我的lambda在代码完成之前就结束了,我不知道为什么

我的Lambda函数在所有代码运行之前就结束了。我无法在此代码中检索转换后的文件URL。为什么?

export const handler = async (event, context) => {
  // Geth the object from S3
  const bucket = "s3fileconverterinput";
  const key = event.Records[0].s3.object.key;

  var file = await getObject(bucket, key);
  console.log(file);
  var filePath = "/tmp/" + key;
  fs.writeFile(filePath, file, (err) => {
    if (err) {
    } else {
      console.log("File saved successfully!");
      convertapi.convert("pdf", { File: filePath }).then(function (result) {
        console.log("Converted file url: " + result.file.url);

      });
    }
  });
};