cms-export: OpenVMS CMS library export-to-git utility {#main}

Overview

cms-export is a utility for OpenVMS to export CMS library content and revisions history. CMS is a version control system commonly used in OpenVMS environment (part of DECset). Valued for being efficient and time-proven, CMS also has its share of drawbacks -- lack of export options being one of these. cms-export utility allows export of a specified CMS library (or a set of library elements) into a file in git-fast-export format, which subsequently can be used to create a repository with an alternative version management system such as git, fossil etc.

cms-export is a free software; the use, copy, and distribution rights are granted under the terms of the @ref xcmslicense | MIT License.

Features

cms-export utility may be useful in software development efforts to expand OpenVMS-specific projects to other platforms for portability or migration objectives. In fact this utility came to being exactly in process of porting an in-house developed set of OpenVMS-based applications onto Linux platform.

In such scenarios an OpenVMS-based CMS library may be used to populate source code repositories used for development on other platforms. cms-export utility provides a way to export not only the current state of the library content but also version/generation history, including defined releases/classes.

CMS library content is described in terms of elements and groups -- for file management; generations and classes -- for revisions management. These concepts, while simple and flexible, do not map fully onto repository-commit-tag concepts common to many popular distributed source management systems.

cms-export is designed around the following mappings:

• CMS elements => git files/blobs
• CMS element generations => git commits
• CMS variant generations => git branches/tags
• CMS generation classes => git branches/tags
• CMS groups => NOT MAPPED
• CMS time-stamps => git commit time-stamps*

Optionally, CMS classes may be individually mapped to user-specified git branches (e.g. release version classes => commits on release branch).

Output from cms-export utility is an export file in git-fast-export format as specified for git fast-import command input (or fossil import --git).

Refer to @ref xcmsusage | cms-export Usage page for more details.

Updates and details about the current version listed in @ref xcmschangelog | cms-export ChangeLog.

Quick Start

cms-export utility is expected to run on OpenVMS system which hosts the CMS library to be exported. In current release the cms-export utility essentially consists of a single DCL script ready to run. However, it would be more robust to set up cms-export from the release package (zip-file), which also includes tests and user-documentation:

• Download the latest cms-export release source package (zip-file) from cms-export project space and extract into a work directory:

  unzip cms-export.zip
  set def [.cms-export]
  

  NOTE: It is important to perform the extraction (unzip) on the OpenVMS side -- this preserves file attributes (in this case, keeps the Stream-LF record attribute) of some files used for testing, otherwise the tests will fail due to mismatching line-endings.

• Create a build directory and start build script from inside it:

  create /dir [.build]
  set def [.build]
  @[-]build clean all test
  

• OR do a logged build (all messages are redirected to a log-file):

  define err_output log_output
  pipe @[-]build clean all test >build.log 2>&1
  

• On successful completion all tests have passed and the cms-export utility is available for use or installation:

  dir [.tests]*.*FAILED
  dir [.tests]*.*PASSED
  dir [.bin]
  

• Also, you may look at the git-fast export files resulting from the completed tests -- they correspond to the test CMS library exported at each stage of the completed test sequence:

  dir [.tests]*.git-fast
  cms set lib [.tests.testlib]
  

• Once familiar with general cms-export operation, export your own CMS library or just try it with the very same testlib as above:

  EXPORTCMS := @[path-to-cmsexport-bin]exportcms-git.com
  create /dir [.work]
  set def [.work]
  cms set lib [path-to-cmslib]
  EXPORTCMS
  dir *.git-fast
  

• OR redirect messages to a log-file:

  define err_output log_output
  pipe EXPORTCMS  >exportcms.log 2>&1
  

  NOTE: For better use of system resources it is recommended to run export process from a batch queue. This also makes sure the export process starts from a fresh logical environment. When submitting to batch queue, a log-file can be set for the whole batch job.

  To enable verify or debug statements for the export process, define VERIFY_EXPORTCMS or DBG_EXPORTCMS process logicals prior to starting the export job.

• Any of the resulting test git-fast export file may then be used to create a new git repository on other platform (e.g. Linux):

  mkdir testlib
  cd testlib
  git init
  git fast-import < ../testlib.git-fast
  git checkout master
  

  NOTE: In general, the resulting git-fast export files are of BINARY/IMAGE type, so make sure to properly set the transfer mode if copying these via FTP.

  Also it may make sense to zip the resulting git-fast file before transferring it to other platform, especially when exported CMS library is rather big or spanning far-back in-time (a lot of revisions).

Refer to @ref xcmsusage | cms-export Usage page for more details and advanced use examples.

Support

In its original release the cms-export utility has helped us successfully export CMS libraries for our in-house developed OpenVMS applications and set up Linux-based repositories (we use fossil SCM). So as such, cms-export has already paid back its worth to us, but we would hope it may as well be suitable for similar projects of fellow OpenVMS developers.

Let us know of your experience, challenges or problems (bugs?) with it -- quite possible we have dealt with these too and may have work-arounds or may suggest some alternatives.

A public issue tracker may be eventually set up to address possible user-feedback. Meanwhile, please direct your feedback to cms-export GitHub project page.

Of course, Fork us on GitHub! as it goes to welcome your contribution.