Two things that made reading logs harder than it needed to be. Query input: the API accepts an absolute time only if it is quoted AND carries an explicit offset, so someone reading logs in America/Denver who wanted "9am today" had to convert to UTC in their head and remember the quotes. Now a time typed without an offset is read as wall-clock time in that reader's display timezone and converted to the instant it names; anything with an explicit offset is taken at its word, and relative ranges never depended on a zone. This widens what's accepted rather than reinterpreting anything -- every naive form now handled is one the parser rejects outright today, so no query that works now can change meaning. The conversion happens before a query is sent *or saved*: a stored dashboard range becomes an explicit instant, because storing "2026-08-22 10:00" would mean 10am in whatever zone each viewer sat in, and one shared dashboard would show two people two different windows. It also fixes two bugs that predate the timezone work. injectTimeRange emitted absolute values unquoted, which the parser rejects -- so zooming a time-series chart into a range, and clicking a chart to drill down, both produced a syntax error on every panel. Both fed an ISO string straight into that unquoted path. Width: the query page's 64rem cap is gone, so the query bar and results table use the whole window -- a log table is the widest thing in this app and that cap was the horizontal scrolling. Prose keeps a readable measure, since full-width paragraphs are harder to read, not easier. Ambiguous local times -- the hour that repeats when clocks go back, the hour skipped when they go forward -- resolve to one instant. That is inherent to naming a moment by wall clock; an explicit offset sidesteps it. Documented at the conversion.
web
SvelteKit frontend. Phase 0: one page, one query box, one table. No auth,
no styling polish, no routing beyond /.
What it does
Textarea for a raw SQL string → POST {VITE_API_BASE_URL}/query on /api
→ renders {columns, rows} as an HTML table, or shows {error} from a
rejected/failed query. That's the whole app — see src/routes/+page.svelte.
Why a static build, not a Node server
Scaffolded with @sveltejs/adapter-static: this page has no server-side
data loading (all data comes from a client-side fetch triggered by the
submit button), so there's nothing here that needs a running SvelteKit
server. A prerendered static site is simpler to build, deploy, and reason
about than running Node in production for a page that's this thin.
Because it's static, VITE_API_BASE_URL is baked in at build time, not
read at container start. Set it before npm run build (or pass
--build-arg VITE_API_BASE_URL=... to docker build) — changing it later
means rebuilding, not just restarting the container.
Timestamps and the display timezone
Everything in Cairn OBS is UTC: ingest records Unix nanoseconds,
ClickHouse stores UTC, and every API response is RFC3339 with a Z. The
web UI renders those instants in whichever zone the reader picked
(Settings → Display timezone), which changes presentation only --
never which rows a query returns, never their order, and never what
earliest=/latest= mean. Two people in two zones looking at one log
line see the same instant written two ways.
src/lib/time.ts-- pure formatting.formatTimestampis the one entry point; it detects timestamps by value, not by column name, since query output is arbitrary. Sub-second digits are copied verbatim from the source string rather than round-tripped through a JSDate, which is millisecond-precision and would silently drop the last six digits of a ClickHouse nanosecond timestamp.src/lib/timezone.svelte.ts-- where the choice is stored, which differs by deployment on purpose: per named user server-side when local login is on (PUT /auth/timezone, so it follows a person across browsers), per browser session on a public demo (a shared account's visitors shouldn't inherit each other's settings), per browser otherwise.- Charts format their own axis and tooltip labels through the same
helper. ECharts'
type: 'time'axis otherwise renders in the browser's zone with no way to override it, which would put a chart's clock out of step with the table beside it.
Query input follows the same setting: an absolute time written without
an offset (earliest=2026-08-22 09:00) is read as wall-clock time in the
reader's zone and converted to UTC before the query is sent -- see
src/lib/querytime.ts. Anything with an explicit offset is taken at its
word, and relative ranges (-24h) never depended on a zone.
That conversion happens before a query is sent or saved, so a stored dashboard range is an explicit instant rather than "10am, whoever you are" -- otherwise one shared dashboard would show two different windows to two people. The API itself is unchanged and still accepts only quoted RFC3339 with an offset; everything this adds is a form it rejects today, so no query that works now can change meaning.
Building & running
npm install
cp .env.example .env # adjust VITE_API_BASE_URL if /api isn't on localhost:8080
npm run dev # local dev server with hot reload
npm run check # svelte-check, type errors
npm run build # static output to build/
npm run preview # serve the static build locally to sanity-check it
docker build -f Dockerfile -t cairnobs-web . # context is web/, not the repo root
docker run -p 3000:3000 cairnobs-web
Tenant picker (Phase 4)
src/routes/select-tenant is the one route that isn't reachable by
clicking around the app -- enterprise-auth's internal/loginhandler
redirects a browser here after an SSO login resolves to more than one
tenant_memberships row (see that package's doc comment), carrying a
short-lived cairnobs_pending_login cookie instead of a real session. The
page calls GET /auth/memberships to list the choices, and
POST /auth/select-tenant on a click, both via
fetch(..., {credentials: 'include'}) ($lib/api.ts's
listMemberships/selectTenant) so that cookie -- and, on success, the
real session cookie the POST response sets -- actually cross the origin
boundary between this app and enterprise-auth. enterprise-auth's
default POST_LOGIN_REDIRECT_URL (this app's own base URL) is also
where CORS_ALLOWED_ORIGIN defaults to, and it has to be a literal
origin, not * -- see api/httpserver.WithCredentialedCORS's doc
comment for why a credentialed fetch and a wildcard CORS origin can
never be combined; getAuthFeatures above deliberately doesn't send
credentials for exactly this reason, and is why it could stay on the
plain WithCORS every other endpoint in this repo uses.
Like every other route (export const prerender = true in this route's
own +page.ts), no server-side data loading -- the membership list and
the tenant choice both come from client-side fetch calls the same way
the root query page's does.
Verified in a real browser in this environment: a throwaway Node server
standing in for enterprise-auth (implementing the exact
GET /auth/memberships/POST /auth/select-tenant wire contract,
including the plain-text http.Error bodies the real handler sends, not
JSON) on a different origin/port than this app's dev server, driven
through the full flow -- cross-origin pending-login cookie set, the
credentialed preflight + GET/POST round trip, a real click choosing
a tenant, and the post-selection redirect landing back on / -- plus
the missing/expired-cookie error path separately. No Docker or live
Postgres/IdP needed for this, since the whole point was exercising this
app's own fetch/CORS/cookie wiring against a contract-accurate fake, not
enterprise-auth's internals (those are enterprise/internal/ loginhandler's own tests' job, already covered there).
Why nginx, not distroless
The repo convention prefers distroless/scratch base images. Serving a
static SPA still needs some HTTP server, though, and nginx:alpine is
the boring, standard choice for that job — writing a custom static-file
binary just to stay distroless would be more engineering than a Phase 0
placeholder page justifies. nginx.conf here is minimal: serve build/,
fall back to index.html for client-side routing (only one route exists
today, but this is what you want the moment a second one is added).