feat: add support for CPU temperature metrics on Apple Silicon

Signed-off-by: Ingmar Stein <490610+IngmarStein@users.noreply.github.com>

collector/thermal_darwin.go

@@ -58,6 +58,7 @@ type thermCollector struct {
 	cpuSchedulerLimit typedDesc
 	cpuAvailableCPU   typedDesc
 	cpuSpeedLimit     typedDesc
+	temperature       typedDesc
 	logger            *slog.Logger
 }
 
@@ -96,6 +97,15 @@ func NewThermCollector(logger *slog.Logger) (Collector, error) {
 			),
 			valueType: prometheus.GaugeValue,
 		},
+		temperature: typedDesc{
+			desc: prometheus.NewDesc(
+				prometheus.BuildFQName(namespace, thermal, "temperature_celsius"),
+				"Temperature of the thermal sensor in Celsius.",
+				[]string{"sensor"},
+				nil,
+			),
+			valueType: prometheus.GaugeValue,
+		},
 		logger: logger,
 	}, nil
 }
@@ -114,7 +124,8 @@ func (c *thermCollector) Update(ch chan<- prometheus.Metric) error {
 	if value, ok := cpuPowerStatus[(string(C.kIOPMCPUPowerLimitProcessorSpeedKey))]; ok {
 		ch <- c.cpuSpeedLimit.mustNewConstMetric(float64(value) / 100.0)
 	}
-	return nil
+
+	return c.updateTemperatures(ch)
 }
 
 func fetchCPUPowerStatus() (map[string]int, error) {

collector/thermal_darwin_amd64.go

@@ -0,0 +1,22 @@
+// Copyright The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+//go:build !notherm && darwin && amd64 && cgo
+
+package collector
+
+import "github.com/prometheus/client_golang/prometheus"
+
+func (c *thermCollector) updateTemperatures(ch chan<- prometheus.Metric) error {
+	return nil
+}

collector/thermal_darwin_arm64.go

@@ -0,0 +1,154 @@
+// Copyright The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+//go:build !notherm && darwin && arm64
+
+package collector
+
+/*
+#cgo LDFLAGS: -framework IOKit -framework CoreFoundation
+#include <CoreFoundation/CoreFoundation.h>
+#include <IOKit/IOKitLib.h>
+#include <stdlib.h>
+
+typedef struct __IOHIDEventSystemClient * IOHIDEventSystemClientRef;
+typedef struct __IOHIDServiceClient * IOHIDServiceClientRef;
+typedef struct __IOHIDEvent * IOHIDEventRef;
+
+#define kIOHIDEventTypeTemperature 15
+#define IOHIDEventFieldBase(type) (type << 16)
+
+int32_t GetIOHIDEventFieldBase(int32_t type) {
+    return IOHIDEventFieldBase(type);
+}
+
+// External functions
+IOHIDEventSystemClientRef IOHIDEventSystemClientCreate(CFAllocatorRef allocator);
+void IOHIDEventSystemClientSetMatching(IOHIDEventSystemClientRef client, CFDictionaryRef match);
+CFArrayRef IOHIDEventSystemClientCopyServices(IOHIDEventSystemClientRef client);
+IOHIDEventRef IOHIDServiceClientCopyEvent(IOHIDServiceClientRef service, int64_t type, int32_t options, int64_t timestamp);
+double IOHIDEventGetFloatValue(IOHIDEventRef event, int32_t field);
+CFTypeRef IOHIDServiceClientCopyProperty(IOHIDServiceClientRef service, CFStringRef key);
+*/
+import "C"
+
+import (
+	"unsafe"
+
+	"github.com/prometheus/client_golang/prometheus"
+	"github.com/prometheus/node_exporter/collector/utils"
+)
+
+const absoluteZeroCelsius = -273.15
+
+func (c *thermCollector) updateTemperatures(ch chan<- prometheus.Metric) error {
+	client := C.IOHIDEventSystemClientCreate(C.kCFAllocatorDefault)
+	if client == nil {
+		return nil
+	}
+	defer C.CFRelease(C.CFTypeRef(unsafe.Pointer(client)))
+
+	page := 0xff00
+	usage := 5
+
+	pageNum := C.CFNumberCreate(C.kCFAllocatorDefault, C.kCFNumberIntType, unsafe.Pointer(&page))
+	defer C.CFRelease(C.CFTypeRef(pageNum))
+	usageNum := C.CFNumberCreate(C.kCFAllocatorDefault, C.kCFNumberIntType, unsafe.Pointer(&usage))
+	defer C.CFRelease(C.CFTypeRef(usageNum))
+
+	keyPage := C.CString("PrimaryUsagePage")
+	defer C.free(unsafe.Pointer(keyPage))
+	keyUsage := C.CString("PrimaryUsage")
+	defer C.free(unsafe.Pointer(keyUsage))
+
+	cfKeyPage := C.CFStringCreateWithCString(C.kCFAllocatorDefault, keyPage, C.kCFStringEncodingUTF8)
+	defer C.CFRelease(C.CFTypeRef(cfKeyPage))
+	cfKeyUsage := C.CFStringCreateWithCString(C.kCFAllocatorDefault, keyUsage, C.kCFStringEncodingUTF8)
+	defer C.CFRelease(C.CFTypeRef(cfKeyUsage))
+
+	keys := []C.CFTypeRef{C.CFTypeRef(cfKeyPage), C.CFTypeRef(cfKeyUsage)}
+	values := []C.CFTypeRef{C.CFTypeRef(pageNum), C.CFTypeRef(usageNum)}
+
+	matching := C.CFDictionaryCreate(C.kCFAllocatorDefault,
+		(*unsafe.Pointer)(unsafe.Pointer(&keys[0])),
+		(*unsafe.Pointer)(unsafe.Pointer(&values[0])),
+		2,
+		&C.kCFTypeDictionaryKeyCallBacks,
+		&C.kCFTypeDictionaryValueCallBacks)
+	defer C.CFRelease(C.CFTypeRef(matching))
+
+	C.IOHIDEventSystemClientSetMatching(client, matching)
+
+	services := C.IOHIDEventSystemClientCopyServices(client)
+	if services == 0 {
+		return nil
+	}
+	defer C.CFRelease(C.CFTypeRef(services))
+
+	count := C.CFArrayGetCount(services)
+
+	prodKey := C.CString("Product")
+	defer C.free(unsafe.Pointer(prodKey))
+	cfProdKey := C.CFStringCreateWithCString(C.kCFAllocatorDefault, prodKey, C.kCFStringEncodingUTF8)
+	defer C.CFRelease(C.CFTypeRef(cfProdKey))
+
+	for i := 0; i < int(count); i++ {
+		service := C.CFArrayGetValueAtIndex(services, C.CFIndex(i))
+
+		event := C.IOHIDServiceClientCopyEvent((C.IOHIDServiceClientRef)(service), C.kIOHIDEventTypeTemperature, 0, 0)
+		if event == nil {
+			continue
+		}
+
+		temp := C.IOHIDEventGetFloatValue(event, C.GetIOHIDEventFieldBase(C.kIOHIDEventTypeTemperature))
+		C.CFRelease(C.CFTypeRef(unsafe.Pointer(event)))
+
+		// Observed invalid values on some Apple Silicon devices are around -9200.
+		// Filter out physically impossible temperatures.
+		if temp < absoluteZeroCelsius {
+			continue
+		}
+
+		nameRef := C.IOHIDServiceClientCopyProperty((C.IOHIDServiceClientRef)(service), cfProdKey)
+		name := "Unknown"
+		if nameRef != 0 {
+			name = cfStringToString((C.CFStringRef)(nameRef))
+			C.CFRelease(C.CFTypeRef(nameRef))
+		}
+
+		ch <- c.temperature.mustNewConstMetric(float64(temp), name)
+	}
+	return nil
+}
+
+func cfStringToString(s C.CFStringRef) string {
+	p := C.CFStringGetCStringPtr(s, C.kCFStringEncodingUTF8)
+	if p != nil {
+		return C.GoString(p)
+	}
+	length := C.CFStringGetLength(s)
+	if length <= 0 {
+		return ""
+	}
+	maxBufLen := C.CFStringGetMaximumSizeForEncoding(length, C.kCFStringEncodingUTF8)
+	if maxBufLen <= 0 {
+		return ""
+	}
+	if maxBufLen > 4096 {
+		maxBufLen = 4096
+	}
+	buf := make([]byte, maxBufLen)
+	var usedBufLen C.CFIndex
+	_ = C.CFStringGetBytes(s, C.CFRange{0, length}, C.kCFStringEncodingUTF8, C.UInt8(0), C.false, (*C.UInt8)(&buf[0]), maxBufLen, &usedBufLen)
+	return utils.SafeBytesToString(buf[:usedBufLen])
+}