Shared library dependencies for NETCONF-related software

Please note that a Verified: +1 vote only means that all these libraries managed to build. There's some cross-project checking, but it is currently not enforced. Since Zuul+Gerrit do not support "atomic cross-repo changes" and there will be occasional changes which require updates of multiple repositories, use caution.

Updating software

When uploading, make sure that all changes share the same topic in Gerrit (e.g., git push ... -o topic=update-netconf).

1. Make a modification here in CzechLight/dependencies. This will be the change A. A subset of build targets of "downstream procjets" will be rebuilt. Those which have failed require follow-up commits.

2. Push commits to all "leaf" repositories (changes B, C, D, E, F) which require modifications:

• CzechLight/cla-sysrepo
• CzechLight/netconf-cli
• CzechLight/velia
• CzechLight/rousette
• CzechLight/sysrepo-ietf-alarms

Use these Depends-on footer tags:

Depends-on: https://gerrit.cesnet.cz/c/CzechLight/dependencies/+/${A}

3. Finally, update CzechLight/br2-external so that it includes all changes made above. The following Depends-on are needed:

Depends-on: https://gerrit.cesnet.cz/c/CzechLight/dependencies/+/${A}
Depends-on: https://gerrit.cesnet.cz/c/CzechLight/cla-sysrepo/+/${B}
Depends-on: https://gerrit.cesnet.cz/c/CzechLight/netconf-cli/+/${C}
Depends-on: https://gerrit.cesnet.cz/c/CzechLight/velia/+/${D}
Depends-on: https://gerrit.cesnet.cz/c/CzechLight/rousette/+/${E}
Depends-on: https://gerrit.cesnet.cz/c/CzechLight/sysrepo-ietf-alarms/+/${F}

If everything builds, then the change is good to go 🌈 🦄 🍻.

Adding new repositories

• Create project within Gerrit: ssh import.gerrit.cesnet.cz gerrit create-project --parent github/acl github/ORGANIZATION/REPO --owner '"Git Importers"' --description "'MIRROR: ...'"
• Run the first import script as the github-mirror user on gerrit.cesnet.cz: REPO=org/repo ./oneshot.sh
• Update configuration of the public tenant in Zuul (example)
• Reconfigure Zuul (as zuul on zuul.gerrit.cesnet.cz, run zuul-scheduler full-reconfigure)
• Add the submodule here: git submodule add ../../github/ORG/REPO REPO
• Modify ci/build.sh to start building this dependency
• Propose changes to all consumers as shown above

Testing experimental changes

When an upstream project fixes a bug or implements a suggestion that we asked for, their commits typically end up in their GitHub repo, but not neccessarily in a branch that we're tracking. Also, the CI builds against a Gerrit copy of these projects, and the mirroring script only runs twice a day. In order to test changes earlier, all CzechLight developers can push changes to branches named cesnet/*. E.g., changes to libyang can be pushed to the repo github/CESNET/libyang, branch cesnet/2020-07-24-fix-random-stuff.