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[new release] capnp-rpc (4 packages) (2.0)
CHANGES:
capnp-rpc 2.0 switches from using Lwt to Eio.
The `capnp-rpc-lwt` package is now just Lwt wrappers around the Eio functions in `capnp-rpc`.
This allows libraries using the old Lwt API to be used with applications and libraries using the new Eio one,
in the same binary.
Because Lwt libraries (using `capnp-rpc-lwt`) can be used with Eio applications (using `capnp-rpc-unix`),
you should first upgrade your application and then upgrade the libraries afterwards.
It is recommended to upgrade in stages, checking your application still works after each step:
1. Upgrade to the latest Lwt version (`opam install capnp-rpc-unix.1.2.4`).
This uses the new version of mirage-crypto, tls, etc,
which may be incompatible with other libraries you are using.
Get that sorted out before switching to capnp-rpc 2.0.
2. Use [lwt_eio][] to allow using Eio and Lwt together in your application.
This means replacing your call to `Lwt_main.run` with code to run Eio and Lwt together,
as explained at the start of the `lwt_eio` README.
3. Upgrade your main application to capnp-rpc-unix 2.0.
Calls to functions in the `Capnp_rpc_unix` and `Capnp_rpc_net` modules will need minor updates.
They were previously called from Lwt context, so you'll need to wrap them with `Lwt_eio.run_eio`
(or remove a `Lwt_eio.run_lwt` if you already updated the surrounding code).
You should also use `mirage-crypto-rng-eio` to ensure randomness is available
(`capnp-rpc-unix` no longer does this, although some other library might).
4. Upgrade code and libraries using `Capnp_rpc_lwt`:
1. Replace `open Capnp_rpc_lwt` with `open Capnp_rpc.Std`.
2. Replace all other uses of `Capnp_rpc_lwt` with just `Capnp_rpc`.
3. In `dune` and `opam` files, replace `capnp-rpc-lwt` with `capnp-rpc`.
4. Some modules are in `Capnp_rpc` but not the `Capnp_rpc.Std` subset.
Those should now be fully qualified (e.g. replace `Persistence` with
`Capnp_rpc.Persistence`).
5. Replace `Service.return_lwt` with `Lwt_eio.run_lwt`.
Replace `Lwt.return (Ok x)` with `Service.return x`.
Once all Lwt code is gone, you can remove the dependencies on `lwt` and `lwt_eio`.
New features:
- Allow numeric IPv6 listen addresses (@talex5 mirage/capnp-rpc#296, requested by @BChabanne).
API changes:
- Eio port (@talex5 mirage/capnp-rpc#280 mirage/capnp-rpc#284 mirage/capnp-rpc#298 mirage/capnp-rpc#292 mirage/capnp-rpc#297 mirage/capnp-rpc#300 mirage/capnp-rpc#304).
This switches capnp-rpc from Lwt to Eio.
One particularly nice side effect of this is that `Service.return_lwt` has gone,
as there is no distinction now between concurrent and non-concurrent service methods.
Uses of `Capnp_rpc_lwt` should be replaced by uses of `Capnp_rpc`
(and the old `Capnp_rpc` is now an internal module, `Capnp_rpc_proto`).
The new `Capnp_rpc` now provides `Error`, `Exception` and `Debug` aliases to the same modules in `Capnp_rpc_proto`,
so that `Capnp_rpc_proto` doesn't need to be used directly.
`Capnp_rpc_lwt` now provides (deprecated) compatibility wrappers, using `lwt_eio`.
This also adds `Capnp_rpc.Std` with some common module aliases,
to reduce the need to `open Capnp_rpc` (which is rather large).
- Deprecate `Debug.failf` (@talex5 mirage/capnp-rpc#291).
Performance and bug fixes:
- Add buffering of outgoing messages (@talex5 mirage/capnp-rpc#287 mirage/capnp-rpc#303).
Sending each message in its own TCP packet isn't very efficient, and also interacts very badly with Nagle's algorithm.
See <https://roscidus.com/blog/blog/2024/07/22/performance/> for details.
- Only disconnect socket when sending is done (@talex5 mirage/capnp-rpc#295).
Allows sending the reason for the disconnection in some cases.
- Fix type of `Capability.call` (@talex5 mirage/capnp-rpc#293).
It was previously unusable.
- Work around FreeBSD `close` problem (@talex5 mirage/capnp-rpc#302).
Build:
- Update to capnp 3.6.0 (@talex5 mirage/capnp-rpc#285).
- Update to dune 3.16 and fix warnings (@talex5 mirage/capnp-rpc#282).
- Use `String.starts_with` instead of `Astring` (@talex5 mirage/capnp-rpc#290).
- Remove unused `tls-mirage` dependency (@talex5 mirage/capnp-rpc#289).
- Remove `asetmap` dependency (@talex5 mirage/capnp-rpc#288).
[lwt_eio]: https://github.com/ocaml-multicore/lwt_eio- Loading branch information
