[receiver/hostmetricsreceiver] Add support for cpu frequency metric (#…

…27445)

**Description:** : Added support for host's cpu frequency as part
                   of the hostmetricsreceiver.

**Link to tracking Issue:** #26532

**Testing:**

1. Using the following configuration:
```yml
receivers:
  hostmetrics:
    collection_interval: 5s
    scrapers:
      cpu:
        metrics:
          system.cpu.frequency:
            enabled: true

processors:
  resourcedetection/system:
    detectors: ["system"]
    system:
      hostname_sources: ["lookup", "cname", "dns", "os"]
      resource_attributes:
        host.name:
          enabled: true
        host.id:
          enabled: true
        host.cpu.cache.l2.size:
          enabled: true
        host.cpu.family:
          enabled: true
        host.cpu.model.id:
          enabled: true
        host.cpu.model.name:
          enabled: true
        host.cpu.stepping:
          enabled: true
        host.cpu.vendor.id:
          enabled: true

service:
  pipelines:
    metrics:
      receivers: [hostmetrics]
      exporters: [file]
      processors: [resourcedetection/system]

exporters:
  file:
    path: ./output.json
```

2. Start the collector with ./bin/otelcontribcol_linux_amd64 --config
examples/host_config.yaml
3. The output reports the added metric successfully:

```json
{
   "resourceMetrics":[
      {
         "scopeMetrics":[
            {
               "scope":{
                  "name":"otelcol/hostmetricsreceiver/cpu",
                  "version":"0.85.0-dev"
               },
               "metrics":[
                  {
                     "name":"system.cpu.frequency",
                     "description":"Current frequency of the CPU core in MHz.",
                     "unit":"MHz",
                     "gauge":{
                        "dataPoints":[
                           {
                              "attributes":[
                                 {
                                    "key":"cpu",
                                    "value":{
                                       "stringValue":"cpu0"
                                    }
                                 }
                              ],
                              "startTimeUnixNano":"1696487580000000000",
                              "timeUnixNano":"1696512423758783158",
                              "asDouble":3000
                           },
                           {
                              "attributes":[
                                 {
                                    "key":"cpu",
                                    "value":{
                                       "stringValue":"cpu1"
                                    }
                                 }
                              ],
                              "startTimeUnixNano":"1696487580000000000",
                              "timeUnixNano":"1696512423758783158",
                              "asDouble":3000
                           },
...
```

Signed-off-by: ChrsMark <chrismarkou92@gmail.com>

.chloggen/cpuinfo_frequency_metric.yaml

@@ -0,0 +1,27 @@
+# Use this changelog template to create an entry for release notes.
+
+# One of 'breaking', 'deprecation', 'new_component', 'enhancement', 'bug_fix'
+change_type: enhancement
+
+# The name of the component, or a single word describing the area of concern, (e.g. filelogreceiver)
+component: receiver/hostmetricsreceiver
+
+# A brief description of the change.  Surround your text with quotes ("") if it needs to start with a backtick (`).
+note: Added support for host's cpuinfo frequnecies.
+
+# Mandatory: One or more tracking issues related to the change. You can use the PR number here if no issue exists.
+issues: [27445]
+
+# (Optional) One or more lines of additional information to render under the primary note.
+# These lines will be padded with 2 spaces and then inserted directly into the document.
+# Use pipe (|) for multiline entries.
+subtext: In Linux the current frequency is populated using the values from /proc/cpuinfo. An os specific implementation will be needed for Windows and others.
+
+# If your change doesn't affect end users or the exported elements of any package,
+# you should instead start your pull request title with [chore] or use the "Skip Changelog" label.
+# Optional: The change log or logs in which this entry should be included.
+# e.g. '[user]' or '[user, api]'
+# Include 'user' if the change is relevant to end users.
+# Include 'api' if there is a change to a library API.
+# Default: '[user]'
+change_logs: []

receiver/hostmetricsreceiver/go.mod

@@ -8,6 +8,7 @@ require (
 	github.com/open-telemetry/opentelemetry-collector-contrib/internal/coreinternal v0.88.0
 	github.com/open-telemetry/opentelemetry-collector-contrib/internal/filter v0.88.0
 	github.com/open-telemetry/opentelemetry-collector-contrib/pkg/pdatatest v0.88.0
+	github.com/prometheus/procfs v0.11.1
 	github.com/shirou/gopsutil/v3 v3.23.9
 	github.com/stretchr/testify v1.8.4
 	github.com/yusufpapurcu/wmi v1.2.3
@@ -79,7 +80,6 @@ require (
 	github.com/prometheus/client_golang v1.17.0 // indirect
 	github.com/prometheus/client_model v0.5.0 // indirect
 	github.com/prometheus/common v0.45.0 // indirect
-	github.com/prometheus/procfs v0.11.1 // indirect
 	github.com/prometheus/statsd_exporter v0.22.7 // indirect
 	github.com/shoenig/go-m1cpu v0.1.6 // indirect
 	github.com/sirupsen/logrus v1.9.3 // indirect

receiver/hostmetricsreceiver/internal/scraper/cpuscraper/cpu_scraper.go

@@ -5,6 +5,7 @@ package cpuscraper // import "github.com/open-telemetry/opentelemetry-collector-
 
 import (
 	"context"
+	"fmt"
 	"time"
 
 	"github.com/shirou/gopsutil/v3/common"
@@ -21,6 +22,7 @@ import (
 )
 
 const metricsLen = 2
+const hzInAMHz = 1_000_000
 
 // scraper for CPU Metrics
 type scraper struct {
@@ -35,6 +37,11 @@ type scraper struct {
 	now      func() time.Time
 }
 
+type cpuInfo struct {
+	frequency float64
+	processor uint
+}
+
 // newCPUScraper creates a set of CPU related metrics
 func newCPUScraper(_ context.Context, settings receiver.CreateSettings, cfg *Config) *scraper {
 	return &scraper{settings: settings, config: cfg, bootTime: host.BootTimeWithContext, times: cpu.TimesWithContext, ucal: &ucal.CPUUtilizationCalculator{}, now: time.Now}
@@ -79,5 +86,15 @@ func (s *scraper) scrape(ctx context.Context) (pmetric.Metrics, error) {
 	}
 	s.mb.RecordSystemCPULogicalCountDataPoint(now, int64(numCPU))
 
+	if s.config.MetricsBuilderConfig.Metrics.SystemCPUFrequency.Enabled {
+		cpuInfos, err := s.getCPUInfo()
+		if err != nil {
+			return pmetric.NewMetrics(), scrapererror.NewPartialScrapeError(err, metricsLen)
+		}
+		for _, cInfo := range cpuInfos {
+			s.mb.RecordSystemCPUFrequencyDataPoint(now, cInfo.frequency*hzInAMHz, fmt.Sprintf("cpu%d", cInfo.processor))
+		}
+	}
+
 	return s.mb.Emit(), nil
 }

receiver/hostmetricsreceiver/internal/scraper/cpuscraper/cpu_scraper_linux.go

@@ -7,8 +7,10 @@
 package cpuscraper // import "github.com/open-telemetry/opentelemetry-collector-contrib/receiver/hostmetricsreceiver/internal/scraper/cpuscraper"
 
 import (
+	"github.com/prometheus/procfs"
 	"github.com/shirou/gopsutil/v3/cpu"
 	"go.opentelemetry.io/collector/pdata/pcommon"
+	"go.opentelemetry.io/collector/receiver/scrapererror"
 
 	"github.com/open-telemetry/opentelemetry-collector-contrib/receiver/hostmetricsreceiver/internal/scraper/cpuscraper/internal/metadata"
 	"github.com/open-telemetry/opentelemetry-collector-contrib/receiver/hostmetricsreceiver/internal/scraper/cpuscraper/ucal"
@@ -35,3 +37,23 @@ func (s *scraper) recordCPUUtilization(now pcommon.Timestamp, cpuUtilization uca
 	s.mb.RecordSystemCPUUtilizationDataPoint(now, cpuUtilization.Steal, cpuUtilization.CPU, metadata.AttributeStateSteal)
 	s.mb.RecordSystemCPUUtilizationDataPoint(now, cpuUtilization.Iowait, cpuUtilization.CPU, metadata.AttributeStateWait)
 }
+
+func (s *scraper) getCPUInfo() ([]cpuInfo, error) {
+	var cpuInfos []cpuInfo
+	fs, err := procfs.NewDefaultFS()
+	if err != nil {
+		return nil, scrapererror.NewPartialScrapeError(err, metricsLen)
+	}
+	cInf, err := fs.CPUInfo()
+	if err != nil {
+		return nil, scrapererror.NewPartialScrapeError(err, metricsLen)
+	}
+	for _, cInfo := range cInf {
+		c := cpuInfo{
+			frequency: cInfo.CPUMHz,
+			processor: cInfo.Processor,
+		}
+		cpuInfos = append(cpuInfos, c)
+	}
+	return cpuInfos, nil
+}

receiver/hostmetricsreceiver/internal/scraper/cpuscraper/cpu_scraper_others.go

@@ -27,3 +27,8 @@ func (s *scraper) recordCPUUtilization(now pcommon.Timestamp, cpuUtilization uca
 	s.mb.RecordSystemCPUUtilizationDataPoint(now, cpuUtilization.Idle, cpuUtilization.CPU, metadata.AttributeStateIdle)
 	s.mb.RecordSystemCPUUtilizationDataPoint(now, cpuUtilization.Irq, cpuUtilization.CPU, metadata.AttributeStateInterrupt)
 }
+
+func (s *scraper) getCPUInfo() ([]cpuInfo, error) {
+	var cpuInfos []cpuInfo
+	return cpuInfos, nil
+}

receiver/hostmetricsreceiver/internal/scraper/cpuscraper/documentation.md

@@ -39,6 +39,20 @@ metrics:
     enabled: true
 ```
 
+### system.cpu.frequency
+
+Current frequency of the CPU core in Hz.
+
+| Unit | Metric Type | Value Type |
+| ---- | ----------- | ---------- |
+| Hz | Gauge | Double |
+
+#### Attributes
+
+| Name | Description | Values |
+| ---- | ----------- | ------ |
+| cpu | Logical CPU number starting at 0. | Any Str |
+
 ### system.cpu.logical.count
 
 Number of available logical CPUs.

receiver/hostmetricsreceiver/internal/scraper/cpuscraper/internal/metadata/testdata/config.yaml

@@ -1,6 +1,8 @@
 default:
 all_set:
   metrics:
+    system.cpu.frequency:
+      enabled: true
     system.cpu.logical.count:
       enabled: true
     system.cpu.physical.count:
@@ -11,6 +13,8 @@ all_set:
       enabled: true
 none_set:
   metrics:
+    system.cpu.frequency:
+      enabled: false
     system.cpu.logical.count:
       enabled: false
     system.cpu.physical.count:

receiver/hostmetricsreceiver/internal/scraper/cpuscraper/metadata.yaml

@@ -50,3 +50,11 @@ metrics:
       value_type: int
       monotonic: false
       aggregation_temporality: cumulative
+
+  system.cpu.frequency:
+    enabled: false
+    description: Current frequency of the CPU core in Hz.
+    unit: "Hz"
+    gauge:
+      value_type: double
+    attributes: [cpu]