From be7773d48118387fdcec31a04753450f4fe0e959 Mon Sep 17 00:00:00 2001
From: Cheng-Zhen Yang <chengzhenyang@gmail.com>
Date: Sun, 27 Oct 2024 02:00:22 +1300
Subject: [PATCH] Simpler level transformer

---
 bridges/otellogr/example_test.go |  4 ++--
 bridges/otellogr/logsink.go      | 32 ++++++++++++++------------------
 bridges/otellogr/logsink_test.go | 12 +++++-------
 3 files changed, 21 insertions(+), 27 deletions(-)

diff --git a/bridges/otellogr/example_test.go b/bridges/otellogr/example_test.go
index 10cfda271c9..e8858a7521f 100644
--- a/bridges/otellogr/example_test.go
+++ b/bridges/otellogr/example_test.go
@@ -20,8 +20,8 @@ func Example() {
 		"my/pkg/name",
 		otellogr.WithLoggerProvider(provider),
 		// Optionally, set the log level severity mapping.
-		otellogr.WithLevelSeverity(func(i int) log.Severity {
-			switch i {
+		otellogr.WithLevelSeverity(func(level int) log.Severity {
+			switch level {
 			case 0:
 				return log.SeverityInfo
 			case 1:
diff --git a/bridges/otellogr/logsink.go b/bridges/otellogr/logsink.go
index bac072a2063..7e51e815a30 100644
--- a/bridges/otellogr/logsink.go
+++ b/bridges/otellogr/logsink.go
@@ -18,27 +18,17 @@
 //     added as attributes. If there are multiple [context.Context] the last one
 //     is used.
 //
-// The V-level is transformed by using the [WithLevelSeverity] option. If this is
-// not provided it would default to a function that inverses the level with an
-// offset such that [logr.Info] is transformed to [log.SeverityInfo] as the higher
-// the V-level of a log line, the less critical it is considered. By default,
-// V-level higher than 8 is not supported and will result in negative severity.
-// For example:
+// The V-level is transformed by using the [WithLevelSeverity] option. If option is
+// not provided then V-level is transformed in the following way:
 //
-//   - [logr.Info] is transformed to [log.SeverityInfo].
-//   - [logr.V(0)] is transformed to [log.SeverityInfo].
-//   - [logr.V(1)] is transformed to [log.SeverityDebug4].
-//   - [logr.V(2)] is transformed to [log.SeverityDebug3].
-//   - ...
-//   - [logr.V(8)] is transformed to [log.SeverityTrace].
-//   - [logr.V(9)] is transformed to [log.SeverityUndefined].
-//   - [logr.V(10)] is transformed to log.Severity(-1).
-//   - [logr.Error] is transformed to [log.SeverityError].
+//   - logr.Info and logr.V(0) are transformed to [log.SeverityInfo].
+//   - logr.V(1) is transformed to [log.SeverityDebug].
+//   - logr.V(2) and higher are transformed to [log.SeverityTrace].
 //
 // If possible, look at alternative log bridges that provide less abstract log
 // level mapping such as [go.opentelemetry.io/contrib/bridges/otelslog],
 // [go.opentelemetry.io/contrib/bridges/otelzap], or
-// [go.opentelemetry.io/contrib/bridges/otellogrus]. Which provide more direct
+// [go.opentelemetry.io/contrib/bridges/otellogrus]. They provide more direct
 // translation of log levels.
 //
 // KeysAndValues values are transformed based on their type. The following types are
@@ -97,8 +87,14 @@ func newConfig(options []Option) config {
 
 	if c.levelSeverity == nil {
 		c.levelSeverity = func(level int) log.Severity {
-			const sevOffset = int(log.SeverityInfo)
-			return log.Severity(sevOffset - level)
+			switch level {
+			case 0:
+				return log.SeverityInfo
+			case 1:
+				return log.SeverityDebug
+			default:
+				return log.SeverityTrace
+			}
 		}
 	}
 
diff --git a/bridges/otellogr/logsink_test.go b/bridges/otellogr/logsink_test.go
index 30820ea181f..9e310e443e0 100644
--- a/bridges/otellogr/logsink_test.go
+++ b/bridges/otellogr/logsink_test.go
@@ -145,19 +145,17 @@ func TestLogSink(t *testing.T) {
 		{
 			name: "info_with_level_severity",
 			f: func(l *logr.Logger) {
+				l.V(0).Info("msg")
 				l.V(1).Info("msg")
-				l.V(4).Info("msg")
-				l.V(8).Info("msg")
-				l.V(9).Info("msg")
-				l.V(10).Info("msg")
+				l.V(2).Info("msg")
+				l.V(3).Info("msg")
 			},
 			wantRecords: map[string][]log.Record{
 				name: {
-					buildRecord(log.StringValue("msg"), time.Time{}, log.SeverityDebug4, nil),
+					buildRecord(log.StringValue("msg"), time.Time{}, log.SeverityInfo, nil),
 					buildRecord(log.StringValue("msg"), time.Time{}, log.SeverityDebug, nil),
 					buildRecord(log.StringValue("msg"), time.Time{}, log.SeverityTrace, nil),
-					buildRecord(log.StringValue("msg"), time.Time{}, log.SeverityUndefined, nil),
-					buildRecord(log.StringValue("msg"), time.Time{}, log.Severity(-1), nil),
+					buildRecord(log.StringValue("msg"), time.Time{}, log.SeverityTrace, nil),
 				},
 			},
 		},