Hi,
i’ve a question regarding the AWS S3 storage option for the file storage of CUBA. I used the instructions from here. In local mode (running via studio) everything worked fine.
On a deployment scenario with two different tomcats and app-core.war and app.war separated, an error occurs while uploading the file to S3 (see below):
17:10:37.047 ERROR c.h.c.c.c.FileUploadController - Unable to upload file
com.haulmont.cuba.core.global.FileStorageException: I/O error: Could not save file 0ea0d0ea-8616-5097-f609-6feb822866e4.png. <?xml version="1.0" encoding="UTF-8"?>
<Error><Code>SignatureDoesNotMatch</Code><Message>The request signature we calculated does not match the signature you provided. Check your key and signing method.</Message><AWSAccessKeyId>********</AWSAccessKeyId><StringToSign>********</CanonicalRequest><CanonicalRequestBytes>********</CanonicalRequestBytes><RequestId>FD5A06F41AAB8B17</RequestId><HostId>********</HostId></Error>
at com.haulmont.cuba.core.app.filestorage.amazon.AmazonS3FileStorage.saveStream(AmazonS3FileStorage.java:126) ~[cuba-core-6.2.3.jar:6.2.3]
The configuration did not change with the two options so i would guess that this is not the problem. The desired region is “eu-west-1”. Since i’ve no glue why this is not working in an environment with two wars in two tomcats within two docker containers but in the studio environment i just searched through the code.
I came across one thing that i don’t have any idea if it helps but perhaps you can give me an answer to this:
In the method “getAmazonUrl” of the Class AmazonS3FileStorage it says that it uses S3 - path style for the URL: “the region-specific endpoint to the target object expressed in path style”. But in the docs of AWS it says that if using path style a region specific URL has to be set (like s3-eu-west-1.amazonaws.com/… ) as described here:
<b>Important</b>
Amazon S3 supports virtual hosted-style and path-style access in all regions. The path-style syntax, however, requires that you use the region-specific endpoint when attempting to access a bucket. For example, if you have a bucket called mybucket that resides in the EU (Ireland) region, you want to use path-style syntax, and the object is named puppy.jpg, the correct URI is http://s3-eu-west-1.amazonaws.com/mybucket/puppy.jpg.
Unlike the comment says, the URL creation looks a little bit more like virtual host style if i understand the implementation correctly:
return new URL(String.format("https://%s.s3.amazonaws.com/%s", amazonS3Config.getBucket(), resolveFileName(fileDescr)));As i said i’m not even sure if this thing has anything to do with the actual error, but it just was the first obvious straw to clutch at 
Perhaps you can give me a little hint about the implementation or even about the error that occurs only in “production” mode but not in studio mode.
Bye,
Mario