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Lightweight RFC Process

To be Reviewed By: June 25th 2019

Authors: amurmann@apache.org

Status: Draft | Discussion | Development | Active | Dropped | Superseded

Superseded by: N/A

Related: N/A

Problem

With some of our recent efforts, we have seen consensus on design decisions take a very long time. In order to be able to keep moving forward as a successful project, we need to be able to get to consensus faster and ultimately get to execution faster. Therefore I propose a slightly more formal process for us to get to consensus.

We already have gotten pretty good at sharing proposals with each other. Not much should need to change with that. It’s mainly the process around it that needs to be ironed out. This document will refer to that process as the “Request For Comments (RFC) process”. The main questions that the process needs to address are: What is enough consensus? How can we get to consensus in a reasonable time frame?

Solution

The proposed solution to address the problem described above is to have an individual author or even better a group of authors submit a proposal to the community in order to gather feedback and achieve consensus. The RFC follows the same format as used by this proposal.

Much inspiration for this proposal and in some cases whole segments have been drawn from Phil Calçado’s Structured RFC Process. This proposal adopts Calçado’s work for use in an open source project like ours.

Some aspects are also based on Apache Kafka’s KPI process.

All RFCs are created as a new wiki page under Project Proposals and Specifications. In addition a [DISCUSS] email should be send to the dev mailing list. Discussion will take place in the email thread.

Collaboration

Comments and feedback should be provided on the email thread and focus on the technical content. As long as they don't impact the content, collaborators should avoid commenting on formatting, writing style and other maybe relevant, but not critical aspects.

Authors must address all comments written by the deadline. This doesn't mean every comment and suggestion must be accepted and incorporated, but they must be carefully read and responded to. Comments written after the deadline may be addressed by the author, but they should be considered as a lower priority.

Every RFC has a lifecycle. The life cycle has the following phases:

  • Draft: This is the initial state of the RFC, before the author(s) have started the discussion and are still working on the proposal.
  • Discussion: Once the [DISCUSS] email has been sent to the mailing list, the proposal should be transitioned to this state.
  • Development: The deadline for comments on this RFC has passed and the authors have decided to go ahead with it. The work proposed by the RFC is being implemented right now.
  • Active:  The RFC has been accepted and the implementation work is complete.
  • Dropped: The authors have decided not to move forward with the changes proposed in this RFC. This might even happen after the proposal was approved.
  • Superseded: The changes proposed on this RFC aren't in effect anymore, the document is kept for historical purposes and there is a new RFC that’s more current.

When a proposal transitions to Dropped or Superseded state it should be moved under the Icebox grouping.

Approval

The proposal should be posted with a date by which the author would like to see the approval decision to be made. How much time is given to comment depends on the size and complexity of the proposed changes. Anything between 1 week and 3 weeks seems like a reasonable timespan. Driving the actual decisions should follow the lazy majority approach. If a discussion is still going strong once it’s approaching the initially set date, the author(s) might consider extending the time for discussion. This should happen explicitly and be announced in the email that starts the [DISCUSS] thread.

When to write an RFC?

Writing an RFC should be entirely voluntary. There is always the option of going straight to a pull request. However, for larger changes, it might be wise to de-risk the risk of rejection of the pull request by first gathering input from the community. Therefore it’s up to every member of our community to decide themselves when they want to reach for this tool.

It’s encouraged to write an RFC for any major change. A major change might be:

  • Addition of any major new feature or subsystem
  • Changes that impact existing, public APIs. This includes Java APIs, but also things like GFSH commands and externally exposed protocols.

How to write an RFC?

  1. Copy the RFC template and write your proposal! It's up to the author's discretion to decide which section in the template make sense for their proposal. It's recommended to cover the problem the proposal is solving, who it affects, how you’re proposing to solve it, and answers to frequently asked questions. Explicitly listing the goals will also make it easier to retrospect later on the proposal.
  2. Start a [DISCUSS] thread on the mailing list and link to the proposal's wiki page. Make sure to state the deadline clearly in your email. The duration of the deadline is up to the author(s) and should depend on the size and complexity of the proposal. A reasonable time frame might be somewhere between a week and a month.
  3. Answer questions and concerns on the email thread. Consider adding questions that get asked more than once to the FAQ section of the RFC.
  4. After the deadline for feedback has been reached summarize the consensus and your decision on the [DISCUSS] thread.
    1. If the decision is to drop the proposal, the status should be updated to Dropped.
    2. If we are moving forward the status goes to Active
    3. When there is a newer RFC that replaces this one the status goes to Superseded and the Superseded By gets updated with a link to the new RFC.

Immutability & Errata

Once approved the existing body of the RFC should remain immutable.

Once the proposed work starts, we likely will learn things that require minor changes to the RFC to keep it current. These changes should be captured in an Errata section at the end of the document rather than modifying the existing body of the document directly. This is to highlight that and how the approach has changed, since initial discussion.

Humble Advice

Some things can be helpful to keep in mind when writing technical documents:

  1. Keep the document brief but complete. People don’t have time to thoroughly read and think about extremely long documents and they’ll receive less feedback compared with a shorter document. If you find it challenging to meet this limit then maybe the proposal is too big and could be broken up.
  2. Include evidence of the problem if at all possible, even if it’s anecdotal. This can help others see the core causes of the issue rather than only being able to comment on the diagnosis or solution. For example, consider linking to evidence inline, brief inline quotes, and/or footnotes.
  3. IETF RFCs you may see contain strict rules conveyed within the semantic meaning of SHOULD, MUST, and MAY. You don’t need to stress about the particulars of language or semantics when writing Geode-RFCs. Place importance explaining your problem and proposal clearly, succinctly, and convincingly over the specifics of implementation.

Prior Art

There are some existing solutions that might accomplish the same as this proposal. However, we believe that those solutions are inferior for the reasons below.

IEEE RFC Model as-is

Although any collaborative development process will have feedback as a core component, the name RFC was made popular by the process used by the IETF to document fundamental standards for what eventually became the Internet. We could follow the IETF RFC model, and maybe even require authors to use terms like MUST, SHOULD, and MAY as formally specified by RFC2119 to avoid ambiguity.

The main reason to avoid this style is that IETF RFCs have evolved into "the Internet documents of record", containing "very detailed technical information" about standards that browser vendors and network middleware need to implement. These documents will impact the whole industry and hence warrant a complex publishing workflow. The process we propose in this document, on the other hand, is about putting forward an idea as early as possible and receiving feedback on it by a wide audience. With this goal in mind, a less formal process like the one described here is preferred.

Architecture Decision Record

Michael Nygard published a model to document and manage change in software architecture called Architecture Decision Record (ADR). The ADR seems to be more focused on documenting architectural decisions rather than on arriving at a consensus about them.

The primary problem this lightweight RFC proposal is solving is how to arrive at a consensus, not how we document architecture.

FAQ

Errata

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