Stamp the tag or short commit in a plain docker build (closes #166)

.dockerignore now lets .git into the build context, without
.git/config, which can hold a remote URL with a credential. ARG VERSION
has no default: given none, the build stage takes the version from
git describe --tags --always, and fails if the context carries .git
and no version comes out. pixad now logs its name, version and
architecture as its first log line, through the existing
Logger.Identify, which nothing called.

Model: opus-5-5

.dockerignore

@@ -1,4 +1,8 @@
-.git
+# .git is sent without its config. Without a VERSION build argument the
+# stage that compiles runs `git describe --tags --always` on .git, which
+# does not need .git/config; that file can hold a credential, such as a
+# password in a remote URL or the token the CI checkout step stores there.
+.git/config
 .gitignore
 .DS_Store
 .env*

CONVENTIONS.md

@@ -114,13 +114,11 @@ import (
 var (
     Appname string = "CHANGEME"
     Version string
-    Buildarch string
 )
 
 func main() {
     globals.Appname = Appname
     globals.Version = Version
-    globals.Buildarch = Buildarch
 
     fx.New(
         fx.Provide(
@@ -859,7 +857,7 @@ func (l *Logger) Identify() {
     l.log.Info("starting",
         "appname", l.params.Globals.Appname,
         "version", l.params.Globals.Version,
-        "buildarch", l.params.Globals.Buildarch,
+        "arch", runtime.GOARCH,
     )
 }
 ```
@@ -981,20 +979,17 @@ import "go.uber.org/fx"
 var (
     Appname string
     Version string
-    Buildarch string
 )
 
 // Struct for DI
 type Globals struct {
     Appname string
     Version string
-    Buildarch string
 }
 
 func New(lc fx.Lifecycle) (*Globals, error) {
     n := &Globals{
         Appname: Appname,
-        Buildarch: Buildarch,
         Version: Version,
     }
     return n, nil
@@ -1008,13 +1003,11 @@ func New(lc fx.Lifecycle) (*Globals, error) {
 var (
     Appname string = "CHANGEME"  // Default, overridden by build
     Version string               // Set at build time
-    Buildarch string               // Set at build time
 )
 
 func main() {
     globals.Appname = Appname
     globals.Version = Version
-    globals.Buildarch = Buildarch
     // ...
 }
 ```
@@ -1025,10 +1018,9 @@ Use ldflags to inject version information at build time:
 
 ```makefile
 VERSION := $(shell git describe --tags --always)
-BUILDARCH := $(shell go env GOARCH)
 
 build:
-    go build -ldflags "-X main.Version=$(VERSION) -X main.Buildarch=$(BUILDARCH)" ./cmd/httpd
+    go build -ldflags "-X main.Version=$(VERSION)" ./cmd/httpd
 ```
 
 ---

Dockerfile

@@ -43,12 +43,23 @@ COPY . .
 RUN make test
 
 # VERSION is declared here, not earlier: a new value reruns only the
-# build, not script/bootstrap or the tests. CGO stays enabled for
-# govips; -trimpath keeps build paths out of the binary, and -s -w
-# leave out the symbol table and debug information.
-ARG VERSION=dev
-RUN CGO_ENABLED=1 GOTOOLCHAIN=auto go build -trimpath \
-    -ldflags "-s -w -X main.Version=${VERSION}" \
+# build, not script/bootstrap or the tests. Given none, the version is
+# `git describe --tags --always` of the .git in the build context (git
+# comes from script/bootstrap): the tag on a tagged commit, tag-N-gHASH
+# after one, the short commit when no tag is reachable. A context that
+# carries .git and still yields no version fails the build; one without
+# .git, as from a source tarball, stamps an empty version. CGO stays
+# enabled for govips; -trimpath keeps build paths out of the binary, and
+# -s -w leave out the symbol table and debug information.
+ARG VERSION
+RUN version="${VERSION:-$(git describe --tags --always)}"; \
+    if [ -e .git ] && { [ -z "$version" ] || [ "$version" = dev ] || \
+        [ "$version" = unknown ]; }; then \
+        echo "the build context carries .git but yields no version" >&2; \
+        exit 1; \
+    fi; \
+    CGO_ENABLED=1 GOTOOLCHAIN=auto go build -trimpath \
+        -ldflags "-s -w -X main.Version=${version}" \
         -o /pixad ./cmd/pixad
 
 # Runtime stage

README.md

@@ -238,7 +238,7 @@ variables set by the file's `env:` section are checked the same way.
 | `PIXA_UPSTREAM_FETCH_TIMEOUT`        | `upstream_fetch_timeout`        | Time allowed for one fetch from an upstream host; default `30s`              |
 | `PIXA_UPSTREAM_MAX_RESPONSE_SIZE`    | `upstream_max_response_size`    | Largest upstream response accepted, in bytes; default 50 MiB                 |
 | `PIXA_DOWNSTREAM_TIMEOUT`            | `downstream_timeout`            | Time allowed for answering one client request; default `60s`                 |
-| `PIXA_ACCESS_CONTROL_ALLOW_ORIGIN`   | `access_control_allow_origin`   | CORS origin allowed to read image responses: `*` or one origin; default `*`  |
+| `PIXA_ACCESS_CONTROL_ALLOW_ORIGIN`   | `access_control_allow_origin`   | CORS origin allowed to read responses: `*` or one origin; default `*`        |
 | `PIXA_METRICS_USERNAME`              | `metrics.username`              | Username for `/metrics`, which is served only when both are set              |
 | `PIXA_METRICS_PASSWORD`              | `metrics.password`              | Password for `/metrics`; set together with the username                      |
 | `PIXA_SENTRY_DSN`                    | `sentry_dsn`                    | Sentry DSN for error reporting; empty disables it                            |
@@ -247,9 +247,8 @@ variables set by the file's `env:` section are checked the same way.
 
 Key settings in more detail:
 
-- `access_control_allow_origin` — the origin a browser lets read the responses
-  of the image routes, `/v1/image/` and `/v1/e/`, sent as the CORS
-  `Access-Control-Allow-Origin` header; no other route sends it. `*`, the
+- `access_control_allow_origin` — the origin a browser lets read pixa's
+  responses, sent as the CORS `Access-Control-Allow-Origin` header: `*`, the
   default, is any site; otherwise one `http` or `https` origin such as
   `https://example.com`, whose host is a lowercase host name (letters,
   digits, hyphens and dots, with a letter in its last part) or an IP address

TODO.md

@@ -29,12 +29,13 @@ P2: security: referer blacklist
 
 # Completed Steps
 
-- 2026-09-29 only the image routes send CORS headers (closes #98): the CORS
-  middleware, with the `access_control_allow_origin` origin, moved from the
-  router root onto a `/v1` subrouter holding `/v1/image/` and `/v1/e/`, where it
-  still answers a preflight `OPTIONS` request; the login and URL generator
-  pages, `/metrics` and the other routes send no `Access-Control-Allow-Origin`;
-  documented in `README.md` and `config.example.yml`.
+- 2026-10-02 a plain `docker build .` stamps the tag or short commit, not
+  `dev` (closes #166): `.dockerignore` lets `.git` into the build context,
+  without `.git/config`; with no `VERSION` build argument the `Dockerfile`
+  takes the version from `git describe --tags --always`, and fails the build if
+  the context carries `.git` and no version comes out; `ARG VERSION` has no
+  default; pixad logs its version, with its name and architecture, as its first
+  log line at startup.
 - 2026-09-29 the container makes `/var/lib/pixa` usable by itself (closes
   #159): `deploy/docker-entrypoint.sh` creates the directory if it is missing,
   gives the directory and everything in it to `pixad` when the directory or one

cmd/pixad/main.go

@@ -56,6 +56,9 @@ func run(_ *cobra.Command, _ []string) {
 			middleware.New,
 			healthcheck.New,
 		),
-		fx.Invoke(func(*server.Server) {}),
+		fx.Invoke(
+			func(log *logger.Logger) { log.Identify() },
+			func(*server.Server) {},
+		),
 	).Run()
 }

config.example.yml

@@ -103,9 +103,8 @@ upstream_max_response_size: 52428800
 # longer than upstream_fetch_timeout plus 20 seconds.
 downstream_timeout: 60s
 
-# The origin a browser lets read the responses of the image routes,
-# /v1/image/ and /v1/e/, sent as the CORS Access-Control-Allow-Origin
-# header; no other route sends it. "*" (the default) is any site;
+# The origin a browser lets read pixa's responses, sent as the CORS
+# Access-Control-Allow-Origin header: "*" (the default) is any site;
 # otherwise one http or https origin such as https://example.com, whose
 # host is a lowercase host name (letters, digits, hyphens and dots, with a
 # letter in its last part) or an IP address (IPv6 in brackets, in its

internal/server/cors_internal_test.go

@@ -1,64 +0,0 @@
-package server
-
-import (
-	"net/http"
-	"net/http/httptest"
-	"testing"
-)
-
-// TestCORSOnlyOnImageRoutes verifies that the image routes answer with the
-// configured access_control_allow_origin, a preflight request included, and
-// that the login and URL generator pages send no Access-Control-Allow-Origin,
-// so no other site can read them. /metrics is left out: its middleware
-// registers with the process-wide Prometheus registry, which only one test
-// in this package can do.
-func TestCORSOnlyOnImageRoutes(t *testing.T) {
-	t.Parallel()
-
-	const appOrigin = "https://app.example.com"
-
-	s := newTestServer(t)
-	s.config.AccessControlAllowOrigin = appOrigin
-	s.SetupRoutes()
-
-	requests := []struct {
-		method string
-		path   string
-		want   string
-	}{
-		{http.MethodGet, unsignedImagePath, appOrigin},
-		{http.MethodHead, unsignedImagePath, appOrigin},
-		{http.MethodOptions, unsignedImagePath, appOrigin},
-		{http.MethodGet, encryptedImagePath, appOrigin},
-		{http.MethodGet, "/", ""},
-		{http.MethodOptions, "/", ""},
-		{http.MethodPost, "/generate", ""},
-		{http.MethodGet, "/logout", ""},
-	}
-
-	for _, tc := range requests {
-		t.Run(tc.method+" "+tc.path, func(t *testing.T) {
-			t.Parallel()
-
-			req := httptest.NewRequestWithContext(
-				t.Context(), tc.method, tc.path, nil)
-			req.Header.Set("Origin", appOrigin)
-
-			// An OPTIONS request naming the method it asks about is the
-			// preflight a browser sends before some cross-origin requests.
-			if tc.method == http.MethodOptions {
-				req.Header.Set("Access-Control-Request-Method", http.MethodGet)
-			}
-
-			rec := httptest.NewRecorder()
-			s.ServeHTTP(rec, req)
-			t.Logf("status %d", rec.Code)
-
-			got := rec.Header().Get("Access-Control-Allow-Origin")
-			if got != tc.want {
-				t.Errorf("Access-Control-Allow-Origin = %q, want %q",
-					got, tc.want)
-			}
-		})
-	}
-}

internal/server/maintenance_internal_test.go

@@ -13,10 +13,6 @@ import (
 // unsignedImagePath is an image URL that carries no signature.
 const unsignedImagePath = "/v1/image/cdn.example.com/cat.jpg/100x100.jpeg"
 
-// encryptedImagePath is an encrypted image URL whose token cannot be
-// decrypted.
-const encryptedImagePath = "/v1/e/token/cat.jpg"
-
 // TestMaintenanceModeRefusesImageRequests verifies that while maintenance
 // mode is on, both image routes answer 503 Service Unavailable with a
 // Retry-After header and the JSON error body the image handlers send.
@@ -32,7 +28,7 @@ func TestMaintenanceModeRefusesImageRequests(t *testing.T) {
 	}{
 		{http.MethodGet, unsignedImagePath},
 		{http.MethodHead, unsignedImagePath},
-		{http.MethodGet, encryptedImagePath},
+		{http.MethodGet, "/v1/e/token/cat.jpg"},
 	}
 
 	for _, tc := range requests {
@@ -99,7 +95,7 @@ func TestImageRequestsServedWithoutMaintenanceMode(t *testing.T) {
 	}{
 		{http.MethodGet, unsignedImagePath, http.StatusUnauthorized},
 		{http.MethodHead, unsignedImagePath, http.StatusUnauthorized},
-		{http.MethodGet, encryptedImagePath, http.StatusBadRequest},
+		{http.MethodGet, "/v1/e/token/cat.jpg", http.StatusBadRequest},
 	}
 
 	for _, tc := range requests {

internal/server/routes.go

@@ -38,6 +38,7 @@ func (s *Server) SetupRoutes() {
 		s.router.Use(s.mw.Metrics())
 	}
 
+	s.router.Use(s.mw.CORS())
 	s.router.Use(middleware.Timeout(s.config.DownstreamTimeout))
 
 	if s.sentryEnabled {
@@ -73,31 +74,22 @@ func (s *Server) SetupRoutes() {
 
 	s.router.Get("/logout", s.h.HandleLogout())
 
-	// Image routes, the only ones that send CORS headers, as pages on other
-	// sites read them. They are a subrouter rather than a group: a group's
-	// middleware runs only for a request that matches one of its routes,
-	// and a browser's preflight OPTIONS request matches none, so the CORS
-	// middleware could not answer it.
-	s.router.Route("/v1", func(r chi.Router) {
-		r.Use(s.mw.CORS())
-
-		// Refused while maintenance mode is on. Only these: the image's
-		// Docker HEALTHCHECK requests the health check, a 503 there would
-		// make the container unhealthy, and upaas marks a deploy failed
+	// Image routes, refused while maintenance mode is on. Only these: the
+	// image's Docker HEALTHCHECK requests the health check, a 503 there
+	// would make the container unhealthy, and upaas marks a deploy failed
 	// when its container is unhealthy.
-		r.Group(func(r chi.Router) {
+	s.router.Group(func(r chi.Router) {
 		r.Use(s.refuseDuringMaintenance)
 
 		// Main image proxy route
 		// /v1/image/<host>/<path>/<width>x<height>.<format>
-			r.Get("/image/*", s.h.HandleImage())
-			r.Head("/image/*", s.h.HandleImage())
+		r.Get("/v1/image/*", s.h.HandleImage())
+		r.Head("/v1/image/*", s.h.HandleImage())
 
 		// Encrypted image URL route
 		// The trailing filename (e.g., /img.jpg) is ignored but helps
 		// browsers with content type
-			r.Get("/e/{token}/*", s.h.HandleImageEnc())
-		})
+		r.Get("/v1/e/{token}/*", s.h.HandleImageEnc())
 	})
 
 	// Metrics endpoint with auth