3. Development

This section only needs to be read by developers of the zhmccli package. People that want to make a fix or develop some extension, and people that want to test the project are also considered developers for the purpose of this section.

3.1. Code of Conduct

Help us keep the zhmccli package open and inclusive. Please read and follow our Code of Conduct.

3.2. Repository

The source code repository for the zhmccli package is on GitHub:

https://github.com/zhmcclient/zhmccli

3.3. Setting up the development environment

The development environment is pretty easy to set up.

Besides having a supported operating system with a supported Python version (see Supported environments), it is recommended that you set up a virtual Python environment.

Then, with a virtual Python environment active, clone the Git repo of this project and prepare the development environment with make develop:

$ git clone git@github.com:zhmcclient/zhmccli.git
$ cd zhmccli
$ make develop

This will install all prerequisites the package needs to run, as well as all prerequisites that you need for development.

Generally, this project uses Make to do things in the currently active Python environment. The command make help (or just make) displays a list of valid Make targets and a short description of what each target does.

3.4. Building the documentation

The ReadTheDocs (RTD) site is used to publish the documentation for the zhmccli package at http://zhmccli.readthedocs.io/

This page automatically gets updated whenever the master branch of the Git repo for this package changes.

In order to build the documentation locally from the Git work directory, issue:

$ make builddoc

The top-level document to open with a web browser will be build_doc/html/docs/index.html.

3.5. Testing

There are two kinds of tests:

function tests: Function testcases run against a zhmcclient_mock environment.
end2end tests: End2end testcases run against an HMC or set of HMCs defined in an HMC inventory file, with credentials from an HMC vault file.

3.5.1. Running function tests

To run the function tests in the currently active Python environment, issue one of these example variants of make test:

$ make test                                  # Run all function tests
$ TESTCASES=test_info.py make test           # Run only this function test source file
$ TESTCASES=TestInfo make test               # Run only this function test class
$ TESTCASES="test_info_help or test_info_error_no_host" make test  # py.test -k expressions are possible

To run the function tests and some more commands that verify the project is in good shape in all supported Python environments, use Tox:

$ tox                              # Run all function tests on all supported Python versions
$ tox -e py39                      # Run all function tests on Python 3.9
$ tox -e py39 test_info.py         # Run only this function test source file on Python 3.9
$ tox -e py39 TestInfo             # Run only this function test class on Python 3.9
$ tox -e py39 test_info_help or test_info_error_no_host  # py.test -k expressions are possible

The positional arguments of the tox command are passed to py.test using its -k option. Invoke py.test --help for details on the expression syntax of its -k option.

In addition to TESTCASES, the environment variable TESTOPTS can be specified for function tests. Invoke make help for details.

3.5.2. Running end2end tests

To run the end2end tests in the currently active Python environment, you first need to prepare an HMC inventory file that defines real and/or mocked HMCs the tests should be run against, and an HMC vault file with credentials for the real HMCs.

There are examples for these files, that describe their format in the comment header:

To run the end2end tests in the currently active Python environment, issue:

$ make end2end

By default, the HMC inventory file named .zhmc_inventory.yaml in the home directory of the current user is used. A different path name can be specified with the TESTINVENTORY environment variable.

By default, the HMC vault file named .zhmc_vault.yaml in the home directory of the current user is used. A different path name can be specified with the TESTVAULT environment variable.

By default, the tests are run against the group name or HMC nickname default defined in the HMC inventory file. A different group name or HMC nickname can be specified with the TESTHMC environment variable.

To show the defined HMC nicknames and groups that can be used, issue:

$ make end2end_show

Examples:

Run against group or HMC nickname ‘default’ using the default HMC inventory and vault files:
```
$ make end2end
```
Run against group or HMC nickname ‘HMC1’ using the default HMC inventory and vault files:
```
$ TESTHMC=HMC1 make end2end
```
Run against group or HMC nickname ‘default’ using the specified HMC inventory and vault files:
```
$ TESTINVENTORY=./hmc_inventory.yaml TESTVAULT=./hmc_vault.yaml make end2end
```

In addition to TESTHMC, TESTINVENTORY and TESTVAULT, the environment variables TESTCASES, TESTOPTS, TESTRESOURCES and TESTLOG can be specified for end2end tests. Invoke make help for details.

3.6. Contributing

Third party contributions to this project are welcome!

In order to contribute, create a Git pull request, considering this:

Test is required.
Each commit should only contain one “logical” change.
A “logical” change should be put into one commit, and not split over multiple commits.
Large new features should be split into stages.
The commit message should not only summarize what you have done, but explain why the change is useful.
The commit message must follow the format explained below.

What comprises a “logical” change is subject to sound judgement. Sometimes, it makes sense to produce a set of commits for a feature (even if not large). For example, a first commit may introduce a (presumably) compatible API change without exploitation of that feature. With only this commit applied, it should be demonstrable that everything is still working as before. The next commit may be the exploitation of the feature in other components.

For further discussion of good and bad practices regarding commits, see:

3.7. Making a change

To make a change, create a topic branch. You can assume that you are the only one using that branch, so force-pushes to that branch and rebasing that branch is fine.

When you are ready to push your change, describe the change for users of the package in a change fragment file. To create a change fragment file, execute:

For changes that have a corresponding issue:

towncrier create <issue>.<type>.rst --edit

For changes that have no corresponding issue:

towncrier create noissue.<number>.<type>.rst --edit

For changes where you do not want to create or modify a change log entry, simply don’t provide a change fragment file.

where:

<issue> - The issue number of the issue that is addressed by the change. If the change addresses more than one issue, copy the new change fragment file after its content has been edited, using the other issue number in the file name. It is important that the file content is exactly the same, so that towncrier can create a single change log entry from the two (or more) files.

If the change has no related issue, use the noissue.<number>.<type>.rst file name format, where <number> is any number that results in a file name that does not yet exist in the changes directory.
<type> - The type of the change, using one of the following values:
- incompatible - An incompatible change. This will show up in the “Incompatible Changes” section of the change log. The text should include a description of the incompatibility from a user perspective and if possible, how to mitigate the change or what replacement functionality can be used instead.
- deprecation - An externally visible functionality is being deprecated in this release. This will show up in the “Deprecations” section of the change log. The deprecated functionality still works in this release, but may go away in a future release. If there is a replacement functionality, the text should mention it.
- fix - A bug fix in the code, documentation or development environment. This will show up in the “Bug fixes” section of the change log.
- feature - A feature or enhancement in the code, documentation or development environment. This will show up in the “Enhancements” section of the change log.
- cleanup - A cleanup in the code, documentation or development environment, that does not fix a bug and is not an enhanced functionality. This will show up in the “Cleanup” section of the change log.

This command will create a new change fragment file in the changes directory and will bring up your editor (usually vim).

If your change does multiple things of different types listed above, create a separate change fragment file for each type.

If you need to modify an existing change log entry as part of your change, edit the existing corresponding change fragment file.

Add the new or changed change fragment file(s) to your commit. The test workflow running on your Pull Request will check whether your change adds or modifies change fragment files.

You can review how your changes will show up in the final change log for the upcoming release by running:

towncrier build --draft

Always make sure that your pushed branch has either just one commit, or if you do multiple things, one commit for each logical change. What is not OK is to keep the possibly multiple commits it took you to get to the final result for the change.

3.8. Format of commit messages

A commit message must start with a short summary line, followed by a blank line.

Optionally, the summary line may start with an identifier that helps identifying the type of change or the component that is affected, followed by a colon.

It can include a more detailed description after the summary line. This is where you explain why the change was done, and summarize what was done.

It must end with the DCO (Developer Certificate of Origin) sign-off line in the format shown in the example below, using your name and a valid email address of yours. The DCO sign-off line certifies that you followed the rules stated in DCO 1.1. In short, you certify that you wrote the patch or otherwise have the right to pass it on as an open-source patch.

We use GitCop during creation of a pull request to check whether the commit messages in the pull request comply to this format. If the commit messages do not comply, GitCop will add a comment to the pull request with a description of what was wrong.

Example commit message:

cookies: Add support for delivering cookies

Cookies are important for many people. This change adds a pluggable API for
delivering cookies to the user, and provides a default implementation.

Signed-off-by: Random J Developer <random@developer.org>

Use git commit --amend to edit the commit message, if you need to.

Use the --signoff (-s) option of git commit to append a sign-off line to the commit message with your name and email as known by Git.

If you like filling out the commit message in an editor instead of using the -m option of git commit, you can automate the presence of the sign-off line by using a commit template file:

Create a file outside of the repo (say, ~/.git-signoff.template) that contains, for example:

<one-line subject>

<detailed description>

Signed-off-by: Random J Developer <random@developer.org>

Configure Git to use that file as a commit template for your repo:
```
git config commit.template ~/.git-signoff.template
```

3.9. Releasing a version

This section shows the steps for releasing a version to PyPI.

It covers all variants of versions that can be released:

Releasing a new major version (Mnew.0.0) based on the master branch
Releasing a new minor version (M.Nnew.0) based on the master branch or based on an earlier stable branch
Releasing a new update version (M.N.Unew) based on the stable branch of its minor version

This description assumes that you are authorized to push to the remote repo at https://github.com/zhmcclient/zhmccli and that the remote repo has the remote name origin in your local clone.

Any commands in the following steps are executed in the main directory of your local clone of the zhmccli Git repo.

On GitHub, verify open items in milestone M.N.U.

Verify that milestone M.N.U has no open issues or PRs anymore. If there are open PRs or open issues, make a decision for each of those whether or not it should go into version M.N.U you are about to release.

If there are open issues or PRs that should go into this version, abandon the release process.

If none of the open issues or PRs should go into this version, change their milestones to a future version, and proceed with the release process. You may need to create the milestone for the future version.
Run the Safety tool:
```
make safety
```
If any of the two safety runs fails, fix the safety issues that are reported, in a separate branch/PR.

Roll back the PR into any maintained stable branches.
Check for any dependabot alerts.

If there are any dependabot alerts, fix them in a separate branch/PR.

Roll back the PR into any maintained stable branches.
Create and push the release branch (replace M,N,U accordingly):
```
VERSION=M.N.U make release_branch
```
This uses the default branch determined from VERSION: For M.N.0, the master branch is used, otherwise the stable_M.N branch is used. That covers for all cases except if you want to release a new minor version based on an earlier stable branch. In that case, you need to specify that branch:
```
VERSION=M.N.0 BRANCH=stable_M.N make release_branch
```
This includes the following steps:
- create the release branch (release_M.N.U), if not yet existing
- make sure the AUTHORS.md file is up to date
- update the change log from the change fragment files, and delete those
- commit the changes to the release branch
- push the release branch
If this command fails, the fix can be committed to the release branch and the command above can be retried.
On GitHub, create a Pull Request for branch release_M.N.U.

Important: When creating Pull Requests, GitHub by default targets the master branch. When releasing based on a stable branch, you need to change the target branch of the Pull Request to stable_M.N.

Set the milestone of that PR to version M.N.U.

This PR should normally be set to be reviewed by at least one of the maintainers.

The PR creation will cause the “test” workflow to run. That workflow runs tests for all defined environments, since it discovers by the branch name that this is a PR for a release.
On GitHub, once the checks for that Pull Request have succeeded, merge the Pull Request (no review is needed). This automatically deletes the branch on GitHub.

If the PR did not succeed, fix the issues.
On GitHub, close milestone M.N.U.

Verify that the milestone has no open items anymore. If it does have open items, investigate why and fix (probably step 1 was not performed).
Publish the package (replace M,N,U accordingly):
```
VERSION=M.N.U make release_publish
```
or (see step 4):
```
VERSION=M.N.0 BRANCH=stable_M.N make release_publish
```
This includes the following steps:
- create and push the release tag
- clean up the release branch
Pushing the release tag will cause the “publish” workflow to run. That workflow builds the package, publishes it on PyPI, creates a release for it on GitHub, and finally creates a new stable branch on GitHub if the master branch was released.
Verify the publishing

Wait for the “publish” workflow for the new release to have completed: https://github.com/zhmcclient/zhmccli/actions/workflows/publish.yml

Then, perform the following verifications:
- Verify that the new version is available on PyPI at https://pypi.python.org/pypi/zhmccli/
- Verify that the new version has a release on Github at https://github.com/zhmcclient/zhmccli/releases
- Verify that the new version has documentation on ReadTheDocs at https://zhmccli.readthedocs.io/en/latest/changes.html
  
  The new version M.N.U should be automatically active on ReadTheDocs, causing the documentation for the new version to be automatically built and published.
  
  If you cannot see the new version after some minutes, log in to https://readthedocs.org/projects/zhmccli/versions/ and activate the new version.

3.10. Starting a new version

This section shows the steps for starting development of a new version.

This section covers all variants of new versions:

Starting a new major version (Mnew.0.0) based on the master branch
Starting a new minor version (M.Nnew.0) based on the master branch
Starting a new update version (M.N.Unew) based on the stable branch of its minor version

This description assumes that you are authorized to push to the remote repo at https://github.com/zhmcclient/zhmccli and that the remote repo has the remote name origin in your local clone.

Any commands in the following steps are executed in the main directory of your local clone of the zhmccli Git repo.

Create and push the start branch (replace M,N,U accordingly):
```
VERSION=M.N.U make start_branch
```
This uses the default branch determined from VERSION: For M.N.0, the master branch is used, otherwise the stable_M.N branch is used. That covers for all cases except if you want to start a new minor version based on an earlier stable branch. In that case, you need to specify that branch:
```
VERSION=M.N.0 BRANCH=stable_M.N make start_branch
```
This includes the following steps:
- create the start branch (start_M.N.U), if not yet existing
- create a dummy change
- commit and push the start branch (start_M.N.U)
On GitHub, create a milestone for the new version M.N.U.

You can create a milestone in GitHub via Issues -> Milestones -> New Milestone.
On GitHub, create a Pull Request for branch start_M.N.U.

Important: When creating Pull Requests, GitHub by default targets the master branch. When starting a version based on a stable branch, you need to change the target branch of the Pull Request to stable_M.N.

No review is needed for this PR.

Set the milestone of that PR to the new version M.N.U.
On GitHub, go through all open issues and pull requests that still have milestones for previous releases set, and either set them to the new milestone, or to have no milestone.

Note that when the release process has been performed as described, there should not be any such issues or pull requests anymore. So this step here is just an additional safeguard.
On GitHub, once the checks for the Pull Request for branch start_M.N.U have succeeded, merge the Pull Request (no review is needed). This automatically deletes the branch on GitHub.
Update and clean up the local repo (replace M,N,U accordingly):
```
VERSION=M.N.U make start_tag
```
or (see step 1):
```
VERSION=M.N.0 BRANCH=stable_M.N make start_tag
```
This includes the following steps:
- checkout and pull the branch that was started (master or stable_M.N)
- delete the start branch (start_M.N.U) locally and remotely
- create and push the start tag (M.N.Ua0)