hostmetrics: Adding process.uptime metric (open-telemetry#37492)

#### Description
Adding new metric into hostmetric process scraper to track process
uptime

#### Link to tracking issue
Fixes
open-telemetry#36667

#### Testing

Added tests to validate coverage.

#### Documentation

Added as part of mdatagen

.chloggen/msg_process-uptime-addition.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: hostmetrics/process
+
+# A brief description of the change.  Surround your text with quotes ("") if it needs to start with a backtick (`).
+note: Added support for tracking process.uptime
+
+# Mandatory: One or more tracking issues related to the change. You can use the PR number here if no issue exists.
+issues: [36667]
+
+# (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:
+
+# 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: [user]

exporter/datadogexporter/go.mod

@@ -334,6 +334,7 @@ require (
 	github.com/spf13/pflag v1.0.5 // indirect
 	github.com/stormcat24/protodep v0.1.8 // indirect
 	github.com/stretchr/objx v0.5.2 // indirect
+	github.com/tilinna/clock v1.1.0 // indirect
 	github.com/tinylib/msgp v1.2.5 // indirect
 	github.com/tklauser/go-sysconf v0.3.14 // indirect
 	github.com/tklauser/numcpus v0.8.0 // indirect

receiver/hostmetricsreceiver/go.mod

@@ -12,6 +12,7 @@ require (
 	github.com/prometheus/procfs v0.15.1
 	github.com/shirou/gopsutil/v4 v4.24.12
 	github.com/stretchr/testify v1.10.0
+	github.com/tilinna/clock v1.1.0
 	github.com/yusufpapurcu/wmi v1.2.4
 	go.opentelemetry.io/collector/component v0.118.1-0.20250123125445-24f88da7b583
 	go.opentelemetry.io/collector/component/componenttest v0.118.1-0.20250123125445-24f88da7b583

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

@@ -172,6 +172,14 @@ Process threads count.
 | ---- | ----------- | ---------- | ----------------------- | --------- |
 | {threads} | Sum | Int | Cumulative | false |
 
+### process.uptime
+
+The time the process has been running.
+
+| Unit | Metric Type | Value Type |
+| ---- | ----------- | ---------- |
+| s | Gauge | Double |
+
 ## Resource Attributes
 
 | Name | Description | Values | Enabled |

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

@@ -27,6 +27,8 @@ all_set:
       enabled: true
     process.threads:
       enabled: true
+    process.uptime:
+      enabled: true
   resource_attributes:
     process.cgroup:
       enabled: true
@@ -72,6 +74,8 @@ none_set:
       enabled: false
     process.threads:
       enabled: false
+    process.uptime:
+      enabled: false
   resource_attributes:
     process.cgroup:
       enabled: false

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

@@ -207,3 +207,10 @@ metrics:
       aggregation_temporality: cumulative
       monotonic: true
     attributes: [direction]
+
+  process.uptime:
+    enabled: false
+    description: The time the process has been running.
+    unit: s
+    gauge:
+      value_type: double

receiver/hostmetricsreceiver/internal/scraper/processscraper/process_scraper.go

@@ -13,6 +13,7 @@ import (
 	"github.com/shirou/gopsutil/v4/cpu"
 	"github.com/shirou/gopsutil/v4/host"
 	"github.com/shirou/gopsutil/v4/process"
+	"github.com/tilinna/clock"
 	"go.opentelemetry.io/collector/component"
 	"go.opentelemetry.io/collector/pdata/pcommon"
 	"go.opentelemetry.io/collector/pdata/pmetric"
@@ -36,8 +37,9 @@ const (
 	fileDescriptorMetricsLen    = 1
 	handleMetricsLen            = 1
 	signalMetricsLen            = 1
+	uptimeMetricsLen            = 1
 
-	metricsLen = cpuMetricsLen + memoryMetricsLen + diskMetricsLen + memoryUtilizationMetricsLen + pagingMetricsLen + threadMetricsLen + contextSwitchMetricsLen + fileDescriptorMetricsLen + signalMetricsLen
+	metricsLen = cpuMetricsLen + memoryMetricsLen + diskMetricsLen + memoryUtilizationMetricsLen + pagingMetricsLen + threadMetricsLen + contextSwitchMetricsLen + fileDescriptorMetricsLen + signalMetricsLen + uptimeMetricsLen
 )
 
 // scraper for Process Metrics
@@ -132,7 +134,7 @@ func (s *processScraper) scrape(ctx context.Context) (pmetric.Metrics, error) {
 	for _, md := range data {
 		presentPIDs[md.pid] = struct{}{}
 
-		now := pcommon.NewTimestampFromTime(time.Now())
+		now := pcommon.NewTimestampFromTime(clock.Now(ctx))
 
 		if err = s.scrapeAndAppendCPUTimeMetric(ctx, now, md.handle, md.pid); err != nil {
 			errs.AddPartial(cpuMetricsLen, fmt.Errorf("error reading cpu times for process %q (pid %v): %w", md.executable.name, md.pid, err))
@@ -174,6 +176,10 @@ func (s *processScraper) scrape(ctx context.Context) (pmetric.Metrics, error) {
 			errs.AddPartial(signalMetricsLen, fmt.Errorf("error reading pending signals for process %q (pid %v): %w", md.executable.name, md.pid, err))
 		}
 
+		if err = s.scrapeAndAppendUptimeMetric(ctx, now, md.handle); err != nil {
+			errs.AddPartial(uptimeMetricsLen, fmt.Errorf("error calculating uptime for process %q (pid %v): %w", md.executable.name, md.pid, err))
+		}
+
 		s.mb.EmitForResource(metadata.WithResource(md.buildResource(s.mb.NewResourceBuilder())),
 			metadata.WithStartTimeOverride(pcommon.Timestamp(md.createTime*1e6)))
 	}
@@ -465,3 +471,20 @@ func (s *processScraper) scrapeAndAppendSignalsPendingMetric(ctx context.Context
 
 	return nil
 }
+
+func (s *processScraper) scrapeAndAppendUptimeMetric(ctx context.Context, now pcommon.Timestamp, handle processHandle) error {
+	if !s.config.MetricsBuilderConfig.Metrics.ProcessUptime.Enabled {
+		return nil
+	}
+
+	ts, err := s.getProcessCreateTime(handle, ctx)
+	if err != nil {
+		return err
+	}
+	// Since create time is in milliseconds, it needs to be multiplied
+	// by the constant value so that it can be used as part of the time.Unix function.
+	uptime := now.AsTime().Sub(time.Unix(0, ts*int64(time.Millisecond)))
+	s.mb.RecordProcessUptimeDataPoint(now, uptime.Seconds())
+
+	return nil
+}