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September 23, 2014 12:00-2:00 PDT

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Discussion Items


Winter2015 Package Reorganization Planning

  • BaBar had many packages (3.5MLOC, 40% in core library, rest application-specific)
    • Had 1000 packages in production builds; easy to create new ones; made it easy to manage dependencies
    • 5 sub-pipelines doing completely different things, sharing only limited common code (10%)
    • Evolved that way; could possibly have worked with a different approach
    • Did not work with one package per area of responsibility; needed to use them for dependency control
    • Could work within system touching only a few of the packages
    • Working within shared environment; global build provided most of code; developers only changed a little
    • Testing depended on stack of libraries, but those were already built
    • Also had tool to test effects of lower changes on upper packages
    • Renamings weren't particularly difficult
    • Abstraction/interface + implementation(s) led to separate packages
    • No one person knew whole picture, though
    • Hard to take a slice of the code and deliver it to people
      • Could have used a coarser-grained organization on top of fine-grained
  • Frossie: want limited number to improve adoptability by outsiders
    • Agree with interface/implementation split
    • Want to be able to test packages in isolation; not install lots of dependencies to build/test a single one
    • Test control flow of tasks without science by stubbing/mocking it out
      • GPDF: But can't stub out all science and still be useful
  • But afw in particular is a library with a wide interface that is hard to mock out
  • Linux kernel model:
    • Build via a hierarchy of drivers
    • Stack should be thought of as a Linux/Anaconda distribution: install whole thing or parts
    • Or are we more like PyPI/CPAN/Ruby gems?
  • Repos and packages don't have to be aligned
  • GPDF: Class-rich data objects lead to complex dependencies
    • As opposed to something like byte streams
  • GPDF: Algorithms built as layers of functionality also lead to more dependencies
  • Issue is more distribution of packages and making them easily used for development (and not forcing rebuilding of the entire stack)
Action RequestKTL

DM-934 - Getting issue details... STATUS ; with further update, can this be recommended?

  • No discussion or action
Action RequestFrossie

DM-1203 - Getting issue details... STATUS

  • Want fewer timezones overall, particularly between system logs and application logs
  • Unclear whether better to shift the application logs to GMT or system logs to local time
  • Tentative conclusion: probably best to try to get all logs into GMT
  • Also crontabs and other things?
  • Still a potential issue with TAI and UTC, which are a lot easier to confuse than different timezones

How legalistic should the SAT be?

  • No discussion or action
Design Deep DiveKTL

DM-35 - Getting issue details... STATUS Alert Generation and Distribution

  • People were not prepared to follow up
  • Mario promises to look over this by Thursday
Design Deep DiveKTL

Data Release Production Overview

  • No discussion
  • Mario promises to look over this by Thursday