Excluding the header docker exec from buffer.

dockerutil.js

const EXEC_HEADER_LEN = 8;
const EXEC_HEADER_STREAM_LEN = 4;
const EXEC_HEADER_SIZE_LEN = 4;

function excludeDockerExecHeader(buffer) {
  if (buffer.length <= EXEC_HEADER_LEN) {
    return "";
  }

  let bodyLength = buffer.readUInt32BE(EXEC_HEADER_STREAM_LEN, EXEC_HEADER_SIZE_LEN);
  let nextOffset = EXEC_HEADER_LEN + bodyLength;
  let bodyBuffer = buffer.slice(EXEC_HEADER_LEN, nextOffset);
  return bodyBuffer.toString() + excludeDockerExecHeader(buffer.slice(nextOffset));
}