Sunday, February 7, 2016

Master development problem with pictures

we need to decide: Jenkins should test pre-rollout state or post prollout state of sources.

Workflow:  master --> development --> topicBranch
Advantages:
Simple exception stack trace examination from PROD (only require switch to master)
new iteration/feature come with version bump so PROD code could be bumped with mvn-release-plugin without worries to interfere with development.
only 2 branches are required
Disadvantages:
master is not correspond to PROD after release was roll-backed on PROD!!!!! no way to revert/reset master without pain for all developers (conflicts are unavoidable).
person that do rollout to PROD have to remember to do merge from development to master before rollout to PROD - RomanIvanov always fail to this on time. Rollout could be done in out of working hours by SysAdm, so it impossible to sync that events.
"hot fix branches"(http://git.server.com/cgit/ld/log/?h=master-1.7-hotfix) is better than do changes in master and then force rebase on development that could not be that simple. Two master("master","mastr-hotfix") branch appear and same problem is raised "Where is prod code?"
in case of hotfix over "master" Jenkins have no easy ability to test changes before rollout (if you follow a model merge to master after rollout ) ...
any changes to master, with development far in forward, make it impossible to keep Fast forward merge
keep master-1.7-hotfix branch is not good for jenkins as it does not aware of it - so you deploy changes that are not tested.

Problem: we released to RPOD repgen but not a RP, so I can not do merge to master as this two projects lives in same repo - is it git structure problem or problem of your workflow?
Problem: reports 1.3 and 1.4  - we cannot do fast-forward merge as we have conflicts in changes (we did cherry-pick from master to development), we can not do just merge without conflicts, with non fast-forward we will loose all commits history as all of them will come to one merge-commit, tags will be lost as we change SHA1 for commits. Should we do reset of master till common commit and then do fast-forward merge ? should we store all hot fixes ? should we name it like branch and keep in git for a while but in this case how it is different from alternative git workflow ?
Problem: 'themes' - fix was applied to master and then in few days was applied to development, on merge development to master I got conflict, I could resolve it - but in master I will got merge-commit. I could revert that fix in master that will help me to merge without problem but still - one merge commit(history is lost). I did HACK by reset to common commit with development and that allowed me do fast-forward (master keep history).  Resume: looks like to keep history we need to work in master, or treat development branch as the most valuable branch (that never have to be removed or lost).

Delema: how to merge from developement to master?  up to a tag(3.1.6) or next commit after tag ?
in case of "next commit after tag" - it is convenient to do versioning as we stay on SNAPSHOT
in case of "up to tag" - is more correct as we rollouted exact version, it even make more sense as it comes to master-X.X.X-hotfix creation where it will unclear in history why it was required to revert changes from 3.1.7-SNAPSHOT to 3.1.6.1-SNAPSHOT as in master 3.1.7 have never existed.

Problem: master, master-3.2.12-hotfix, master-3.2-hotfix  (all branches were created as mentioned here) -  master-3.2.12-hotfix contains tag 3.2.12.3 that rollouted on PROD, after rollout from master-3.2-hotfix by tag 3.2.14 we can not remove master-3.2.12-hotfix branch as it contains tag that could be useful in case rolback on PROD.
Command "git merge -s ours master-3.2.12-hotfix" will not help as do exactly what we need from keeping commits/tags in history, but it DO CREATE ADDITIONAL/MERGE commit, that will make problem when it comes to development->master merge.

problem: master ans master-hotfix, master-hotfix depend on DB changes that is incompatible with master code. So we have master that is failing on UTs but master-hotfix is not. So model of checksout "master*" in Jenkins does not help.

!!problem!!: if repository is composite of few projects that could be releases/rollouted/tagged separately (ld and ld-data-job) we can not merge to master all as ld-data-job is rollouted to RPOD, but some changes in ld-server are not rollouted and cannot be merged to master as it brake main idea that master===prod  code.

Workflow : hot-fix branch <-- master --> topicbranch
Advantages:
...
only 1 common branches is required
Disadvantages:
not clean when remove hot-fix branches - but will not be a problem
Problem: we didnot bumped minor version in pom till rollout to prod we do few rollouts with build number increase, but still not ready to prod, and now we got PROD critical issue, we come back to prod revision to create branch, but we cannot use maven:release plugin as next few build numbers already occupied by rollouts to dev. Will be jars override in maven secure, can we trust to this ?
How we will secure UT passed for Prod version before rollout to prod ? not sure that developer will remember to goto Jenkins change config to new commit reference and launch configuration.... but I could be not right here .

It is highly required for ease and speed of development and fix delivering to have hot-fix branch to backport some features/fixes and rollout them more frequently, without being blocked by next rollout changes.

Alternatives:
http://blogs.atlassian.com/2013/05/maven-git-flow-plugin-for-better-releases/

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