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https://issues.apache.org/jira/browse/HADOOP-9972?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13776870#comment-13776870
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Binglin Chang commented on HADOOP-9972:
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bq. Also, if we want to add more options in the future, we don't want to create
listLinkStatusWithFoo and listLinkStatusWithFooAndBar. Just listStatus(Path,
PathOption).
That is exactly why I propose listStatus(Path, PathOption) implemented in
FileSystem using more primitive listLinkStatus(Path), so If we add an option,
we don't end up modify all sub FileSystems code.
bq. we don't want to create listLinkStatusWithFoo and
listLinkStatusWithFooAndBar. Just listStatus(Path, PathOption).
I am not against listStatus(Path, PathOption) API, just its implementation
detail, this issue can be solved by listStatus(Path, PathOption).
bq. Hadoop and HDFS exist in an environment where there are unreliable networks.
I don't think "ignore all error" including network issues, it is like disk
failure/temporary unreadable issues in linux, globbing can't ignore that
either, in that case error should just be passed all the way up to user, most
user don't want to handle this error in ErrorHandler too.
bq. So if globStatus swallows unresolved symlink errors.
Are you saying network issue can cause unresolved symlink error? If dead link
error is already mixed up with network errors, plus compatibility reasons, I
agree with you, we can't follow linux practice.
> new APIs for listStatus and globStatus to deal with symlinks
> ------------------------------------------------------------
>
> Key: HADOOP-9972
> URL: https://issues.apache.org/jira/browse/HADOOP-9972
> Project: Hadoop Common
> Issue Type: Improvement
> Components: fs
> Affects Versions: 2.1.1-beta
> Reporter: Colin Patrick McCabe
> Assignee: Colin Patrick McCabe
>
> Based on the discussion in HADOOP-9912, we need new APIs for FileSystem to
> deal with symlinks. The issue is that code has been written which is
> incompatible with the existence of things which are not files or directories.
> For example,
> there is a lot of code out there that looks at FileStatus#isFile, and
> if it returns false, assumes that what it is looking at is a
> directory. In the case of a symlink, this assumption is incorrect.
> It seems reasonable to make the default behavior of {{FileSystem#listStatus}}
> and {{FileSystem#globStatus}} be fully resolving symlinks, and ignoring
> dangling ones. This will prevent incompatibility with existing MR jobs and
> other HDFS users. We should also add new versions of listStatus and
> globStatus that allow new, symlink-aware code to deal with symlinks as
> symlinks.
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