Severity impl json.Marshaler/json.Unmarshaler

Author: MrAlias

processors/minsev/severity.go

@@ -5,6 +5,7 @@ package minsev // import "go.opentelemetry.io/contrib/processors/minsev"
 
 import (
 	"encoding"
+	"encoding/json"
 	"errors"
 	"fmt"
 	"strconv"
@@ -23,6 +24,10 @@ type Severity int
 var (
 	// Ensure Severity implements fmt.Stringer.
 	_ fmt.Stringer = Severity(0)
+	// Ensure Severity implements json.Marshaler.
+	_ json.Marshaler = Severity(0)
+	// Ensure Severity implements json.Unmarshaler.
+	_ json.Unmarshaler = (*Severity)(nil)
 	// Ensure Severity implements encoding.TextMarshaler.
 	_ encoding.TextMarshaler = Severity(0)
 	// Ensure Severity implements encoding.TextUnmarshaler.
@@ -161,6 +166,26 @@ func (s Severity) String() string {
 	}
 }
 
+// MarshalJSON implements [encoding/json.Marshaler] by quoting the output of
+// [Severity.String].
+func (s Severity) MarshalJSON() ([]byte, error) {
+	// AppendQuote is sufficient for JSON-encoding all Severity strings. They
+	// don't contain any runes that would produce invalid JSON when escaped.
+	return strconv.AppendQuote(nil, s.String()), nil
+}
+
+// UnmarshalJSON implements [encoding/json.Unmarshaler] It accepts any string
+// produced by [Severity.MarshalJSON], ignoring case. It also accepts numeric
+// offsets that would result in a different string on output. For example,
+// "ERROR-8" will unmarshal as SeverityInfo.
+func (s *Severity) UnmarshalJSON(data []byte) error {
+	str, err := strconv.Unquote(string(data))
+	if err != nil {
+		return err
+	}
+	return s.parse(str)
+}
+
 // AppendText implements [encoding.TextAppender] by calling [Severity.String].
 func (s Severity) AppendText(b []byte) ([]byte, error) {
 	return append(b, s.String()...), nil

processors/minsev/severity_test.go

@@ -4,6 +4,7 @@
 package minsev
 
 import (
+	"encoding/json"
 	"sync"
 	"testing"
 
@@ -157,6 +158,48 @@ func TestSeverityString(t *testing.T) {
 	}
 }
 
+func TestSeverityMarshalJSON(t *testing.T) {
+	for _, test := range validEncodingTests {
+		t.Run(test.Name, func(t *testing.T) {
+			got, err := json.Marshal(test.Severity)
+			require.NoError(t, err)
+			assert.Equal(t, `"`+test.Text+`"`, string(got))
+		})
+	}
+}
+
+func TestSeverityUnmarshalJSON(t *testing.T) {
+	for _, test := range validDecodingTests {
+		t.Run(test.Name, func(t *testing.T) {
+			var sev Severity
+			data := []byte(`"` + test.Text + `"`)
+			require.NoError(t, sev.UnmarshalJSON(data))
+			const msg = "UnmarshalJSON(%q) != %d (%[2]s)"
+			assert.Equalf(t, test.Severity, sev, msg, data, test.Severity)
+		})
+	}
+}
+
+func TestSeverityUnmarshalJSONError(t *testing.T) {
+	invalidJSON := []string{
+		`"UNKNOWN"`,
+		`"DEBUG3+abc"`,
+		`"INFO+abc"`,
+		`"ERROR-xyz"`,
+		`"not-a-level"`,
+		`invalid-json`,
+		`42`, // number instead of string
+	}
+
+	for _, test := range invalidJSON {
+		t.Run(test, func(t *testing.T) {
+			var sev Severity
+			err := sev.UnmarshalJSON([]byte(test))
+			assert.Error(t, err)
+		})
+	}
+}
+
 func TestSeverityMarshalText(t *testing.T) {
 	for _, test := range validEncodingTests {
 		t.Run(test.Name, func(t *testing.T) {