thermograph/frontend/CLAUDE.md
Emi Griffith b2b56bdc1a frontend: fix the three inconsistencies the onboarding guide found
1. CLAUDE.md and README.md described the superseded Python service. Both now
   describe server/ (Go), say plainly that the Python files at that level are
   the original the port was made from, and drop CLAUDE.md's claim that
   `make test-unit` is "the tier CI runs" — CI's only frontend check is the
   Dockerfile builder stage's gofmt + vet + go test.

2. static/units.js's F_REGIONS was guarded by nothing, despite three source
   comments claiming "a test asserts all three stay identical": the only check
   compared the Go set against the backend's Python. TestFCountriesMatchesUnitsJS
   now diffs the browser copy both directions.

   That backend cross-check also skips in CI — the image build context is
   frontend/, so backend/ is unreachable from the builder stage, which is the
   only place CI runs these tests. static/ IS in the context, so the Dockerfile
   copies units.js into the builder and the new assertion runs during the image
   build. Verified by mutating units.js and confirming the build fails.

3. Both docker-compose.test.yml files defaulted to the retired
   emi/thermograph-backend/app path, and the frontend harness pinned the
   split-era v0.0.2-split-ci tag. Path corrected in both. Rather than swap one
   hardcoded pin for another, backend-for-tests.sh now derives the tag from the
   checkout — sha-<12hex of `git log -1 -- backend/`>, the same domain-keyed
   rule build-push.yml and deploy.yml use — and compose requires the variable
   so a stale pin cannot creep back in.

Verified: backend 429 passed/8 skipped; frontend go vet clean and all packages
ok; frontend image builds; `make backend-up` pulls and serves on the derived
tag; shellcheck zero findings across the tree.

Unrelated pre-existing issue noted in the docs, not fixed here:
`make test-integration` fails 7/16 with 503 against a cold throwaway backend
(empty database, nothing warm). Reproduced identically on the old image, so it
predates this change.

Claude-Session: https://claude.ai/code/session_01AfXqHrxCJLs2D7hpQkiUiJ
2026-07-25 11:43:22 -07:00

6.4 KiB

frontend/ — agent instructions

The SSR + static-asset service: server-rendered crawlable pages, the interactive tool's SPA shells, and every static asset. No climate data, no DB, no compute — everything comes from backend/'s content API over HTTP.

Read the root CLAUDE.md first for the branch model, deploy contract and image names.

The live service is Go — server/

server/ (module thermograph/frontend, Go 1.26) is what builds, tests, ships and runs. It is the only thing in the emi/thermograph/frontend image.

The Python files at this level — app.py, content.py, api_client.py, format.py, content_loader.py, paths.py, templates/*.html.j2 — are the superseded original implementation, kept as the reference the port was made from. Nothing deploys them. Don't add features there; don't take their file paths as current. (They still carry duplicate copies of some contracts below — notably api_client.py's API_VERSION pin and format.py's F_COUNTRIES. If you use them locally, keep them in step or you will debug a phantom.)

Deleting them is a live question, not a settled one — the Python test tiers still run against the fixtures the Go tests share. Raise it rather than doing it in passing.

Build & verify

  • cd server && go build ./... && go vet ./... && go test ./...the suite that matters.
  • CI runs it inside Dockerfile's builder stage, which does gofmt -l + go vet + go test ./... before compiling. A failing Go test therefore fails the image build — that is the whole frontend check. There is no separate frontend test step in any workflow.
  • make test-unit / make test-integration — the Python tiers. Local only; CI runs neither. The unit tier is hermetic (SSR rendering fed committed fixtures); the integration tier pulls and runs a real backend image.
  • make backend-up / make backend-down — a local backend container for dev. The image tag is derived from this checkout (last commit touching backend/, the same domain-keyed rule build-push and deploy use); override with THERMOGRAPH_BACKEND_TEST_TAG=sha-<12hex>.
  • make capture-fixtures — refresh tests/fixtures/*.json from a live backend. These fixtures feed the Go tests too, not just the Python ones.

Running it

THERMOGRAPH_API_BASE_INTERNAL is required — the boot fails loudly without it, as the Python raised at import.

Build in server/, run from frontend/: static/ and content/ resolve relative to the working directory, while templates are embedded in the binary.

cd server && go build -o thermograph-frontend .
cd ..
THERMOGRAPH_API_BASE_INTERNAL=http://127.0.0.1:8137 THERMOGRAPH_BASE=/thermograph \
  ./server/thermograph-frontend

Other env: THERMOGRAPH_BASE (default /thermograph; the Dockerfile sets /), THERMOGRAPH_API_VERSION (default v2), THERMOGRAPH_API_BASE_PUBLIC (browser-facing backend origin when cross-origin; empty = same-origin, today's default), THERMOGRAPH_SSR_CACHE_TTL (default 600s), THERMOGRAPH_GOOGLE_VERIFY / THERMOGRAPH_BING_VERIFY, PORT (default 8080).

Boot is fail-loud on bad config or content: a missing backend URL, a garbage TTL, or malformed content/*.yaml all stop the process rather than 500 on the first request.

Layout

  • server/internal/content/ — the SSR page handlers (climate hub, city, month, records, glossary, about, privacy) + robots.txt + sitemap.xml, plus the template funcmap and SEO helpers. The backend's content_payloads.py owns page_title / canonical_path / breadcrumb / jsonld, not this domain.
  • server/internal/contentapi/ — the backend /content/* client: TTL cache, bounded LRU, per-key single-flight, origin forwarding. All four properties are load-bearing; read the file before changing caching.
  • server/internal/render/ + render/templates/*.tmplhtml/template over an embed.FS, plus the ETag helpers. Templates are embedded, so a template change needs a rebuild.
  • server/internal/{config,format,contentdata,handlers}/ — env parsing, unit-aware °C/°F formatting and band names, the glossary/pages loader, and the SPA-shell + static handlers.
  • static/*.jsapp.js (map/search/results + inline SVG chart), calendar.js/day.js/score.js/compare.js (SPA shells), account.js (auth), cache.js (IndexedDB cache + /cell bundle prefetch), shared.js.
  • static/style.css — the single hand-written stylesheet; design tokens live here, documented in DESIGN.md.
  • content/*.yaml — structured SSR copy, loaded by server/internal/contentdata.

Contracts with the backend

  • API version is pinned in exactly two placesserver/internal/config's THERMOGRAPH_API_VERSION (Go) and static/account.js's exported API_VERSION plus the uv(path) helper (JS). Never hardcode api/v2/... anywhere else. Bump both in one PR, and only after the target backend's /api/version confirms it serves that version and its min_frontend doesn't exclude the one you're leaving.
  • shared.js::pctOrd() must mirror backend's data/grading.py::pct_ordinal() in behaviour — floor into 1..99, never 0 or 100 — and so must server/internal/format's PctOrdinal. Every percentile on every surface goes through one of the three; if they diverge, the same reading says two different things in two places.
  • /cell bundle + ETagcache.js fetches /api/v2/cell once per view-set and slices it, revalidating with If-None-Match. The slice→view map must track the backend's payload shape.
  • Fahrenheit country setserver/internal/format's FCountries and static/units.js's F_REGIONS must stay identical to the backend's F_COUNTRIES. Both are now asserted by tests in server/internal/format/format_test.go: the backend cross-check is a checkout-only guard (the image build context is frontend/, so backend/ is unreachable there), while the units.js check runs in the image build too — Dockerfile copies that one file into the builder stage for exactly that reason.
  • Boot must survive an unreachable backend. The IndexNow-key fetch is tried once at boot, caught, and falls back to a lazy per-request lookup. Asynchronous FE/BE deploys depend on this — don't make it fatal.

Commits & PRs

Concise and technical. Never mention AI, assistants or automated authorship.