From d08877352bf51b70e1aef864e892f451abf9d95a Mon Sep 17 00:00:00 2001
From: Raj Nishtala <rnishtala@sumologic.com>
Date: Fri, 15 Nov 2024 17:33:26 -0700
Subject: [PATCH] Adding an option to specify the string to trim

---
 pkg/ottl/ottlfuncs/README.md         |  8 +++++---
 pkg/ottl/ottlfuncs/func_trim.go      | 13 +++++++++----
 pkg/ottl/ottlfuncs/func_trim_test.go | 25 +++++++++++++++++++------
 3 files changed, 33 insertions(+), 13 deletions(-)

diff --git a/pkg/ottl/ottlfuncs/README.md b/pkg/ottl/ottlfuncs/README.md
index a99445b27ac4..b2fb08c5127b 100644
--- a/pkg/ottl/ottlfuncs/README.md
+++ b/pkg/ottl/ottlfuncs/README.md
@@ -1782,17 +1782,19 @@ If the `target` is not a string or does not exist, the `Split` Converter will re
 
 ### Trim
 
-```Trim(target)```
+```Trim(target, replacement)```
 
-The `Trim` Converter removes the leading and trailing whitespace.
+The `Trim` Converter removes the leading and trailing character (default: whitespace).
 
 If the `target` is not a string or does not exist, the `Trim` Converter will return an error.
 
 `target` is a string.
+`replacement` is an optional string representing the character to replace with.
 
 Examples:
 
-- `Trim(" this is a test ")`
+- `Trim(" this is a test ", " ")`
+- `Trim("!!this is a test!!", "!!")`
 
 ### String
 
diff --git a/pkg/ottl/ottlfuncs/func_trim.go b/pkg/ottl/ottlfuncs/func_trim.go
index fadaf087fffa..f732b0116aca 100644
--- a/pkg/ottl/ottlfuncs/func_trim.go
+++ b/pkg/ottl/ottlfuncs/func_trim.go
@@ -12,7 +12,8 @@ import (
 )
 
 type TrimArguments[K any] struct {
-	Target ottl.StringGetter[K]
+	Target      ottl.StringGetter[K]
+	Replacement ottl.Optional[string]
 }
 
 func NewTrimFactory[K any]() ottl.Factory[K] {
@@ -26,15 +27,19 @@ func createTrimFunction[K any](_ ottl.FunctionContext, oArgs ottl.Arguments) (ot
 		return nil, fmt.Errorf("TrimFactory args must be of type *TrimArguments[K]")
 	}
 
-	return trim(args.Target), nil
+	return trim(args.Target, args.Replacement), nil
 }
 
-func trim[K any](target ottl.StringGetter[K]) ottl.ExprFunc[K] {
+func trim[K any](target ottl.StringGetter[K], replacement ottl.Optional[string]) ottl.ExprFunc[K] {
 	return func(ctx context.Context, tCtx K) (any, error) {
+		replacementString := replacement.Get()
 		val, err := target.Get(ctx, tCtx)
 		if err != nil {
 			return nil, err
 		}
-		return strings.Trim(val, " "), nil
+		if replacementString == "" {
+			return strings.Trim(val, " "), nil
+		}
+		return strings.Trim(val, replacementString), nil
 	}
 }
diff --git a/pkg/ottl/ottlfuncs/func_trim_test.go b/pkg/ottl/ottlfuncs/func_trim_test.go
index a69b71b6f509..8814857258b0 100644
--- a/pkg/ottl/ottlfuncs/func_trim_test.go
+++ b/pkg/ottl/ottlfuncs/func_trim_test.go
@@ -14,9 +14,10 @@ import (
 
 func Test_trim(t *testing.T) {
 	tests := []struct {
-		name     string
-		target   ottl.StringGetter[any]
-		expected any
+		name        string
+		target      ottl.StringGetter[any]
+		replacement ottl.Optional[string]
+		expected    any
 	}{
 		{
 			name: "trim string",
@@ -25,7 +26,8 @@ func Test_trim(t *testing.T) {
 					return " this is a test ", nil
 				},
 			},
-			expected: "this is a test",
+			replacement: ottl.NewTestingOptional[string](" "),
+			expected:    "this is a test",
 		},
 		{
 			name: "trim empty string",
@@ -34,12 +36,23 @@ func Test_trim(t *testing.T) {
 					return "", nil
 				},
 			},
-			expected: "",
+			replacement: ottl.NewTestingOptional[string](" "),
+			expected:    "",
+		},
+		{
+			name: "trim empty replacement string",
+			target: &ottl.StandardStringGetter[any]{
+				Getter: func(_ context.Context, _ any) (any, error) {
+					return " this is a test ", nil
+				},
+			},
+			replacement: ottl.Optional[string]{},
+			expected:    "this is a test",
 		},
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
-			exprFunc := trim(tt.target)
+			exprFunc := trim(tt.target, tt.replacement)
 			result, err := exprFunc(nil, nil)
 			assert.NoError(t, err)
 			assert.Equal(t, tt.expected, result)