next into main (#73)

Reviewed-on: #73

.dockerignore

@@ -4,6 +4,3 @@ tmp
 .DS_Store
 *.log
 .claude
-
-# .git is sent so the build can stamp the version, without its config.
-.git/config

Dockerfile

@@ -20,10 +20,7 @@ RUN make lint
 # golang:1.25-alpine (2026-02-27)
 FROM golang:1.25-alpine@sha256:f6751d823c26342f9506c03797d2527668d095b0a15f1862cddb4d927a7a4ced AS builder
 
-# gcc and musl-dev are for make test: its race detector needs cgo, which
-# Go turns on by itself once a C compiler is present. make build still
-# sets CGO_ENABLED=0, so the binary stays static.
-RUN apk add --no-cache gcc git make musl-dev
+RUN apk add --no-cache make
 
 WORKDIR /src
 
@@ -40,24 +37,11 @@ RUN make test
 
 # make build is a shim around backend/script/build, the one definition
 # of the build command:
-# CGO_ENABLED=0 go build -trimpath -ldflags "-s -w -X main.Version=..."
+# CGO_ENABLED=0 go build -trimpath -ldflags "-s -w -X main.Version=... -X main.Buildarch=..."
 # That script reads VERSION from the environment, so it is handed over
 # there rather than as a make variable.
-#
-# The version is the VERSION build argument when one is given, otherwise
-# `git describe --tags --always` of the repo's .git: the tag on a tagged
-# commit, tag-N-gHASH on a commit after one, the short commit when no
-# tag is reachable. A version that still comes out empty, dev or unknown
-# fails the build. .git goes to /git, not /src/.git, where go build would
-# find it and record VCS details of a work tree holding only backend/.
-COPY .git /git
-ARG VERSION
-RUN version="${VERSION:-$(git --git-dir=/git describe --tags --always)}"; \
-    case "$version" in ""|dev|unknown) \
-        echo "version is '$version' although .git is present" >&2; \
-        exit 1 ;; \
-    esac; \
-    VERSION="$version" make build
+ARG VERSION=dev
+RUN VERSION="${VERSION}" make build
 
 # Frontend stage
 # node:22-alpine as of 2026-02-22
@@ -68,9 +52,8 @@ RUN yarn install --frozen-lockfile
 RUN apk add --no-cache git make
 COPY . .
 # make frontend-check is the frontend half of make check (test + lint +
-# fmt-check); its test step runs the unit tests, then the production
-# yarn build, so this both produces dist/ and gates the image on
-# lint/fmt-check/test regressions.
+# fmt-check); its test step is the production yarn build, so this both
+# produces dist/ and gates the image on lint/fmt-check/test regressions.
 # This node stage has neither Go nor Docker; the lint and builder stages
 # above gate the backend half.
 RUN make frontend-check

README.md

@@ -39,23 +39,21 @@ halves, so the root `make check` fails if either one is broken. We provide:
 - `script/bootstrap` — install all dependencies (the pinned node via nvm unless
   one new enough for the frontend's dependencies is installed, yarn via
   corepack, `yarn install --frozen-lockfile`, the pinned Go unless one at least
-  as new as `backend/go.mod` asks for is installed, the Go modules, and gcc with
-  the C library headers unless gcc is installed, for the race detector in
-  `make test`), linking what it installs itself into `~/.local/bin`, which has
-  to be on `PATH`. It installs no Go linter and not Docker: `make lint` runs the
-  linter in Docker
+  as new as `backend/go.mod` asks for is installed, and the Go modules), linking
+  what it installs itself into `~/.local/bin`, which has to be on `PATH`. It
+  installs no Go linter and not Docker: `make lint` runs the linter in Docker
 - `script/setup` — make a fresh clone ready for development: bootstrap plus the
   git pre-commit hook
 - `script/projectname` — print the project name (used for the Docker image tag)
-- `script/test` — run `script/frontend-test`, then the backend's Go tests, each
-  under its own 30-second timeout
+- `script/test` — run `script/frontend-test`, then the backend's Go tests, both
+  within one 30-second timeout
 - `script/lint` — run `script/frontend-lint`, then golangci-lint in Docker, by
   building the lint stage of `Dockerfile` without the cache
 - `script/fmt` — format all files (writes): prettier, then gofmt over `backend/`
 - `script/fmt-check` — check formatting (read-only): prettier, then gofmt
 - `script/check` — run test, lint, and fmt-check
-- `script/frontend-test` — run the unit tests in `test/unit/` with Node's
-  built-in test runner, then the production build
+- `script/frontend-test` — run the production build as the frontend's test (no
+  unit tests yet)
 - `script/frontend-lint` — run prettier in check mode
 - `script/frontend-fmt` — format everything prettier understands (writes)
 - `script/frontend-fmt-check` — check prettier formatting (read-only)
@@ -104,10 +102,9 @@ code lives in `src/main.js` with a class-based architecture:
   color-coded line segments, error regions, and DPR-aware scaling
 - **UI functions**: `buildUI()` constructs the DOM, `updateHostRow()` /
   `updateSummary()` / `updateHealthBox()` handle incremental updates
-- **`tick()`**: Main loop — measures all hosts in parallel, pushing each host's
-  sample and redrawing its row as soon as its check ends, then sorts and redraws
-  the summary and health box once the last check ends. When paused, pushes blank
-  markers (no probes, no false outage)
+- **`tick()`**: Main loop — measures all hosts in parallel via `Promise.all`,
+  pushes samples, redraws UI. When paused, pushes blank markers (no probes, no
+  false outage)
 - **`Reporter`**: Posts collected samples to the backend
 
 ### Reporting
@@ -139,14 +136,8 @@ Local hosts are tracked separately from WAN stats.
 ### Latency measurement
 
 HEAD requests with `mode: 'no-cors'` and `cache: 'no-store'`, timed with
-`performance.now()`. Each check times out after 80% of the refresh interval (24
-seconds at 30 seconds) and is then recorded as a timeout, so a round's checks
-have all finished before the next round is due. When no WAN host answers, a
-recovery probe checks 4 random WAN hosts every half second, giving up the checks
-it started half a second before. As soon as one answers, a new round starts at
-once, as it does after an interval change. A round started early gives up the
-last round's checks if they are still waiting, and that round records nothing
-more, so rounds never overlap. IPv4 only.
+`performance.now()`. 1-second timeout; anything over 1000ms is clamped to
+unreachable. IPv4 only.
 
 ### Color coding
 

TODO.md

@@ -23,31 +23,6 @@ latest run passes.
 
 # Completed Steps
 
-- 2026-10-03: each target's row shows its result as soon as its check ends
-  (issue #91), where every row waited for the round's slowest check, up to 24
-  seconds at a 30-second interval. Sorting, the summary, the health box and
-  offline detection still run once, when the round's last check ends. A check
-  that ends after the user pauses or after its round is given up shows nothing,
-  and the first round is still discarded as a whole
-- 2026-10-03: the Go tests run with the race detector and coverage (issue #88):
-  `backend/script/test` runs `go test -timeout 30s -race -cover ./...` and, if
-  that fails, runs it again with `-v` and fails. Go's `-timeout` bounds the
-  tests, not their compile; the root `script/test` no longer puts one 30-second
-  timeout around both halves, which a cold Go build cache could use up on
-  compiling alone. The race detector needs a C compiler: the builder stage of
-  `Dockerfile` has gcc and musl-dev, and `script/bootstrap` installs gcc, with
-  the C library headers on apt and apk, when gcc is missing; the binary is still
-  built with `CGO_ENABLED=0`. New tests cover the health check's answer, a valid
-  report's answer, a report file's exact contents, and the flush when the buffer
-  reaches 10 MiB; the handlers' `TestImport` stub is gone
-- 2026-10-03: each target check times out after 80% of the refresh interval
-  (issue #78), 24 seconds at 30 seconds, where it was capped at 3 seconds. A
-  round started early, after an interval change or when the recovery probe finds
-  a target answering, gives up the last round's checks if they are still
-  waiting, so rounds never overlap; the recovery probe gives up its own checks
-  after half a second. The frontend has its first unit tests, run by
-  `script/frontend-test` with Node's built-in test runner; for them,
-  `index.html` now links `src/styles.css`, which `src/main.js` used to import
 - 2026-09-29: the container sets up its own data directory (issue #75):
   `bin/entrypoint.sh`, still as root, creates `DATA_DIR` if missing and gives it
   and `/data` to the `netwatch` user with mode 750 before starting the backend

backend/README.md

@@ -32,13 +32,10 @@ pattern as the repo root: the targets in `backend/Makefile` are thin shims over
 `test`, `fmt` and `fmt-check`:
 
 - `script/build` — compile the static `netwatch-server` binary with its version
-  stamped in. The version is `VERSION` from the environment;
+  and architecture stamped in. The version is `VERSION` from the environment;
   when that is unset or empty, it falls back to `git describe` inside a git
   checkout, then to `dev`
-- `script/test` — run the Go tests with the race detector and coverage. Go's
-  `-timeout 30s` bounds the tests, not their compile. If they fail, they run
-  again with `-v` for the details, and the script fails. The race detector needs
-  a C compiler
+- `script/test` — run the Go tests under a 30-second timeout
 - `script/lint` — check `.golangci.yml` against its pinned sha256, then run
   golangci-lint. It runs inside the golangci-lint image of the lint stage of
   the root `Dockerfile`; from a checkout, run `make lint` at the repo root,

backend/cmd/netwatch-server/main.go

@@ -19,8 +19,9 @@ import (
 
 //nolint:gochecknoglobals // set via ldflags at build time
 var (
-	Appname = "netwatch-server"
-	Version string
+	Appname   = "netwatch-server"
+	Version   string
+	Buildarch string
 )
 
 func main() {
@@ -39,6 +40,7 @@ func main() {
 
 	globals.Appname = Appname
 	globals.Version = Version
+	globals.Buildarch = Buildarch
 
 	fx.New(
 		fx.Provide(

backend/internal/globals/globals.go

@@ -10,18 +10,22 @@ var (
 	Appname string
 	// Version is the git version tag.
 	Version string
+	// Buildarch is the build architecture.
+	Buildarch string
 )
 
 // Globals holds build-time metadata for the application.
 type Globals struct {
-	Appname string
-	Version string
+	Appname   string
+	Version   string
+	Buildarch string
 }
 
 // New creates a Globals instance from package-level variables.
 func New(_ fx.Lifecycle) (*Globals, error) {
 	return &Globals{
-		Appname: Appname,
-		Version: Version,
+		Appname:   Appname,
+		Buildarch: Buildarch,
+		Version:   Version,
 	}, nil
 }

backend/internal/handlers/handlers_test.go

@@ -0,0 +1,13 @@
+package handlers_test
+
+import (
+	"testing"
+
+	_ "sneak.berlin/go/netwatch/internal/handlers"
+)
+
+func TestImport(t *testing.T) {
+	t.Parallel()
+	// Compilation check — verifies the package parses
+	// and all imports resolve.
+}

backend/internal/handlers/healthcheck_test.go

@@ -1,120 +0,0 @@
-package handlers_test
-
-import (
-	"encoding/json"
-	"maps"
-	"net/http"
-	"net/http/httptest"
-	"slices"
-	"testing"
-	"time"
-
-	"sneak.berlin/go/netwatch/internal/globals"
-	"sneak.berlin/go/netwatch/internal/handlers"
-	"sneak.berlin/go/netwatch/internal/healthcheck"
-	"sneak.berlin/go/netwatch/internal/logger"
-
-	"go.uber.org/fx/fxtest"
-)
-
-// newStartedHandlers builds Handlers with a real health check for the
-// server named in g, and starts them, which records the time the
-// uptime counts from.
-func newStartedHandlers(t *testing.T, g *globals.Globals) *handlers.Handlers {
-	t.Helper()
-
-	lc := fxtest.NewLifecycle(t)
-
-	log, err := logger.New(lc, logger.Params{Globals: g})
-	if err != nil {
-		t.Fatalf("logger: %v", err)
-	}
-
-	hc, err := healthcheck.New(lc,
-		healthcheck.Params{Globals: g, Logger: log})
-	if err != nil {
-		t.Fatalf("health check: %v", err)
-	}
-
-	h, err := handlers.New(lc,
-		handlers.Params{Globals: g, Healthcheck: hc, Logger: log})
-	if err != nil {
-		t.Fatalf("handlers: %v", err)
-	}
-
-	lc.RequireStart()
-	t.Cleanup(lc.RequireStop)
-
-	return h
-}
-
-// TestHandleHealthCheck checks the health check's answer: 200, a JSON
-// content type, and a JSON object with exactly the fields of
-// healthcheck.Response, carrying this server's name and version and
-// an uptime counted from its start.
-func TestHandleHealthCheck(t *testing.T) {
-	t.Parallel()
-
-	g := &globals.Globals{Appname: "netwatch-server", Version: "v1.2.3"}
-	h := newStartedHandlers(t, g)
-
-	rec := httptest.NewRecorder()
-	req := httptest.NewRequestWithContext(t.Context(),
-		http.MethodGet, "/.well-known/healthcheck", http.NoBody)
-
-	h.HandleHealthCheck().ServeHTTP(rec, req)
-
-	if rec.Code != http.StatusOK {
-		t.Fatalf("status = %d, want %d", rec.Code, http.StatusOK)
-	}
-
-	contentType := rec.Header().Get("Content-Type")
-	if contentType != "application/json; charset=utf-8" {
-		t.Errorf("Content-Type = %q, want %q",
-			contentType, "application/json; charset=utf-8")
-	}
-
-	var body map[string]any
-
-	err := json.Unmarshal(rec.Body.Bytes(), &body)
-	if err != nil {
-		t.Fatalf("body not a JSON object: %v (%q)", err, rec.Body.String())
-	}
-
-	fields := []string{
-		"appname", "now", "status", "uptimeHuman", "uptimeSeconds", "version",
-	}
-	if got := slices.Sorted(maps.Keys(body)); !slices.Equal(got, fields) {
-		t.Fatalf("fields = %v, want %v", got, fields)
-	}
-
-	for field, want := range map[string]string{
-		"appname": g.Appname, "status": "ok", "version": g.Version,
-	} {
-		if body[field] != want {
-			t.Errorf("%s = %v, want %q", field, body[field], want)
-		}
-	}
-
-	now, _ := body["now"].(string)
-
-	at, err := time.Parse(time.RFC3339Nano, now)
-	if err != nil || time.Since(at).Abs() > time.Minute {
-		t.Errorf("now = %q, want the current time in RFC 3339 (%v)", now, err)
-	}
-
-	// Started just now, so the uptime is well under a minute.
-	human, _ := body["uptimeHuman"].(string)
-
-	uptime, err := time.ParseDuration(human)
-	if err != nil || uptime > time.Minute {
-		t.Errorf("uptimeHuman = %q, want a duration under a minute (%v)",
-			human, err)
-	}
-
-	seconds, ok := body["uptimeSeconds"].(float64)
-	if !ok || seconds < 0 || seconds > time.Minute.Seconds() {
-		t.Errorf("uptimeSeconds = %v, want a number of seconds under a minute",
-			body["uptimeSeconds"])
-	}
-}

backend/internal/handlers/report_test.go

@@ -46,63 +46,6 @@ func decodeStatus(t *testing.T, body []byte) string {
 	return resp.Status
 }
 
-// TestHandleReportAcceptsValidReports checks the answer to a valid
-// report, one with no hosts and one shaped as the frontend sends them:
-// 200 and {"status":"ok"} as JSON.
-func TestHandleReportAcceptsValidReports(t *testing.T) {
-	t.Parallel()
-
-	tests := []struct {
-		name string
-		body string
-	}{
-		{
-			name: "no hosts",
-			body: `{"clientId":"c1","geo":null,"hosts":[],` +
-				`"timestamp":"2026-10-03T12:00:00.000Z"}`,
-		},
-		{
-			name: "a host with a latency and an error sample",
-			body: `{"clientId":"c1","geo":null,"hosts":[{` +
-				`"name":"Example","url":"https://example.com/",` +
-				`"status":"error","history":[` +
-				`{"t":1790000000000,"latency":42,"error":null},` +
-				`{"t":1790000003000,"latency":null,"error":"timeout"}]}],` +
-				`"timestamp":"2026-10-03T12:00:00.000Z"}`,
-		},
-	}
-
-	for _, tt := range tests {
-		t.Run(tt.name, func(t *testing.T) {
-			t.Parallel()
-
-			h := newTestHandlers(stubAppender{}, io.Discard)
-
-			rec := httptest.NewRecorder()
-			req := httptest.NewRequestWithContext(t.Context(),
-				http.MethodPost, "/api/v1/reports",
-				strings.NewReader(tt.body),
-			)
-
-			h.HandleReport().ServeHTTP(rec, req)
-
-			if rec.Code != http.StatusOK {
-				t.Fatalf("status = %d, want %d", rec.Code, http.StatusOK)
-			}
-
-			contentType := rec.Header().Get("Content-Type")
-			if contentType != "application/json; charset=utf-8" {
-				t.Errorf("Content-Type = %q, want %q",
-					contentType, "application/json; charset=utf-8")
-			}
-
-			if got := rec.Body.String(); got != "{\"status\":\"ok\"}\n" {
-				t.Errorf("body = %q, want %q", got, "{\"status\":\"ok\"}\n")
-			}
-		})
-	}
-}
-
 func TestHandleReportStorageFailureIsNon2xx(t *testing.T) {
 	t.Parallel()
 

backend/internal/logger/logger.go

@@ -5,7 +5,6 @@ package logger
 import (
 	"log/slog"
 	"os"
-	"runtime"
 
 	"sneak.berlin/go/netwatch/internal/globals"
 
@@ -96,6 +95,6 @@ func (l *Logger) Identify() {
 	l.log.Info("starting",
 		"appname", l.params.Globals.Appname,
 		"version", l.params.Globals.Version,
-		"arch", runtime.GOARCH,
+		"buildarch", l.params.Globals.Buildarch,
 	)
 }

backend/internal/reportbuf/export_test.go

@@ -2,10 +2,6 @@ package reportbuf
 
 import "time"
 
-// FlushSizeThreshold exposes the buffer size at which Append starts
-// writing a report file to the external tests.
-const FlushSizeThreshold = flushSizeThreshold
-
 // Flush writes the buffered reports to a file now, as the periodic
 // flush does, so tests need not wait a minute for it.
 func (b *Buffer) Flush() error {

backend/internal/reportbuf/reportbuf_test.go

@@ -334,11 +334,7 @@ func TestTwoFlushesInOneMillisecond(t *testing.T) {
 		}
 	}
 
-	files, err := readReportFiles(dir)
-	if err != nil {
-		t.Fatalf("read report files: %v", err)
-	}
-
+	files := readReportFiles(t, dir)
 	if len(files) != flushes {
 		t.Fatalf("%d report files after %d flushes", len(files), flushes)
 	}
@@ -351,88 +347,6 @@ func TestTwoFlushesInOneMillisecond(t *testing.T) {
 	}
 }
 
-// TestReportFileHoldsTheLinesAppended flushes three reports and reads
-// their file back: it must decompress to exactly their JSON lines, in
-// the order they were appended.
-func TestReportFileHoldsTheLinesAppended(t *testing.T) {
-	dir := t.TempDir()
-	t.Setenv("DATA_DIR", dir)
-
-	buf := startBuffer(t)
-
-	for _, id := range []int{1, 2, 3} {
-		err := buf.Append(map[string]int{"id": id})
-		if err != nil {
-			t.Fatalf("append report %d: %v", id, err)
-		}
-	}
-
-	err := buf.Flush()
-	if err != nil {
-		t.Fatalf("flush: %v", err)
-	}
-
-	files, err := readReportFiles(dir)
-	if err != nil {
-		t.Fatalf("read report files: %v", err)
-	}
-
-	want := `{"id":1}` + "\n" + `{"id":2}` + "\n" + `{"id":3}` + "\n"
-	if len(files) != 1 || files[0] != want {
-		t.Fatalf("report files = %q, want one holding %q", files, want)
-	}
-}
-
-// TestFlushAtSizeThreshold appends reports until the buffer holds
-// FlushSizeThreshold bytes. The append that gets it there must write
-// them all to one report file, with no call to Flush and the periodic
-// flush a minute away, and no earlier append may write one.
-func TestFlushAtSizeThreshold(t *testing.T) {
-	dir := t.TempDir()
-	t.Setenv("DATA_DIR", dir)
-
-	buf := startBuffer(t)
-
-	// Large reports, so the threshold takes a few hundred appends.
-	pad := strings.Repeat("a", 64<<10)
-
-	var appended strings.Builder
-
-	for id := 0; appended.Len() < reportbuf.FlushSizeThreshold; id++ {
-		report := map[string]any{"id": id, "pad": pad}
-
-		err := buf.Append(report)
-		if err != nil {
-			t.Fatalf("append report %d: %v", id, err)
-		}
-
-		line, err := json.Marshal(report)
-		if err != nil {
-			t.Fatalf("marshal report %d: %v", id, err)
-		}
-
-		appended.Write(line)
-		appended.WriteByte('\n')
-	}
-
-	// Append writes the file in the background, so wait for it.
-	deadline := time.Now().Add(10 * time.Second)
-
-	for {
-		files, err := readReportFiles(dir)
-		if err == nil && len(files) == 1 && files[0] == appended.String() {
-			return
-		}
-
-		if time.Now().After(deadline) {
-			t.Fatalf("%d report files (error: %v), want one holding the "+
-				"%d bytes appended", len(files), err, appended.Len())
-		}
-
-		time.Sleep(10 * time.Millisecond)
-	}
-}
-
 // reportFilesBytes returns the total size of the report files in dir.
 func reportFilesBytes(t *testing.T, dir string) int64 {
 	t.Helper()
@@ -457,19 +371,20 @@ func reportFilesBytes(t *testing.T, dir string) int64 {
 }
 
 // readReportFiles returns the decompressed contents of each report
-// file in dir. A file still being written does not decompress, so it
-// gives an error.
-func readReportFiles(dir string) ([]string, error) {
+// file in dir.
+func readReportFiles(t *testing.T, dir string) []string {
+	t.Helper()
+
 	files := os.DirFS(dir)
 
 	names, err := fs.Glob(files, "reports-*.jsonl.zst")
 	if err != nil {
-		return nil, fmt.Errorf("list report files: %w", err)
+		t.Fatalf("list report files: %v", err)
 	}
 
 	dec, err := zstd.NewReader(nil)
 	if err != nil {
-		return nil, fmt.Errorf("create zstd decoder: %w", err)
+		t.Fatalf("create zstd decoder: %v", err)
 	}
 	defer dec.Close()
 
@@ -478,18 +393,18 @@ func readReportFiles(dir string) ([]string, error) {
 	for _, name := range names {
 		compressed, readErr := fs.ReadFile(files, name)
 		if readErr != nil {
-			return nil, fmt.Errorf("read %s: %w", name, readErr)
+			t.Fatalf("read %s: %v", name, readErr)
 		}
 
 		data, decErr := dec.DecodeAll(compressed, nil)
 		if decErr != nil {
-			return nil, fmt.Errorf("decompress %s: %w", name, decErr)
+			t.Fatalf("decompress %s: %v", name, decErr)
 		}
 
 		contents = append(contents, string(data))
 	}
 
-	return contents, nil
+	return contents
 }
 
 func writeBytes(t *testing.T, path string, n int) {

backend/internal/server/http.go

@@ -4,7 +4,6 @@ import (
 	"errors"
 	"net"
 	"net/http"
-	"runtime"
 	"strconv"
 	"time"
 
@@ -54,7 +53,7 @@ func (s *Server) listenAndServe() {
 	s.log.Info("http begin listen",
 		"listenaddr", s.httpServer.Addr,
 		"version", s.params.Globals.Version,
-		"arch", runtime.GOARCH,
+		"buildarch", s.params.Globals.Buildarch,
 	)
 
 	err := s.httpServer.ListenAndServe()

backend/script/build

@@ -1,6 +1,6 @@
 #!/bin/sh
 # script/build: compile the static netwatch-server binary into the
-# backend project root, with its version stamped in.
+# backend project root, with its version and architecture stamped in.
 set -eu
 
 ROOT="$(cd "$(dirname "$0")/.." && pwd -P)"
@@ -14,7 +14,7 @@ main() {
     version="${VERSION:-$(git describe --always --dirty 2>/dev/null || echo dev)}"
 
     CGO_ENABLED=0 go build -trimpath \
-        -ldflags "-s -w -X main.Version=$version" \
+        -ldflags "-s -w -X main.Version=$version -X main.Buildarch=$(uname -m)" \
         -o netwatch-server ./cmd/netwatch-server/
 }
 

backend/script/test

@@ -1,20 +1,12 @@
 #!/bin/sh
-# script/test: run the backend test suite with the race detector and
-# coverage. Go's own -timeout bounds the tests and not their compile,
-# so a cold build cache cannot fail it. The race detector needs cgo,
-# and so a C compiler. If the tests fail, they run again with -v for
-# the details, and the script fails even if that run passes.
+# script/test: run the backend test suite.
 set -eu
 
 ROOT="$(cd "$(dirname "$0")/.." && pwd -P)"
 
 main() {
     cd "$ROOT"
-    go test -timeout 30s -race -cover ./... || {
-        echo "--- Rerunning with -v for details ---"
-        go test -timeout 30s -race -v ./...
-        exit 1
-    }
+    timeout 30 go test ./...
 }
 
 main "$@"

index.html

@@ -9,9 +9,6 @@
             type="image/svg+xml"
             href="data:image/svg+xml,<svg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 100 100'><text y='.9em' font-size='90'>📡</text></svg>"
         />
-        <!-- Linked here, not imported by src/main.js, so the unit tests can
-             import that module in Node, which cannot import CSS. -->
-        <link rel="stylesheet" href="/src/styles.css" />
     </head>
     <body class="bg-gray-900 text-white min-h-screen">
         <div id="app"></div>

script/bootstrap

@@ -64,8 +64,7 @@ detect_pkgmgr() {
     fi
 }
 
-# pkg_install <nix-attr> <apt-pkgs> <brew-formula> <apk-pkgs>: the apt
-# and apk arguments may each list several packages, separated by spaces.
+# pkg_install <nix-attr> <apt-pkg> <brew-formula> <apk-pkg>
 pkg_install() {
     detect_pkgmgr
     case "$PKGMGR" in
@@ -75,10 +74,10 @@ pkg_install() {
                 $SUDO env DEBIAN_FRONTEND=noninteractive apt-get update
                 APT_UPDATED=1
             fi
-            $SUDO env DEBIAN_FRONTEND=noninteractive apt-get install -y $2
+            $SUDO env DEBIAN_FRONTEND=noninteractive apt-get install -y "$2"
             ;;
         brew) brew install "$3" ;;
-        apk) apk add --no-cache $4 ;;
+        apk) apk add --no-cache "$4" ;;
     esac
 }
 
@@ -254,12 +253,6 @@ main() {
 
     if missing make; then pkg_install gnumake make make make; fi
     if missing git; then pkg_install git git git git; fi
-    # The race detector in make test needs cgo, which Go turns on only
-    # when it finds its C compiler, gcc on Linux. apt and apk ship the C
-    # library headers apart from gcc.
-    if missing gcc; then
-        pkg_install gcc "gcc libc6-dev" gcc "gcc musl-dev"
-    fi
 
     ensure_node
     ensure_yarn

script/cibuild

@@ -16,8 +16,9 @@ main() {
     "$SCRIPT_DIR/check"
     # Own line: a failing command substitution inside an argument does
     # not trip `set -e`, so the inline form degrades silently to an
-    # empty constant. The VERSION build argument takes precedence over
-    # the version a build stage derives from the .git in the context.
+    # empty constant. VERSION is computed here because .dockerignore
+    # excludes .git, so `git describe` in a build stage yields an empty
+    # version without failing.
     version="$(git describe --tags --always --dirty 2>/dev/null || true)"
     [ -n "$version" ] || version="unknown"
     docker build --no-cache \

script/docker

@@ -12,8 +12,9 @@ main() {
     cd "$ROOT"
     # Own line: a failing command substitution inside an argument does
     # not trip `set -e`, so the inline form degrades silently to an
-    # empty constant. The VERSION build argument takes precedence over
-    # the version a build stage derives from the .git in the context.
+    # empty constant. VERSION is computed here because .dockerignore
+    # excludes .git, so `git describe` in a build stage yields an empty
+    # version without failing.
     version="$(git describe --tags --always --dirty 2>/dev/null || true)"
     [ -n "$version" ] || version="unknown"
     docker build --no-cache \

script/frontend-test

@@ -1,14 +1,13 @@
 #!/bin/sh
-# script/frontend-test: run the frontend test suite: the unit tests in
-# test/unit/ with Node's built-in test runner, then the production
-# build, which fails on broken code.
+# script/frontend-test: run the frontend test suite. The frontend has no
+# unit tests; the production build serves as the test (fails on broken
+# code).
 set -eu
 
 ROOT="$(cd "$(dirname "$0")/.." && pwd -P)"
 
 main() {
     cd "$ROOT"
-    timeout 30 node --test test/unit/*.test.js
     timeout 30 yarn build
 }
 

script/test

@@ -1,17 +1,14 @@
 #!/bin/sh
 # script/test: run the test suite for the whole repo: the frontend at
-# the repo root, then the Go backend in backend/. Each half has its own
-# 30-second limit, and there is none around both: from a cold Go build
-# cache, compiling the backend's tests with the race detector can take
-# 30 seconds on its own, and Go's -timeout leaves the compile out.
+# the repo root, then the Go backend in backend/. Both halves together
+# get 30 seconds; each also keeps its own limit for the Dockerfiles.
 set -eu
 
 ROOT="$(cd "$(dirname "$0")/.." && pwd -P)"
 
 main() {
     cd "$ROOT"
-    script/frontend-test
-    backend/script/test
+    timeout 30 sh -c 'script/frontend-test && backend/script/test'
 }
 
 main "$@"

src/main.js

@@ -1,14 +1,14 @@
+import "./styles.css";
+
 // --- Configuration -----------------------------------------------------------
 
-// Timing, axis labels, and display constants. A target check times out
-// after requestTimeout, 80% of updateInterval, so a round's checks have
-// all finished before the next round is due; latency above maxLatency is
-// recorded as a timeout. The sparkline Y-axis is capped at
+// Timing, axis labels, and display constants. Latency above maxLatency is
+// clamped to "unreachable". The sparkline Y-axis is capped at
 // graphMaxLatency — values above it pin to the top of the chart but still
 // display their real value in the latency figure. The history buffer holds
 // maxHistoryPoints samples (historyDuration / updateInterval).
 // reportInterval is how often collected samples are POSTed to the backend.
-export const CONFIG = {
+const CONFIG = {
     updateInterval: 3000,
     maxHistoryPoints: 100,
     reportInterval: 60000,
@@ -16,7 +16,7 @@ export const CONFIG = {
         return (this.maxHistoryPoints * this.updateInterval) / 1000;
     },
     get requestTimeout() {
-        return this.updateInterval * 0.8;
+        return Math.min(this.updateInterval - 100, 3000);
     },
     get maxLatency() {
         return this.requestTimeout;
@@ -263,7 +263,7 @@ class HostState {
     }
 }
 
-export class AppState {
+class AppState {
     constructor(localHosts) {
         this.wan = WAN_HOSTS.map(
             (h) => new HostState(h, h.name === "datavi.be"),
@@ -503,16 +503,12 @@ class Reporter {
 
 // --- Latency Measurement -----------------------------------------------------
 
-// Checks one target. The check times out after CONFIG.requestTimeout; the
-// caller can give it up sooner through the optional signal, which also ends
-// it as a timeout.
-export async function measureLatency(url, signal) {
+async function measureLatency(url) {
     const controller = new AbortController();
     const timeoutId = setTimeout(
         () => controller.abort(),
         CONFIG.requestTimeout,
     );
-    signal?.addEventListener("abort", () => controller.abort());
 
     const targetUrl = new URL(url);
     targetUrl.searchParams.set("_cb", Date.now().toString());
@@ -1105,7 +1101,7 @@ function sortAndRebuildWAN(state) {
 
 // --- Main Loop ---------------------------------------------------------------
 
-export async function tick(state, signal, onOffline) {
+async function tick(state, onOffline) {
     const ts = Date.now();
 
     if (state.paused) {
@@ -1126,27 +1122,12 @@ export async function tick(state, signal, onOffline) {
 
     log.debug(`Tick #${state.tickCount + 1} started`);
 
-    // Each host's row shows its result as soon as its check ends. The
-    // result is discarded if by then the user has paused or the next round
-    // has given up this one's checks, and in the first tick (tickCount is
-    // still 0), which is discarded as a whole below. The row is looked up
-    // when the check ends, as a pin click may have re-sorted the rows since
-    // the round started.
-    await Promise.all(
-        state.allHosts.map(async (host) => {
-            const r = await measureLatency(host.url, signal);
-            if (state.paused || signal.aborted || state.tickCount === 0) {
-                return;
-            }
-            host.pushSample(ts, r);
-            updateHostRow(host, state.allHosts.indexOf(host));
-            log.debug(`${host.name}: ${r.error ? r.error : r.latency + "ms"}`);
-        }),
+    const results = await Promise.all(
+        state.allHosts.map((h) => measureLatency(h.url)),
     );
 
-    // User may have paused, or the next round may have given up this
-    // one's checks, while awaiting results — skip the rest of the round
-    if (state.paused || signal.aborted) return;
+    // User may have paused while awaiting results — discard them
+    if (state.paused) return;
 
     state.tickCount++;
 
@@ -1156,6 +1137,13 @@ export async function tick(state, signal, onOffline) {
         return;
     }
 
+    state.allHosts.forEach((host, i) => {
+        const r = results[i];
+        host.pushSample(ts, r);
+        updateHostRow(host, i);
+        log.debug(`${host.name}: ${r.error ? r.error : r.latency + "ms"}`);
+    });
+
     // Sort after the first real check, then every 10 ticks thereafter
     if (state.tickCount === 2 || state.tickCount % 10 === 1) {
         sortAndRebuildWAN(state);
@@ -1180,10 +1168,9 @@ export async function tick(state, signal, onOffline) {
 
 // --- Recovery Probe ----------------------------------------------------------
 
-// When offline, check 4 random WAN hosts every 500ms, giving up the checks
-// started 500ms before, so at most 4 are ever waiting. As soon as one
-// answers, stop probing and start a new round at once.
-function startRecoveryProbe(state, startRounds) {
+// When offline, rapidly poll 4 random WAN hosts every 500ms. As soon as any
+// responds, stop probing and fire a normal tick to refresh all hosts.
+function startRecoveryProbe(state, triggerTick) {
     if (state._recoveryProbeId) return; // already running
     const candidates = [...state.wan];
     for (let i = candidates.length - 1; i > 0; i--) {
@@ -1194,18 +1181,15 @@ function startRecoveryProbe(state, startRounds) {
     log.notice(
         `Recovery probe started (${canaries.map((h) => h.name).join(", ")})`,
     );
-    state._recoveryProbeId = setInterval(() => {
+    state._recoveryProbeId = setInterval(async () => {
         if (state.paused) return;
-        state._recoveryProbeChecks?.abort();
-        const checks = new AbortController();
-        state._recoveryProbeChecks = checks;
-        for (const host of canaries) {
-            measureLatency(host.url, checks.signal).then((r) => {
-                if (r.error !== null || checks.signal.aborted) return;
-                log.notice("Recovery probe: connectivity detected");
-                stopRecoveryProbe(state);
-                startRounds();
-            });
+        const results = await Promise.all(
+            canaries.map((h) => measureLatency(h.url)),
+        );
+        if (results.some((r) => r.error === null)) {
+            log.notice("Recovery probe: connectivity detected");
+            stopRecoveryProbe(state);
+            triggerTick();
         }
     }, 500);
 }
@@ -1214,7 +1198,6 @@ function stopRecoveryProbe(state) {
     if (state._recoveryProbeId) {
         clearInterval(state._recoveryProbeId);
         state._recoveryProbeId = null;
-        state._recoveryProbeChecks?.abort();
     }
 }
 
@@ -1391,34 +1374,18 @@ async function init() {
     updateClocks();
     setInterval(updateClocks, 1000);
 
-    // Rounds never overlap: a round first gives up the last round's checks
-    // if they are still waiting, and the last round then records nothing
-    // more. At a steady interval they never are, as they time out at 80% of
-    // it; they can be when a round starts early, after an interval change
-    // or when the recovery probe finds a target answering.
-    let roundChecks = new AbortController();
     function doTick() {
-        roundChecks.abort();
-        roundChecks = new AbortController();
-        tick(state, roundChecks.signal, () =>
-            startRecoveryProbe(state, startRounds),
-        );
+        tick(state, () => startRecoveryProbe(state, doTick));
     }
 
-    // Starts a round now and then one every CONFIG.updateInterval.
-    let tickIntervalId;
-    function startRounds() {
-        clearInterval(tickIntervalId);
-        doTick();
-        tickIntervalId = setInterval(doTick, CONFIG.updateInterval);
-    }
-
-    startRounds();
+    doTick();
+    let tickIntervalId = setInterval(doTick, CONFIG.updateInterval);
 
     document
         .getElementById("interval-select")
         .addEventListener("change", (e) => {
             const newInterval = parseInt(e.target.value, 10);
+            clearInterval(tickIntervalId);
             CONFIG.updateInterval = newInterval;
             log.notice(
                 `Interval changed to ${humanDuration(newInterval / 1000)}, history reset`,
@@ -1467,7 +1434,8 @@ async function init() {
 
             // Start immediately with new interval
             stopRecoveryProbe(state);
-            startRounds();
+            doTick();
+            tickIntervalId = setInterval(doTick, CONFIG.updateInterval);
         });
 
     window.addEventListener("resize", () => handleResize(state));
@@ -1476,7 +1444,7 @@ async function init() {
 
 // Bootstrap only when loaded as the page: a real DOM containing the #app
 // mount point this module renders into. Importing the module in a unit test
-// (which has no #app) runs nothing, so its exports can be tested in isolation.
+// (which has no #app) runs nothing, so buildReport can be tested in isolation.
 if (typeof document !== "undefined" && document.getElementById("app")) {
     if (document.readyState === "loading") {
         document.addEventListener("DOMContentLoaded", init);

test/unit/main.test.js

@@ -1,122 +0,0 @@
-// Unit tests for src/main.js, run by script/frontend-test with Node's
-// built-in test runner. Importing the module does not start the page.
-
-import { test } from "node:test";
-import assert from "node:assert/strict";
-import { AppState, CONFIG, measureLatency, tick } from "../../src/main.js";
-
-// There is no page here, so the tests stand in for it. The debug log looks
-// for its panel by id and finds none. Each element of a host's row that
-// tick draws into is a plain object, made the first time it is looked up
-// and kept in elements under its selector. Drawing a sparkline does
-// nothing; it looks for the pixel ratio on window and finds none.
-const elements = {};
-const doNothing = () => {};
-const canvasContext = {
-    clearRect: doNothing,
-    beginPath: doNothing,
-    moveTo: doNothing,
-    lineTo: doNothing,
-    stroke: doNothing,
-    fill: doNothing,
-    fillRect: doNothing,
-    fillText: doNothing,
-    arc: doNothing,
-};
-globalThis.window = {};
-globalThis.document = {
-    getElementById: () => null,
-    querySelector: (selector) =>
-        (elements[selector] ??= { getContext: () => canvasContext }),
-};
-
-// What tick last wrote into the latency figure in host's row, or undefined
-// if it has written nothing there.
-function latencyFigure(state, host) {
-    const index = state.allHosts.indexOf(host);
-    return elements[`.latency-value[data-host="${index}"]`]?.innerHTML;
-}
-
-// Mocks the clock for test t, so that a check lasting seconds takes no real
-// time, and replaces fetch with targets that each answer after
-// answerAfter(url) milliseconds of that clock, or never when that is
-// Infinity. Both are restored when the test ends.
-function mockTargets(t, answerAfter) {
-    t.mock.timers.enable({ apis: ["setTimeout", "Date"] });
-    t.mock.method(performance, "now", () => Date.now());
-    t.mock.method(
-        globalThis,
-        "fetch",
-        (url, { signal }) =>
-            new Promise((resolve, reject) => {
-                if (answerAfter(url) !== Infinity) {
-                    setTimeout(resolve, answerAfter(url));
-                }
-                signal.addEventListener("abort", () => reject(signal.reason));
-            }),
-    );
-}
-
-// The result of check if it has ended, otherwise "still waiting".
-function settled(check) {
-    return Promise.race([
-        check,
-        new Promise((resolve) => setImmediate(resolve, "still waiting")),
-    ]);
-}
-
-for (const interval of [10000, 30000]) {
-    const timeout = interval * 0.8;
-    // Over 3 seconds, which the timeout used to be capped at.
-    const slowAnswer = timeout - 1000;
-
-    test(`at a ${interval}ms interval, an answer after ${slowAnswer}ms is recorded with its real time`, async (t) => {
-        CONFIG.updateInterval = interval;
-        mockTargets(t, () => slowAnswer);
-        const check = measureLatency("https://target.test");
-        t.mock.timers.tick(slowAnswer);
-        assert.deepEqual(await settled(check), {
-            latency: slowAnswer,
-            error: null,
-        });
-    });
-
-    test(`at a ${interval}ms interval, a target that never answers is recorded as a timeout after ${timeout}ms`, async (t) => {
-        CONFIG.updateInterval = interval;
-        mockTargets(t, () => Infinity);
-        const check = measureLatency("https://target.test");
-        t.mock.timers.tick(timeout - 1);
-        assert.equal(await settled(check), "still waiting");
-        t.mock.timers.tick(1);
-        assert.deepEqual(await settled(check), {
-            latency: null,
-            error: "timeout",
-        });
-    });
-}
-
-test("at a 30000ms interval, a target answering after 1000ms shows in its row while another target's check is still waiting", async (t) => {
-    CONFIG.updateInterval = 30000;
-    const state = new AppState([
-        { name: "Answering", url: "https://answering.test" },
-    ]);
-    const answering = state.local[0];
-    const waiting = state.wan[0];
-    // No target but the answering one ever answers.
-    mockTargets(t, (url) => (url.startsWith(answering.url) ? 1000 : Infinity));
-    // The third tick: the first is discarded as a whole, and the second ends
-    // by sorting the rows, which rebuilds a page that is not here.
-    state.tickCount = 2;
-
-    const round = tick(state, new AbortController().signal);
-    t.mock.timers.tick(1000);
-    assert.equal(await settled(round), "still waiting");
-    assert.match(latencyFigure(state, answering), />1000</);
-    assert.equal(latencyFigure(state, waiting), undefined);
-    assert.equal(state.tickCount, 2);
-
-    // The round ends, once, when the last check times out.
-    t.mock.timers.tick(CONFIG.requestTimeout - 1000);
-    assert.notEqual(await settled(round), "still waiting");
-    assert.equal(state.tickCount, 3);
-});