[io] Silently fallback if full xroot path is not found on EOS

[vepadulano]

Sometimes the getxattr call returns a valid string, but the string is incomplete. Namely, part of the full URL to the file on EOS is missing (usually the filename itself). Workaround by checking for the presence of the filename in the xurl string and in case it is not present, avoid calling TFile::Open.

[github-actions]

Test Results

    18 files      18 suites   4d 20h 18m 12s ⏱️
 2 683 tests  2 682 ✅ 0 💤 1 ❌
46 598 runs  46 597 ✅ 0 💤 1 ❌

For more details on these failures, see this check.

Results for commit bcffa30.

♻️ This comment has been updated with latest results.

[hahnjo]

LG iff the URL really contains the full path. If not, maybe it's enough that the last part has the right filename?

[vepadulano]

Sorry for coming back to this after a long time. I have rebased and tested on lxplus. Indeed GetFile() returns just the file name as passed to TFile::Open, so we want to check that the string ends with the file name rather than doing the full comparison.

root [0] auto f1 = TFile::Open("/eos/root/h1/dstarmb.root");
TFile::Open:
	fileurl.GetFile()=/eos/root/h1/dstarmb.root
	xurl=root://eospublic.cern.ch//eos/root-eos/h1/dstarmb.root
root [1] auto f2 = TFile::Open("myfile.root", "recreate");
TFile::Open:
	fileurl.GetFile()=myfile.root
	xurl=root://eoshome-v.cern.ch//eos/user/v/vpadulan/myfile.root

[amadio]

Looks good to me. When EOS fails, usually it just returns the URL of the MGM (the namespace server), without a path. So this should be good to skip the cases in which the file has just been created as intended.

[amadio]

Sorry for coming back to this after a long time. I have rebased and tested on lxplus. Indeed GetFile() returns just the file name as passed to TFile::Open, so we want to check that the string ends with the file name rather than doing the full comparison.

root [0] auto f1 = TFile::Open("/eos/root/h1/dstarmb.root");
TFile::Open:
	fileurl.GetFile()=/eos/root/h1/dstarmb.root
	xurl=root://eospublic.cern.ch//eos/root-eos/h1/dstarmb.root
root [1] auto f2 = TFile::Open("myfile.root", "recreate");
TFile::Open:
	fileurl.GetFile()=myfile.root
	xurl=root://eoshome-v.cern.ch//eos/user/v/vpadulan/myfile.root

Note, however, that in your first case, because EOS is mounted not onto /eos/root-eos as it is on the server, but /eos/root, the comparison will fail. Normally the paths would be the same, but it might be better to use basename on the fileurl and just check that the name of the file is at the end of the URL, as suggested by Vincenzo.