fdb47c954d
"
This patch series consists of the following patches:
1. The first one turned out to be a massive rewrite of almost
everything in `idl-compiler.py`. It aims to decouple parser
structures from the internal representation which is used
in the code-generation itself.
Prior to the patch everything was working with raw token lists and
the code was extremely fragile and hard to understand and modify.
Moreover, every change in the parser code caused a cascade effect
of breaking things at many different places, since they were relying
on the exact format of output produced by parsing rules.
Now there is a bunch of supplementary AST structures which provide
hierarchical and strongly typed structure as the output of parsing
routine.
It is much easier to verify (by the means of `isinstance`, for example)
and extend since the internal structures used in code-generation are
decoupled from the structure of parsing rules, which are now controlled
by custom parse actions providing high-level abstractions.
It is tested manually by checking that the old code produces exactly
the same autogenerated sources for all Scylla IDLs as the new one.
2 and 3. Cosmetics changes only: fixed a few typos and moved from
old-fashioned `string.Template` to python f-strings.
This improves readability of the idl-compiler code by a lot.
Only one non-functional whitespace change introduced.
4. This patch adds a very basic support for the parser to
understand `const` specifier in case it's used with a template
parameter for a data member in a class, e.g.
struct my_struct {
std::vector<const raft::log_entry> entries;
};
It actually does two things:
* Adjusts `static_asserts` in corresponding serializer methods
to match const-ness of fields.
* Defines a second serializer specialization for const type in
`.dist.hh` right next to non-const one.
This seems to be sufficient for raft-related uses for now.
Please note there is no support for the following cases, though:
const std::vector<raft::log_entry> entries;
const raft::term_t term;
None of the existing IDLs are affected by the change, so that
we can gradually improve on the feature and write the idl
unit-tests to increase test coverage with time.
5. A basic unit-test that writes a test struct with an
`std::vector<S<const T>>` field and reads it back to verify
that serialization works correctly.
6. Basic documentation for AST classes.
TODO: should also update the docs in `docs/IDL.md`. But it is already
quite outdated, and some changes would even be out of scope for this
patch set.
"
* 'idl-compiler-refactor-v5' of https://github.com/ManManson/scylla:
idl: add docstrings for AST classes
idl: add unit-test for `const` specifiers feature
idl: allow to parse `const` specifiers for template arguments
idl: fix a few typos in idl-compiler
idl: switch from `string.Template` to python f-strings and format string in idl-compiler
idl: Decouple idl-compiler data structures from grammar structure
Scylla
What is Scylla?
Scylla is the real-time big data database that is API-compatible with Apache Cassandra and Amazon DynamoDB. Scylla embraces a shared-nothing approach that increases throughput and storage capacity to realize order-of-magnitude performance improvements and reduce hardware costs.
For more information, please see the ScyllaDB web site.
Build Prerequisites
Scylla is fairly fussy about its build environment, requiring very recent versions of the C++20 compiler and of many libraries to build. The document HACKING.md includes detailed information on building and developing Scylla, but to get Scylla building quickly on (almost) any build machine, Scylla offers a frozen toolchain, This is a pre-configured Docker image which includes recent versions of all the required compilers, libraries and build tools. Using the frozen toolchain allows you to avoid changing anything in your build machine to meet Scylla's requirements - you just need to meet the frozen toolchain's prerequisites (mostly, Docker or Podman being available).
Building Scylla
Building Scylla with the frozen toolchain dbuild is as easy as:
$ git submodule update --init --force --recursive
$ ./tools/toolchain/dbuild ./configure.py
$ ./tools/toolchain/dbuild ninja build/release/scylla
For further information, please see:
- Developer documentation for more information on building Scylla.
- Build documentation on how to build Scylla binaries, tests, and packages.
- Docker image build documentation for information on how to build Docker images.
Running Scylla
To start Scylla server, run:
$ ./tools/toolchain/dbuild ./build/release/scylla --workdir tmp --smp 1 --developer-mode 1
This will start a Scylla node with one CPU core allocated to it and data files stored in the tmp directory.
The --developer-mode is needed to disable the various checks Scylla performs at startup to ensure the machine is configured for maximum performance (not relevant on development workstations).
Please note that you need to run Scylla with dbuild if you built it with the frozen toolchain.
For more run options, run:
$ ./tools/toolchain/dbuild ./build/release/scylla --help
Testing
See test.py manual.
Scylla APIs and compatibility
By default, Scylla is compatible with Apache Cassandra and its APIs - CQL and Thrift. There is also support for the API of Amazon DynamoDB™, which needs to be enabled and configured in order to be used. For more information on how to enable the DynamoDB™ API in Scylla, and the current compatibility of this feature as well as Scylla-specific extensions, see Alternator and Getting started with Alternator.
Documentation
Documentation can be found in ./docs and on the wiki. There is currently no clear definition of what goes where, so when looking for something be sure to check both. Seastar documentation can be found here. User documentation can be found here.
Training
Training material and online courses can be found at Scylla University. The courses are free, self-paced and include hands-on examples. They cover a variety of topics including Scylla data modeling, administration, architecture, basic NoSQL concepts, using drivers for application development, Scylla setup, failover, compactions, multi-datacenters and how Scylla integrates with third-party applications.
Contributing to Scylla
If you want to report a bug or submit a pull request or a patch, please read the contribution guidelines.
If you are a developer working on Scylla, please read the developer guidelines.
Contact
- The users mailing list and Slack channel are for users to discuss configuration, management, and operations of the ScyllaDB open source.
- The developers mailing list is for developers and people interested in following the development of ScyllaDB to discuss technical topics.