feat(expressions): add CEL log filtering calls

Signed-off-by: Xe Iaso <me@xeiaso.net>

lib/policy/expressions/logging_test.go

@@ -0,0 +1,65 @@
+package expressions
+
+import (
+	"context"
+	"fmt"
+	"io"
+	"log/slog"
+	"strings"
+	"testing"
+	"time"
+)
+
+func BenchmarkFilter(b *testing.B) {
+	log := slog.New(slog.NewTextHandler(io.Discard, nil))
+	filter, err := NewFilter(log, "benchmark", `msg == "hello"`)
+	if err != nil {
+		b.Fatalf("NewFilter() error = %v", err)
+	}
+
+	record := slog.NewRecord(time.Now(), slog.LevelInfo, "hello", 0)
+	record.AddAttrs(slog.String("foo", "bar"))
+
+	ctx := context.Background()
+
+	b.ReportAllocs()
+
+	for b.Loop() {
+		filter.Filter(ctx, record)
+	}
+}
+
+func BenchmarkFilterAttributes(b *testing.B) {
+	for _, numAttrs := range []int{1, 2, 4, 8, 16, 32} {
+		b.Run(fmt.Sprintf("%d_attributes", numAttrs), func(b *testing.B) {
+			log := slog.New(slog.NewTextHandler(io.Discard, nil))
+
+			var sb strings.Builder
+			sb.WriteString(`msg == "hello" && "foo" in attrs`)
+
+			attrs := make([]slog.Attr, numAttrs)
+			for i := range numAttrs {
+				key := fmt.Sprintf("foo%d", i)
+				val := "bar"
+				attrs[i] = slog.String(key, val)
+			}
+
+			filter, err := NewFilter(log, "benchmark", sb.String())
+			if err != nil {
+				b.Fatalf("NewFilter() error = %v", err)
+			}
+
+			record := slog.NewRecord(time.Now(), slog.LevelInfo, "hello", 0)
+			record.AddAttrs(attrs...)
+
+			ctx := context.Background()
+
+			b.ResetTimer()
+			b.ReportAllocs()
+
+			for b.Loop() {
+				filter.Filter(ctx, record)
+			}
+		})
+	}
+}