feat: log execution file:line

Author: roman-vanesyan

_examples/debug/hello_world.go

@@ -0,0 +1,5 @@
+package main
+
+func helloworld() {
+	d("hello, %s", "world")
+}

_examples/debug/main.go

@@ -1,7 +1,6 @@
 package main
 
 import (
-	"net/http"
 	_ "net/http/pprof"
 
 	"go.inout.gg/foundations/debug"
@@ -10,9 +9,5 @@ import (
 var d = debug.Debuglog("main")
 
 func main() {
-	d("hello, %s", "world")
-
-	if err := http.ListenAndServe(":3000", nil); err != nil {
-		panic(err)
-	}
+	helloworld()
 }

debug/debuglog.go

@@ -5,6 +5,8 @@ package debug
 import (
 	"fmt"
 	"os"
+	"path/filepath"
+	"runtime"
 )
 
 // Debuglog creates a print function that prints a message to stdout.
@@ -16,6 +18,23 @@ import (
 func Debuglog(tag string) func(string, ...any) {
 	return func(m string, args ...any) {
 		pid := os.Getpid()
-		fmt.Println(fmt.Sprintf("%s %d: %s", tag, pid, fmt.Sprintf(m, args...)))
+
+		var pcs [1]uintptr
+		runtime.Callers(2, pcs[:]) // skip [Debuglog, closure]
+		cf := runtime.CallersFrames([]uintptr{pcs[0]})
+		f, _ := cf.Next()
+
+		var caller string
+		if f.File != "" {
+			file, line := f.File, f.Line
+			caller = format(file, line)
+		}
+
+		fmt.Println(fmt.Sprintf("%s %d [%s]: %s", tag, pid, caller, fmt.Sprintf(m, args...)))
 	}
 }
+
+func format(file string, line int) string {
+	dir, file := filepath.Split(file)
+	return fmt.Sprintf("%s:%d", filepath.Join(filepath.Base(dir), file), line)
+}