nicktrn
b42e5c3771
The pod-count backpressure source read
`apiserver_storage_objects{resource="pods"}` from an apiserver
`/metrics` scrape. That gauge is a periodically-refreshed cached count,
and it is served by whichever apiserver replica the scrape lands on —
replicas disagree with each other at the same instant, by enough to
swamp the engage/release hysteresis band. Engage and release timing was
therefore partly a function of scrape routing.
This replaces it with a single `limit=1` list of the workload namespace
and computes `remainingItemCount + items.length`. One pod object
transferred, no informer, no watch cache.
Two request-shape constraints are load-bearing and called out in the
code: passing a label or field selector makes the apiserver omit
`remainingItemCount` entirely, and setting `resourceVersion` serves a
cached count rather than a quorum read. Neither is passed.
`remainingItemCount` is only set when the list is truncated, so
`_continue` is the truncation signal — if it is absent the returned page
is the whole collection and `items.length` is already exact. If the list
*is* truncated and the count is missing or implausible, the fetcher
throws rather than guessing.
Failure semantics are unchanged: a throw lands in the monitor's existing
catch, exactly as the previous parse did. The hysteresis, verdict shape,
and gauge are untouched. RBAC is unchanged — the existing role already
grants `pods: list`.
The `/metrics` non-resource grant in the deployment role becomes unused,
and the scrape-timeout env var is now a slight misnomer. Both left alone
deliberately: the grant may be wanted again for other apiserver signals,
and renaming the var would need a coordinated config change for no
behavioural gain.
Tests cover the not-truncated, truncated, missing-count, negative-count
and timeout paths.
Server Changes
This directory tracks changes to server-only components (webapp, supervisor, etc.) that are not captured by changesets. Changesets only track published npm packages — server changes would otherwise go undocumented.
When to add a file
Server-only PRs: If your PR only changes apps/webapp/, apps/supervisor/, or other server components (and does NOT change anything in packages/), add a .server-changes/ file.
Mixed PRs (both packages and server): Just add a changeset as usual. No .server-changes/ file needed — the changeset covers it.
Package-only PRs: Just add a changeset as usual.
File format
Create a markdown file with a descriptive name:
.server-changes/fix-batch-queue-stalls.md
With this format:
---
area: webapp
type: fix
---
Speed up batch queue processing by removing stalls and fixing retry race
Fields
- area (required):
webapp|supervisor - type (required):
feature|fix|improvement|breaking
Description
The body text (below the frontmatter) is a one-line description of the change. Keep it concise — it will appear in release notes.
Writing guidance
These entries are public-facing - they ship verbatim in user-visible release notes. A few rules to keep them clean:
- Write for the user, not the reviewer. Lead with what the user notices or has to do. If a reader who doesn't know the codebase can't tell what changed for them, rewrite it.
- One sentence is usually enough. The body is the bullet in the changelog. If you need a paragraph, you're probably describing the implementation rather than the change.
- Describe behavior, not implementation. Skip internal scopes, middleware names, library specifics, framework internals. Users care about what's different for them, not how it's wired.
- Never name internal tools or infra. Observability stacks, internal services, infra components, monitoring backends, CI surfaces, AWS specifics - none of these belong in user-facing notes.
Before / after:
- ❌ "The image verification step now parses the manifest's layer media types and returns a new result the finalizer rejects." (describes the wiring; a user can't act on it)
- ✅ "Deploying with an outdated CLI could produce an image that fails to start on every run. These deploys are now stopped before going live, with a message asking you to upgrade the CLI and re-deploy." (what the user sees and does)
Lifecycle
- Engineer adds a
.server-changes/file in their PR - Files accumulate on
mainas PRs merge - The changeset release PR includes these in its summary
- After the release merges, CI cleans up the consumed files
Examples
New feature:
---
area: webapp
type: feature
---
TRQL query language and the Query page
Bug fix:
---
area: webapp
type: fix
---
Fix schedule limit counting for orgs with custom limits
Improvement:
---
area: webapp
type: improvement
---
Use the replica for API auth queries to reduce primary load