Renamed package runtime to diag (Azure#15278)

* Renamed package runtime to diag

Since it deals with diagnostics and we want to use the name runtime for
a package in azcore.
Deleted FrameError as it's not very useful.
Added Caller() for times when a full stack trace isn't needed.

* Remove log.Listener

sdk/internal/runtime/runtime.go → sdk/internal/diag/diag.go

@@ -3,22 +3,38 @@
 // Copyright (c) Microsoft Corporation. All rights reserved.
 // Licensed under the MIT License.
 
-package runtime
+package diag
 
 import (
 	"fmt"
 	"runtime"
 	"strings"
 )
 
+// Caller returns the file and line number of a frame on the caller's stack.
+// If the funtion fails an empty string is returned.
+// skipFrames - the number of frames to skip when determining the caller.
+//  Passing a value of 0 will return the immediate caller of this function.
+func Caller(skipFrames int) string {
+	if pc, file, line, ok := runtime.Caller(skipFrames + 1); ok {
+		// the skipFrames + 1 is to skip ourselves
+		frame := runtime.FuncForPC(pc)
+		return fmt.Sprintf("%s()\n\t%s:%d", frame.Name(), file, line)
+	}
+	return ""
+}
+
 // StackTrace returns a formatted stack trace string.
+// If the funtion fails an empty string is returned.
 // skipFrames - the number of stack frames to skip before composing the trace string.
 // totalFrames - the maximum number of stack frames to include in the trace string.
 func StackTrace(skipFrames, totalFrames int) string {
-	sb := strings.Builder{}
 	pcCallers := make([]uintptr, totalFrames)
-	runtime.Callers(skipFrames, pcCallers)
+	if frames := runtime.Callers(skipFrames, pcCallers); frames == 0 {
+		return ""
+	}
 	frames := runtime.CallersFrames(pcCallers)
+	sb := strings.Builder{}
 	for {
 		frame, more := frames.Next()
 		sb.WriteString(frame.Function)

sdk/internal/runtime/runtime_test.go → sdk/internal/diag/diag_test.go

@@ -3,13 +3,36 @@
 // Copyright (c) Microsoft Corporation. All rights reserved.
 // Licensed under the MIT License.
 
-package runtime
+package diag
 
 import (
+	"regexp"
 	"strings"
 	"testing"
 )
 
+func TestCallerBasic(t *testing.T) {
+	c := Caller(0)
+	matched, err := regexp.MatchString(`/diag_test.go:\d+$`, c)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if !matched {
+		t.Fatalf("got %s", c)
+	}
+}
+
+func TestCallerSkipFrame(t *testing.T) {
+	c := Caller(1)
+	matched, err := regexp.MatchString(`/testing.go:\d+$`, c)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if !matched {
+		t.Fatalf("got %s", c)
+	}
+}
+
 func TestStackTraceBasic(t *testing.T) {
 	trace := StackTrace(0, 1)
 	trace = strings.TrimSpace(trace)
@@ -24,7 +47,7 @@ func TestStackTraceSkipFrame(t *testing.T) {
 	trace := StackTrace(1, 1)
 	trace = strings.TrimSpace(trace)
 	parts := strings.Split(trace, "\n")
-	const topFrame = "runtime.StackTrace()"
+	const topFrame = "diag.StackTrace()"
 	if strings.LastIndex(parts[0], topFrame) == -1 {
 		t.Fatalf("%s didn't end with %s", parts[0], topFrame)
 	}

sdk/internal/log/log.go

@@ -31,15 +31,10 @@ const (
 	LongRunningOperation Classification = "LongRunningOperation"
 )
 
-// Listener is the funciton signature invoked when writing log entries.
-// A Listener is required to perform its own synchronization if it's expected to be called
-// from multiple Go routines
-type Listener func(Classification, string)
-
 // logger controls which classifications to log and writing to the underlying log.
 type logger struct {
 	cls []Classification
-	lst Listener
+	lst func(Classification, string)
 }
 
 // SetClassifications is used to control which classifications are written to
@@ -48,8 +43,8 @@ func SetClassifications(cls ...Classification) {
 	log.cls = cls
 }
 
-// SetListener will set the Logger to write to the specified Listener.
-func SetListener(lst Listener) {
+// SetListener will set the Logger to write to the specified listener.
+func SetListener(lst func(Classification, string)) {
 	log.lst = lst
 }
 
@@ -74,7 +69,7 @@ func Should(cls Classification) bool {
 	return false
 }
 
-// Write invokes the underlying Listener with the specified classification and message.
+// Write invokes the underlying listener with the specified classification and message.
 // If the classification shouldn't be logged or there is no listener then Write does nothing.
 func Write(cls Classification, message string) {
 	if !Should(cls) {
@@ -83,7 +78,7 @@ func Write(cls Classification, message string) {
 	log.lst(cls, message)
 }
 
-// Writef invokes the underlying Listener with the specified classification and formatted message.
+// Writef invokes the underlying listener with the specified classification and formatted message.
 // If the classification shouldn't be logged or there is no listener then Writef does nothing.
 func Writef(cls Classification, format string, a ...interface{}) {
 	if !Should(cls) {