As a sample, platform/broadcom/docker-orchagent-brcm.mk is updated to add a docker-orchagent-brcm-dbg.gz target.

Now "BLDENV=stretch make target/docker-orchagent-brcm-dbg.gz" will build the debug image.

NOTE: If you don't specify NOSTRETcH=1, it implicitly calls "make stretch", which builds all stretch targets and that would include debug dockers too.

This debug image can be used in any linux box to inspect core file. If your module's external dependency can be suitably mocked, you my even manually run it inside.

"docker run -it --entrypoint=/bin/bash e47a8fb8ed38"

You may map the core file path to this docker run.

… to help readability.

…UG_TOOLS=y.

When this change ('building debug docker image transparently') is extended to all dockers, this flag would become redundant. Yet, there can be some test based use cases that rely on this flag.

Until after all the dockers gets their debug images by default and we switch all use cases of this flag to use the newly built debug images, we need to maintain the existing behavior.

2) Debug template builder: renamed build_dbg_j2.sh to build_debug_docker_j2.sh
3) Dropped insignifcant statement CMD from debug Docker file, as base docker has Entrypoint.

"User, uid, guid, frr-uid & frr-guid" are required for all docker images, with exception of debug images.

…(SONIC_STRETCH_DOCKERS_FOR_INSTALLERS) and build debug-dockers only for those to be built and debug target is available.

merge with upstream

Where needed a platform entry can override the template.
This avoids duplication, hence easier to maintain.

Just take the platform code and do the rest in template.

sync with upstream

…e under rules/docker-orchagent.mk

2) Extened debug image to all stretch dockers

1) Dropped LIBSAIREDIS_DBG from database, teamd, router-advertiser, telemetry, and platform-monitor docker*.mk files from _DBG_DEPENDS list
2) W.r.t docker make for syncd, moved DEPENDS from template to specific makefile and let the template has stuff that is applicable to all.