Remove dependency on cookiecutter

[zhan9san]

Fix #3486

@ssbarnea

Both cookiecutter and ansible template are using Jinja. So I decide to continue to use Jinja as a template engine.

To avoid reinventing the wheel, the template render logic is migrated from cookiecutter with tailored function and parameters.

I'd like to confirm with you whether the above way is accepted.
If yes, I'll add more tests later and fix the lint issue in this PR.
If no, do you have any suggestions?

To do

Do you have any concerns for to-do?

1. Fix CI issue in this PR
2. Add template directory with out {{ and mark {{ directory deprecated in another PR

Backward compatible

Currently, the following commands work as before. It means, this change is backward-compatible, and for other drivers, too.

1. delegated by default

$ molecule init role acme.my_new_role_docker --driver-name docker
INFO     Initializing new role my_new_role_docker...
No config file found; using defaults
- Role my_new_role_docker was created successfully
[WARNING]: No inventory was parsed, only implicit localhost is available
localhost | CHANGED => {"backup": "","changed": true,"msg": "line added"}
INFO     Initialized role in /Users/jackzhang/tmp/my_new_role_docker successfully.

4. docker driver

molecule init role acme.my_new_role
INFO     Initializing new role my_new_role...
No config file found; using defaults
- Role my_new_role was created successfully
[WARNING]: No inventory was parsed, only implicit localhost is available
localhost | CHANGED => {"backup": "","changed": true,"msg": "line added"}
INFO     Initialized role in /Users/jackzhang/Downloads/tmp/roles/my_new_role successfully.

Related: cookiecutter/cookiecutter#1555 cookiecutter/cookiecutter#1636 cookiecutter/cookiecutter#1642

[ssbarnea]

That looks awesome but I did not perform a deep review as I am still in vacation. Lets get help from at least one more reviewer before acting as we do want to be confident in it.

[zhan9san]

@ssbarnea

Enjoy yourself.

At least, you made me think I am on the right track.

[ssbarnea]

@zhan9san Do not forget to fix the linting.

[zhan9san]

@ssbarnea

I am working on it.

[apatard]

I'm seeing no documentation change so I assume that it fully transparent to the user ?

[apatard]

why not using something like (untested) ? :

file_name = os.path.basename(context_file)
file_stem = file_name.splitext(file_name)[0]

[zhan9san]

Hi @apatard

Thanks for your review.

It is referred to cookiecutter generater.py

They do the same thing getting the filename without extension.

[zhan9san]

Hi @apatard

file_name generated by os.path.basename(context_file) is string, which does not have splitext function.

So I only change the file_name from os.path.split(context_file)[1] to os.path.basename(context_file).

[felixfontein]

I think @apatard meant os.path.splitext(file_name)[0] and not file_name.splitext(file_name)[0]. While I think that would be better, it is a potentially breaking change, since the current code splits at the first ., while os.path.splitext splits at the last ..

[zhan9san]

Hi @felixfontein

Thanks for your review. You are right.

The file_stem is generated by os.path.splitext(file_name)[0] in new commit.

For this specific case, as cookiecutter.json is used, the value of file_stem would be cookiecutter.

[zhan9san]

@ssbarnea

All CI, including lint jobs pass.

Would you kindly review this PR?

[felixfontein]

I'm not a lawyer, but if this contains code that was taken from cookiecutter, doesn't it need to carry the license and copyright from cookiecutter? (Same for other code taken from that project.)

[zhan9san]

@felixfontein

Thanks for your reminder.

The cookiecutter license and copyright are added in new commit, referring to how interpolation.py did.
https://github.com/ansible-community/molecule/blob/04157c3684a46987ba00a6223261e3da30ff5b0c/src/molecule/interpolation.py#L1-L16

[zhan9san]

I'm seeing no documentation change so I assume that it fully transparent to the user ?

Yes, it's a backward compatible migration.

[ssbarnea]

@apatard @felixfontein Any more concerns?

[zhan9san]

Cookiecutter is live again - we released 2.1.0 https://pypi.org/project/cookiecutter/2.1.0/

Originally posted by @jensens in #3486 (comment)

If we continue to use cookiecutter, we can close this PR.

[ssbarnea]

Closed in favour of #3568 -- please rebase that one. I want to merge that change in a feature branch as cookiecutter had finnally got a new release and we might not need to remove it. Still, i do not want to lose your work.

[zhan9san]

Thanks.

I think it's not urgent. I'll try to make it work.

Besides, if cookiecutter works well, we don't want to reinvent the wheel.