feat(pprof): Added pprof

Signed-off-by: Vimal Kumar <[email protected]>

Author: vimalk78

cmd/kepler/main.go

@@ -229,11 +229,18 @@ func createServices(logger *slog.Logger, cfg *config.Config) ([]service.Service,
 		prometheus.WithCollectors(collectors),
 	)
 
-	return []service.Service{
+	services := []service.Service{
 		promExporter,
 		apiServer,
 		pm,
-	}, nil
+	}
+
+	if cfg.EnablePprof {
+		pprof := server.NewPprof(apiServer)
+		services = append(services, pprof)
+	}
+
+	return services, nil
 }
 
 func createPowerMonitor(logger *slog.Logger, cfg *config.Config) (*monitor.PowerMonitor, error) {

config/config.go

@@ -33,19 +33,23 @@ type (
 	}
 
 	Config struct {
-		Log  Log  `yaml:"log"`
-		Host Host `yaml:"host"`
-		Dev  Dev  `yaml:"dev"` // WARN: do not expose dev settings as flags
+		Log         Log  `yaml:"log"`
+		Host        Host `yaml:"host"`
+		Dev         Dev  `yaml:"dev"` // WARN: do not expose dev settings as flags
+		EnablePprof bool `yaml:"enable-pprof"`
 	}
 )
 
 const (
 	// Flags
-	LogLevelFlag   = "log.level"
-	LogFormatFlag  = "log.format"
+	LogLevelFlag  = "log.level"
+	LogFormatFlag = "log.format"
+
 	HostSysFSFlag  = "host.sysfs"
 	HostProcFSFlag = "host.procfs"
 
+	EnablePprofFlag = "enable.pprof"
+
 // WARN:  dev settings shouldn't be exposed as flags as flags are intended for end users
 )
 
@@ -123,6 +127,7 @@ func RegisterFlags(app *kingpin.Application) ConfigUpdaterFn {
 	logFormat := app.Flag(LogFormatFlag, "Logging format: text or json").Default("text").Enum("text", "json")
 	hostSysFS := app.Flag(HostSysFSFlag, "Host sysfs path").Default("/sys").ExistingDir()
 	hostProcFS := app.Flag(HostProcFSFlag, "Host procfs path").Default("/proc").ExistingDir()
+	enablePprof := app.Flag(EnablePprofFlag, "Enable pprof").Default("false").Bool()
 	return func(cfg *Config) error {
 		// Logging settings
 		if flagsSet[LogLevelFlag] {
@@ -141,6 +146,10 @@ func RegisterFlags(app *kingpin.Application) ConfigUpdaterFn {
 			cfg.Host.ProcFS = *hostProcFS
 		}
 
+		if flagsSet[EnablePprofFlag] {
+			cfg.EnablePprof = *enablePprof
+		}
+
 		cfg.sanitize()
 		return cfg.Validate()
 	}

config/config_test.go

@@ -379,3 +379,36 @@ func TestConfigString(t *testing.T) {
 		})
 	}
 }
+
+func TestEnablePprof(t *testing.T) {
+	tt := []struct {
+		name    string
+		args    []string
+		enabled bool
+	}{{
+		name:    "enable pprof with flag",
+		args:    []string{"--enable.pprof"},
+		enabled: true,
+	}, {
+		name:    "disable pprof no flag",
+		args:    []string{"--log.level=debug"},
+		enabled: false,
+	}, {
+		name:    "disable pprof with flag",
+		args:    []string{"--no-enable.pprof"},
+		enabled: false,
+	}}
+
+	for _, tc := range tt {
+		t.Run(tc.name, func(t *testing.T) {
+			app := kingpin.New("test", "Test application")
+			updateConfig := RegisterFlags(app)
+			_, parseErr := app.Parse(tc.args)
+			assert.NoError(t, parseErr, "unexpected flag parsing error")
+			cfg := DefaultConfig()
+			err := updateConfig(cfg)
+			assert.NoError(t, err, "unexpected config update error")
+			assert.Equal(t, cfg.EnablePprof, tc.enabled, "unexpected flag value")
+		})
+	}
+}

internal/server/pprof.go

@@ -0,0 +1,45 @@
+// SPDX-FileCopyrightText: 2025 The Kepler Authors
+// SPDX-License-Identifier: Apache-2.0
+
+package server
+
+import (
+	"context"
+	"net/http"
+	"net/http/pprof"
+
+	"github.com/sustainable-computing-io/kepler/internal/service"
+)
+
+type pp struct {
+	api APIService
+}
+
+var _ service.Service = (*pp)(nil)
+var _ service.Initializer = (*pp)(nil)
+
+func NewPprof(api APIService) *pp {
+	return &pp{
+		api: api,
+	}
+}
+
+func (p *pp) Name() string {
+	return "pprof"
+}
+
+func (p *pp) Init(ctx context.Context) error {
+	return p.api.Register("/debug/pprof/", "pprof", "Profiling Data", handlers())
+}
+
+func handlers() http.Handler {
+	mux := http.NewServeMux()
+
+	mux.HandleFunc("/debug/pprof/", pprof.Index)
+	mux.HandleFunc("/debug/pprof/cmdline", pprof.Cmdline)
+	mux.HandleFunc("/debug/pprof/profile", pprof.Profile)
+	mux.HandleFunc("/debug/pprof/symbol", pprof.Symbol)
+	mux.HandleFunc("/debug/pprof/trace", pprof.Trace)
+
+	return mux
+}

internal/server/pprof_test.go

@@ -0,0 +1,103 @@
+// SPDX-FileCopyrightText: 2025 The Kepler Authors
+// SPDX-License-Identifier: Apache-2.0
+
+package server
+
+import (
+	"context"
+	"net/http"
+	"net/http/httptest"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/mock"
+	"net/http/pprof"
+)
+
+// MockAPIService is an implementation of the APIService interface for testing.
+type MockAPIService struct {
+	mock.Mock
+}
+
+func (m *MockAPIService) Register(path, name, description string, handler http.Handler) error {
+	args := m.Called(path, name, description, handler)
+	return args.Error(0)
+}
+
+func (m *MockAPIService) Name() string {
+	return "mockApiService"
+}
+
+// TestNewPprof tests the NewPprof constructor.
+func TestNewPprof(t *testing.T) {
+	api := &MockAPIService{}
+	p := NewPprof(api)
+
+	assert.NotNil(t, p, "NewPprof should return a non-nil pointer")
+	assert.Equal(t, api, p.api, "NewPprof should set the api field correctly")
+}
+
+// TestPprofName tests the Name method.
+func TestPprofName(t *testing.T) {
+	api := &MockAPIService{}
+	p := NewPprof(api)
+
+	name := p.Name()
+	assert.Equal(t, "pprof", name, "Name should return 'pprof'")
+}
+
+// TestPprofInit_Success tests the Init method when the API registration succeeds.
+func TestPprofInit_Success(t *testing.T) {
+	api := &MockAPIService{}
+	p := NewPprof(api)
+
+	// Set up mock expectation
+	api.On("Register", "/debug/pprof/", "pprof", "Profiling Data", mock.AnythingOfType("*http.ServeMux")).Return(nil)
+
+	err := p.Init(context.Background())
+	assert.NoError(t, err, "Init should not return an error when registration succeeds")
+	api.AssertExpectations(t)
+}
+
+// TestPprofInit_Failure tests the Init method when the API registration fails.
+func TestPprofInit_Failure(t *testing.T) {
+	api := &MockAPIService{}
+	p := NewPprof(api)
+
+	// Set up mock expectation
+	expectedErr := assert.AnError
+	api.On("Register", "/debug/pprof/", "pprof", "Profiling Data", mock.AnythingOfType("*http.ServeMux")).Return(expectedErr)
+
+	err := p.Init(context.Background())
+	assert.Error(t, err, "Init should return an error when registration fails")
+	assert.Equal(t, expectedErr, err, "Init should return the expected error")
+	api.AssertExpectations(t)
+}
+
+// TestPprofHandlers tests the handlers function to ensure it registers the correct pprof endpoints.
+func TestPprofHandlers(t *testing.T) {
+	handler := handlers()
+	mux, ok := handler.(*http.ServeMux)
+	assert.True(t, ok, "handlers should return an http.ServeMux")
+
+	// Test cases for each pprof endpoint
+	tests := []struct {
+		path        string
+		handlerFunc http.HandlerFunc
+	}{
+		{"/debug/pprof/", pprof.Index},
+		{"/debug/pprof/cmdline", pprof.Cmdline},
+		{"/debug/pprof/profile", pprof.Profile},
+		{"/debug/pprof/symbol", pprof.Symbol},
+		{"/debug/pprof/trace", pprof.Trace},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.path, func(t *testing.T) {
+			req := httptest.NewRequest("GET", tt.path, nil)
+			rr := httptest.NewRecorder()
+			mux.ServeHTTP(rr, req)
+			assert.NotEqual(t, http.StatusNotFound, rr.Code, "Handler for %s should be registered", tt.path)
+		})
+	}
+}

internal/server/server.go

@@ -159,6 +159,7 @@ func (s *APIServer) Shutdown() error {
 }
 
 func (s *APIServer) Register(endpoint, summary, description string, handler http.Handler) error {
+	s.logger.Debug("Endpoint Registered", "endpoint", endpoint)
 	s.mux.Handle(endpoint, handler)
 	s.endpointDescription += fmt.Sprintf("<li> <a href=\"%s\"> %s </a> %s </li>\n", endpoint, summary, description)
 	return nil