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cvmfs-contrib / python-cvmfsutils

BSD 3-Clause "New" or "Revised" License
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Feature: Backtracking File Path from Content Hashes in Catalogs #19

Closed reneme closed 6 years ago

reneme commented 8 years ago

This allows to backtrace a CernVM-FS file path for a given content hash. Both partial objects and bulk chunks are fine. Currently this only works on catalog level, not on an entire catalog tree. Furthermore the feature is rather slow, as this catalog lookup is only partially backed by an SQLite index. It's anyway useful for repository backend troubleshooting.

Example:

import cvmfs
r = cvmfs.open_repository("http://cvmfs-stratum-one.cern.ch/cvmfs/cms.cern.ch")
root_clg = r.get_current_revision().retrieve_root_catalog()
print root_clg.backtrace_content_hash("9a90537c5241495f08bb4e9a73a77f38d837ed9e")

Output:

['/lcg/SCRAMV1/V2_2_6_pre2/src/BuildSystem/TemplateInterface.pm',
'/lcg/SCRAMV1/V2_2_5_pre6/src/BuildSystem/TemplateInterface.pm',
'/lcg/SCRAMV1/V2_2_6_pre5/src/BuildSystem/TemplateInterface.pm',
'/lcg/SCRAMV1/V2_2_6_pre4/src/BuildSystem/TemplateInterface.pm',
'/lcg/SCRAMV1/V2_2_5_pre8/src/BuildSystem/TemplateInterface.pm',
'/lcg/SCRAMV1/V2_2_5_pre3/src/BuildSystem/TemplateInterface.pm',
'/lcg/SCRAMV1/V2_2_5_pre4/src/BuildSystem/TemplateInterface.pm',
'/lcg/SCRAMV1/V2_2_6_pre3/src/BuildSystem/TemplateInterface.pm',
'/lcg/SCRAMV1/V2_2_5_pre5/src/BuildSystem/TemplateInterface.pm',
'/lcg/SCRAMV1/V2_2_5_pre1/src/BuildSystem/TemplateInterface.pm',
'/lcg/SCRAMV1/V2_2_5_pre2/src/BuildSystem/TemplateInterface.pm',
'/lcg/SCRAMV1/V2_2_6_pre1/src/BuildSystem/TemplateInterface.pm',
'/lcg/SCRAMV1/V2_2_5_pre9/src/BuildSystem/TemplateInterface.pm']

Note that the result is a list because a single content hash might be referred to by many CernVM-FS paths.

DrDaveD commented 6 years ago

@jblomer I think we might as well merge this PR too, it can't hurt anything. Then I will submit another PR with a new version number in the .spec, then the repo needs to get a tag of that number, then I can build for the cvmfs-contrib yum repo.