One graph, not micro-stacks
Once an infrastructure repo has a few concerns in it (account hardening, the security baseline, the signing stack still to come) there’s a steady pressure to split them into separate stacks with separate state, and …
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12 pages
Architecture
Why I hand-rolled every module
There are well-known community module libraries for AWS: Cloud Posse, the terraform-aws-modules collection, plenty more. Both terraform-aws-bootstrap and terraform-aws-security-baseline use almost none of them. Every …
Supporting a provider, or actually using it
If your CLI tool talks to an AI model, you don’t want to hard-wire one vendor. So you reach for a single client interface over several providers, which is the right call. The trap is the next step: build that interface …
Two kinds of feature flag
go-tool-base has feature flags: switches that decide which built-in commands are live in a given run. rust-tool-base has those too. But it also has a second, completely separate kind of flag, and the difference between …
Reloading config without a restart
A config file changes. Someone edits a setting, rotates a credential, flips a feature flag. How does the running process find out? For most processes the answer is blunt: it doesn’t, until you restart it. For a …
Registering commands without life before main
I ended the last post promising to show how a Rust command registers itself when the language flatly refuses to run any of your code before main(). This is that post, and it’s a lovely example of reaching the same …
What survives a port, and what doesn't
Rebuilding go-tool-base in Rust turned out to be the most honest design review I’ve ever sat through, and I didn’t have to do anything except keep going. Porting a framework into a language with completely different …
An AI interface that fits on one screen
The moment you decide a CLI tool should talk to an LLM, there’s a strong gravitational pull towards reaching for LangChain, or one of its many relatives. It’s the obvious move. It’s also, for most CLI work, a bit like …
Middleware for CLI commands, not just web servers
Every CLI tool past a certain size grows a category of logic that doesn’t really belong to any one command, and yet has to happen for loads of them. Timing. An auth check. Panic recovery, so a crash becomes a clean error …
A logging interface that doesn't leak its backend
The same tool, in two different lives, wants two completely different kinds of log. On my laptop I want logs I can actually read: colour, alignment, friendly timestamps. The very same tool running as a daemon in a …
