angee.fs

Filesystem primitives shared by Angee's runtime and SDL emitters.

A namespace-root utility (peer to :mod:angee.paths): both the build-time composer (:mod:angee.compose.runtime) and the GraphQL SDL owner (:mod:angee.graphql.sdl) write generated files through one primitive, so the atomic-write behaviour lives once.

GENERATED_SENTINEL

Marker every Angee-generated file carries; the gate before destructive cleanup.

Lives here, beside :func:write_atomic, because it is the sentinel for all generated files — Python runtime modules, the GraphQL SDL, and the composed runtime/web artifacts — so both the composer and the web projector import it from one namespace-root owner rather than from each other.

write_atomic

def write_atomic(path: Path, text: str) -> None

Write text to path atomically, skipping an unchanged file.

A concurrent reader (another Django boot importing a generated module, the Vite dev server reading the SDL) sees either the old file or the new one, never a half-written one: the bytes go to a temp file in the same directory and are then os.replace-d into place, an atomic rename on the one filesystem. The unchanged-file short-circuit preserves the emitters' behaviour of not touching a file whose contents already match, so neither the autoreloader nor Vite sees a spurious modification. A failed write removes its own temp file so a leftover .tmp never lingers in runtime/ to trip drift checks.