Next (#364)

Reviewed-on: #364

Dockerfile

@@ -88,7 +88,9 @@ RUN CGO_ENABLED=1 make build VERSION="$VERSION" GO_LDFLAGS='-extldflags "-static
 # alpine:3.21, 2026-03-17
 FROM alpine:3.21@sha256:c3f8e73fdb79deaebaa2037150150191b9dcbfba68b4a46d70103204c53f4709
 
-RUN apk --no-cache add ca-certificates
+# su-exec 0.2-r3 (Alpine 3.21), 2026-09-29: the entrypoint runs the app
+# as webhooker with it.
+RUN apk --no-cache add ca-certificates su-exec=0.2-r3
 
 # Create non-root user
 RUN addgroup -g 1000 -S webhooker && \
@@ -99,13 +101,17 @@ WORKDIR /app
 # Copy binary from builder
 COPY --from=builder /build/bin/webhooker /app/webhooker
 
+# Not under /app, which belongs to webhooker: this script runs as root.
+COPY deploy/docker-entrypoint.sh /usr/local/bin/docker-entrypoint.sh
+
 # Create data directory for all SQLite databases (main app DB +
 # per-webhook event DBs). DATA_DIR defaults to /var/lib/webhooker.
 RUN mkdir -p /var/lib/webhooker
 
 RUN chown -R webhooker:webhooker /app /var/lib/webhooker
 
-USER webhooker
+# No USER: the entrypoint starts as root to make the data directory
+# webhooker's, then runs the app as webhooker.
 
 EXPOSE 8080
 
@@ -124,4 +130,5 @@ ENV BIND_ADDRESS=0.0.0.0
 HEALTHCHECK --interval=30s --timeout=3s --start-period=5s --retries=3 \
     CMD wget --no-verbose --tries=1 --spider http://localhost:8080/.well-known/healthcheck || exit 1
 
+ENTRYPOINT ["/usr/local/bin/docker-entrypoint.sh"]
 CMD ["/app/webhooker"]

README.md

@@ -538,6 +538,12 @@ its Argon2id hash. There is no second account and no forgot-password
 flow, so the banner and the reset command below are the only two ways
 in.
 
+A start that finds no `webhooker.db` in `DATA_DIR` also logs
+`created a new, empty database` at `WARN`, with the file's path,
+shortly before the banner. On a deployment that has run before, that
+line means `DATA_DIR` was empty, most often because its volume is not
+mounted.
+
 #### Recovering a lost admin password
 
 `webhooker resetpw` sets an existing account's password from the
@@ -552,8 +558,9 @@ printf '%s' "$NEW_PASSWORD" | \
     DATA_DIR=/var/lib/webhooker webhooker resetpw admin
 ```
 
-In a container it is the same binary, which the image sets as `CMD`
+In a container it is the same binary. The image's `CMD` is
-rather than `ENTRYPOINT`, so the whole command has to be given:
+`/app/webhooker`, and a command given to `docker run` replaces all of
+it, so the whole command has to be given:
 
 ```bash
 docker run --rm -v webhooker-data:/var/lib/webhooker \
@@ -690,38 +697,22 @@ those three values rather than trusting the figure. Measured at 65s on
 Docker 29.7.2.) A container `unhealthy` with `connection refused` in
 its health log, or a published port that resets connections, is this.
 
-The container runs as a non-root user (`webhooker`, UID 1000), exposes
+The app runs as a non-root user (`webhooker`, UID 1000), exposes port
-port 8080, and includes a health check against
+8080, and includes a health check against `/.well-known/healthcheck`.
-`/.well-known/healthcheck`. The `/var/lib/webhooker` volume holds all
+The `/var/lib/webhooker` volume holds all SQLite databases: the main
-SQLite databases: the main application database (`webhooker.db`), the
+application database (`webhooker.db`), the per-webhook event databases
-per-webhook event databases (`events-{uuid}.db`), and any archive
+(`events-{uuid}.db`), and any archive databases written by `database`
-databases written by `database` targets (`archive-{uuid}.db`). Mount
+targets (`archive-{uuid}.db`). Mount this as a persistent volume to
-this as a persistent volume to preserve data across container
+preserve data across container restarts.
-restarts.
 
-**The bind-mounted directory must be owned by UID 1000, or the
+**The container sets its data directory's owner and mode itself
-container does not start.** Docker creates a `-v` source path that
+before the app starts**, so a host directory can be mounted as it is,
-does not exist yet as `root:root`, and the process runs as UID 1000,
+whoever owns it. The image's `ENTRYPOINT`,
-so it cannot take its `DATA_DIR` lock:
+`deploy/docker-entrypoint.sh`, starts as root, creates `DATA_DIR` if
-
+it is missing, gives the directory and anything in it that belongs to
-```
+another user to `webhooker`, sets the directory to `0750`, and only
-webhooker: locking data directory /var/lib/webhooker: open
+then runs the app as `webhooker`. Started with `--user`, it changes
-/var/lib/webhooker/webhooker.lock: permission denied
+nothing and runs the app as that user.
-```
-
-It exits non-zero at that point, before opening any database. Create
-the directory ahead of the first `docker run`:
-
-```bash
-mkdir -p /path/to/data
-chown 1000:1000 /path/to/data
-chmod 750 /path/to/data
-```
-
-The same `chown` is what a restore needs — see step 4 of
-[Restore](#restore). A **named volume** does not have this problem:
-Docker copies the image's ownership onto a volume it initializes, and
-the image creates `/var/lib/webhooker` owned by `webhooker`.
 
 **The file modes are not yours to set, and do not depend on the
 directory.** `webhooker.db` holds target configuration in plaintext —
@@ -729,13 +720,10 @@ bearer tokens, API keys, Slack webhook URLs — along with the session
 encryption key, so webhooker creates every SQLite file it owns `0600`:
 each database and both of its `-wal` and `-shm` sidecars, across all
 three tiers. Files an earlier build left `0644` are tightened when
-they are opened. A `DATA_DIR` webhooker creates itself is `0750`, but
+they are opened. The directory's `0750` is defence in depth — it stops
-a bind mount supplies its own directory and Docker's default for one
+other local users listing the directory and learning your webhook
-it creates is `0755`; the `0600` files hold there regardless. The
+UUIDs from the `events-{uuid}.db` filenames — not the barrier
-`chmod 750` above is defence in depth — it stops other local users
+protecting the credentials.
-listing the directory and learning your webhook UUIDs from the
-`events-{uuid}.db` filenames — not the barrier protecting the
-credentials.
 
 ### Running under upaas
 
@@ -751,17 +739,6 @@ repository's `Dockerfile` and runs it. The app needs:
   app name, port `8080`. Leave `PORT` unset: the image's health check
   probes `8080`.
 - **Volume:** one host directory mounted at `/var/lib/webhooker`.
-  upaas bind-mounts the host path it is given and does not create it,
-  and the container does not start unless UID 1000 owns it (see
-  [Running with Docker](#running-with-docker)). Create it before the
-  first deploy:
-
-    ```bash
-    mkdir -p /path/to/data
-    chown 1000:1000 /path/to/data
-    chmod 750 /path/to/data
-    ```
-
 - **Environment variables:**
     - `WEBHOOKER_ENVIRONMENT=prod`
     - `TRUSTED_PROXIES`: your reverse proxy's address on that Docker
@@ -1020,12 +997,12 @@ done
 `.backup` reads through the WAL and writes a single consistent file with
 no sidecars of its own, so the destination is complete as it stands.
 Two caveats. First, the runtime image is `alpine:3.21` with only
-`ca-certificates` added — the `sqlite3` CLI is **not** in it, so run
+`ca-certificates` and `su-exec` added — the `sqlite3` CLI is **not** in
-this on the host against the volume path, or from a throwaway container
+it, so run this on the host against the volume path, or from a
-that mounts the volume. Second, each file is captured at its own
+throwaway container that mounts the volume. Second, each file is
-instant, so a webhook created or an event delivered between two files
+captured at its own instant, so a webhook created or an event delivered
-being copied lands in one and not the other. If you need the whole set
+between two files being copied lands in one and not the other. If you
-coherent as of a single moment, stop the service.
+need the whole set coherent as of a single moment, stop the service.
 
 Note that `sqlite3 <db> .dump` is **not** one of these procedures: it is
 an export, it holds a read transaction open for as long as it runs, and
@@ -1079,21 +1056,11 @@ with any `-wal`/`-shm` beside it, or wait until there are none.
    archive not opened since a crash. A copy salvaged from a crashed
    instance has them for everything, and needs all of them.
 
-4. **Fix ownership.** The container runs as the non-root `webhooker`
+4. Start the service. The container gives the directory and the
-   user, UID 1000 / GID 1000. Restored files must be owned by (or
+   restored files to the `webhooker` user before the app starts,
-   writable by) that UID, and so must the directory itself — SQLite
+   whoever restored them (see
-   creates the `-wal` and `-shm` sidecars beside the database, so a
+   [Running with Docker](#running-with-docker)). `AutoMigrate` runs
-   writable file inside a directory it cannot write is not enough:
+   against each restored database as it is opened.
-
-    ```bash
-    chown -R 1000:1000 /path/to/data
-    ```
-
-    Restoring as `root` on the host and forgetting this step is the
-    usual way a restore fails.
-
-5. Start the service. `AutoMigrate` runs against each restored database
-   as it is opened.
 
 ### Upgrades
 
@@ -1472,7 +1439,7 @@ A registered user of the webhooker service.
 | Field      | Type     | Description |
 | ---------- | -------- | ----------- |
 | `id`       | UUID     | Primary key |
-| `username` | string   | Unique login name, at most 1024 bytes so that it fits in the session cookie |
+| `username` | string   | Unique login name |
 | `password` | string   | Argon2id hash (never exposed via API) |
 
 **Relations:** Has many Webhooks. Has many APIKeys.
@@ -2412,14 +2379,14 @@ Removing either cap fails 14 subtests.
 
 `internal/middleware/logbound_test.go` and
 `internal/handlers/logbound_test.go` drive 8 KB of client-chosen text
-at each of these — just under 1 KB at `invalid password`, whose
+at each of these — 1 KB at `invalid password`, whose accounts are
-accounts are shared with the successful-login line and so must stay
+shared with the successful-login line, where a username past 4 KB
-within the 1024-byte username limit — through both handlers, and
+overflows the session cookie and answers 500 before that line is
-through seven fills: plain text as the baseline, and then the
+written — through both handlers, and through seven fills: plain text
-quotation mark, backslash, tab, newline, C0 control and astral
+as the baseline, and then the quotation mark, backslash, tab, newline,
-non-printable, six characters the wider of the two handlers spends
+C0 control and astral non-printable, six characters the wider of the
-more on than the client spent sending them. Every case holds each
+two handlers spends more on than the client spent sending them. Every
-line to the 2,560-byte ceiling. That per-line ceiling
+case holds each line to the 2,560-byte ceiling. That per-line ceiling
 is what the figure above states, and every row establishes it.
 
 Three of the sites go further and bound the whole flood's output — the
@@ -2721,7 +2688,7 @@ abuse limit later; they are tracked as future work.
 | ------ | --------------------------- | ----------- |
 | `GET`  | `/`                         | Root redirect, 303 (authenticated → `/sources`, unauthenticated → `/pages/login`) |
 | `GET`  | `/.well-known/healthcheck`  | Health check (JSON: `status`, `now`, `uptimeSeconds`, `uptimeHuman`, `version`, `appname`, `maintenanceMode`) |
-| any    | `/s/*`                      | Static file serving (embedded CSS, JS). Mounted for every method, not just `GET`/`HEAD`: chi's `Mount` registers all methods and `http.FileServer` special-cases only `HEAD` (by omitting the body), so a `POST` or `DELETE` to an asset is answered `200` with the file. Pinned by `TestStaticServesEveryMethod` |
+| `GET`, `HEAD` | `/s/*`              | Static file serving (embedded CSS, JS). `GET` and `HEAD` only — `POST`, `PUT`, `PATCH`, `DELETE`, `OPTIONS`, `TRACE` and `CONNECT` are answered `405 Method Not Allowed` with `Allow: GET, HEAD`. Any other method (such as `PROPFIND`) is refused by chi before it reaches this route, and gets `405` without an `Allow` header. Pinned by `TestStaticServesOnlyGetAndHead` |
 | `POST` | `/webhook/{uuid}`           | Webhook receiver endpoint. `POST` only — every other method is answered `405 Method Not Allowed` with `Allow: POST`. Rate limited (see [Rate Limiting](#rate-limiting)) |
 
 #### Authentication Endpoints
@@ -3071,7 +3038,11 @@ check, see [The login endpoint](#the-login-endpoint).
 - Prometheus metrics behind basic auth
 - Static assets embedded in binary (no filesystem access needed at
   runtime)
-- Container runs as non-root user (UID 1000)
+- The app runs as the non-root `webhooker` user (UID 1000) in the
+  container. The image sets no `USER`, so these run as root: the
+  `ENTRYPOINT` script, which sets the data directory's owner and mode
+  before the app starts; the image's health check; and `docker exec`,
+  unless given `--user`
 - GORM soft deletes on every entity that carries `BaseModel`, which is
   all of them but `Setting` (data preserved for audit)
 
@@ -3198,10 +3169,13 @@ version is fixed independently of the compiler's:
    `GO_LDFLAGS`, so neither can drop the `-X` that stamps the version.
    The version arrives as the `VERSION` build arg, since the context
    has no `.git` (see [Version stamping](#version-stamping)).
-3. **Runtime stage** (`alpine:3.21`) — copies the static binary,
+3. **Runtime stage** (`alpine:3.21`) — copies the static binary and
-   creates the `/var/lib/webhooker` directory for all SQLite databases,
+   `deploy/docker-entrypoint.sh`, creates the `/var/lib/webhooker`
-   runs as the non-root `webhooker` user (UID 1000), exposes port 8080,
+   directory for all SQLite databases, exposes port 8080, and includes
-   and includes a health check against `/.well-known/healthcheck`.
+   a health check against `/.well-known/healthcheck`. It sets no
+   `USER`: the `ENTRYPOINT` script starts as root, sets the data
+   directory's owner and mode, and runs the app as the non-root
+   `webhooker` user (UID 1000) through `su-exec`.
 
 The lint stage invokes `golangci-lint` directly rather than `make lint`:
 it is already the pinned linter image, and `make lint` builds
@@ -3280,3 +3254,5 @@ MIT
 ## Author
 
 [@sneak](https://sneak.berlin)
+
+

deploy/docker-entrypoint.sh

@@ -0,0 +1,22 @@
+#!/bin/sh
+# deploy/docker-entrypoint.sh: the image's ENTRYPOINT. A bind-mounted
+# data directory keeps its owner from the host, often root, and the app
+# could not write to it. Started as root, this creates DATA_DIR if
+# needed, gives it and everything in it to webhooker, sets its mode, and
+# runs the command as webhooker, so the app never runs as root. Started
+# as another user, it only runs the command.
+set -eu
+
+main() {
+    if [ "$(id -u)" != 0 ]; then
+        exec "$@"
+    fi
+
+    dir="${DATA_DIR:-/var/lib/webhooker}"
+    mkdir -p "$dir"
+    find "$dir" ! -user webhooker -exec chown -h webhooker:webhooker {} +
+    chmod 750 "$dir"
+    exec su-exec webhooker "$@"
+}
+
+main "$@"

internal/database/bootstrap_banner_test.go

@@ -3,6 +3,8 @@ package database_test
 import (
 	"bytes"
 	"context"
+	"log/slog"
+	"path/filepath"
 	"strings"
 	"testing"
 
@@ -83,3 +85,37 @@ func TestFirstBoot_PrintsTheAdminPasswordAsABanner(t *testing.T) {
 		t, ok, "the printed password must open the seeded account",
 	)
 }
+
+// TestNewDatabase_IsLoggedWithItsPath is the log half of
+// https://git.eeqj.de/sneak/webhooker/issues/359. A DATA_DIR that is
+// unexpectedly empty boots exactly like a first start, so the start
+// that creates the database must say so, and where. Opening that
+// database again must not.
+func TestNewDatabase_IsLoggedWithItsPath(t *testing.T) {
+	t.Parallel()
+
+	dir := t.TempDir()
+
+	open := func() string {
+		var out bytes.Buffer
+
+		db, err := database.Open(dir, slog.New(slog.NewTextHandler(&out, nil)))
+		require.NoError(t, err)
+		require.NoError(t, db.Close())
+
+		return out.String()
+	}
+
+	const created = `level=WARN msg="created a new, empty database"`
+
+	first := open()
+	second := open()
+
+	assert.Contains(
+		t, first,
+		created+" path="+filepath.Join(dir, database.MainDBFileName),
+	)
+	assert.NotContains(
+		t, second, created, "an existing database is not new",
+	)
+}

internal/database/database.go

@@ -8,6 +8,7 @@ import (
 	"errors"
 	"fmt"
 	"io"
+	"io/fs"
 	"log/slog"
 	"os"
 	"path/filepath"
@@ -199,6 +200,12 @@ func (d *Database) connectTo(dataDir string) error {
 	// Construct the main application database path inside DATA_DIR.
 	dbPath := filepath.Join(dataDir, MainDBFileName)
 
+	// Checked before opening, which creates the file. A DATA_DIR that
+	// is unexpectedly empty -- its volume not mounted, say -- looks
+	// exactly like a first start, so a new database is a warning.
+	_, statErr := os.Stat(dbPath)
+	created := errors.Is(statErr, fs.ErrNotExist)
+
 	// Opened through OpenSQLite so this handle carries the same WAL
 	// journaling, busy timeout, immediate-transaction locking, and pool
 	// bounds as every other database file. See sqlite_open.go.
@@ -229,7 +236,12 @@ func (d *Database) connectTo(dataDir string) error {
 	}
 
 	d.db = db
-	d.log.Info("connected to database", "path", dbPath)
+
+	if created {
+		d.log.Warn("created a new, empty database", "path", dbPath)
+	} else {
+		d.log.Info("connected to database", "path", dbPath)
+	}
 
 	// Run migrations
 	return d.migrate()

internal/database/model_user.go

@@ -1,57 +1,13 @@
 package database
 
-import (
-	"errors"
-	"fmt"
-
-	"gorm.io/gorm"
-)
-
-// MaxUsernameBytes is the longest username, in bytes, that a user may
-// have. The same number appears in the check constraint on
-// User.Username, because a struct tag cannot reference a constant.
-//
-// A login stores the username in the session cookie, and both
-// securecookie and browsers refuse a cookie value past about 4096
-// bytes. That value is the session base64-encoded twice, so it holds
-// 4096 × 3/4 × 3/4 = 2304 bytes of session, and the signature,
-// timestamp and the session's other values take about 270 of those: a
-// username longer than about 2030 bytes can never log in. The limit is
-// about half that, so the session can carry more values later without
-// locking out an account whose username is already at the limit.
-const MaxUsernameBytes = 1024
-
-// ErrUsernameTooLong is returned when a user is saved with a username
-// longer than MaxUsernameBytes.
-var ErrUsernameTooLong = errors.New("username is too long")
-
 // User represents a user of the webhooker service
-//
-//nolint:lll // a struct tag cannot wrap
 type User struct {
 	BaseModel
 
-	Username string `gorm:"uniqueIndex;not null;check:length(CAST(username AS BLOB)) <= 1024" json:"username"`
+	Username string `gorm:"uniqueIndex;not null" json:"username"`
-	Password string `gorm:"not null"                                                          json:"-"` // Argon2 hashed
+	Password string `gorm:"not null"             json:"-"` // Argon2 hashed
 
 	// Relations
 	Webhooks []Webhook `json:"webhooks,omitempty"`
 	APIKeys  []APIKey  `json:"apiKeys,omitempty"`
 }
-
-// BeforeSave rejects a username longer than MaxUsernameBytes, so every
-// path that saves a user through GORM gets ErrUsernameTooLong rather
-// than the database's constraint error. The check constraint behind it
-// holds for any path that writes the table without this model.
-func (u *User) BeforeSave(_ *gorm.DB) error {
-	if len(u.Username) > MaxUsernameBytes {
-		return fmt.Errorf(
-			"%w: %d bytes, limit is %d",
-			ErrUsernameTooLong,
-			len(u.Username),
-			MaxUsernameBytes,
-		)
-	}
-
-	return nil
-}

internal/database/model_user_test.go

@@ -1,65 +0,0 @@
-package database_test
-
-import (
-	"strings"
-	"testing"
-
-	"github.com/google/uuid"
-	"github.com/stretchr/testify/assert"
-	"github.com/stretchr/testify/require"
-	"sneak.berlin/go/webhooker/internal/database"
-)
-
-// usernameAtLimit is exactly MaxUsernameBytes long, built from a
-// two-byte character. A check that counted characters rather than bytes
-// would see half the length and let the one-byte-longer name through.
-func usernameAtLimit() string {
-	return strings.Repeat("é", database.MaxUsernameBytes/2)
-}
-
-func TestUserCreate_RejectsOverlongUsername(t *testing.T) {
-	t.Parallel()
-
-	db := startedTestDB(t)
-
-	err := db.Create(&database.User{
-		Username: usernameAtLimit() + "x",
-		Password: "hash",
-	}).Error
-
-	require.ErrorIs(t, err, database.ErrUsernameTooLong)
-}
-
-func TestUserCreate_AcceptsUsernameAtLimit(t *testing.T) {
-	t.Parallel()
-
-	db := startedTestDB(t)
-
-	require.NoError(t, db.Create(&database.User{
-		Username: usernameAtLimit(),
-		Password: "hash",
-	}).Error)
-}
-
-// TestUsersTable_EnforcesUsernameLimitWithoutTheModel inserts with raw
-// SQL, as a path that bypassed User.BeforeSave would, so only the
-// table's check constraint stands between it and an over-long
-// username. Accepting the name at the limit and refusing the next byte
-// also pins the constraint's number to MaxUsernameBytes.
-func TestUsersTable_EnforcesUsernameLimitWithoutTheModel(t *testing.T) {
-	t.Parallel()
-
-	db := startedTestDB(t)
-
-	insert := "INSERT INTO users (id, username, password) VALUES (?, ?, ?)"
-
-	require.NoError(t, db.Exec(
-		insert, uuid.New().String(), usernameAtLimit(), "hash",
-	).Error)
-
-	err := db.Exec(
-		insert, uuid.New().String(), usernameAtLimit()+"x", "hash",
-	).Error
-	require.Error(t, err)
-	assert.Contains(t, err.Error(), "CHECK constraint failed")
-}

internal/handlers/auth_test.go

@@ -453,33 +453,3 @@ func TestLogin_SuccessCreatesSession(t *testing.T) {
 		"the issued cookie must carry an authenticated session",
 	)
 }
-
-// TestLogin_UsernameAtLimitCanLogIn shows that a username of exactly
-// database.MaxUsernameBytes still fits in the session cookie. Past
-// what the cookie can carry, a correct login answers 500.
-func TestLogin_UsernameAtLimitCanLogIn(t *testing.T) {
-	t.Parallel()
-
-	var (
-		h  *handlers.Handlers
-		db *database.Database
-	)
-
-	app := newTestApp(t, &h, &db)
-	app.RequireStart()
-
-	t.Cleanup(app.RequireStop)
-
-	username := strings.Repeat("a", database.MaxUsernameBytes)
-
-	hash, err := database.HashPassword(operatorPassword)
-	require.NoError(t, err)
-	require.NoError(t, db.DB().Create(&database.User{
-		Username: username,
-		Password: hash,
-	}).Error)
-
-	w := submitLogin(h, sharedProxyPeer, username, operatorPassword)
-
-	assert.Equal(t, http.StatusSeeOther, w.Code)
-}

internal/handlers/logbound_test.go

@@ -339,9 +339,11 @@ const storedUserPassword = "correct-horse-battery-staple"
 // storedFillBytes is the raw length of the client-chosen value in
 // those accounts' usernames. It is well past the 512-byte field
 // budget, so the line is still truncated, but short enough that the
-// whole username, markers and fill name included, stays within
+// session cookie a successful login writes stays inside
-// database.MaxUsernameBytes.
+// securecookie's 4 KB limit: the cookie is written BEFORE the
-const storedFillBytes = 960
+// "user logged in" line, so an 8 KB username answers 500 and never
+// reaches it.
+const storedFillBytes = 1024
 
 // storedFill builds a username fill of storedFillBytes raw bytes out
 // of repetitions of ch, with both markers at its far end.

internal/server/routes.go

@@ -92,11 +92,25 @@ func (s *Server) setupGlobalMiddleware() {
 func (s *Server) setupRoutes() {
 	s.router.Get("/", s.h.HandleIndex())
 
-	s.router.Mount(
+	// Static assets answer GET and HEAD only. chi's default 405
-		"/s",
+	// carries no Allow header, so this group supplies its own.
-		http.StripPrefix("/s", http.FileServer(http.FS(static.Static))),
+	staticFiles := http.StripPrefix(
+		"/s", http.FileServer(http.FS(static.Static)),
 	)
 
+	s.router.Route("/s", func(r chi.Router) {
+		r.MethodNotAllowed(func(w http.ResponseWriter, _ *http.Request) {
+			w.Header().Set("Allow", "GET, HEAD")
+			http.Error(
+				w,
+				"Method Not Allowed",
+				http.StatusMethodNotAllowed,
+			)
+		})
+		r.Method(http.MethodGet, "/*", staticFiles)
+		r.Method(http.MethodHead, "/*", staticFiles)
+	})
+
 	s.router.Route("/api/v1", func(_ chi.Router) {
 		// API routes will be added here.
 	})

internal/server/routes_test.go

@@ -7,6 +7,7 @@ import (
 	"net/http/httptest"
 	"net/url"
 	"regexp"
+	"slices"
 	"strconv"
 	"strings"
 	"testing"
@@ -220,9 +221,21 @@ func (e *testEnv) csrfFrom(
 	// out of the markup has to be unescaped before it is submitted.
 	token := html.UnescapeString(match[1])
 
-	combined := make([]*http.Cookie, 0, len(cookies))
+	// A cookie the page sets replaces the one of the same name, as in
-	combined = append(combined, cookies...)
+	// a browser. Sent both, the server would read the first, older one.
-	combined = append(combined, w.Result().Cookies()...)
+	set := w.Result().Cookies()
+	combined := make([]*http.Cookie, 0, len(cookies)+len(set))
+
+	for _, c := range cookies {
+		replaced := slices.ContainsFunc(set, func(n *http.Cookie) bool {
+			return n.Name == c.Name
+		})
+		if !replaced {
+			combined = append(combined, c)
+		}
+	}
+
+	combined = append(combined, set...)
 
 	return token, combined
 }
@@ -396,13 +409,15 @@ func (e *testEnv) storedHash(t *testing.T, username string) string {
 
 // --- /s static group ---
 
-// TestStaticServesEveryMethod pins what the static mount actually
+// TestStaticServesOnlyGetAndHead pins the methods the static group
-// answers. chi's Mount registers the handler for all methods and
+// answers: GET and HEAD are served the asset, and the other methods
-// http.FileServer only special-cases HEAD (by suppressing the body),
+// chi routes (POST, PUT, DELETE and the rest) are refused with 405
-// so a POST or a DELETE to an asset is served the file rather than
+// and an Allow header naming those two. A method chi does not route,
-// refused. The README documents this; the test is what keeps the two
+// such as PROPFIND, is refused with 405 by the top-level router
-// from drifting.
+// before it reaches the static group, so it gets no Allow header.
-func TestStaticServesEveryMethod(t *testing.T) {
+// The README documents this; the test is what keeps the two from
+// drifting.
+func TestStaticServesOnlyGetAndHead(t *testing.T) {
 	t.Parallel()
 
 	env := newTestEnv(t)
@@ -417,6 +432,7 @@ func TestStaticServesEveryMethod(t *testing.T) {
 		http.MethodPost,
 		http.MethodPut,
 		http.MethodDelete,
+		"PROPFIND",
 	} {
 		t.Run(method, func(t *testing.T) {
 			t.Parallel()
@@ -428,18 +444,38 @@ func TestStaticServesEveryMethod(t *testing.T) {
 			w := httptest.NewRecorder()
 			env.router.ServeHTTP(w, req)
 
-			assert.Equal(t, http.StatusOK, w.Code,
+			switch method {
-				"static mount answers every method")
+			case http.MethodGet:
-
+				assert.Equal(t, http.StatusOK, w.Code)
-			if method == http.MethodHead {
+				assert.Equal(t, body, w.Body.Bytes(),
+					"the asset itself is returned")
+			case http.MethodHead:
+				assert.Equal(t, http.StatusOK, w.Code)
 				assert.Empty(t, w.Body.Bytes(),
 					"HEAD must not carry a body")
-
+			case "PROPFIND":
-				return
+				assert.Equal(
+					t, http.StatusMethodNotAllowed, w.Code,
+				)
+				assert.Empty(t, w.Header().Get("Allow"),
+					"chi refuses a method it does not route "+
+						"before the static group runs")
+				assert.NotContains(
+					t, w.Body.String(), string(body),
+					"a refused method must not get the asset",
+				)
+			default:
+				assert.Equal(
+					t, http.StatusMethodNotAllowed, w.Code,
+				)
+				assert.Equal(
+					t, "GET, HEAD", w.Header().Get("Allow"),
+				)
+				assert.NotContains(
+					t, w.Body.String(), string(body),
+					"a refused method must not get the asset",
+				)
 			}
-
-			assert.Equal(t, body, w.Body.Bytes(),
-				"the asset itself is returned")
 		})
 	}
 }
@@ -591,6 +627,59 @@ func TestPagesLogin_CorrectPasswordSurvivesASpentBudget(
 	)
 }
 
+// TestPagesLogin_CookiesFromAnEarlierDatabase is
+// https://git.eeqj.de/sneak/webhooker/issues/359. A new database
+// brings a new session key, and the operator's browser still holds
+// the session and CSRF cookies signed with the old one. Logging in
+// must work as from a fresh browser and leave cookies the new key
+// accepts.
+func TestPagesLogin_CookiesFromAnEarlierDatabase(t *testing.T) {
+	t.Parallel()
+
+	const (
+		username = "operator"
+		password = "correct-horse-battery-staple"
+	)
+
+	earlier := newTestEnv(t)
+	earlierID, _ := earlier.seedUser(t, username, password)
+	_, stale := earlier.csrfFrom(t, "/pages/login", nil)
+	stale = append(stale, earlier.authCookies(t, earlierID, username)...)
+
+	env := newTestEnv(t)
+	env.seedUser(t, username, password)
+
+	token, cookies := env.csrfFrom(t, "/pages/login", stale)
+
+	form := url.Values{}
+	form.Set("csrf_token", token)
+	form.Set("username", username)
+	form.Set("password", password)
+
+	w := env.post("/pages/login", form, cookies)
+	require.Equal(
+		t, http.StatusSeeOther, w.Code,
+		"a session cookie from another key must not fail the login",
+	)
+
+	// The response deletes the old session cookie and then sets the
+	// new one; a browser keeps the last.
+	var fresh *http.Cookie
+
+	for _, c := range w.Result().Cookies() {
+		if c.Name == session.SessionName {
+			fresh = c
+		}
+	}
+
+	require.NotNil(t, fresh, "login must set a session cookie")
+	assert.Equal(
+		t, "/sources",
+		env.get("/", []*http.Cookie{fresh}).Header().Get("Location"),
+		"the new session cookie must authenticate",
+	)
+}
+
 // --- /user/{username} group ---
 
 // TestPasswordChange_OversizeBody_RejectedAndPasswordUnchanged

internal/session/codec_test.go

@@ -19,8 +19,8 @@ import (
 )
 
 // The tests below exercise the securecookie codecs underneath the
-// store and nothing else: Session.Get only decodes, so no server-side
+// store and nothing else: they decode through the store itself, so no
-// expiry check takes part in the result. They exist because
+// server-side expiry check takes part in the result. They exist because
 // NewCookieStore gives its codecs a 30-day max age that assigning
 // store.Options does not override, which would let the codec accept a
 // cookie weeks past the cap the cookie attribute advertises.
@@ -75,10 +75,11 @@ func restamp(
 	return base64.URLEncoding.EncodeToString(payload)
 }
 
-// decodeCookie feeds value back through the store's decode path.
+// decodeCookie feeds value back through the store's decode path. It
+// asks the store rather than Session.Get, which treats a cookie that
+// does not decode as absent and so hides the codec's reason.
 func decodeCookie(
 	t *testing.T,
-	s *session.Session,
 	value string,
 ) (*sessions.Session, error) {
 	t.Helper()
@@ -94,7 +95,7 @@ func decodeCookie(
 		SameSite: http.SameSiteLaxMode,
 	})
 
-	sess, err := s.Get(req)
+	sess, err := session.NewStore(testKey()).Get(req, session.SessionName)
 	require.NotNil(t, sess)
 
 	return sess, err
@@ -105,7 +106,7 @@ func TestCodec_AcceptsCookieInsideAbsoluteCap(t *testing.T) {
 
 	s := testSession(t)
 
-	sess, err := decodeCookie(t, s, restamp(
+	sess, err := decodeCookie(t, restamp(
 		t,
 		issuedCookie(t, s),
 		time.Now().Add(-(testAbsoluteMaxAge-time.Hour)),
@@ -126,7 +127,7 @@ func TestCodec_RejectsCookiePastAbsoluteCap(t *testing.T) {
 
 	s := testSession(t)
 
-	sess, err := decodeCookie(t, s, restamp(
+	sess, err := decodeCookie(t, restamp(
 		t,
 		issuedCookie(t, s),
 		time.Now().Add(-(testAbsoluteMaxAge+time.Hour)),

internal/session/session.go

@@ -224,10 +224,22 @@ func New(
 }
 
 // Get retrieves a session for the request.
+//
+// A session cookie that does not decode -- one signed with an earlier
+// session key, say, because the database was made anew -- is treated
+// as absent: the caller gets a new, empty session and no error, and
+// the next save replaces the cookie.
 func (s *Session) Get(
 	r *http.Request,
 ) (*sessions.Session, error) {
-	return s.store.Get(r, SessionName)
+	sess, err := s.store.Get(r, SessionName)
+	if sess == nil {
+		return nil, err
+	}
+
+	// For a cookie that does not decode, gorilla/sessions returns a
+	// new, empty session alongside the error that is dropped here.
+	return sess, nil
 }
 
 // GetKey returns the raw 32-byte authentication key used for