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0 pointsderriz1mo ago0 comments

How do you internalize it?

Our bazel system is full of custom skylark code so understanding the build means effectively reading a bunch of ad-hoc code written with varying degrees of competence and with confusing dependencies. I’m kinda ashamed I don’t have a deep understanding of a tool I use daily - but every time I try reading the documentation I quickly give up.

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5 comments · 3 top-level

zhengyi131mo ago· 2 in thread

Probably not in the way that you might mean it, but for me (Xoogler, 2010 - 2023) internalizing bazel means:

"Hey, where's your tool's code in $MONOREPO?" "<path/to/stuff>"

Cool:

    g4d my-citc-client # moral equivalent to `cd ~/repos/stuff`
    blaze run path/to/stuff:target

... and you get a running version of whatever $stuff is, immediately built from head, quickly - no matter the set of dependencies, or which language they were built in. I can just try your thing out immediately with a common interface for all the builds, and I don't need to understand the build at all, unless or until I do, and then OK, absolutely every single build is always expressed in exactly the same way, same idioms, same patterns...

derrizOP1mo ago

Probably it's just down to a different understanding of the word "internalize".

I know how to _use_ bazel effectively to do my work. I'm comfortable with its well-designed surface but whenever I've tried to understand the inner machinery I've given up - especially when presented with a bunch of custom skylark rules code.

It's like an anti-git in some regards - the surface of git (the CLI) is an abomination in many ways but the the mechanics of the tool are so ingrained and the model is so clear and simple - I never feel uncomfortable.

I've a need to have some comprehension of the inner machinery or the underlying model of my tools.

trashburger1mo ago

I've personally driven adoption of Bazel across two teams in our company over the last two years (we have an extremely fragmented set of repos that touches everything from hardware, to end-to-end simulation, to cloud software, to CDK stacks that deploy the software). There are still some aspects (ha) that confuse me like transitions, exec groups and constraints, but most of the time it's all about building a graph of actions (command executions) by executing code, and hooking up external dependencies into the graph inputs. Mind telling what confuses you in particular? Maybe I can be of help somehow.

barrkel1mo ago

The first thing is hermeticity and and what it implies: caching. That if targets are a strict function of inputs, and inputs can be hashed, then you can reliably cache them - including test results!

The second thing is distributed caching. Done right, not only are your test results cached, but CI's test results can be cached too.

The third thing is distributed builds. This only starts to matter in big projects, but compilation is inherently a spiky load and if you can share a big pool of compute between a big pool of engineers, you get higher hardware utilization and lower latency to build artifacts.

The fourth thing, something that isn't really feasible outside big tech, is you could be bazel all the way down in a big monorepo. One of the niftiest things at Google is to be able to put a printf inside a database server and run your client test, and blaze knows that it needs to rebuild the database server and it will do it automatically, so that you can get extra insight at almost any level in the stack.

ASinclair1mo ago

I would recommend learning the various "bazel query" variants starting with a plain "bazel query" https://bazel.build/query/language

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