Add Core Cache API Support
Nadie ha tomado este issue todavía.
Evaluación
- Dificultad
- 5/5
- Tiempo estimado
- Más de una semana
- Aptitud para principiantes
- 35/100
Línea de trabajo
Comienza con stubs/wit_world/imports/cache.py y compara el wrapper propuesto con la integración de streaming existente del KV Store. Verifica la invocación de hostcall, la asignación de opciones y flags de estado, el manejo de errores, las transacciones con gestores de contexto y el streaming del body compatible con IOBase; se considera terminado cuando las pruebas centradas en el wrapper cubren estos comportamientos sin probar la persistencia de la caché de Viceroy.
Escrito por el modelo de indexación a partir del texto del issue.
Descripción
Overview
Add support for Fastly's Core Cache API, providing advanced caching capabilities with request collapsing, stale-while-revalidate, and streaming.
WIT Interface
interface cache {
use types.{error};
use http-body.{body};
use http-req.{request};
use async-io.{pollable as pending-entry};
resource entry {
lookup: static func(key: list<u8>, options: lookup-options) -> result<entry, error>;
transaction-lookup: static func(key: list<u8>, options: lookup-options) -> result<entry, error>;
transaction-lookup-async: static func(key: list<u8>, options: lookup-options) -> result<pending-entry, error>;
transaction-insert: func(options: write-options) -> result<body, error>;
transaction-insert-and-stream-back: func(options: write-options) -> result<tuple<body, entry>, error>;
transaction-update: func(options: write-options) -> result<_, error>;
get-state: func() -> result<lookup-state, error>;
get-user-metadata: func(max-len: u64) -> result<option<list<u8>>, error>;
get-body: func(options: get-body-options) -> result<body, error>;
get-length: func() -> result<option<object-length>, error>;
get-max-age-ns: func() -> result<option<duration-ns>, error>;
get-stale-while-revalidate-ns: func() -> result<option<duration-ns>, error>;
get-age-ns: func() -> result<option<duration-ns>, error>;
get-hits: func() -> result<option<cache-hit-count>, error>;
transaction-cancel: func() -> result<_, error>;
}
resource replace-entry {
replace: static func(key: list<u8>, options: replace-options) -> result<replace-entry, error>;
get-age-ns: func() -> result<option<duration-ns>, error>;
get-body: func(options: get-body-options) -> result<option<body>, error>;
get-hits: func() -> result<option<cache-hit-count>, error>;
get-length: func() -> result<option<object-length>, error>;
get-max-age-ns: func() -> result<option<duration-ns>, error>;
get-stale-while-revalidate-ns: func() -> result<option<duration-ns>, error>;
get-state: func() -> result<option<lookup-state>, error>;
get-user-metadata: func(max-len: u64) -> result<option<list<u8>>, error>;
}
type object-length = u64;
type duration-ns = u64;
type cache-hit-count = u64;
resource extra-lookup-options {
constructor();
}
record lookup-options {
request-headers: option<borrow<request>>,
always-use-requested-range: bool,
extra: option<borrow<extra-lookup-options>>,
}
resource extra-write-options {
constructor();
}
record write-options {
max-age-ns: duration-ns,
request-headers: option<borrow<request>>,
vary-rule: option<string>,
initial-age-ns: option<duration-ns>,
stale-while-revalidate-ns: option<duration-ns>,
surrogate-keys: option<string>,
length: option<object-length>,
user-metadata: option<list<u8>>,
edge-max-age-ns: option<duration-ns>,
sensitive-data: bool,
extra: option<borrow<extra-write-options>>,
}
resource extra-get-body-options;
record get-body-options {
%from: option<u64>,
to: option<u64>,
extra: option<borrow<extra-get-body-options>>,
}
flags lookup-state {
found,
usable,
stale,
must-insert-or-update,
usable-if-error,
}
resource extra-replace-options {
constructor();
}
enum replace-strategy {
immediate,
immediate-force-miss,
wait,
}
record replace-options {
request-headers: option<borrow<request>>,
replace-strategy: option<replace-strategy>,
always-use-requested-range: bool,
extra: option<borrow<extra-replace-options>>,
}
insert: func(key: list<u8>, options: write-options) -> result<body, error>;
await-entry: func(handle: pending-entry) -> result<entry, error>;
close-pending-entry: func(handle: pending-entry) -> result<_, error>;
close-entry: func(handle: entry) -> result<_, error>;
replace-insert: func(handle: replace-entry, options: write-options) -> result<body, error>;
close-replace-entry: func(handle: replace-entry) -> result<_, error>;
}
WIT bindings: stubs/wit_world/imports/cache.py
API Design
- Implement
CacheEntryresource wrapper for cache operations - Support lookup and transaction-based caching patterns
- Implement
LookupOptionsandWriteOptionsdataclasses - Provide access to cache metadata: age, TTL, hits, state flags
- Transaction methods:
transaction_lookup(),insert(),update(),cancel() - Entry body should implement
io.IOBasefor streaming (similar to KV Store) get_body()returns file-like object that can be read in chunks or passed to stdlib functions
Cross-SDK Comparison: All SDKs provide lookup(), insert(), transaction_lookup() with similar semantics. Rust uses strong typing for state/options enums, Go uses simple structs, JS uses async/Promise-based API. Python should support both blocking operations and context managers for transactions.
Viceroy Testing
Viceroy's cache implementation is limited/stubbed. Testing focus should be on:
- Verifying hostcall invocations work correctly
- Testing SDK wrapper logic (option parsing, state flag handling, error mapping)
- Ensuring body streaming integration functions properly
Do NOT:
- Try to verify actual cache persistence behavior
- Create elaborate tests around Viceroy's stubbed functionality
- Test cache hit/miss logic (this is host behavior, not SDK code)
The goal is to verify our Python wrapper code works, not to test Viceroy's cache implementation.
Reference
- Lenguaje dominante
- Python
- Estrellas
- 5
- Forks
- 1
- Métricas de merge de PR
- Sin PR fusionados en 30 d
Guía de contribución
Primeros pasos
- Lee el issue completo y luego la guía de contribución del proyecto.
- Comenta en el issue que vas a ocuparte — evita que dos personas hagan lo mismo.
- Haz un fork del repositorio y trabaja en una rama.
- Abre un pull request que haga referencia al número del issue.
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