relates to: https://github.com/coder/internal/issues/1094
This is number 1 of 5 pull requests in an effort to add agent script
ordering. It adds a unit manager, which uses an underlying DAG and a
list of subscribers to inform units when their dependencies have changed
in status.
In follow-up PRs:
* This unit manager will be plumbed into the workspace agent struct.
* It will then be exposed to users via a new socket based drpc API
* The agentsocket API will then become accessible via CLI commands that
allow coder scripts to express their dependencies on one another.
This is an experimental feature. There may be ways to improve the
efficiency of the manager struct, but it is more important to validate
this feature with customers before we invest in such optimizations.
See the tests for examples of how units may communicate with one
another. Actual CLI usage will be analogous.
I used an LLM to produce some of these changes, but I have conducted
thorough self review and consider this contribution to be ready for an
external reviewer.
Relates to https://github.com/coder/internal/issues/1093
This is the first of N pull requests to allow coder script ordering.
It introduces what is for now dead code, but paves the way for various
interfaces that allow coder scripts and other processes to depend on one
another via CLI commands and terraform configurations.
The next step is to add reactivity to the graph, such that changes in
the status of one vertex will propagate and allow other vertices to
change their own statuses.
Concurrency and stress testing yield the following:
CPU Profile:
<img width="1512" height="862" alt="Screenshot 2025-10-17 at 10 38 52"
src="https://github.com/user-attachments/assets/f46cf1a2-a0b2-4c02-81a0-069798108ee5"
/>
Mem Profile:
<img width="1512" height="862" alt="Screenshot 2025-10-17 at 10 38 01"
src="https://github.com/user-attachments/assets/45be1235-fff6-45ba-a50d-db9880377bd0"
/>
Predictably, lock contention and memory allocation are the largest
components of this system under stress. Nothing seems untoward.
Sas Swart