Purpose:
Reduce build times after a repo sync by pulling in pre-generated
srpms and rpms and other build products created by a local reference build.
Usage:
repo sync
generate-cgcs-centos-repo.sh ...
populate_downloads.sh ...
build-pkgs --build-avoidance [--build-avoidance-user <user> \
--build-avoidance-host <addr> --build-avoidance-dir <dir>]
Reference builds:
- A server performs a regular (daily?), automated builds using
existing methods. Call these the reference builds.
- The builds are timestamped, and preserved for some time. (weeks?)
The MY_WORKSPACE directory for the build shall have a common root
directory, and a leaf directory that is a UTC time stamp of format
YYYYMMDDThhmmssZ.
e.g.
MY_WORKSPACE=/localdisk/loadbuild/jenkins/StarlingX/20180719T113021Z
Alternative formats are possible by setting values in ...
"$MY_REPO/local-build-data/build_avoidance_source"
e.g.
BUILD_AVOIDANCE_DATE_FORMAT="%Y-%m-%d"
BUILD_AVOIDANCE_TIME_FORMAT="%H-%M-%S"
BUILD_AVOIDANCE_DATE_TIME_DELIM="_"
BUILD_AVOIDANCE_DATE_TIME_POSTFIX=""
BUILD_AVOIDANCE_DATE_UTC=0
Which results in YYYY-MM-DD_hh-mm-ss format using local time.
The one property that the timestamp must have is that they
are sortable, and that the reference build and the consumer of
the reference builds agree on the format.
- A build CONTEXT is captured, consisting of the SHA of each and every
git that contributed to the build.
- For each package built, a file shall capture he md5sums of all the
source code inputs to the build of that package.
- All these build products are accessible locally (e.g. a regional
office) via rsync (other protocols can be added later). ssh
is also required to run remote query commands on the reference build.
Initial ground work to support a selection variable ....
BUILD_AVOIDANCE_FILE_TRANSFER="my-transfer-protocol"
in $MY_REPO/local-build-data/build_avoidance_source"
has been created, but "rsync" is the only valid value at this time.
- Location of the reference build can be specified via command line, or
defaults can be put in $MY_REPO/local-build-data/build_avoidance_source.
The local-build-data directory is gitignored by stx-root and so can be
customized for local needs.
e.g.
cat $MY_REPO/local-build-data/build_avoidance_source
BUILD_AVOIDANCE_USR="jenkins"
BUILD_AVOIDANCE_HOST="stx-build-server.myco.com"
BUILD_AVOIDANCE_DIR="/localdisk/loadbuild/jenkins/StarlingX"
Notes:
- Build avoidance is only used if requested.
- Build avoidance does not necessarily use the latest reference build.
It compares the git context of all available reference builds vs your
own git context, and chooses the most recent for which you gits have
all the conent. i.e. all your gits will be same or newer than that
used by the reference build. This also meens that some packages might
still need to be rebuilt after the download step.
- Normally build avoidance remembers the last download context and will only
consider reference builds newer than the last download. You can reset
using 'build-pkgs --build-avoidance --clear' to erase the download history.
When might this matter to me? If you change to an old branch that
hasn't been synced recently and want to build in that context.
- The primary assumtion of Build Avoidance is that it is faster to
download packages than to build them. This is typically true of a
good LAN, but likely not true of a WAN. This is why we emphasize the
local nature of your reference build server.
Also in this update:
- reworked context generation to be relative to 'dirname $MY_REPO'
- Moved md5sum calculation to a common file, and fixed case where
symlinks where canonacalized to paths outside of $MY_REPO.
We'll make an exception to canonacalization to keep paths
relative to $MY_REPO.
- In future other functions could be moved to the common file.
Story: 2002835
Task: 22754
Change-Id: I757780190cc6063d0a2d3ad9d0a6020ab5169e99
Signed-off-by: Scott Little <scott.little@windriver.com>
b20ac0164d