Changing event record information in Clearcase

Question

At our work, we are forced to use Clearcase UCM as our central repository (specifically for labelling/baselining, builds and code reviews), but our team wants to use Git as our real SCM system.

What we want to achieve is essentially a scraping service that takes the commits as they are pushed to our central Git repo, and push them on to a Clearcase VOB that is read-only as far as the development team is concerned, including important information such as the comment and the user name (exact date/time matching is not important, but getting the user correct is).

Our centralized Git server has been configured (using the excellent scm-manager) to accept Windows domain users and passwords, and our Clearcase servers use Windows domain accounts, but I am unsure how a scraper service would "impersonate" the correct user so this information is duplicated correctly in Clearcase.
I thought the chevent command might hold some promise, but that only gives access to the comment.

Is there any way to amend the details of a Clearcase event record once it is in the database, in particular the user-name? Or is there a better way to do this?
Again, we don't need a bi-directional bridge - all access to the Clearcase VOB as far as code commits is concerned would be through the scraper.

Answer 1

ClearCase is a file-by-file SCM, not a revision-based SCM.
(See "What are the basic ClearCase concepts every developer should know?" for a more detailed comparison between ClearCase and git)

That means, for each git commit, you need to:

• clearfsimport into ClearCase any file included in the git commit.
  Create a specific UCM activty for that import.

• As a ClearCase admin, cleartool protect -chown on the activity: see "Why is the owner of the clearcase activity 'nobody'" (as well as a protect -chgrp, if the CLEARCASE_PRIMARY_GROUP environment variable wasn't correctly set at the time of the import).

Note that cleartool protect affects the entire "element" (file or directory), not just one version, so you cannot record the user id that way: the next import would overwrite that id with the id of the new committer whom content is imported.
Plus, you cannot changed the initial creator (see "Changing the name of the original creator of an element")

That means you should record that information (author and creator git id) in attribute:
see cleartool mkattr.

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If I did want to accurately reflect the Git user as the "creator" of the new version of the file does that mean I would need a way to run clearfsimport as that user - impersonate them?

Yes: for each commit, you would need to clearfsimport "as" (runas in Windows, as mentioned in this thread) that use, in order for ClearCase to properly set the creator (if this is a new element) or the version author (if this is an update of an existing version).

The reason I didn't mention that possibility in the first place is that I don't have access to the credentials of another user, for me to switch to for each clearfsimport.

Other import tools (CVS, PCVS, RCS, SCCS, SSafe) simply:

• ignore that creator/author information entirely.
• add attributes of their own for tool-specific information (like the promotion group 'PVCS_GROUP', or RCS_REVISION.

Each time, you will find the limitation similar to:

clearexport_sccs ignores information in SCCS files that is not related to version-tree structure; this includes flags, ID keywords, user lists, and Modification Request numbers

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most of our other systems that need the Clearcase history use the creator to reflect who made that change

That means your other systems can rely on the user ID version, except if it is the one used for the import (in which case they would consult the special attribute recording that data from the import)