计算 AWS4 签名后无法重置流

Question

有一段代码。

 List<PartETag> uploadPartsOfAsset(AssetUploadRequestVO requestVO) {
    final SingleClient singleClient = clientProvider.getClient(requestVO.getAssetKind());
    final List<PartETag> parts = new ArrayList<>();
    final String key = String.join(DELIMITER, requestVO.getClientName(), requestVO.getAssetGroup(), requestVO.getAssetName());

    final long contentSize = requestVO.getContentSize();
    long position = 0;
    long partSize = minPartSize;

    final UploadPartRequest request = new UploadPartRequest();

    try (InputStream source = requestVO.getSource()) {
        for (int partNumber = requestVO.getPartNumber(); position < requestVO.getContentSize(); partNumber++) {
            partSize = Math.min(partSize, (requestVO.getContentSize() - position));

            final long nextFilePosition = position + partSize;
            if((requestVO.getContentSize() - nextFilePosition) < minPartSize){
                partSize = contentSize - position;
                position = contentSize;
            }

            request.withBucketName(singleClient.getBucketName())
                    .withKey(key)
                    .withUploadId(requestVO.getUploadId()).withPartNumber(partNumber)
                    .withInputStream(source)
                    .withPartSize(partSize);

            PartETag partETag = null;
            try {
                partETag = singleClient.getAmazonS3Client().uploadPart(request).getPartETag();
            } catch (AmazonS3Exception e){
                throw new AssetNotFoundException(e.getMessage());
            }
            parts.add(partETag);

            position += partSize;
        }
    } catch (IOException e) {
        throw new AssetUploadException("The asset cannot be upload.", e);
    }

    return parts;
}

AssetUploadRequestVO.getSource() 是 S3ObjectInputStream 的实例。问题是这个抛出异常：

com.amazonaws.SdkClientException: Unable to reset stream after calculating AWS4 signature
at com.amazonaws.auth.AWS4Signer.calculateContentHash(AWS4Signer.java:542) ~[aws-java-sdk-core-1.11.125.jar:na]
at com.amazonaws.services.s3.internal.AWSS3V4Signer.calculateContentHash(AWSS3V4Signer.java:118) ~[aws-java-sdk-s3-1.11.125.jar:na]
at com.amazonaws.auth.AWS4Signer.sign(AWS4Signer.java:213) ~[aws-java-sdk-core-1.11.125.jar:na]
at com.amazonaws.http.AmazonHttpClient$RequestExecutor.executeOneRequest(AmazonHttpClient.java:1164) ~[aws-java-sdk-core-1.11.125.jar:na]

...

Caused by: java.io.IOException: Resetting to invalid mark
at java.io.BufferedInputStream.reset(BufferedInputStream.java:448) ~[na:1.8.0_144]
at com.amazonaws.internal.SdkBufferedInputStream.reset(SdkBufferedInputStream.java:106) ~[aws-java-sdk-core-1.11.125.jar:na]
at com.amazonaws.internal.SdkFilterInputStream.reset(SdkFilterInputStream.java:102) ~[aws-java-sdk-core-1.11.125.jar:na]
at com.amazonaws.event.ProgressInputStream.reset(ProgressInputStream.java:168) ~[aws-java-sdk-core-1.11.125.jar:na]

我已经找到了解决这个bug的方法，但问题是我真的不明白为什么会这样。

所以解决方案是将 S3ObjectInputStream 更改为其他输入流。就我而言，我已将其更改为：

new ByteArrayInputStream(IOUtils.toByteArray(requestVO.getSource()))

所以有人能帮我解释一下问题出在哪里吗？我的解决方案好吗？另外我想补充一点，如果我们使用 S3 并且仅在 ECS 上失败，则此代码可以正常工作。

Answer 1

问题是EC2返回的Stream不支持mark。您必须将其保存到 FileInputStream 或 ByteArrayInputStream。或者在我的情况下合并亚马逊内的所有内容而不将其获取到我的服务器

计算 AWS4 签名后无法重置流

Unable to reset stream after calculating AWS4 signature

java

inputstream

amazon-ec2

java-io