The image creates SWW_STATE_DIR when it is missing (closes #337)

Before `waf` starts, the image's `run` script now makes `SWW_STATE_DIR` if it is missing (`mkdir -p`), gives it to `sww:sww` and sets its mode to `0700`, as it already does for the cache directory's owner. A value that is not an absolute path, or an unreadable `SWW_STATE_DIR_FILE`, still changes nothing, and `waf` stops naming the setting. The `Dockerfile` comment, `docs/image.md`, `docs/settings.md` and `SPEC.md` say the image makes the directory. `script/example-app` checks that a missing `SWW_STATE_DIR` is made, owned by `sww` with mode `0700`.

- `chmod 0700` also applies to an existing directory, a mounted volume included, at every start of `waf`.

Model: opus-5-5

script/example-app

@@ -18,8 +18,8 @@
 #     client;
 #   - that a waf container with its state files on a new volume mounted at
 #     the directory SWW_STATE_DIR_FILE names becomes healthy;
-#   - that one whose SWW_STATE_DIR does not exist logs waf's message
-#     about it.
+#   - that the run script makes a SWW_STATE_DIR that does not exist, owned
+#     by sww with mode 0700, and that waf then becomes healthy.
 # waf runs with SWW_LOOKUP_SOURCE=off, so that no address is sent to
 # GeoJS. The containers, the network, the volumes and both images are removed
 # however the script ends. Building the app needs network access, for nixpkgs'
@@ -159,6 +159,12 @@ owner_of() {
     docker exec "$1" stat --format '%U' "$2"
 }
 
+# owner_and_mode_of <container> <dir>: print who owns dir there, and its
+# mode in octal.
+owner_and_mode_of() {
+    docker exec "$1" stat --format '%U %a' "$2"
+}
+
 main() {
     cd "$ROOT"
     trap cleanup EXIT
@@ -251,9 +257,11 @@ main() {
         --env SWW_STATE_DIR=/srv/missing \
         --env SWW_LOOKUP_SOURCE=off \
         "$IMAGE" >/dev/null
-    wait_for "waf did not report the missing state directory" \
-        logged "$WAF" "SWW_STATE_DIR cannot be written"
-    echo "example-app: waf reports a state directory that does not exist"
+    wait_for "waf's health check did not pass" healthy "$WAF"
+    [ "$(owner_and_mode_of "$WAF" /srv/missing)" = "sww 700" ] ||
+        fail "the run script did not make SWW_STATE_DIR for sww with mode 0700"
+    echo "example-app: the run script makes a missing SWW_STATE_DIR for sww" \
+        "with mode 0700"
 }
 
 main "$@"