[cpu] - Split the initialisation into multiple files

go.mod

@@ -4,7 +4,7 @@ go 1.22.8
 
 require (
 	github.com/docker/docker v26.1.5+incompatible
-	github.com/elastic/elastic-agent-libs v0.9.13
+	github.com/elastic/elastic-agent-libs v0.17.4-0.20241126154321-6ed75416832d
 	github.com/elastic/go-licenser v0.4.2
 	github.com/elastic/go-structform v0.0.9
 	github.com/elastic/go-sysinfo v1.14.1

go.sum

@@ -21,8 +21,8 @@ github.com/docker/go-connections v0.4.0 h1:El9xVISelRB7BuFusrZozjnkIM5YnzCViNKoh
 github.com/docker/go-connections v0.4.0/go.mod h1:Gbd7IOopHjR8Iph03tsViu4nIes5XhDvyHbTtUxmeec=
 github.com/docker/go-units v0.5.0 h1:69rxXcBk27SvSaaxTtLh/8llcHD8vYHT7WSdRZ/jvr4=
 github.com/docker/go-units v0.5.0/go.mod h1:fgPhTUdO+D/Jk86RDLlptpiXQzgHJF7gydDDbaIK4Dk=
-github.com/elastic/elastic-agent-libs v0.9.13 h1:D1rh1s67zlkDWmixWQaNWzn+qy6DafIDPTQnLpBNBUA=
-github.com/elastic/elastic-agent-libs v0.9.13/go.mod h1:G9ljFvDE+muOOOQBf2eRituF0fE4suGkv25rfjTwY+c=
+github.com/elastic/elastic-agent-libs v0.17.4-0.20241126154321-6ed75416832d h1:nY8LSeTYU1uSDAAg7WwGH/cALgdovAXLdIzV25Ky0Bo=
+github.com/elastic/elastic-agent-libs v0.17.4-0.20241126154321-6ed75416832d/go.mod h1:5CR02awPrBr+tfmjBBK+JI+dMmHNQjpVY24J0wjbC7M=
 github.com/elastic/go-licenser v0.4.2 h1:bPbGm8bUd8rxzSswFOqvQh1dAkKGkgAmrPxbUi+Y9+A=
 github.com/elastic/go-licenser v0.4.2/go.mod h1:W8eH6FaZDR8fQGm+7FnVa7MxI1b/6dAqxz+zPB8nm5c=
 github.com/elastic/go-structform v0.0.9 h1:HpcS7xljL4kSyUfDJ8cXTJC6rU5ChL1wYb6cx3HLD+o=

metric/cpu/metrics.go → metric/cpu/cpu.go

@@ -24,7 +24,6 @@ import (
 	"github.com/elastic/elastic-agent-libs/mapstr"
 	"github.com/elastic/elastic-agent-libs/opt"
 	"github.com/elastic/elastic-agent-system-metrics/metric"
-	"github.com/elastic/elastic-agent-system-metrics/metric/system/resolve"
 )
 
 // CPU manages the CPU metrics from /proc/stat
@@ -79,21 +78,17 @@ func (cpu CPU) Total() uint64 {
 	return opt.SumOptUint(cpu.User, cpu.Nice, cpu.Sys, cpu.Idle, cpu.Wait, cpu.Irq, cpu.SoftIrq, cpu.Stolen)
 }
 
-/*
-The below code implements a "metrics tracker" that gives us the ability to
-calculate CPU percentages, as we average usage across a time period.
-*/
-
-// Monitor is used to monitor the overall CPU usage of the system over time.
-type Monitor struct {
-	lastSample CPUMetrics
-	Hostfs     resolve.Resolver
+type option struct {
+	usePerformanceCounter bool
 }
 
-// New returns a new CPU metrics monitor
-// Hostfs is only relevant on linux and freebsd.
-func New(hostfs resolve.Resolver) *Monitor {
-	return &Monitor{Hostfs: hostfs}
+type OptionFunc func(*option)
+
+// Note: WithPerformanceCounter option is only effective for windows and is ineffective if used by other OS'.
+func WithPerformanceCounter() OptionFunc {
+	return func(o *option) {
+		o.usePerformanceCounter = true
+	}
 }
 
 // Fetch collects a new sample of the CPU usage metrics.

metric/cpu/cpu_other.go

@@ -0,0 +1,39 @@
+// Licensed to Elasticsearch B.V. under one or more contributor
+// license agreements. See the NOTICE file distributed with
+// this work for additional information regarding copyright
+// ownership. Elasticsearch B.V. licenses this file to you 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 !windows
+
+package cpu
+
+import "github.com/elastic/elastic-agent-system-metrics/metric/system/resolve"
+
+/*
+The below code implements a "metrics tracker" that gives us the ability to
+calculate CPU percentages, as we average usage across a time period.
+*/
+
+// Monitor is used to monitor the overall CPU usage of the system over time.
+type Monitor struct {
+	lastSample CPUMetrics
+	Hostfs     resolve.Resolver
+}
+
+// New returns a new CPU metrics monitor
+// Hostfs is only relevant on linux and freebsd.
+func New(hostfs resolve.Resolver, _ ...OptionFunc) (*Monitor, error) {
+	return &Monitor{Hostfs: hostfs}, nil
+}

metric/cpu/cpu_windows.go

@@ -0,0 +1,72 @@
+// Licensed to Elasticsearch B.V. under one or more contributor
+// license agreements. See the NOTICE file distributed with
+// this work for additional information regarding copyright
+// ownership. Elasticsearch B.V. licenses this file to you 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 windows
+
+package cpu
+
+import (
+	"fmt"
+
+	"github.com/elastic/elastic-agent-libs/helpers/windows/pdh"
+	"github.com/elastic/elastic-agent-system-metrics/metric/system/resolve"
+)
+
+/*
+The below code implements a "metrics tracker" that gives us the ability to
+calculate CPU percentages, as we average usage across a time period.
+*/
+
+// Monitor is used to monitor the overall CPU usage of the system over time.
+type Monitor struct {
+	lastSample CPUMetrics
+	Hostfs     resolve.Resolver
+
+	// windows specific fields
+	query *pdh.Query
+}
+
+// New returns a new CPU metrics monitor
+// Hostfs is only relevant on linux and freebsd.
+func New(hostfs resolve.Resolver, opts ...OptionFunc) (*Monitor, error) {
+	var query *pdh.Query
+	var err error
+
+	op := option{}
+	for _, o := range opts {
+		o(&op)
+	}
+	if !op.usePerformanceCounter {
+		if query, err = buildQuery(); err != nil {
+			return nil, err
+		}
+	}
+
+	return &Monitor{
+		Hostfs: hostfs,
+		query:  query,
+	}, nil
+}
+
+func buildQuery() (*pdh.Query, error) {
+	var q pdh.Query
+	if err := q.Open(); err != nil {
+		return nil, fmt.Errorf("failed to open query: %w", err)
+	}
+	// TODO: implement performance counters as a follow up
+	return &q, nil
+}

metric/cpu/metrics_test.go

@@ -31,7 +31,8 @@ import (
 
 func TestMonitorSample(t *testing.T) {
 	_ = logp.DevelopmentSetup()
-	cpu := &Monitor{lastSample: CPUMetrics{}, Hostfs: systemtests.DockerTestResolver()}
+	cpu, err := New(systemtests.DockerTestResolver())
+	require.NoError(t, err)
 	s, err := cpu.Fetch()
 	require.NoError(t, err)
 
@@ -46,7 +47,9 @@ func TestCoresMonitorSample(t *testing.T) {
 	cpuMetrics, err := Get(systemtests.DockerTestResolver())
 	assert.NoError(t, err, "error in Get()")
 
-	cores := &Monitor{lastSample: CPUMetrics{list: make([]CPU, len(cpuMetrics.list))}, Hostfs: systemtests.DockerTestResolver()}
+	cores, err := New(systemtests.DockerTestResolver())
+	require.NoError(t, err)
+	cores.lastSample = CPUMetrics{list: make([]CPU, len(cpuMetrics.list))}
 	sample, err := cores.FetchCores()
 	require.NoError(t, err)