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Cultural tenets of the Fuchsia FIDL team

Here are four cultural tenets which have helped keep the members of the Fuchsia FIDL team focused. Having these values helps to choose the appropriate course of action when multiple seemingly appropriate paths are available. These cultural tenets are meant to guide how we approach our work, our projects, how we present our team, and helps to define how we work together.

Keep design inventory in check

We care about keeping the "designed but not yet implemented" inventory low. We code our ideas, and refrain from ideating too far out in the future.

We want to keep the number of accepted-not-yet-implemented RFCs low, or avoid engaging on plans which we know will not see the light of day in a reasonable amount of time, i.e. our time horizon. Over time, what a "reasonable amount of time" is has grown from months, to half a year, to now about 1 to 2 years.This horizon expansion was fueled by various things1. We have also observed that unimplemented designs do not age well, and that requirements and architecture that made sense when they were first etched are rarely the right fit for the reality we find ourselves in down the road.

We strive to avoid the "current is deprecated, future is not working" trap by maintaining high velocity towards building the future, actively migrating our customer base to these new features, and generally keeping the number of in-flight migrations low.

We also strive to provide concrete answers as to how to solve the problem with current tooling, rather than provide a non-answer by deferring to future features "it will be fixed with [insert outdated design doc here]". Providing advice with current tooling when we know something better is coming around the corner is painful, and is a good reminder of the urgency we should feel to deliver this value to our users in a codebase near them (as opposed to in a design doc, which is only potential impact).

One voice

When representing the Fuchsia FIDL team's position, we speak in harmony. We strive to present a clear and consistent message to our peers. We should all answer questions consistently, speak about our roadmap consistently, describe technical direction consistently, align ourselves on prioritization, etc.

For instance, when providing help on fidl-dev@fuchsia.dev, any team member should provide the same advice. If we have differing opinions in the team, it is our responsibility to resolve them, so that we can present a common view to our users.

Failure to align internally spills our indecisiveness or doubts onto our users, who have less context of the technical trade offs that we do. Sometimes, that means that we have to acknowledge that "we don't know", or that we "don't have a best practice yet". In such cases, we should describe the options, and their pros and cons, and work with our users to guide them as to what is the best course of action for them.

Bias for action

We lead with action, we place a premium on work, and deliverables. We comment, steer, and critique where we care to walk the talk.

In everything we do, it is useful to think about what is the positive outcome, what is the stepping stone that we can lay to move forward. For instance, if we have an interesting design conversation during a team sync, it is quick to summarize what we discussed in a few bullet points. The next time around, this context will be there at the ready to re-open the conversation from a stronger basis. Or if we discuss during a 1:1 the presence of technical debt in some code base, and complain about the state of things, we can choose to turn this into something concrete, even if it is just raising awareness to all, and naming the problem and desired end state.

We start small2

We execute on a big vision in steps, break down the work, and start with small proof-of-concepts. We are comfortable with taking temporary shortcuts, and focus on keeping momentum towards our long term goals.

This is about prioritizing, breaking the work down, and doing incremental improvements towards an ideal. For instance, we have taken liberties and sometimes done work out-of-order to first unblock the user facing issue, knowing we would later close the architectural gap.

For instance, the introduction of Dart FIDL JSON template was problematic because it took advantage of careful assembly (ensuring no handles we present, by visual review sort of) and was received negatively initially. The architectural gap this Dart FIDL JSON feature took advantage of was only closed by RFC-0057: Default No Handles, more than 18 months later.

Another example is work on code size analysis (see PS1 of 76). We decided to start with an imperfect solution which got us some data. Then, little by little, we iterated and refined this solution. What was key is that improvements to the measurements were made in tandem with concrete changes to reduce binary size in FIDL owned code. As a result, we invested enough to generate an "ideas list". We executed on that list, and rinsed, and repeated the process. After a quarter following this cycle, the resulting tool became quite precise, and its reporting capabilities were perfectly geared towards a concrete use case. This tool then generalized, and is now a key piece of Fuchsia's size dieting efforts.

A third example, work on describing the Zircon API using the FIDL language. This initially started with very hacky FIDL files, some that didn't even compile. A new backend (kazoo) was born, with support for various targets added one after the other. Still today, the FIDL files rely on hacks, experimental features, and the like. But, we are confident in the long term direction of this work, and have been careful not to take design debt that would paint FIDL in a corner.

There is a continuum between pure research on one end, and addressing the immediate issue right in front without regard to impact on future plans. We should be conscious about where we are on that continuum, and actively work to right size how future proof or expedient we are. Navigating the balance of what shortcuts are fine relative to shortcuts which can be devastating is part of the craft of being an engineer. Practice makes perfect.


  1. Contributing factors to expanding the time horizon: 

    • Fuchsia FIDL team size, i.e. more fire power;
    • Solving short term issues (e.g. FTP backlog in 2018, fidlc bugs blocking other teams);
    • Clear expectations of how work happens (e.g. guidelines for team syncs, or project updates), further speeding up execution;
    • Design precedent (e.g. RFCs) anchoring design principles, and simplifying the research, and review of new ideas.
  2. This tenet's punchy title "We start small" is borrowed from Jack Dorsey's "Square's Four Corners" which were the company values circa 2012. The tenet itself is expanded here to be relevant to our work.