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The Apache Project Maturity Model provides a suggested framework for evaluating the overall maturity of an Apache project community and the codebase that it maintains. While this model is specific to projects of the Apache Software Foundation (ASF), many of these factors apply to any open source project.
The goals of this maturity model are to describe how Apache projects operate in a concise and high-level way, and to provide a basic framework that projects may choose to use to evaluate themselves.
It is usable outside of the ASF as well, for projects that might want to adopt some or all of these principles. Projects that envision moving to the ASF at some point might start working towards this to prepare for their move.
It does not describe all the details of how our projects operate, but aims to capture the invariants of Apache projects and point to additional information where needed. To be as concise as possible we use footnotes for anything that’s not part of the core model.
Contrary to other maturity models, we do not define staged partial compliance levels. A mature Apache project complies with all the elements of this model, and other projects are welcome to adopt the elements that suit their goals.
Note that we try to avoid using the word “must” below. The model describes the state of a mature project, as opposed to a set of rules.
Projects which incubate at the ASF might not fit into all the parts of this model; however a major goal of incubation is to bring the project’s community closer to it.
We welcome questions and feedback about this model on the comdev mailing list.
The Apache Project Maturity Model
Each item in the model has a unique ID to allow it to be easily referenced elsewhere.
- The project produces Open Source software for distribution to the public, at no charge. 1
- Anyone can easily discover and access the project's code.
- Anyone using standard, widely-available tools, can build the code in a reproducible way.
- The full history of the project's code is available via a source code control system, in a way that allows anyone to recreate any released version.
- The source code control system establishes the provenance of each line of code in a reliable way, based on strong authentication of the committer. When third parties contribute code, commit messages provide reliable information about the code provenance. 2
Licenses and Copyright
- The Apache License, version 2.0, covers the released code.
- Libraries that are mandatory dependencies of the project's code do not create more restrictions than the Apache License does. 3 4
- The libraries mentioned in LC20 are available as Open Source software.
- Committers are bound by an Individual Contributor Agreement (the "Apache iCLA") that defines which code they may commit and how they need to identify code that is not their own.
- The project clearly defines and documents the copyright ownership of everything that the project produces. 5
- Releases consist of source code, distributed using standard and open archive formats that are expected to stay readable in the long term. 6
- The project's PMC (Project Management Committee, see CS10) approves each software release in order to make the release an act of the Foundation.
- Releases are signed and/or distributed along with digests that anyone can reliably use to validate the downloaded archives.
- The project can distribute convenience binaries alongside source code, but they are not Apache Releases, they are provided with no guarantee.
- The project documents a repeatable release process so that someone new to the project can independently generate the complete set of artifacts required for a release.
- The project is open and honest about the quality of its code. Various levels of quality and maturity for various modules are natural and acceptable as long as they are clearly communicated.
- The project puts a very high priority on producing secure software. 7
- The project provides a well-documented, secure and private channel to report security issues, along with a documented way of responding to them. 8
- The project puts a high priority on backwards compatibility and aims to document any incompatible changes and provide tools and documentation to help users transition to new features.
- The project strives to respond to documented bug reports in a timely manner.
- The project has a well-known homepage that points to all the information required to operate according to this maturity model.
- The community welcomes contributions from anyone who acts in good faith and in a respectful manner, and who adds value to the project.
- Contributions include source code, documentation, constructive bug reports, constructive discussions, marketing and generally anything that adds value to the project.
- The community strives to be meritocratic and gives more rights and responsibilities to contributors who, over time, add value to the project.
- The project documents how contributors can earn more rights such as commit access or decision power, and applies these principles consistently.
- The community operates based on consensus of its members (see CS10) who have decision power. Dictators, benevolent or not, are not welcome in Apache projects.
- The project strives to answer user questions in a timely manner.
- The project is independent from any corporate or organizational influence. 12
- Contributors act as themselves, not as representatives of a corporation or organization.
How To Use The Apache Project Maturity Model
Remember: This model is a guide; it is not a requirements document. The model shows what generally good behaviors in an Apache project look like.
So far, inside the ASF, podlings preparing their graduation from the Apache Incubator have used this model, mostly for self-assessment.
It might be useful for top-level ASF projects to regularly assess their maturity based on this model, but this is not a requirement at this time.
Here are a few self-assessment examples:
- Apache Groovy podling self-assessment, 2015
- Apache Taverna Graduation Maturity Assessment, 2016
- Apache CarbonData Podling Maturity Assessment, 2017
- Apache ServiceComb Maturity Model Assessment, 2018
Other Open Source Project Models
See https://s.apache.org/apache_maturity_model for the discussions that led to this document. Thanks to the many people who provided input! The links below are both inspirations for our model, and are some of the other ways that FOSS project participants have tried to quantify ways to measure open source projects.
Status / Document Version
v 1.0, February 2015, defined by consensus by Apache Community Development project.
v 1.1, October 2016 added RE50.
v 1.2, February 2018, reworked the “how to use” section with more links to self-assessments.
v 1.3, June 2021, improve readability and simplify the language where possible.
"For distribution to the public at no charge" is straight from the from the ASF Bylaws at https://apache.org/foundation/bylaws.html.
See also LC40.
It's ok for platforms (like a runtime used to execute our code) to have different licenses as long as they don't impose reciprocal licensing on
what we are distributing.
https://apache.org/legal/resolved.html has information about acceptable licenses for third-party dependencies.
In Apache projects, the ASF owns the copyright for the collective work,
i.e. the project's releases. Contributors retain copyright on their
contributions but grant the ASF a perpetual copyright license for them.
See https://www.apache.org/legal/release-policy.html for more info on Apache releases.
The required level of security depends on the software's intended uses, of course. Projects should clearly document security expectations.
Apache projects can just point to https://www.apache.org/security/ or use their own security contacts page, which should also point to that.
In Apache projects, "consensus" means widespread agreement among people who have decision power. It does not necessarily mean "unanimity".
For Apache projects, https://www.apache.org/foundation/voting.html defines the voting rules.
Each Apache project has a private mailing list that its PMC is expected to use
only when really needed. The private list is typically used for
discussions about people, for example to discuss and to vote on PMC
and committer candidates.
Independence can be understood as basing the project's decisions on the open
discussions that happen on the project's main communications channel,
with no hidden agendas.