PyPI changelog compatibility

Warehouse's mirroring API accepts XML-RPC POST requests at /pypi, /pypi/, and /RPC2. peryx will support the two methods needed to consume an ordered changelog:

• changelog_last_serial() returns the newest local journal serial.
• changelog_since_serial(serial) returns no more than 50,000 rows in (name, version, timestamp, action, serial) order. Results include records whose serial is greater than the argument and stay sorted by serial.

The protocol codec accepts Warehouse's int, i4, and i8 serial forms. It emits i8 when a peryx serial no longer fits an XML-RPC int, represents an absent version with nil, strips XML control characters, and escapes text fields. Malformed calls must return an XML-RPC fault instead of a partial result.

Storage contract

The endpoint must read the journal key as the authoritative serial; the placeholder inside the driver payload is not a serial. Each record also needs its mutation timestamp. The journal write must commit that timestamp; readers must not reconstruct it.

Local actions need stable Warehouse-facing names. An upload becomes add file <filename>; deletion becomes remove file <filename>; yank and unyank retain their action and filename. Promotion records must identify each changed file rather than emit one ambiguous project event.

The first endpoint version will expose hosted-index mutations. Cached upstream serials belong to a different serial domain, so an overlay cannot publish one scalar until peryx defines its composition rule. It must omit an uncombined serial rather than present local and upstream events as one ordered stream.

Client compatibility

Warehouse limits each changelog call to 50,000 rows, so clients advance from the highest returned serial and request the next page. A response must come from one metadata snapshot; otherwise a concurrent write could move the reported end past an event omitted from the page.

Current bandersnatch releases discover changes from the PEP 691 root project list and its per-project _last-serial extension. The XML-RPC endpoint supports older mirror clients, while bandersnatch compatibility also requires those project serials in /simple/ JSON.