RE: Proposal: Generalize S3FileSystem

[Matt Rudary <Ma...@twosigma.com>]

I've filed https://issues.apache.org/jira/browse/BEAM-12435 to track this improvement.

From: Matt Rudary <Ma...@twosigma.com>
Sent: Monday, May 24, 2021 4:49 PM
To: dev@beam.apache.org
Subject: Re: Proposal: Generalize S3FileSystem


Thanks for the comments all. I forgot to subscribe to dev before I sent out the email, so this response isn't threaded properly.



My proposed design is to do the following (for both aws and aws2 packages):

1.       Add a public class, S3FileSystemConfiguration, that mostly maps to the S3Options, plus a Scheme field.

2.       Add a public interface, S3FileSystemSchemeRegistrar, designed for use with AutoService. It will have a method that takes a PipelineOptions and returns an Iterable of S3FileSystemConfiguration. This will be the way that users register their S3 uri schemes with the system.

3.       Add an implementation of S3FileSystemSchemeRegistrar for the s3 scheme that uses the S3Options from PipelineOptions to populate its S3FileSystemConfiguration, maintaining the current behavior by default.

4.       Modify S3FileSystem's constructor to take an S3FileSystemConfiguration object instead of an S3Options, and make the relevant changes.

5.       Modify S3FileSystemRegistrar to load all the AutoService'd file system configurations, raising an exception if multiple scheme registrars attempt to register the same scheme.



I considered alternative methods of configuration, in particular by using some configuration file as in HadoopFileSystemOptions. In the end, I decided that the AutoService approach was better. First, it seems to me more common to do things this way within Beam. Second, unlike with Hadoop, there's no commonly used configuration for these types of file systems already in use, and it's not clear the best way to deal with this (YAML? JSON? Java Properties? XML?). Finally, I think the story for composing multiple registrars is better than the story for composing multiple configuration files; for example, this use case may make sense in case you are dealing with multiple storage vendors.



Matt



On 2021/05/19 13:27:16, Matt Rudary <M....@twosigma.com>> wrote:

> Hi,>

>

> This is a quick sketch of a proposal - I wanted to get a sense of whether there's general support for this idea before fleshing it out further, getting internal approvals, etc.>

>

> I'm working with multiple storage systems that speak the S3 api. I would like to support FileIO operations for these storage systems, but S3FileSystem hardcodes the s3 scheme (the various systems use different URI schemes) and it is in any case impossible to instantiate more than one in the current design.>

>

> I'd like to refactor the code in org.apache.beam.sdk.io.aws.s3 (and maybe ...aws.options) somewhat to enable this use-case. I haven't worked out the details yet, but it will take some thought to make this work in a non-hacky way.>

>

> Thanks>

> Matt Rudary>

>