Function copyLastLogLines

scripts/debug-log-subset.ts:4–43

()

import path from 'path'

async function copyLastLogLines() {
  const projectRoot = path.join(__dirname, '..')
  const debugLogPath = path.join(projectRoot, 'backend', 'src', 'debug.log')
  const subsetLogPath = path.join(projectRoot, 'backend', 'debug-subset.log')
  const linesToCopy = 100

  try {
    // Check if debug.log exists
    if (!fs.existsSync(debugLogPath)) {
      console.error(`Error: Input file not found at ${debugLogPath}`)
      process.exit(1)
    }

    // Read the debug log file
    const content = await fs.promises.readFile(debugLogPath, 'utf-8')
    const lines = content.split('\n')

    // Get the last N lines (handle files with fewer lines)
    const startLine = Math.max(0, lines.length - linesToCopy)
    // If the last line is empty, we might want to exclude it unless it's the only line
    const relevantLines = lines.slice(startLine, lines.length)
    // Filter out potentially empty last line if file ends with newline and has more than one line
    const lastLines =
      lines.length > 1 && lines[lines.length - 1] === ''
        ? relevantLines.slice(0, -1)
        : relevantLines

    const subsetContent = lastLines.join('\n')

    // Write the subset to the new file
    await fs.promises.writeFile(subsetLogPath, subsetContent, 'utf-8')

    console.log(
      `Successfully copied the last ${lastLines.length} lines from ${debugLogPath} to ${subsetLogPath}`,
    )
  } catch (error) {
    console.error('An error occurred:', error)
    process.exit(1)
  }
}

copyLastLogLines()