This feature caches all the deb files during docker build and stores them
into version cache.
It loads the cache file if already exists in the version cache and copies the extracted
deb file from cache file into Debian cache path( /var/cache/apt/archives).
The apt-install always installs the deb file from the cache if exists, this
avoid unnecessary package download from the repo and speeds up the overall build.
The cache file is selected based on the SHA value of version dependency
files.
Why I did it
How I did it
How to verify it
* 03.Version-cache - framework environment settings
It defines and passes the necessary version cache environment variables
to the caching framework.
It adds the utils script for shared cache file access.
It also adds the post-cleanup logic for cleaning the unwanted files from
the docker/image after the version cache creation.
* 04.Version cache - debug framework
Added DBGOPT Make variable to enable the cache framework
scripts in trace mode. This option takes the part name of the script to
enable the particular shell script in trace mode.
Multiple shell script names can also be given.
Eg: make DBGOPT="image|docker"
Added verbose mode to dump the version merge details during
build/dry-run mode.
Eg: scripts/versions_manager.py freeze -v \
'dryrun|cmod=docker-swss|cfile=versions-deb|cname=all|stage=sub|stage=add'
* 05.Version cache - docker dpkg caching support
This feature caches all the deb files during docker build and stores them
into version cache.
It loads the cache file if already exists in the version cache and copies the extracted
deb file from cache file into Debian cache path( /var/cache/apt/archives).
The apt-install always installs the deb file from the cache if exists, this
avoid unnecessary package download from the repo and speeds up the overall build.
The cache file is selected based on the SHA value of version dependency
files.
During docker build, host files can be passed to the docker build through
docker context files. But there is no straightforward way to transfer
the files from docker build to host.
This feature provides a tricky way to pass the cache contents from docker
build to host. It tar's the cached content and encodes them as base64 format
and passes it through a log file with a special tag as 'VCSTART and VCENT'.
Slave.mk in the host, it extracts the cache contents from the log and stores them
in the cache folder. Cache contents are encoded as base64 format for
easy passing.
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#### Why I did it
#### How I did it
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