Alertmanager: Add alerting logger (#8170)

* Alertmanager: Add alerting logger

* make linter ignore unused functions in log.go

* license header

pkg/alertmanager/log.go

@@ -0,0 +1,58 @@
+// SPDX-License-Identifier: AGPL-3.0-only
+
+package alertmanager
+
+import (
+	"github.com/go-kit/log"
+	"github.com/go-kit/log/level"
+	alertingLogging "github.com/grafana/alerting/logging"
+)
+
+// alertingLogger implements the alertingLogging.Logger interface.
+type alertingLogger struct {
+	kitLogger log.Logger
+}
+
+// newLoggerFactory returns a function that implements the alertingLogging.LoggerFactory interface.
+//
+//lint:ignore U1000 Ignore unused functions for now, they will be used to create the Grafana notifiers.
+func newLoggerFactory(logger log.Logger) alertingLogging.LoggerFactory {
+	return func(loggerName string, ctx ...any) alertingLogging.Logger {
+		keyvals := append([]any{"logger", loggerName}, ctx...)
+		return &alertingLogger{kitLogger: log.With(logger, keyvals...)}
+	}
+}
+
+func (l *alertingLogger) New(ctx ...any) alertingLogging.Logger {
+	return &alertingLogger{log.With(l.kitLogger, ctx...)}
+}
+
+func (l *alertingLogger) Log(keyvals ...any) error {
+	return l.kitLogger.Log(keyvals...)
+}
+
+func (l *alertingLogger) Debug(msg string, ctx ...any) {
+	args := buildKeyvals(msg, ctx)
+	level.Debug(l.kitLogger).Log(args...)
+}
+
+func (l *alertingLogger) Info(msg string, ctx ...any) {
+	args := buildKeyvals(msg, ctx)
+	level.Info(l.kitLogger).Log(args...)
+}
+
+func (l *alertingLogger) Warn(msg string, ctx ...any) {
+	args := buildKeyvals(msg, ctx)
+	level.Warn(l.kitLogger).Log(args...)
+}
+
+func (l *alertingLogger) Error(msg string, ctx ...any) {
+	args := buildKeyvals(msg, ctx)
+	level.Error(l.kitLogger).Log(args...)
+}
+
+// buildKeyvals builds the keyvals for the log message.
+// It adds "msg" and the message string as the first two elements.
+func buildKeyvals(msg string, ctx []any) []any {
+	return append([]any{"msg", msg}, ctx...)
+}

pkg/alertmanager/log_test.go

@@ -0,0 +1,50 @@
+// SPDX-License-Identifier: AGPL-3.0-only
+
+package alertmanager
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestBuildKeyvals(t *testing.T) {
+	tests := []struct {
+		name string
+		msg  string
+		ctx  []any
+		want []any
+	}{
+		{
+			name: "empty context slice",
+			msg:  "test message",
+			ctx:  []any{},
+			want: []any{"msg", "test message"},
+		},
+		{
+			name: "nil context slice",
+			msg:  "test message",
+			ctx:  nil,
+			want: []any{"msg", "test message"},
+		},
+		{
+			name: "context slice with one element",
+			msg:  "test message",
+			ctx:  []any{"key1"},
+			want: []any{"msg", "test message", "key1"},
+		},
+		{
+			name: "context slice with two elements",
+			msg:  "test message",
+			ctx:  []any{"key1", "value1"},
+			want: []any{"msg", "test message", "key1", "value1"},
+		},
+	}
+
+	for _, test := range tests {
+		t.Run(test.name, func(t *testing.T) {
+			got := buildKeyvals(test.msg, test.ctx)
+			require.Equal(t, test.want, got)
+		})
+	}
+}