HDDS-9804. ozone freon dfsg does not work with relative --path

[jojochuang]

What changes were proposed in this pull request?

Add check to prevent invalid --path parameter in ozone freon dfsg command.

Please describe your PR in detail:

• It's a trivial change but took me several hours to troubleshoot so thought it's worth fixing.

What is the link to the Apache JIRA

https://issues.apache.org/jira/browse/HDDS-9804

How was this patch tested?

Manually tested on a cluster.

[nandakumar131]

+1, LGTM.

[ayushtkn]

Shouldn't we use the default FS in that case? If no FS is specified explicitly, the defaultFs should be used, right? Something like this:

    if (scheme == null) {
      URI defaultUri = FileSystem.getDefaultUri(configuration)
      uri = new URI(defaultUri.getScheme(), defaultUri.getAuthority(), uri.getPath());
    }

[adoroszlai]

We don't even need to completely replace uri, can use scheme of default URI only for disabling the cache.

[ayushtkn]

does this work?

    if (!uri.isAbsolute()) {

[adoroszlai]

Thanks @jojochuang for finding this bug, and working on the fix.

file system cache is not disabled properly and all threads share the same FS object

Instead of forcing full URLs, we should fix the way cache is disabled.

[adoroszlai]

We don't even need to completely replace uri, can use scheme of default URI only for disabling the cache.

[adoroszlai]

Suggested change

	String disableCacheName = String.format("fs.%s.impl.disable.cache",
	uri.getScheme());
	String scheme = Optional.ofNullable(uri.getScheme())
	.orElseGet(() -> FileSystem.getDefaultUri(configuration).getScheme());
	String disableCacheName = String.format("fs.%s.impl.disable.cache", scheme);

(also add import java.util.Optional)

Or can use if block, if you prefer.

[adoroszlai]

Maybe should also fail if scheme is file.

[adoroszlai]

Thanks @jojochuang for updating the patch.

[ayushtkn]

LGTM

[adoroszlai]

Thanks @jojochuang for the patch, @ayushtkn, @nandakumar131 for the review.