currWriteBytes = [curr[@"writeBytes"] unsignedLongLongValue];
+        uint64_t currReadOps = [curr[@"readOps"] unsignedLongLongValue];
+        uint64_t currWriteOps = [curr[@"writeOps"] unsignedLongLongValue];
+        
+        uint64_t prevReadBytes = prev ? [prev[@"readBytes"] unsignedLongLongValue] : currReadBytes;
+        uint64_t prevWriteBytes = prev ? [prev[@"writeBytes"] unsignedLongLongValue] : currWriteBytes;
+        uint64_t prevReadOps = prev ? [prev[@"readOps"] unsignedLongLongValue] : currReadOps;
+        uint64_t prevWriteOps = prev ? [prev[@"writeOps"] unsignedLongLongValue] : currWriteOps;
+        
+        double deltaReadBytes = (currReadBytes >= prevReadBytes) ? (double)(currReadBytes - prevReadBytes) : 0.0;
+        double deltaWriteBytes = (currWriteBytes >= prevWriteBytes) ? (double)(currWriteBytes - prevWriteBytes) : 0.0;
+        double deltaReadOps = (currReadOps >= prevReadOps) ? (double)(currReadOps - prevReadOps) : 0.0;
+        double deltaWriteOps = (currWriteOps >= prevWriteOps) ? (double)(currWriteOps - prevWriteOps) : 0.0;
+        
+        double readBps = (timeDelta > 0.0001) ? (deltaReadBytes / timeDelta) : 0.0;
+        double writeBps = (timeDelta > 0.0001) ? (deltaWriteBytes / timeDelta) : 0.0;
+        double readIOPS = (timeDelta > 0.0001) ? (deltaReadOps / timeDelta) : 0.0;
+        double writeIOPS = (timeDelta > 0.0001) ? (deltaWriteOps / timeDelta) : 0.0;
+        
+        totalReadBps += readBps;
+        totalWriteBps += writeBps;
+        totalReadIOPS += readIOPS;
+        totalWriteIOPS += writeIOPS;
+        
+        [disks addObject:@{
+            @"bsdName": bsdName,
+            @"readBytesPerSec": @(readBps),
+            @"writeBytesPerSec": @(writeBps),
+            @"readIOPS": @(readIOPS),
+            @"writeIOPS": @(writeIOPS),
+            @"cumulativeReadBytes": @(currReadBytes),
+            @"cumulativeWriteBytes": @(currWriteBytes),
+            @"cumulativeReadOps": @(currReadOps),
+            @"cumulativeWriteOps": @(currWriteOps)
+        }];
+    }
+    
+    return @{
+        @"disks": disks,
+        @"totalReadBytesPerSec": @(totalReadBps),
+        @"totalWriteBytesPerSec": @(totalWriteBps),
+        @"totalReadIOPS": @(totalReadIOPS),
+        @"totalWriteIOPS": @(totalWriteIOPS),
+        @"timeDelta": @(timeDelta)
+    };
+}
+
+- (nullable NSDictionary<NSString *, id> *)sampleTelemetryWithError:(NSError **)error {
+    uint64_t now = mach_absolute_time();
+    
+    NSMutableDictionary<NSString *, NSDictionary<NSString *, NSNumber *> *> *currentSnapshots = [NSMutableDictionary dictionary];
+    
+    CFMutableDictionaryRef matching = IOServiceMatching(kIOBlockStorageDriverClass);
+    io_iterator_t iterator = IO_OBJECT_NULL;
+    if (IOServiceGetMatchingServices(kIOMainPortDefault, matching, &iterator) == KERN_SUCCESS && iterator != IO_OBJECT_NULL) {
+        io_registry_entry_t entry;
+        while ((entry = IOIteratorNext(iterator)) != IO_OBJECT_NULL) {
+            NSString *bsdName = nil;
+            io_iterator_t childIterator;
+            if (IORegistryEntryGetChildIterator(entry, kIOServicePlane, &childIterator) == KERN_SUCCESS) {
+                io_registry_entry_t child;
+                while ((child = IOIteratorNext(childIterator)) != IO_OBJECT_NULL) {
+                    CFTypeRef nameRef = IORegistryEntryCreateCFProperty(child, CFSTR("BSD Name"), kCFAllocatorDefault, 0);
+                    if (nameRef) {
+                        bsdName = CFBridgingRelease(nameRef);
+                        IOObjectRelease(child);
+                        break;
+                    }
+                    IOObjectRelease(child);
+                }
+                IOObjectRelease(childIterator);
+            }
+            
+            if (bsdName) {
+                CFTypeRef statsRef = IORegistryEntryCreateCFProperty(entry, CFSTR("Statistics"), kCFAllocatorDefault, 0);
+                if (statsRef) {
+                    NSDictionary *stats = CFBridgingRelease(statsRef);
+                    NSNumber *readBytes = stats[@"Bytes (Read)"] ?: @0;
+                    NSNumber *writeBytes = stats[@"Bytes (Write)"] ?: @0;
+                    NSNumber *readOps = stats[@"Operations (Read)"] ?: @0;
+                    NSNumber *writeOps = stats[@"Operations (Write)"] ?: @0;
+                    
+                    currentSnapshots[bsdName] = @{
+                        @"readBytes": readBytes,
+                        @"writeBytes": writeBytes,
+                        @"readOps": readOps,
+                        @"writeOps": writeOps
+                    };
+                }
+            }
+            IOObjectRelease(entry);
+        }
+        IOObjectRelease(iterator);
+    }
+    
+    os_unfair_lock_lock(&_lock);
+    NSDictionary<NSString *, NSDictionary<NSString *, NSNumber *> *> *prev = _previousSnapshots;
+    uint64_t prevTime = _previousTimestamp;
+    
+    _previousSnapshots = currentSnapshots;
+    _previousTimestamp = now;
+    os_unfair_lock_unlock(&_lock);
+    
+    NSTimeInterval timeDelta = 1.0;
+    if (prevTime > 0) {
+        uint64_t elapsed = now - prevTime;
+        timeDelta = (double)elapsed * _timebase.numer / _timebase.denom / 1e9;
+    }
+    
+    return [MMDiskIOProvider calculateDiskIOMetricsWithCurrentSnapshots:currentSnapshots
+                                                      previousSnapshots:prev
+                                                              timeDelta:timeDelta];
+}
+
+@end

Tests/MMDiskIOTests.swift

@@ -0,0 +1,73 @@
+import XCTest
+@testable import MacMonitor
+
+final class MMDiskIOTests: XCTestCase {
+    
+    func testDiskIOMetricsCalculation() {
+        let prev: [String: [String: NSNumber]] = [
+            "disk0": [
+                "readBytes": NSNumber(value: 10_000_000),
+                "writeBytes": NSNumber(value: 5_000_000),
+                "readOps": NSNumber(value: 1_000),
+                "writeOps": NSNumber(value: 500)
+            ],
+            "disk1": [
+                "readBytes": NSNumber(value: 2_000_000),
+                "writeBytes": NSNumber(value: 1_000_000),
+                "readOps": NSNumber(value: 200),
+                "writeOps": NSNumber(value: 100)
+            ]
+        ]
+        
+        let curr: [String: [String: NSNumber]] = [
+            "disk0": [
+                "readBytes": NSNumber(value: 20_000_000), // delta = 10,000,000 bytes
+                "writeBytes": NSNumber(value: 7_000_000),  // delta = 2,000,000 bytes
+                "readOps": NSNumber(value: 1_200),         // delta = 200 ops
+                "writeOps": NSNumber(value: 600)           // delta = 100 ops
+            ],
+            "disk1": [
+                "readBytes": NSNumber(value: 4_000_000),  // delta = 2,000,000 bytes
+                "writeBytes": NSNumber(value: 1_000_000),  // delta = 0
+                "readOps": NSNumber(value: 250),           // delta = 50 ops
+                "writeOps": NSNumber(value: 100)           // delta = 0 ops
+            ]
+        ]
+        
+        let timeDelta: TimeInterval = 2.0 // 2 seconds
+        
+        let metrics = MMDiskIOProvider.calculateDiskIOMetrics(
+            withCurrentSnapshots: curr,
+            previousSnapshots: prev,
+            timeDelta: timeDelta
+        )
+        
+        let totalReadBps = metrics["totalReadBytesPerSec"] as? Double ?? 0
+        let totalWriteBps = metrics["totalWriteBytesPerSec"] as? Double ?? 0
+        let totalReadIOPS = metrics["totalReadIOPS"] as? Double ?? 0
+        let totalWriteIOPS = metrics["totalWriteIOPS"] as? Double ?? 0
+        let disks = metrics["disks"] as? [[String: Any]] ?? []
+        
+        // (10MB + 2MB) / 2s = 6,000,000 B/s
+        XCTAssertEqual(totalReadBps, 6_000_000.0, accuracy: 1.0)
+        // (2MB + 0) / 2s = 1,000,000 B/s
+        XCTAssertEqual(totalWriteBps, 1_000_000.0, accuracy: 1.0)
+        // (200 + 50) / 2s = 125 IOPS
+        XCTAssertEqual(totalReadIOPS, 125.0, accuracy: 0.1)
+        // (100 + 0) / 2s = 50 IOPS
+        XCTAssertEqual(totalWriteIOPS, 50.0, accuracy: 0.1)
+        XCTAssertEqual(disks.count, 2)
+    }
+    
+    func testLiveDiskIOProvider() throws {
+        let provider = MMDiskIOProvider()
+        XCTAssertEqual(provider.domain, .storage)
+        XCTAssertEqual(provider.providerIdentifier, "com.i3omb.macmonitor.telemetry.storage.io")
+        
+        let sample = try provider.sampleTelemetry()
+        XCTAssertNotNil(sample)
+        XCTAssertNotNil(sample["totalReadBytesPerSec"])
+        XCTAssertNotNil(sample["totalWriteBytesPerSec"])
+        XCTAssertNotNil(sample["disks"])
+    }
+}