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From "Chris K Wensel (JIRA)" <j...@apache.org>
Subject [jira] Commented: (HADOOP-930) Add support for reading regular (non-block-based) files from S3 in S3FileSystem
Date Tue, 03 Jun 2008 16:24:45 GMT

    [ https://issues.apache.org/jira/browse/HADOOP-930?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12601991#action_12601991

Chris K Wensel commented on HADOOP-930:

-- Any reason you didn't use the mime type to denote directory files (as jets3t does)?

  public static boolean isDirectory( S3Object object )
    return object.getContentType() != null && object.getContentType().equalsIgnoreCase(

  public static final String MIME_DIRECTORY = "application/x-directory";

-- I believe MD5 checksum should be set on s3 put (via header), and verified on s3 get. I
see plenty of read failures because of checksum failures (though they could be side effects
of stream reading timeouts in retrospect). This is especially useful if non Hadoop applications
are dealing with the S3 data shared with Hadoop.

-- Sometimes 'legacy' buckets have underscores, might consider trying to survive them..

    String userInfo = uri.getUserInfo();

    // special handling for underscores in bucket names
    if( userInfo == null )
      String authority = uri.getAuthority();
      String split[] = authority.split( "[:@]" );

      if( split.length >= 2 )
        userInfo = split[ 0 ] + ":" + split[ 1 ];


    String bucketName = uri.getAuthority();

    // handling for underscore in bucket name
    if( bucketName.contains( "@" ) )
      bucketName = bucketName.split( "@" )[ 1 ];

> Add support for reading regular (non-block-based) files from S3 in S3FileSystem
> -------------------------------------------------------------------------------
>                 Key: HADOOP-930
>                 URL: https://issues.apache.org/jira/browse/HADOOP-930
>             Project: Hadoop Core
>          Issue Type: New Feature
>          Components: fs
>    Affects Versions: 0.10.1
>            Reporter: Tom White
>            Assignee: Tom White
>             Fix For: 0.18.0
>         Attachments: hadoop-930-v2.patch, hadoop-930-v3.patch, hadoop-930-v4.patch, hadoop-930.patch,
> People often have input data on S3 that they want to use for a Map Reduce job and the
current S3FileSystem implementation cannot read it since it assumes a block-based format.
> We would add the following metadata to files written by S3FileSystem: an indication that
it is block oriented ("S3FileSystem.type=block") and a filesystem version number ("S3FileSystem.version=1.0").
Regular S3 files would not have the type metadata so S3FileSystem would not try to interpret
them as inodes.
> An extension to write regular files to S3 would not be covered by this change - we could
do this as a separate piece of work (we still need to decide whether to introduce another
scheme - e.g. rename block-based S3 to "s3fs" and call regular S3 "s3" - or whether to just
use a configuration property to control block-based vs. regular writes).

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