GODRIVER-3090 Optimize logging truncation for large documents

bson/raw_test.go

@@ -356,7 +356,7 @@ func BenchmarkRawString(b *testing.B) {
 	// Create 1KiB and 128B strings to exercise the string-heavy call paths in
 	// the "Raw.String" method.
 	var buf strings.Builder
-	for i := 0; i < 128; i++ {
+	for i := 0; i < 16000000; i++ {
 		buf.WriteString("abcdefgh")
 	}
 	str1k := buf.String()
@@ -405,26 +405,175 @@ func BenchmarkRawString(b *testing.B) {
 					Nested string
 				}
 				Key2 string
-				Key3 int64
+				Key3 []string
 				Key4 float64
 			}{
 				Key1: struct{ Nested string }{Nested: str1k},
 				Key2: str1k,
-				Key3: 1234567890,
+				Key3: []string{str1k, str1k, str1k, str1k},
 				Key4: 1234567890.123456789,
 			},
 		},
+		// Very voluminous document with hundreds of thousands of keys
+		{
+			description: "very_voluminous_document",
+			value:       createVoluminousDocument(100000),
+		},
+		// Document containing large strings and values
+		{
+			description: "large_strings_and_values",
+			value:       createLargeStringsDocument(10),
+		},
+		// Document with massive arrays that are large
+		{
+			description: "massive_arrays",
+			value:       createMassiveArraysDocument(100000),
+		},
 	}
 
 	for _, tc := range cases {
 		b.Run(tc.description, func(b *testing.B) {
 			bs, err := Marshal(tc.value)
 			require.NoError(b, err)
 
+			b.ReportAllocs()
 			b.ResetTimer()
 			for i := 0; i < b.N; i++ {
 				_ = Raw(bs).String()
 			}
 		})
+
+		b.Run(tc.description+"_StringN", func(b *testing.B) {
+			bs, err := Marshal(tc.value)
+			require.NoError(b, err)
+
+			b.ReportAllocs()
+			b.ResetTimer()
+			for i := 0; i < b.N; i++ {
+				_ = bsoncore.Document(bs).StringN(1024) // Assuming you want to limit to 1024 bytes for this benchmark
+			}
+		})
 	}
 }
+
+func TestComplexDocuments_StringN(t *testing.T) {
+	testCases := []struct {
+		description string
+		n           int
+		doc         any
+	}{
+		{"n>0, massive array documents", 1000, createMassiveArraysDocument(1000)},
+		{"n>0, voluminous document with unique values", 1000, createUniqueVoluminousDocument(t, 1000)},
+		{"n>0, large single document", 1000, createLargeSingleDoc(t)},
+		{"n>0, voluminous document with arrays containing documents", 1000, createVoluminousArrayDocuments(t, 1000)},
+	}
+
+	for _, tc := range testCases {
+		t.Run(tc.description, func(t *testing.T) {
+			bson, _ := Marshal(tc.doc)
+			bsonDoc := bsoncore.Document(bson)
+
+			got := bsonDoc.StringN(tc.n)
+			assert.Equal(t, tc.n, len(got))
+		})
+	}
+}
+
+// createVoluminousDocument generates a document with a specified number of keys, simulating a very large document in terms of the number of keys.
+func createVoluminousDocument(numKeys int) D {
+	d := make(D, numKeys)
+	for i := 0; i < numKeys; i++ {
+		d = append(d, E{Key: fmt.Sprintf("key%d", i), Value: "value"})
+	}
+	return d
+}
+
+// createLargeStringsDocument generates a document with large string values, simulating a document with very large data values.
+func createLargeStringsDocument(sizeMB int) D {
+	largeString := strings.Repeat("a", sizeMB*1024*1024)
+	return D{
+		{Key: "largeString1", Value: largeString},
+		{Key: "largeString2", Value: largeString},
+		{Key: "largeString3", Value: largeString},
+		{Key: "largeString4", Value: largeString},
+	}
+}
+
+// createMassiveArraysDocument generates a document with massive arrays, simulating a document that contains large arrays of data.
+func createMassiveArraysDocument(arraySize int) D {
+	massiveArray := make([]string, arraySize)
+	for i := 0; i < arraySize; i++ {
+		massiveArray[i] = "value"
+	}
+
+	return D{
+		{Key: "massiveArray1", Value: massiveArray},
+		{Key: "massiveArray2", Value: massiveArray},
+		{Key: "massiveArray3", Value: massiveArray},
+		{Key: "massiveArray4", Value: massiveArray},
+	}
+}
+
+// createUniqueVoluminousDocument creates a BSON document with multiple key value pairs and unique value types.
+func createUniqueVoluminousDocument(t *testing.T, size int) bsoncore.Document {
+	t.Helper()
+
+	docs := make(D, size)
+
+	for i := 0; i < size; i++ {
+		docs = append(docs, E{
+			Key: "x", Value: NewObjectID(),
+		})
+		docs = append(docs, E{
+			Key: "z", Value: "y",
+		})
+	}
+
+	bsonData, err := Marshal(docs)
+	assert.NoError(t, err)
+
+	return bsoncore.Document(bsonData)
+}
+
+// createLargeSingleDoc creates a large single BSON document.
+func createLargeSingleDoc(t *testing.T) bsoncore.Document {
+	t.Helper()
+
+	var b strings.Builder
+	b.Grow(1048577)
+
+	for i := 0; i < 1048577; i++ {
+		b.WriteByte(0)
+	}
+	s := b.String()
+
+	doc := D{
+		{Key: "x", Value: s},
+	}
+
+	bsonData, err := Marshal(doc)
+	assert.NoError(t, err)
+
+	return bsoncore.Document(bsonData)
+}
+
+// createVoluminousArrayDocuments creates a volumninous BSON document with arrays containing documents.
+func createVoluminousArrayDocuments(t *testing.T, size int) bsoncore.Document {
+	t.Helper()
+
+	docs := make(D, size)
+
+	for i := 0; i < size; i++ {
+		docs = append(docs, E{
+			Key: "x", Value: NewObjectID(),
+		})
+		docs = append(docs, E{
+			Key: "z", Value: A{D{{Key: "x", Value: "y"}}},
+		})
+	}
+
+	bsonData, err := Marshal(docs)
+	assert.NoError(t, err)
+
+	return bsoncore.Document(bsonData)
+}

internal/bsoncoreutil/bsoncoreutil.go

@@ -0,0 +1,40 @@
+// Copyright (C) MongoDB, Inc. 2024-present.
+//
+// Licensed under the Apache License, Version 2.0 (the "License"); you may
+// not use this file except in compliance with the License. You may obtain
+// a copy of the License at http://www.apache.org/licenses/LICENSE-2.0
+
+package bsoncoreutil
+
+// Truncate truncates a given string for a certain width
+func Truncate(str string, width int) string {
+	if width == 0 {
+		return ""
+	}
+
+	if len(str) <= width {
+		return str
+	}
+
+	// Truncate the byte slice of the string to the given width.
+	newStr := str[:width]
+
+	// Check if the last byte is at the beginning of a multi-byte character.
+	// If it is, then remove the last byte.
+	if newStr[len(newStr)-1]&0xC0 == 0xC0 {
+		return newStr[:len(newStr)-1]
+	}
+
+	// Check if the last byte is a multi-byte character
+	if newStr[len(newStr)-1]&0xC0 == 0x80 {
+		// If it is, step back until you we are at the start of a character
+		for i := len(newStr) - 1; i >= 0; i-- {
+			if newStr[i]&0xC0 == 0xC0 {
+				// Truncate at the end of the character before the character we stepped back to
+				return newStr[:i]
+			}
+		}
+	}
+
+	return newStr
+}

internal/bsoncoreutil/bsoncoreutil_test.go

@@ -0,0 +1,59 @@
+// Copyright (C) MongoDB, Inc. 2024-present.
+//
+// Licensed under the Apache License, Version 2.0 (the "License"); you may
+// not use this file except in compliance with the License. You may obtain
+// a copy of the License at http://www.apache.org/licenses/LICENSE-2.0
+
+package bsoncoreutil
+
+import (
+	"testing"
+
+	"go.mongodb.org/mongo-driver/v2/internal/assert"
+)
+
+func TestTruncate(t *testing.T) {
+	t.Parallel()
+
+	for _, tcase := range []struct {
+		name     string
+		arg      string
+		width    int
+		expected string
+	}{
+		{
+			name:     "empty",
+			arg:      "",
+			width:    0,
+			expected: "",
+		},
+		{
+			name:     "short",
+			arg:      "foo",
+			width:    1000,
+			expected: "foo",
+		},
+		{
+			name:     "long",
+			arg:      "foo bar baz",
+			width:    9,
+			expected: "foo bar b",
+		},
+		{
+			name:     "multi-byte",
+			arg:      "你好",
+			width:    4,
+			expected: "你",
+		},
+	} {
+		tcase := tcase
+
+		t.Run(tcase.name, func(t *testing.T) {
+			t.Parallel()
+
+			actual := Truncate(tcase.arg, tcase.width)
+			assert.Equal(t, tcase.expected, actual)
+		})
+	}
+
+}

internal/logger/logger.go

@@ -13,6 +13,10 @@ import (
 	"os"
 	"strconv"
 	"strings"
+
+	"go.mongodb.org/mongo-driver/v2/bson"
+	"go.mongodb.org/mongo-driver/v2/internal/bsoncoreutil"
+	"go.mongodb.org/mongo-driver/v2/x/bsonx/bsoncore"
 )
 
 // DefaultMaxDocumentLength is the default maximum number of bytes that can be
@@ -230,46 +234,32 @@ func selectComponentLevels(componentLevels map[Component]Level) map[Component]Le
 	return selected
 }
 
-// truncate will truncate a string to the given width, appending "..." to the
-// end of the string if it is truncated. This routine is safe for multi-byte
-// characters.
-func truncate(str string, width uint) string {
-	if width == 0 {
-		return ""
-	}
-
-	if len(str) <= int(width) {
-		return str
+// FormatDocument formats a BSON document or RawValue for logging. The document is truncated
+// to the given width.
+func FormatDocument(msg bson.Raw, width uint) string {
+	if len(msg) == 0 {
+		return "{}"
 	}
 
-	// Truncate the byte slice of the string to the given width.
-	newStr := str[:width]
+	str := bsoncore.Document(msg).StringN(int(width))
 
-	// Check if the last byte is at the beginning of a multi-byte character.
-	// If it is, then remove the last byte.
-	if newStr[len(newStr)-1]&0xC0 == 0xC0 {
-		return newStr[:len(newStr)-1] + TruncationSuffix
+	// If the last byte is not a closing bracket, then the document was truncated
+	if len(str) > 0 && str[len(str)-1] != '}' {
+		str += TruncationSuffix
 	}
 
-	// Check if the last byte is in the middle of a multi-byte character. If
-	// it is, then step back until we find the beginning of the character.
-	if newStr[len(newStr)-1]&0xC0 == 0x80 {
-		for i := len(newStr) - 1; i >= 0; i-- {
-			if newStr[i]&0xC0 == 0xC0 {
-				return newStr[:i] + TruncationSuffix
-			}
-		}
-	}
-
-	return newStr + TruncationSuffix
+	return str
 }
 
-// FormatMessage formats a BSON document for logging. The document is truncated
+// FormatString formats a String for logging. The string is truncated
 // to the given width.
-func FormatMessage(msg string, width uint) string {
-	if len(msg) == 0 {
-		return "{}"
+func FormatString(str string, width uint) string {
+	strTrunc := bsoncoreutil.Truncate(str, int(width))
+
+	// Checks if the string was truncating by comparing the lengths of the two strings.
+	if len(strTrunc) < len(str) {
+		strTrunc += TruncationSuffix
 	}
 
-	return truncate(msg, width)
+	return strTrunc
 }