Function readLogs

apps/vis/server/src/lib/log-reader.ts:73–100

(
  paths: readonly string[],
  maxLines = MAX_LINES,
)

 * The MAX_LINES tail cap applies across the combined set.
 */
export async function readLogs(
  paths: readonly string[],
  maxLines = MAX_LINES,
): Promise<LogReadResult | null> {
  const allLines: string[] = [];
  let read = 0;
  for (const path of paths) {
    let raw: string;
    try {
      raw = await readFile(path, 'utf8');
    } catch {
      continue;
    }
    read += 1;
    const lines = raw.split(/\r?\n/);
    // Drop a single trailing empty line from each file's final newline.
    if (lines.length > 0 && lines.at(-1) === '') lines.pop();
    for (const line of lines) allLines.push(line);
  }
  if (read === 0) return null;

  const truncated = allLines.length > maxLines;
  const startLineNo = truncated ? allLines.length - maxLines : 0;
  const slice = truncated ? allLines.slice(startLineNo) : allLines;

  const lines: LogLine[] = slice.map((text, i) => parseLogLine(text, startLineNo + i + 1));
  return { lines, truncated };
}

export function parseLogLine(raw: string, lineNo: number): LogLine {
  const m = LINE_RE.exec(raw);