This improves `pagebench getpage-latest-lsn` gRPC support by:
* Using `page_api::Client`.
* Removing `--protocol`, and using the `page-server-connstring` scheme
instead.
* Adding `--compression` to enable zstd compression.
## Problem
Full basebackups are used in tests, and may be useful for debugging as
well, so we should support them in the gRPC API.
Touches #11728.
## Summary of changes
Add `GetBaseBackupRequest::full` to generate full base backups.
The libpq implementation also allows specifying `prev_lsn` for full
backups, i.e. the end LSN of the previous WAL record. This is omitted in
the gRPC API, since it's not used by any tests, and presumably of
limited value since it's autodetected. We can add it later if we find
that we need it.
## Problem
When converting `proto::GetPageRequest` into `page_api::GetPageRequest`
and validating the request, errors are returned as `tonic::Status`. This
will tear down the GetPage stream, which is disruptive and unnecessary.
## Summary of changes
Emit invalid request errors as `GetPageResponse` with an appropriate
`status_code` instead.
Also move the conversion from `tonic::Status` to `GetPageResponse` out
into the stream handler.
## Problem
The gRPC base backup implementation has a few issues: chunks are not
properly bounded, and it's not possible to omit the LSN.
Touches #11728.
## Summary of changes
* Properly bound chunks by using a limited writer.
* Use an `Option<Lsn>` rather than a `ReadLsn` (the latter requires an
LSN).
## Problem
The `page_api` domain types are missing a few derives.
## Summary of changes
Add `Clone`, `Copy`, and `Debug` derives for all types where
appropriate.
## Problem
Currently, `page_api` domain types validate message invariants both when
converting Protobuf → domain and domain → Protobuf. This is annoying for
clients, because they can't use stream combinators to convert streamed
requests (needed for hot path performance), and also performs the
validation twice in the common case.
Blocks #12099.
## Summary of changes
Only validate the Protobuf → domain type conversion, i.e. on the
receiver side, and make domain → Protobuf infallible. This is where it
matters -- the Protobuf types are less strict than the domain types, and
receivers should expect all sorts of junk from senders (they're not
required to validate anyway, and can just construct an invalid message
manually).
Also adds a missing `impl From<CheckRelExistsRequest> for
proto::CheckRelExistsRequest`.
## Problem
The gRPC `page_api` domain types used smallvecs to avoid heap
allocations in the common case where a single page is requested.
However, this is pointless: the Protobuf types use a normal vec, and
converting a smallvec into a vec always causes a heap allocation anyway.
## Summary of changes
Use a normal `Vec` instead of a `SmallVec` in `page_api` domain types.
## Problem
We should expose the page service over gRPC.
Requires #12093.
Touches #11728.
## Summary of changes
This patch adds an initial page service implementation over gRPC. It
ties in with the existing `PageServerHandler` request logic, to avoid
the implementations drifting apart for the core read path.
This is just a bare-bones functional implementation. Several important
aspects have been omitted, and will be addressed in follow-up PRs:
* Limited observability: minimal tracing, no logging, limited metrics
and timing, etc.
* Rate limiting will currently block.
* No performance optimization.
* No cancellation handling.
* No tests.
I've only done rudimentary testing of this, but Pagebench passes at
least.
## Problem
The page API gRPC errors need a few tweaks to integrate better with the
GetPage machinery.
Touches https://github.com/neondatabase/neon/issues/11728.
## Summary of changes
* Add `GetPageStatus::InternalError` for internal server errors.
* Rename `GetPageStatus::Invalid` to `InvalidRequest` for clarity.
* Rename `status` and `GetPageStatus` to `status_code` and
`GetPageStatusCode`.
* Add an `Into<tonic::Status>` implementation for `ProtocolError`.
## Problem
For the gRPC Pageserver API, we should convert the Protobuf types to
stricter, canonical Rust types.
Touches https://github.com/neondatabase/neon/issues/11728.
## Summary of changes
Adds Rust domain types that mirror the Protobuf types, with conversion
and validation.
