Contributing

Get Source Code

Clone the repo from github:

$ git clone git@github.com:tomcatmanager/tomcatmanager.git

Create Python Environments

tomcatmanager uses tox to run the test suite against multiple python versions. tox expects that when it runs python3.9 it will actually get a python from the 3.9.x series.

I recommend using pyenv with the pyenv-virtualenv plugin to manage these various python versions. If you are a Windows user, pyenv won’t work for you, you’ll probably have to use conda.

This distribution includes a shell script build-pyenvs.sh which automates the creation of these environments.

If you prefer to create these virtual envs by hand, do the following:

$ cd tomcatmanager
$ pyenv install 3.12.0
$ pyenv virtualenv -p python3.12 3.12.0 tomcatmanager-3.12
$ pyenv install 3.11.5
$ pyenv virtualenv -p python3.11 3.11.5 tomcatmanager-3.11
$ pyenv install 3.10.13
$ pyenv virtualenv -p python3.10 3.10.13 tomcatmanager-3.10
$ pyenv install 3.9.18
$ pyenv virtualenv -p python3.9 3.9.18 tomcatmanager-3.9
$ pyenv install 3.8.18
$ pyenv virtualenv -p python3.8 3.8.18 tomcatmanager-3.8

Now set pyenv to make all five of those available at the same time:

$ pyenv local tomcatmanager-3.12 tomcatmanager-3.11 tomcatmanager-3.10 tomcatmanager-3.9 tomcatmanager-3.8

Whether you ran the script, or did it by hand, you now have isolated virtualenvs for each of the minor python versions. This table shows various python commands, the version of python which will be executed, and the virtualenv it will utilize.

Command	python	virtualenv
`python`	3.12.0	tomcatmanager-3.12
`python3`	3.12.0	tomcatmanager-3.12
`python3.12`	3.12.0	tomcatmanager-3.12
`python3.11`	3.11.5	tomcatmanager-3.11
`python3.10`	3.10.13	tomcatmanager-3.10
`python3.9`	3.9.18	tomcatmanager-3.9
`python3.8`	3.8.18	tomcatmanager-3.8
`pip`	3.11.5	tomcatmanager-3.11
`pip3`	3.11.5	tomcatmanager-3.11
`pip3.11`	3.11.5	tomcatmanager-3.11
`pip3.10`	3.10.13	tomcatmanager-3.10
`pip3.9`	3.9.18	tomcatmanager-3.9
`pip3.8`	3.8.18	tomcatmanager-3.8

Install Dependencies

Now install all the development dependencies:

$ pip install -e .[dev]

This installs the tomcatmanager package “in-place”, so the package points to the source code instead of copying files to the python site-packages folder.

All the dependencies now have been installed in the tomcatmanager-3.12 virtualenv. If you want to work in other virtualenvs, you’ll need to manually select it, and install again:

$ pyenv shell tomcatmanager-3.10
$ pip install -e .[dev]

Branches, Tags, and Versions

This project uses a simplified version of the git flow branching strategy. We don’t use release branches, and we generally don’t do hotfixes, so we don’t have any of those branches either. The main branch always contains the latest release of the code uploaded to PyPI, with a tag for the version number of that release.

The develop branch is where all the action occurs. Feature branches are welcome. When it’s time for a release, we merge develop into main.

This project uses semantic versioning.

When this library adds support for a new version of Tomcat or Python, we increment the minor version number. However, if support for these new versions requires API changes incompatible with prior releases of this software, then we increment the major version number.

When this library drops support for a version of Tomcat or Python, we increment the major version number. For example, when this project dropped support for Python 3.6, we released that version as 5.0.0 instead of 4.1.0, even though there were no incompatible API changes.

These versioning rules were chosen so that if you are using this library against a single version of Tomcat, and you specify your pyproject.toml dependency rules like:

[project]
dependencies = [
 "tomcatmanager>=4,<5"
]

you won’t have to worry about a future release of this software breaking your setup.

Invoking Common Development Tasks

This project uses many other python modules for various development tasks, including testing, rendering documentation, and building and distributing releases. These modules can be configured many different ways, which can make it difficult to learn the specific incantations required for each project you are familiar with.

This project uses invoke to provide a clean, high level interface for these development tasks. To see the full list of functions available:

$ invoke -l

You can run multiple tasks in a single invocation, for example:

$ invoke clean docs build

That one command will remove all superflous cache, testing, and build files, render the documentation, and build a source distribution and a wheel distribution.

To make it easy to check everything before you commit, you can just type:

$ invoke check
...
$ echo $?
0

and it will test, lint, and check the format of all the code and the documentation. If this doesn’t complete everything successfully then you still need to fix some stuff before you commit or submit a pull request. In this context, complete everything successfully means: all tests pass, lint returns a perfect score, doc8 finds no errors, etc.

To see what is actually getting executed by invoke, check the tasks.py file.

Testing

Unit testing provides reliability and consistency in released software. This project has 100% unit test coverage. Pull requests which reduce test coverage will not be merged.

This repository has Github Actions configured to run tests when you push or merge a pull request. Any push triggers a test run against all supported versions of python in a linux environment. Any pull request triggers a test run against all supported versions of python on all supported operating systems.

You can run the tests against all the supported versions of python using tox:

$ tox

tox expects that when it runs python3.9 it will actually get a python from the 3.9.x series. That’s why we set up the various python environments earlier.

If you just want to run the tests in your current python environment, use pytest:

$ pytest

This runs all the test in tests/ and also runs doctests in tomcatmanager/ and docs/.

You can speed up the test suite by using pytest-xdist to parallelize the tests across the number of cores you have:

$ pip install pytest-xdist
$ pytest -n8

To ensure the tests can run without an external dependencies, this project includes a mock server for each supported version of Tomcat. This speeds up testing considerably and also allows you to parallelize tests using python-xdist.

By default, pytest runs the mock server corresponding to the latest supported version of Tomcat. If you want to test against a different mock server, do something like:

$ pytest --mocktomcat 9.0

Look in conftest.py to see how these servers are implemented and launched.

When you run the tests with tox, the test suite runs against each supported version of Tomcat using each supported version of Python.

In many of the doctests you’ll see something like:

>>> tomcat = getfixture("tomcat")

This getfixture() helper imports fixtures defined in conftest.py, which has several benefits:

reduces the amount of redundant code in doctests which shows connecting to a tomcat server and handling exceptions
allows doctests to execute against a mock tomcat server

Testing Against A Real Server

If you wish, you can run the test suite against a real Tomcat Server instead of against the mock server included in this distribution. Running the test suite will deploy and undeploy an app hundreds of times, and will definitely trigger garbage collection, so you might not want to run it against a production server.

It’s also slow (which is why the tests normally run against a mock server). When I run the test suite against a stock Tomcat on a Linode with 2 cores and 4GB of memory it takes approximately 3 minutes to complete. I don’t think throwing more CPU at this would make it any faster: during the run of the test suite the Tomcat Server never consumes more than a few percent of the CPU capacity.

You must prepare some files on the server in order for the test suite to run successfully. Some of the tests instruct the Tomcat Server to deploy an application from a warfile stored on the server. I suggest you use the minimal application included in this distribution at tomcatmanager/tests/war/sample.war, but you can use any valid war file. Put this file in some directory on the server; I typically put it in /tmp/sample.war.

You must also construct a minimal context file on the server. You can see an example of such a context file in tomcatmanager/tests/war/context.xml:

<?xml version="1.0" encoding="UTF-8"?>
<!-- Context configuration file for my web application -->
<Context path='/ignored' docBase='/tmp/sample.war'>
</Context>

The docBase attribute must point to a valid war file or the tests will fail. It can be the same minimal war file you already put on the server. The path attribute is ignored for context files that are not visible to Tomcat when it starts up, so it doesn’t matter what you have there. I typically put this context file at /tmp/context.xml.

You will also need:

the url where the manager app of your Tomcat Server is available
a user with the manager-script role
the password for the aforementioned user

With all these prerequisites ready, you can feed them to pytest as shown:

$ pytest --url=http://localhost:8080/manager --user=ace \
--password=newenglandclamchowder --warfile=/tmp/sample.war \
--contextfile=/tmp/context.xml

If your tomcat server uses SSL/TLS client certificates for authentication, you can specify those certificates instead of a user and password:

$ pytest --url=https://localhost:8088/manager --cert=/path/to/cert.file \
--key=/path/to/key.file --warfile=/tmp/sample.war --contextfile=/tmp/context.xml

If your certificate and key are in the same file, pass that file using the --cert command line option.

Warning

The private key to your local certificate must be unencrypted. The Requests library used for network communication does not support using encrypted keys.

Warning

If you test against a real Tomcat server, you should not use the pytest-xdist plugin to parallelize testing across multiple CPUs or many platforms. Many of the tests depend on deploying and undeploying an app at a specific path, and that path is shared across the entire test suite. It wouldn’t help much anyway because the testing is constrained by the speed of the Tomcat server.

If you kill the test suite in the middle of a run, you may leave the test application deployed in your tomcat server. If this happens, you must undeploy it before rerunning the test suite or you will get lots of errors.

When the test suite deploys applications, it will be at the path returned by the safe_path fixture in conftest.py. You can modify that fixture if for some reason you need to deploy at a different path.

Code Quality

Use pylint to check code quality. The default pylint config file pylintrc can be used for both the tests and package:

$ pylint src tests

You are welcome to use the pylint comment directives to disable certain messages in the code, but pull requests containing these directives will be carefully scrutinized.

Code Formatting

Use ruff to format your code. We use the default configuration, including a line length of 88 characters.

To format all the code in the project using ruff, do:

$ ruff format *.py tests src docs

You can check whether ruff would make any formatting changes to the source code by:

$ ruff format --check *.py tests src docs

Ruff integrates with many common editors and IDE’s, that’s the easiest way to ensure that your code is always formatted.

Please format the code in your PR using ruff before submitting it, this project is configured to not allow merges if ruff format would change anything.

Punctuation and Capitalization for Users

Messages generated by InteractiveTomcatManager are intended for consumption by users, rather than developers.

Usage messages for individual commands are in all lower case letters with no periods. If the help for a particular option contains multiple phrases, separate them with a semi-colon. This matches the style of argparse.ArgumentParser. For example the message generated for the -h option is an uncapitalized phrase with no period. ArgumentParser epilogs should be sentences with capitalized first letters.

Error messages are in all lower case letters with no periods. This matches the style of the errors generated by argparse.ArgumentParser.

Command descriptions as shown by the help command come from the docstring for the associated method. For example the description shown for the deploy command comes from the the docstring for do_deploy. The code assumes these docstrings are a single line. These command descriptions are all lower case letters with no periods. ArgumentParser objects should get the first line of the docstring to use for the description, so that connect -h always shows the same description as help.

Documentation in /docs is written in sentences with capitalized first letters.

Punctuation and Capitalization for Developers

Docstrings in TomcatManager and other associated classes are written in sentences with capitalized first letters. This matches the style that Sphinx uses to render the documentation and ensures that all html documentation (user and api) follows the same style.

Documentation

Documentation is not an afterthought for this project. All PR’s must include relevant documentation or they will be rejected.

The documentation is written in reStructured Test, and is assembled from both the docs/ directory and from the docstrings in the code. We use Sphinx formatted docstrings. We encourage references to other methods and classes in docstrings, and choose to optimize docstrings for clarity and usefulness in the rendered output rather than ease of reading in the source code.

The documentation is indented using four spaces, the same as the python code.

The code includes type hints as a convenience, but does not provide stub files nor do we use mypy to check for proper static typing. Our philosophy is that the dynamic nature of Python is a benefit and we shouldn’t impose static type checking, but annotations of expected types can be helpful for documentation purposes.

Sphinx transforms the documentation source files into html:

$ cd docs
$ make html

The output will be in docs/build/html. We treat warnings as errors, and the documentation has none. Pull requests which generate errors when the documentation is build will be rejected.

If you are doing a lot of documentation work, the sphinx-autobuild module has been integrated. Type:

$ cd docs
$ make livehtml

Then point your browser at http://localhost:8000 to see the documentation automatically rebuilt as you save your changes.

Use doc8 to check documentation quality:

$ doc8 docs README.rst CONTRIBUTING.rst CHANGELOG.rst

This project is configured to prevent merges to the main or develop branch if doc8 returns any errors.

When code is pushed to the main branch, which only happens when we cut a new release, the documentation is automatically built and deployed to https://tomcatmanager.readthedocs.io/en/stable/. When code is pushed to the develop branch, the documentation is automatically built and deployed to https://tomcatmanager.readthedocs.io/en/develop/.

Make a Release

To make a release and deploy it to PyPI, do the following:

Merge everything to be included in the release into the develop branch.
Run tox to make sure the tests pass in all the supported python versions.
Review and update CHANGELOG.rst.
Update and close the milestone corresponding to the release at https://github.com/tomcatmanager/tomcatmanager/milestones
Push the develop branch to github.
Tag the develop branch with the new version number and push the tag
Create a pull request on github to merge the develop branch into main. Wait for the checks to pass.
Merge the develop branch into the main branch and close the pull request.
Create a new release on Github summarizing the changelog
Change to the main branch.
Install the released version by pip install -e .[dev]
Build source distribution, wheel distribution, and upload them to testpypi:
```
$ invoke testpypi
```
Build source distribution, wheel distribution, and upload them to pypi:
```
$ invoke pypi
```
Docs are automatically deployed to http://tomcatmanager.readthedocs.io/en/stable/. Make sure they look good. Add a “Version” in readthedocs which points to the tag you just created. Prune old versions as necessary.
Switch back to the develop branch.
Add an Unreleased section to the top of CHANGELOG.rst. Push the change to github.