feat: new collector about thermal conditions on macos (#2032)

* feat: new collector about thermal conditions on macos

Signed-off-by: STRRL <str_ruiling@outlook.com>

README.md

@@ -126,6 +126,7 @@ softnet | Exposes statistics from `/proc/net/softnet_stat`. | Linux
 stat | Exposes various statistics from `/proc/stat`. This includes boot time, forks and interrupts. | Linux
 tapestats | Exposes statistics from `/sys/class/scsi_tape`. | Linux
 textfile | Exposes statistics read from local disk. The `--collector.textfile.directory` flag must be set. | _any_
+thermal | Exposes thermal statistics like `pmset -g therm`. | Darwin
 thermal\_zone | Exposes thermal zone & cooling device statistics from `/sys/class/thermal`. | Linux
 time | Exposes the current system time. | _any_
 timex | Exposes selected adjtimex(2) system call stats. | Linux

collector/thermal_darwin.go

@@ -0,0 +1,183 @@
+// Copyright 2021 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.
+
+// +build !notherm
+
+package collector
+
+/*
+#cgo LDFLAGS: -framework IOKit -framework CoreFoundation
+#include <stdio.h>
+#include <CoreFoundation/CoreFoundation.h>
+#include <IOKit/IOKitLib.h>
+#include <IOKit/pwr_mgt/IOPMLib.h>
+#include <IOKit/pwr_mgt/IOPM.h>
+
+struct ref_with_ret {
+    CFDictionaryRef ref;
+    IOReturn ret;
+};
+
+struct ref_with_ret FetchThermal();
+
+struct ref_with_ret FetchThermal() {
+    CFDictionaryRef ref;
+    IOReturn ret;
+    ret = IOPMCopyCPUPowerStatus(&ref);
+    struct ref_with_ret result = {
+            ref,
+            ret,
+    };
+    return result;
+}
+*/
+import "C"
+
+import (
+	"errors"
+	"fmt"
+	"github.com/go-kit/kit/log"
+	"github.com/prometheus/client_golang/prometheus"
+	"unsafe"
+)
+
+type thermCollector struct {
+	cpuSchedulerLimit typedDesc
+	cpuAvailableCPU   typedDesc
+	cpuSpeedLimit     typedDesc
+	logger            log.Logger
+}
+
+const thermal = "thermal"
+
+func init() {
+	registerCollector(thermal, defaultEnabled, NewThermCollector)
+}
+
+// NewThermCollector returns a new Collector exposing current CPU power levels.
+func NewThermCollector(logger log.Logger) (Collector, error) {
+	return &thermCollector{
+		cpuSchedulerLimit: typedDesc{
+			desc: prometheus.NewDesc(
+				prometheus.BuildFQName(namespace, thermal, "cpu_scheduler_limit_ratio"),
+				"Represents the percentage (0-100) of CPU time available. 100% at normal operation. The OS may limit this time for a percentage less than 100%.",
+				nil,
+				nil),
+			valueType: prometheus.GaugeValue,
+		},
+		cpuAvailableCPU: typedDesc{
+			desc: prometheus.NewDesc(
+				prometheus.BuildFQName(namespace, thermal, "cpu_available_cpu"),
+				"Reflects how many, if any, CPUs have been taken offline. Represented as an integer number of CPUs (0 - Max CPUs).",
+				nil,
+				nil,
+			),
+			valueType: prometheus.GaugeValue,
+		},
+		cpuSpeedLimit: typedDesc{
+			desc: prometheus.NewDesc(
+				prometheus.BuildFQName(namespace, thermal, "cpu_speed_limit_ratio"),
+				"Defines the speed & voltage limits placed on the CPU. Represented as a percentage (0-100) of maximum CPU speed.",
+				nil,
+				nil,
+			),
+			valueType: prometheus.GaugeValue,
+		},
+		logger: logger,
+	}, nil
+}
+
+func (c *thermCollector) Update(ch chan<- prometheus.Metric) error {
+	cpuPowerStatus, err := fetchCPUPowerStatus()
+	if err != nil {
+		return err
+	}
+	if value, ok := cpuPowerStatus[(string(C.kIOPMCPUPowerLimitSchedulerTimeKey))]; ok {
+		ch <- c.cpuSchedulerLimit.mustNewConstMetric(float64(value) / 100.0)
+	}
+	if value, ok := cpuPowerStatus[(string(C.kIOPMCPUPowerLimitProcessorCountKey))]; ok {
+		ch <- c.cpuAvailableCPU.mustNewConstMetric(float64(value))
+	}
+	if value, ok := cpuPowerStatus[(string(C.kIOPMCPUPowerLimitProcessorSpeedKey))]; ok {
+		ch <- c.cpuSpeedLimit.mustNewConstMetric(float64(value) / 100.0)
+	}
+	return nil
+}
+
+func fetchCPUPowerStatus() (map[string]int, error) {
+	cfDictRef, _ := C.FetchThermal()
+	defer func() {
+		C.CFRelease(C.CFTypeRef(cfDictRef.ref))
+	}()
+
+	if C.kIOReturnNotFound == cfDictRef.ret {
+		return nil, errors.New("no CPU power status has been recorded")
+	}
+
+	if C.kIOReturnSuccess != cfDictRef.ret {
+		return nil, fmt.Errorf("no CPU power status with error code 0x%08x", int(cfDictRef.ret))
+	}
+
+	// mapping CFDictionary to map
+	cfDict := CFDict(cfDictRef.ref)
+	return mappingCFDictToMap(cfDict), nil
+}
+
+type CFDict uintptr
+
+func mappingCFDictToMap(dict CFDict) map[string]int {
+	if C.CFNullRef(dict) == C.kCFNull {
+		return nil
+	}
+	cfDict := C.CFDictionaryRef(dict)
+
+	var result map[string]int
+	count := C.CFDictionaryGetCount(cfDict)
+	if count > 0 {
+		keys := make([]C.CFTypeRef, count)
+		values := make([]C.CFTypeRef, count)
+		C.CFDictionaryGetKeysAndValues(cfDict, (*unsafe.Pointer)(unsafe.Pointer(&keys[0])), (*unsafe.Pointer)(unsafe.Pointer(&values[0])))
+		result = make(map[string]int, count)
+		for i := C.CFIndex(0); i < count; i++ {
+			result[mappingCFStringToString(C.CFStringRef(keys[i]))] = mappingCFNumberLongToInt(C.CFNumberRef(values[i]))
+		}
+	}
+	return result
+}
+
+// CFStringToString converts a CFStringRef to a string.
+func mappingCFStringToString(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 ""
+	}
+	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 string(buf[:usedBufLen])
+}
+
+func mappingCFNumberLongToInt(n C.CFNumberRef) int {
+	typ := C.CFNumberGetType(n)
+	var long C.long
+	C.CFNumberGetValue(n, typ, unsafe.Pointer(&long))
+	return int(long)
+}