feat: observer pattern for statistics

internal/profiler/profiler.go

@@ -0,0 +1,48 @@
+package profiler
+
+import (
+	"os"
+	"path/filepath"
+	"runtime/pprof"
+
+	"git.maximhutz.com/max/lambda/pkg/lambda"
+)
+
+type Profiler struct {
+	File        string
+	filePointer *os.File
+	Error       error
+}
+
+func New(file string) *Profiler {
+	return &Profiler{File: file}
+}
+
+func (p *Profiler) Start(*lambda.Expression) {
+	var absPath string
+
+	absPath, p.Error = filepath.Abs(p.File)
+	if p.Error != nil {
+		return
+	}
+
+	p.Error = os.MkdirAll(filepath.Dir(absPath), 0777)
+	if p.Error != nil {
+		return
+	}
+
+	p.filePointer, p.Error = os.Create(absPath)
+	if p.Error != nil {
+		return
+	}
+
+	p.Error = pprof.StartCPUProfile(p.filePointer)
+	if p.Error != nil {
+		return
+	}
+}
+
+func (p *Profiler) End(*lambda.Expression) {
+	pprof.StopCPUProfile()
+	p.filePointer.Close()
+}