Severity impl fmt.Stringer

Author: MrAlias

processors/minsev/severity.go

@@ -4,6 +4,7 @@
 package minsev // import "go.opentelemetry.io/contrib/processors/minsev"
 
 import (
+	"fmt"
 	"sync/atomic"
 
 	"go.opentelemetry.io/otel/log"
@@ -15,6 +16,9 @@ import (
 // as errors and critical events).
 type Severity int
 
+// Ensure Severity implements fmt.Stringer.
+var _ fmt.Stringer = Severity(0)
+
 // Severity values defined by OpenTelemetry.
 const (
 	// A fine-grained debugging log record. Typically disabled in default
@@ -99,6 +103,50 @@ var translations = map[Severity]log.Severity{
 	SeverityFatal4: log.SeverityFatal4,
 }
 
+// String returns a name for the severity level. If the severity level has a
+// name, then that name in uppercase is returned. If the severity level is
+// outside named values, then an signed integer is appended to the uppercased
+// name.
+//
+// Examples:
+//
+//	SeverityWarn1.String() => "WARN"
+//	(SeverityInfo1+2).String() => "INFO2"
+//	(SeverityFatal4+2).String() => "FATAL+6"
+//	(SeverityTrace1-3).String() => "TRACE-3"
+func (s Severity) String() string {
+	str := func(base string, val Severity) string {
+		switch val {
+		case 0:
+			return base
+		case 1, 2, 3:
+			// No sign for known fine-grained severity values.
+			return fmt.Sprintf("%s%d", base, val+1)
+		}
+
+		if val > 0 {
+			// Exclude zero from positive scale count.
+			val++
+		}
+		return fmt.Sprintf("%s%+d", base, val)
+	}
+
+	switch {
+	case s < SeverityDebug1:
+		return str("TRACE", s-SeverityTrace1)
+	case s < SeverityInfo1:
+		return str("DEBUG", s-SeverityDebug1)
+	case s < SeverityWarn1:
+		return str("INFO", s-SeverityInfo1)
+	case s < SeverityError1:
+		return str("WARN", s-SeverityWarn1)
+	case s < SeverityFatal1:
+		return str("ERROR", s-SeverityError1)
+	default:
+		return str("FATAL", s-SeverityFatal1)
+	}
+}
+
 // A SeverityVar is a [Severity] variable, to allow a [LogProcessor] severity
 // to change dynamically. It implements [Severitier] as well as a Set method,
 // and it is safe for use by multiple goroutines.

processors/minsev/severity_test.go

@@ -7,6 +7,7 @@ import (
 	"sync"
 	"testing"
 
+	"github.com/stretchr/testify/assert"
 	"go.opentelemetry.io/otel/log"
 )
 
@@ -36,3 +37,54 @@ func TestSeverityVarConcurrentSafe(*testing.T) {
 
 	wg.Wait()
 }
+
+var validEncodingTests = []struct {
+	Name     string
+	Severity Severity
+	Text     string
+}{
+	// Use offset for values less than SeverityTrace1.
+	{"SeverityTraceMinus2", SeverityTrace - 2, "TRACE-2"},
+
+	{"SeverityTrace", SeverityTrace, "TRACE"},
+	{"SeverityTrace1", SeverityTrace1, "TRACE"},
+	{"SeverityTrace2", SeverityTrace2, "TRACE2"},
+	{"SeverityTrace3", SeverityTrace3, "TRACE3"},
+	{"SeverityTrace4", SeverityTrace4, "TRACE4"},
+	{"SeverityDebug", SeverityDebug, "DEBUG"},
+	{"SeverityDebug1", SeverityDebug1, "DEBUG"},
+	{"SeverityDebug2", SeverityDebug2, "DEBUG2"},
+	{"SeverityDebug3", SeverityDebug3, "DEBUG3"},
+	{"SeverityDebug4", SeverityDebug4, "DEBUG4"},
+	{"SeverityInfo", SeverityInfo, "INFO"},
+	{"SeverityInfo1", SeverityInfo1, "INFO"},
+	{"SeverityInfo2", SeverityInfo2, "INFO2"},
+	{"SeverityInfo3", SeverityInfo3, "INFO3"},
+	{"SeverityInfo4", SeverityInfo4, "INFO4"},
+	{"SeverityWarn", SeverityWarn, "WARN"},
+	{"SeverityWarn1", SeverityWarn1, "WARN"},
+	{"SeverityWarn2", SeverityWarn2, "WARN2"},
+	{"SeverityWarn3", SeverityWarn3, "WARN3"},
+	{"SeverityWarn4", SeverityWarn4, "WARN4"},
+	{"SeverityError", SeverityError, "ERROR"},
+	{"SeverityError1", SeverityError1, "ERROR"},
+	{"SeverityError2", SeverityError2, "ERROR2"},
+	{"SeverityError3", SeverityError3, "ERROR3"},
+	{"SeverityError4", SeverityError4, "ERROR4"},
+	{"SeverityFatal", SeverityFatal, "FATAL"},
+	{"SeverityFatal1", SeverityFatal1, "FATAL"},
+	{"SeverityFatal2", SeverityFatal2, "FATAL2"},
+	{"SeverityFatal3", SeverityFatal3, "FATAL3"},
+	{"SeverityFatal4", SeverityFatal4, "FATAL4"},
+
+	// Use offset for values greater than SeverityFatal4.
+	{"SeverityFatal4Plus2", SeverityFatal4 + 2, "FATAL+6"},
+}
+
+func TestSeverityString(t *testing.T) {
+	for _, test := range validEncodingTests {
+		t.Run(test.Name, func(t *testing.T) {
+			assert.Equal(t, test.Text, test.Severity.String())
+		})
+	}
+}