charts/clustertool/pkg/helper/replace.go

package helper

import (
    "bufio"
    "fmt"
    "io/ioutil"
    "os"
    "strings"
)

// ReplaceInFile reads the content of a file, performs regex replacement, and writes the modified content back to the file.
func ReplaceInFile(filename string, pattern string, replacement string) error {
    // Read the file content
    content, err := ioutil.ReadFile(filename)
    if err != nil {
        return fmt.Errorf("failed to read file: %w", err)
    }

    // Convert content to string
    original := string(content)

    // Replace all instances matching the regex pattern
    replaced := strings.ReplaceAll(original, pattern, replacement)

    // Write the modified content back to the file
    err = ioutil.WriteFile(filename, []byte(replaced), 0644)
    if err != nil {
        return fmt.Errorf("failed to write file: %w", err)
    }

    return nil
}

// ReplaceContentBetweenLines replaces content between specified lines in the target file with content from the source file.
func ReplaceContentBetweenLines(targetFilePath string, sourceFilePath string, from string, till string) error {
    // Read the source file content
    sourceContent, err := ioutil.ReadFile(sourceFilePath)
    if err != nil {
        return fmt.Errorf("failed to read source file: %v", err)
    }

    // Remove the markers from the source content
    sourceContentStr := strings.ReplaceAll(string(sourceContent), from, "")
    sourceContentStr = strings.ReplaceAll(sourceContentStr, till, "")

    // Open the target file
    targetFile, err := os.Open(targetFilePath)
    if err != nil {
        return fmt.Errorf("failed to open target file: %v", err)
    }
    defer targetFile.Close()

    // Read the target file line by line
    var result []string
    scanner := bufio.NewScanner(targetFile)
    inReplaceBlock := false

    for scanner.Scan() {
        line := scanner.Text()

        if strings.Contains(line, from) {
            inReplaceBlock = true
            result = append(result, line)

            // Skip the lines until we find the "till" marker
            for scanner.Scan() {
                line = scanner.Text()
                if strings.Contains(line, till) {
                    break
                }
            }

            // Append the cleaned source content after skipping the block
            result = append(result, sourceContentStr)
        } else if !inReplaceBlock {
            result = append(result, line)
        }

        if inReplaceBlock && strings.Contains(line, till) {
            inReplaceBlock = false
            result = append(result, line)
        }
    }

    if err := scanner.Err(); err != nil {
        return fmt.Errorf("error reading target file: %v", err)
    }

    // Write the result back to the target file
    err = ioutil.WriteFile(targetFilePath, []byte(strings.Join(result, "\n")), 0644)
    if err != nil {
        return fmt.Errorf("failed to write to target file: %v", err)
    }

    return nil
}