Split into `st2`, `st2web`, `st2chatops`

[arm4b]

For simplicity reasons, at the moment we keep all the required roles (12) to install/configure StackStorm in one single repository ansible-st2, available under StackStorm.stackstorm Ansible Galaxy, see meta/main.yml workaround.

Alternative is to add more flexibility, distribute everything as different Ansible Galaxy roles (?)

Some arguments:

• StackStorm can be used in High Availability Deployment
• Could be installed/distributed across many hosts
• Can use external RabbitMQ, PostgreSQL, Mongo, ChatOps server
• Not all packages are needed for everyone

Disadvantages:

• Significant breaking change
• Increased complexity & support (we don't need that yet ?)
• Different repos, harder to maintain (?)
• Hard to test "all in one st2" because of components decoupling (CI, PRs)
• Less visibility (give me everything in one place) https://galaxy.ansible.com/StackStorm/stackstorm/

[cognifloyd]

How about we do both? One main repo for development and unified use with read-only subsplit repos for each of the roles? We could use something like:
https://github.com/dflydev/git-subsplit

[cognifloyd]

I learned about git-subsplit from the Neos community. They use Neos/slicer (which uses git-subsplit) to manage their split repos. I just asked, and they'd like to move to from git-subsplit to splitsh/lite, but the tools create different commit hashes, so they couldn't complete the transition. We should probably start with slitsh/lite to begin with as it is supposed to be much faster.

[cognifloyd]

Right now, I'm mixing the stackstorm roles in a custom playbook that intersperses some of my own roles. I installed StackStorm.stackstorm from galaxy. To use the stackstorm roles individually, however, I have to refer to them as StackStorm.stackstorm/roles/<role>, and if I want to replace one of the stackstorm provided roles, it might still run the stackstorm one, because of meta dependencies. ie: StackStorm.stackstorm/roles/mongodb is not mongodb. Publishing them as individual roles makes it easier to reuse, or override roles selectively.

Current meta dependencies:

• ansible-st2/roles/mongodb/meta/main.yml

  Lines 19 to 21 in 9d34eca

  	dependencies:
  	- role: epel
  	when: ansible_os_family == 'RedHat'

• ansible-st2/roles/st2/meta/main.yml

  Lines 23 to 26 in 01bd535

  	dependencies:
  	- role: epel
  	when: ansible_os_family == 'RedHat'
  	- role: st2repo

• ansible-st2/roles/st2chatops/meta/main.yml

  Lines 23 to 25 in 297e2eb

  	dependencies:
  	- role: nodejs
  	- role: st2

• ansible-st2/roles/st2mistral/meta/main.yml

  Lines 22 to 24 in 01bd535

  	dependencies:
  	- role: postgresql
  	- role: st2repo

• ansible-st2/roles/st2web/meta/main.yml

  Lines 20 to 23 in 01bd535

  	dependencies:
  	- role: nginx
  	- role: st2repo
  	- role: st2

Thus, if I override any of the above roles, it will still use the stackstorm one in addition to my role. Moving to galaxy installed roles solves that because roles can always be referenced individually by name instead of using non-standard paths.

[cognifloyd]

Here is how an initial split can be done with splitsh/lite (with newlines for legibility):

time (git clone git@github.com:cognifloydtest/ansible-st2.git ansible-st2.git);
cd ansible-st2.git;
time (
    for role in roles/*; do
        echo; echo $role;
        git checkout master;
        splitsh-lite --progress --prefix $role --target=refs/heads/ansible-role-${role##*/};
        git checkout ansible-role-${role##*/};
        hub create cognifloydtest/ansible-role-${role##*/};
        git remote add ansible-role-${role##*/} git@github.com:cognifloydtest/ansible-role-${role##*/}.git -t master;
        git push ansible-role-${role##*/} -u ansible-role-${role##*/}:master;
    done;
    git checkout master
)

Check out my example repos at https://github.com/cognifloydtest
Check out the output from this command in https://gist.github.com/cognifloyd/4f4fbd0251ddb7115c3d9475f7eab507

If a copy of the repository is kept (to keep the cached split info) in some CI or ST2 instance somewhere, the split and push could be repeated to quickly update the split repositories when new commits are made on the master branch. That way, the ansible-st2 repo is the main development repo that includes all the CI checking, PRs, etc. But, read-only split copies of the roles can also be published on galaxy.

This does not deal with updating tags on the read-only repositories.

Also: Note that I used hub to create the repos on the fly.

[arm4b]

@cognifloyd The solution you're suggesting with git split is definitely interesting and worth trying/considering. Thanks for showing 👍
We'll research this approach more when we'll reach the migration point.

As @ytjohn noted #12 (comment), it might be a good idea to rename the roles/paths to StackStorm.st2, StackStorm.st2web etc soon to make the further transition smoother.

[cognifloyd]

I would take a two step approach:

1. rename the role folders: st2 => StackStorm.st2
2. split the roles off into their own repos.

I think you want them to be named appropriately in this repo first so that the meta dependencies, the example playbook, and all of the CI infra uses roles named StackStorm.*.