node.js – AWS Lambda copyObject“在完成请求之前退出流程”

但是,AWScopyObject似乎没有执行.我收到以下错误

{
       "errorMessage": "Process exited before completing request"
 }

导致此错误的代码如下;

console.log('Loading function');
var AWS = require('aws-sdk');
var s3 = new AWS.S3();

exports.handler = function(event,context) {
    var srcBucket = event.Records[0].s3.bucket.name;
    var srcKey    = event.Records[0].s3.object.key;
    var dstKey    = srcBucket+'/backup/'+ Date.Now() + '-' +srcKey;

    console.log(srcKey);
    console.log(dstKey);

    var copyParams = {
        Bucket: srcBucket,CopySource : srcBucket + '/' + srcKey,Key: dstKey
    };

s3.copyObject(
    copyParams,function (err,data) {
        if (err) {
            console.log("ERROR copyObject");
            console.log(err);
        }
        else {
            console.log('SUCCESS copyObject');
        }
        context.done();
    });

};

什么可能导致lambda在AWSCopyObject回调之前退出？根据https://aws.amazon.com/blogs/compute/container-reuse-in-lambda/,这个错误表明context.done()永远不会被击中.