Project: userver (App Definition and Development / Streaming & Messaging)
File: roadmap_and_changelog.md

We keep an eye on all the issues and feature requests at the , at the and Telegram support chats. All the good ideas are discussed, big and important ones go to the Roadmap. We also have our in-house feature requests, those could be also found in Roadmap. Important or interesting features go to the changelog as they get implemented. Note that there's also a @ref scripts/docs/en/userver/security_changelog.md. Changelog news also go to the . Codegen parsers and serializers by JSON schema Improve Kafka driver. Add retry budget or retry circuit breaker for clients. Improve OpenTelemetry Protocol (OTLP) support. Add web interface to the Big new features since the v1.0.0: Simplified dynamic configs and embedded defaults into the code. Added PostgreSQL connection pools auto-configuration. Added YDB driver and basic Kafka driver. LISTEN/NOTIFY support for PostgreSQL New landing page for the website Significantly reduced network data transmission for PostgreSQL Supported `install` in CMake and CPack packaging. Implemented middlewares for HTTP server, most of the HTTP server functionality was moved to middlewares. Improved documentation, added more samples and descriptions. Numerous optimizations and build improvements. Detailed descriptions could be found below. Binary Ubuntu 22.04 amd64 package could be found at . Kafka driver is now documented, compiles and works. Thanks to for the work! Added utils::numeric_cast for safe casting of integers of different width. The userver framework is now . YDB driver now can be built on modern Clang compilers in C++20 and above modes. Redis now allows to subscribe to master instances. Improved logging of failures in testsuite. Optimizations: rcu::Variable was optimized to use asymmetric fences and concurrent::StripedCounter. x1000 performance improvement for some edge cases, x3 improvement for the generic use case. Internal `TaskCounter` now uses concurrent::StripedCounter to reduce contention on atomics on each async task construction and destruction. Adjusted the default spinning count in scheduler to better fit modern hardware and typical loads. ~5% faster tasks queue overload detection logic. Many thanks to for the PR! Docs, tests and build Fixed build of utils/rand.hpp related source files. Thanks to for the PR! Improved logic of Telegram support chats URL selection. Many thanks to for the PR! Fixed multiple `@snippet` links in docs. Many thanks to for the PR! Fixed flaky `ThreadLocal.SafeThreadLocalWorks` test. Many thanks to for the PR! Initial CPack support. Now `userver-all.deb` packages could be build via: ``` git clone --depth 1 https://github.com/userver-framework/userver.git docker run --rm -it --network ip6net -v $(pwd):/home/user -w /home/user/userver \ --entrypoint bash ghcr.io/userver-framework/ubuntu-22.04-userver-base:latest ./scripts/docker/runasuser.sh \ ./scripts/buildandinstall_all.sh ``` We'll start publishing the packages soon. New Docker images based on Ubuntu-22.04 with weekly builds and publishing: ghcr.io/userver-framework/ubuntu-22.04-userver-pg:latest - image with preinstalled userver deb package and PostgreSQL database. All the service templates now use it for tests ghcr.io/userver-framework/ubuntu-22.04-userver:latest - image with preinstalled userver deb package. Good starting container for developing servers that do not use POstgreSQL. ghcr.io/userver-framework/ubuntu-22.04-userver-base:latest - an image with only the build dependencies to build userver. Good for development of userver itself. More info at @ref scripts/docs/en/userver/tutorial/build.md All the service templates were moved to a new components naming with `::` (for example `userver::core`) and now attempt to find an installed userver. Now in CMake component names with `::` work regardless of the framework installation (CPM, `add_subdirectory`, or `find_package`). Added userver/utils/hedged_request.hpp with a bunch of helper classes to perform hedged requests. Improved testsuite logging for @ref scripts/docs/en/userver/functional_testing.md "functional tests". Consumers of concurrent queues now have a Reset()

Thanks to for the PR! Fixed gRPC builds and runs with ASAN. Thanks to for the PR! Published early work on Kafka driver. API is not stable, build scripts, improvements and samples to come. Thanks to for the work! Published early work on RocksDB driver. API is not stable, build scripts, improvements and samples to come. Thanks to for the work! Optimizations: WriteAll for TLS became up to 7 times faster if multiple small chunks of data are written. Thanks to and for the PR! Binary sizes were reduced if building without LTO. All the binaries linked with userver became about 1MB smaller. Implemented asymmetric thread fences. This opens the door for optimizations of rcu::Variable and internals of the scheduler. Caches in testsuite are now invalidated concurrently, leading to tens of seconds speedup for services with multiple caches and tests. concurrent::StripedCounter became 8 times more memory efficient. Build and docs: Updated PostgreSQL CMake scripts for Manjaro. Thanks to for the PR! Disabled LTO for Conan builds. Thanks to for the PR! Fixed typo in 'Manjaro'. Thank to for the PR! Installation via `cmake --install` was implemented. See @ref userver_install for more info. Implemented @ref scripts/docs/en/userver/httpservermiddlewares.md @ref USERVERLOGDYNAMIC_DEBUG now provides fine granted runtime control over logging. Now all the modern versions of `libmongoc` are supported in `userver-mongo`. @ref POSTGRESCONNLIMITMODEAUTOENABLED is now `on` by default. A secret value for the digest nonce generating now could be provided in `httpserverdigestauthsecret` key via components::Secdist. Many thanks to for the PR! ugrpc::server::ServerComponent now has a `unix-socket-path` static option to listen on unix domain socket path instead of an inet socket. All the `formats::::ValueBuilder` now support std::string_view. Thanks to for the bug report! clients::http::Form is now movable and slightly more efficient. Thanks to for the PR! Redis now supports `SSUBSCRIBE` and removes dead nodes. engine::WaitAny() now can wait for an engine::io::Socket/engine::io::TlsWrapper to become readable or writable. For example: `engine::WaitAny(socket.GetReadableBase(), task1, tls_socket.GetWritableBase(), future1);` New tracing::Span::MakeRootSpan() helper function. Optimizations: Switched from unmaintained `http_parser` to a 156% faster `llhttp`. Implemented a concurrent::StripedCounter that allows to have a per-cpu data in user space with kernel-provided transactional guarantees. Works at least x2 faster than std::atomic on a single thread and scales linearly (unlike std::atomic). As a result gives more than x10 performance improvement under heavy contention. An explicit control over cache invalidations in testsuite. As a result, less caches are invalidated between tests and the overall time to run tests goes down significantly. Components start was optimized to copy less containers during component dependencies detection. Per each incoming HTTP request: one less `std::chrono::steady_clock::now()` call one less `StrCaseHash` construction (2 calls into `std::uniformintdistribution<std::uint64_t>` over `std::mt19937`) one less `dynamic_config::Snapshot` construction (at least one atomic CAS) HTTP Client now copies less `std::shared_ptr` variables in implementation. Optimized up to an order of magnitude the user types query in PostgreSQL driver. pytestuserver.client.Client.capturelogs() now accepts `log_level` to filter out messages with lower log level in the service itself and minimize CPU and memory consumption during tests. Up to two times faster utils::statistics::RecentPeriod statistics in PostgreSQL driver due to switching to a utils::datetime::SteadyCoarseClock. Build: Workarounds for the Protobuf >= 5.26.0 Removed redundant semicolon, thanks to Oleksii Demchenko for the . utils::FastScopeGuard now uses proper traits. Thanks to for the PR and to for the report! Added missing dependency for Arch based

Thanks to for the PR! PostgreSQL driver now keeps processing the current queries and transactions after encountering a "prepared statement already exists" event. Implemented a new landing page to make userver even more nice&shiny! The whole project was done by frontend developer ; designers and ; manager . Many thanks for the awesome work! HTTP components::Server now has a static configuration option `address` to select network interface to listen to. gRPC futures now can be used efficiently with engine::WaitAny(). Flush headers before starting to produce the body parts in HTTP streaming handlers, so a client can react to the request earlier. Thanks to for the PR! Added tracing::TagScope for comfortable work with local scope tracing tags. Many thanks to for the PR! `INCLUDEDIRECTORIES` is now used in `userveraddgrpclibrary`. Thanks to for the PR! New storages::postgres::QueryQueue class, mostly for executing multiple `SELECT` statements and retrieving the results in one roundtrip. @ref POSTGRESTOPOLOGYSETTINGS to control maximum allowed replication lag. Optimizations: PostgreSQL driver now caches the low-level database (D)escribe responses, workarounds the libpq implementation and does not request query describe information on each request. This results in about ~2 times less data transmitted for select statements that return multiple columns, less CPU consumption for the database server and for the application itself. On Boost 1.74 and newer the engine::SingleConsumerEvent::IsReady() now uses atomic load instead of a much less efficient atomic DWCAS. gRPC deadline propagation now uses less `now()` calls and measures time more precisely. About 16% faster HttpResponse::SetHeader due to using a vectorization friendly algorithm. Improved Redis driver start-up time. dynamic_config::DocsMap::Parse() and dynamic configs retrieval copies less strings. Build: New Docker container for developing userver based projects `ghcr.io/userver-framework/ubuntu-22.04-userver-base:latest`. It contains all the build dependencies preinstalled and a proper setup of PPAs with databases, compilers and tools. Switched to a modern python `venv` instead of the older `virtualenv`. Use system provided Boost.Stacktrace if it is available. Documentation and Diagnostics: Added fix hints for storages::postgres::InvalidParserCategory. Clarify @ref scripts/docs/en/userver/pgusertypes.md More references and info for the metrics documentation. More documentation for dynamicconfig::ValueDict `default_` behavior, and for dynamic configs. `full-update-jitter` default value is now `full-update-interval / 10`. This leads to more responsive databases on full update on multiple instances of the service. server::handlers::ServerMonitor now has a `format` static config option, simplifying userver based services setup with unified agent. Allow creating custom implicit options. Thanks to for the PR! Limit JSON parsing depth to some sane value. Thanks to for the PR! Implemented JSON parsing to `google.protobuf.Value` in userver/ugrpc/proto_json.hpp. Support histogram metrics in testsuite via pytest_userver.metrics.Histogram utils::generators::GenerateUuidV7() was added. Redis retry budget now could be controlled via @ref REDISRETRYBUDGET_SETTINGS drivers::WaitForSubscribableFuture and drivers::TryWaitForSubscribableFuture for simplifying asynchronous driver writing for third-party code that provides futures with `Subscribe` methods (for example - YDB). Optimizations: Up to two times faster dynamic config parsing in updates. Optimized dynamic config updates in testsuite. Thanks to for the PRs! Optimized JSON parsing of std::variant leading to an order of magnitude faster parsing. Minor optimizations: do less work in server::handlers::HttpHandlerBase for higher logging level, do less copies in server::handlers::HttpHandlerJsonBase. Optimized statistics collection for Redis. Build: Namespace of userver is now versioned by default to avoid binary symbols clashing. `lld` used by default if it is available and the compiler is clang `bash` is not required any more by the build scripts. Documentation and Diagnostics: storages::postgres::InvalidParserCategory now provides fix hints for some of the PostgreSQL misuse cases. Document that compiler::ThreadLocal should be used instead of `thread_local`. Documented dynamic_config::ValueDict and related dynamic

Improved documentation for metrics by adding more references to utils::statistics::MetricTag, utils::statistics::Storage and @ref TESTSUITEMETRICSTESTING "testsuite metrics testing". Cleaner docs for the utils::statistics::Percentile. LISTEN/NOTIFY support for PostgreSQL. See storages::postgres::Cluster::Listen() and storages::postgres::NotifyScope for more information. components::Server now has `tls.ca` option for client-side certificates check. Caches now have a `full-update-jitter` option to avoid simultaneous full updates in different servers. Fault injection into transactions. See pytest_userver.sql.RegisteredTrx for sample usage. Improved diagnostics for improper Secdist usage. Added storages::postgres::ResultSet::AsOptionalSingleRow. Thanks to for the PR! Build: Big rewrite of CMake logic. Now `userversetupenvironment()` function is used to setup the environment: before: ```cmake include(third_party/userver/cmake/SetupEnvironment.cmake) addsubdirectory(thirdparty/userver) ``` after: ```cmake addsubdirectory(thirdparty/userver) userversetupenvironment() ``` Requirements are not code generated any more and the default requirements used on `uservertestsuiteadd_simple()` CMake function call. `addgrpclibrary()` renamed to `userveraddgrpc_library()`. `USERVERPIPUSESYSTEMPACKAGES` and `USERVERPIPOPTIONS` CMake options now allow building the userver without internet connection. Thanks to for the PR! Curl library now downloaded automatically if no suitable version found. Added missing check for Mongo in Conan. Thanks to for the PR! Fixed sanitizers error message in CMake. Thanks to for the PR! Updated MacOS dependencies. Thanks to for the PRs! Added PostgreSQL 16 detection. Thanks to for the PR! Optimizations: Optimized Http::Cookie::ToString(). Thanks to for the PR! Documentation: Documented Secdist formats and added notes on possible environment variables usage instead of secdist. Layout of reference pages changes. Now descriptions are at the top of the page rather than being after the list of methods and members. Documented Mongo pool metrics at @ref scripts/docs/en/userver/service_monitor.md. New @ref scripts/docs/en/userver/tutorial/grpcmiddlewareservice.md sample. Switched to Doxygen 1.10 with our search patches upstreamed formats::json::Schema and validation function for it formats::json::Validate were implemented. Many thanks to for the PR! PostgreSQL driver now auto detects the max pool size, see @ref scripts/docs/en/userver/pgconnlimitmode_auto.md server::http::HttpRequest:GetMethod() now can return server::http::HttpMethod::kHEAD. Thanks to for the bugreport and PR! PostgreSQL now has the following static config options: `check-user-types` option to prevent service from starting if database is not ready for work (for example: some migrations were not applied). `discard-all-on-connect` - to force running `DISCARD ALL` on new connections, which could be useful for some PostgreSQLs smart-proxies that reuse the same connections. Boost.PFR 2.2.0 is now in use. The door for compile time reflection pull requests is now open! More metrics and fallbacks for logging errors. More tests for utils::datetime::MockSteadyNow. Thanks to for the PR! components::CachingComponentBase now has a static config option `alert-on-failing-to-update-times` to fire an alert if the cache update failed specified amount of times in a row. Optimizations: Caching of `dlphdrinfo` items is not ON by default, leading up to multiple seconds faster exception handling under heavy load when parts of the executable still being on hard drive rather than in memory. Use `USERVERDISABLEPHDR_CACHE` CMake option to disable it, if the framework reports `dlopen` usage after component start and there's no way to avoid it. Optimized discarding logs by log level from 4ns to 2ns. Added CMake option `USERVERFEATUREERASELOGWITH_LEVEL` to totally eliminate all the CPU and binary size overhead from logging. Implemented utils::SmallString::resizeandoverwrite() function as in C++23 std::string. Thanks to for the PR. Up to an order of magnitude faster generation of HTTP response header via utils::SmallString usage. Thanks to for the PR. Faster logging of durations in tracing::Span, tracing::ScopeTime and friends. Parsing inside storages::postgres::ResultSet now does not compute parsing-failure diagnostic information if parsing is successful. Return PostgreSQL connection to pool earlier, before updating the

fs::RewriteFileContents() now does not `fsync` directories, dumping caches now also do not `fsync` directories leading to better performance while still properly restoring after server power-off. PostgreSQL typed parsing was optimized to not copy std::shared_ptrs. TESTPOINT() and TESTPOINT_CALLBACK() now produce less instructions and guaranteed to not throw it the testpoints are disabled. Documentation: @ref scripts/docs/en/userver/grpc.md now has a deeper explanation of middlewares New @ref scripts/docs/en/userver/dynamic_config.md page and related samples. Samples were significantly simplified, more static configuration options now have good defaults and do not require explicit setup. @ref scripts/docs/en/userver/tutorial/build.md now contains information on how to build service templates. Information on how to build the framework tests was moved to scripts/docs/en/userver/tutorial/build_userver.md Documented the server::handlers::ImplicitOptions. Added from-code alerts via alerts::Storage client and alerts::StorageComponent component. Added utils::statistics::Histogram. HTTP client now uses RATE metrics were possible. tracing::DefaultTracingManagerLocator now has `incoming-format` and `new-requests-format` static config options to configure the tracing headers to receive and send. Clickhouse now supports Array(T) type Added `max-ttl-sec` to the @ref POSTGRESCONNECTIONSETTINGS dynamic config to force connections reopening. RabbitMQ now provides a Get() command to retrieve a single message. Thanks to for the PR! Optimizations: Coroutines working set was reduced, leading to significantly less memory usage under most of the loads that do not use all the coroutines from pool at once. ugrpc::server::ServerComponent now provides a `completion-queue-count` to scale better under heavy load. Primary address string is now cached in HTTP server connection, leading to minor performance improvement. cache::NWayLRU now works faster due to improved hashing logic. Internal per-task timer size was reduced by 176 bytes. Removed rcu::Variable usage on hot path of tracing::Span destruction, optimized writing of Opentracing files. Dynamic configs were changed: dynamic_config::Key now requires config defaults at construction. `dynamic-config-fallbacks` component was merged into `dynamic-config`, see components::DynamicConfig for more info. utils::DaemonMain now has `--print-dynamic-config-defaults` program option that prints all the in-code defaults of the dynamic configs. In-code defaults now could be overridden in static config of components::DynamicConfig via `defaults` option. `USERVERCHECKAUTHINHANDLERS` was removed. Documentation: Documentation version switch was added to the bottom of the page. gRPC SSL server credentials setup info was added into @ref scripts/docs/en/userver/grpc.md Clarified behavior of server::http::HttpRequest::GetArg() Added @ref scripts/docs/en/userver/tutorial/multipart_service.md More clarifications for the @ref scripts/docs/en/userver/component_system.md. @see @ref scripts/docs/en/userver/periodics.md now gives hints on tracing::Span usage. More info on cancellations and different @ref scripts/docs/en/userver/synchronization.md Simplified samples. Build: Multiple build fixes and improvements for gRPC, including gRPC download via . Conan was updated, thanks to for the PR. Big new features since the Beta announcement: Implemented WebSockets server Added MySQL driver RabbitMQ drived was added Implemented TLS server Enabled PostgreSQL pipelining Implemented and enabled Deadline Propagation Improved experience with metrics. Added Prometheus and Graphite metric formats. Provided a modern simple interface to write and test metrics. Added chaos tests for drivers Implemented streaming API for the HTTP Improved documentation, added more samples and descriptions, improved search. Numerous optimizations. Numerous build improvements, including Conan and Docker support. Optimized and improved features that were available at the Beta announcement: gRPC client and server Mongo driver Redis driver PostgreSQL HTTP server and client Logging and Tracing ... and many other features. Detailed descriptions could be found below. WebSockets server and TLS server are now implemented as part of the @ref scripts/docs/en/userver/http_server.md "HTTP server" PostgreSQL pipelining is now implemented and turned on by default, leading to improved response times. @ref scripts/docs/en/userver/mongodb.md "Mongo Congestion Control" is implemented and turned on by default, leading to better stability of the service in case of high load on

Initial logger is now initialized from the component config, leading to a more simple code and setup. The `--initial-logger` option now does nothing and will be removed soon. Added a @ref scripts/docs/en/userver/functionaltesting.md "`uservertestsuiteaddsimple()`" CMake function to simplify testsuite CMake configuration. Expanded list of HTTP codes, thanks to for the PR! Projects from were updated by the original authors. Thanks to , , , , and all the participants for the the great work and PRs! Build: New versions of `yaml-cpp` library are now supported. Thanks to for the bug report! Supported compilation with fmt 10.1.0. Thanks to for the PRs! Fixed unused result warning. Thanks to for the PR! Fixed use of deprecated API. Thanks to for the PR! Fixed build with GCC-13 libstdc++. Thanks to for the PR! Fixed MacOS Protobuf discovery. Thanks to for the PR! Fixed multiple other build warnings and issues. Deadline Propagation is now implemented and @ref scripts/docs/en/userver/deadline_propagation.md "documented". Projects from : Documentation was redesigned by and ; new design was made up by , , , ; the whole process was managed by with feedback from marketing specialist . Many thanks to all the participants for the great work. Implemented initial API for RFC 7616 - HTTP Digest Access Authentication, thanks to , , , and for multiple PRs! std::bitset<N>, std::array<bool, N>, userver::utils::Flags<Enum> and integral values are now mapped to PostgreSQL bit and bit varying types. Thanks to and for the PRs! Initial `Realmedium` sample was implemented and moved into a separate repository at . Thanks to , , , , , , , for the PR! Metrics for CPU usage of particular threads of task processors are now available via new engine::TaskProcessorsLoadMonitor component. gRPC and HTTP handler metrics were switched to utils::statistics::Rate, leading to better handling of service start/stop by metrics storage. server::Server now returns HTTP header "Content-Type: application/octet-stream" if the content type was not set. Implemented `ToString(utils::StrongTypedef<floating point>)`, thanks to for the PR. Optimizations: Signifiacally optimized JSON DOM access to a non-existing element. Logging now does not lock a mutex in fs-task-processor on each log record. Up to 3 times faster logging due to multiple minor tweaks with data copy and memory prereserving. The new asynchronous engine::io::sys::linux::Inotify driver for Linux allows subscriptions to filesystem events. Thanks to it the fs::FsCacheClient now reacts faster. Docs: @ref scripts/docs/en/userver/tutorial/auth_postgres.md now provides a PostgreSQL migrations sample. Fixed broken refs to hello_service page, thanks to for the PR! @ref userver_universal group was added with information on contents of `userver-universal` CMake target. Documented @ref scripts/docs/en/userver/service_monitor.md "PostgreSQL metrics" Build: Dropped spdlog dependency is now used for managing third-party dependencies. Fixed cryptopp compilation error, thanks to for the PR! Fixed -Wsign-conversion -Wctad-maybe-unsupported warnings in utils::TrivialBiMap, thanks to for the PR! server::http::CustomHandlerException now allows to provide a custom HTTP status that is not mapped to protocol-agnostic server::handlers::HandlerErrorCode. Non-coroutine `userver-universal` CMake target was refactored and is now used by the whole framework as a basic dependency. Compile times dropped down drastically for building the whole framework from scratch. Added a non-coroutine usage example @ref scripts/docs/en/userver/tutorial/jsontoyaml.md. It is now possible to subscribe to `SIGUSR1` and `SIGUSR2` in the same class. Thanks to for the bug report. Dynamic config management commands were added to `uctl` tool. Optimizations: storages::redis::SubscribeClient subscriptions were optimized to do less dynamic allocations on new message and use a faster lock-free

Escaping of tags for logging is now done at compile-time by default, which gives up to 30% speedup in some cases. Internal asynchronous logging logic was rewritten, leading to better scalability and more than 25% speedup. HTTP client connection is now preserved on deadline, leading to less connections being reopened. Cleaned up and added docs for redis::CommandControl. MacOS build instructions were enhanced, thanks to for the PR! Conan build was fixed, thanks to for the PR. Numerous build and configure fixes. Static configs of the service now can retrieve environment variables via the `#env` syntax. See yaml_config::YamlConfig for more examples. New testsuite plugins userverconfighttp_client and userverconfigtestsuite_support turned on by default to increase timeouts in tests and make the functional tests more reliable. gRPC now can write access logs, see `access-tskv-logger` static option of ugrpc::server::ServerComponent. Now the waiter is allowed to destroy the engine::SingleConsumerEvent immediately after exiting WaitForEvent, if the wait succeeded. New dynamicconfigfallback_patch fixture could be used to replace some dynamic config values specifically for testsuite tests. Fixed utils::SmallString tests, thanks to for the PR! Optimizations: Counters in the tasks were optimized. New thread local counters use less CPU and scale better on huge amounts of coroutines. engine::TaskProcessor optimized layout with interference shielded atomics uses less CPU and scales better on huge amounts of coroutines. Minor optimizations for HTTP clients URL manipulations. tracing::Span generation of ID was made faster. clients::http::Request now does less atomic counters increments/decrements while the request is being built. `mlockdebuginfo` static configuration option of components::ManagerControllerComponent is now on by default. It improves responsiveness of the service under heavy load on low memory and bad hard drives. engine::io::Socket now has an additional `SendAll` overload that accepts `const struct iovec* list, std::sizet listsize` for implementing low-level vector sends. Mongo driver now uses the new function, resulting in smaller CPU and memory consumption. clients::http::Form::AddContent now instead of `const std::string&` parameters accepts `std::string_view` parameters that allow to copy less data. Docs and diagnostics: gRPC metrics were documented. New documentation page @ref scripts/docs/en/userver/http_server.md. More debug logs for the Mongo error, thanks to for the PR. Improved diagnostics for CurrentSpan() and testsuite tasks. Multiple typos fixed at @ref scripts/docs/en/userver/framework_comparison.md page, thanks to for the PR. Build: Multiple build fixes for gRPC targets. Clickhouse for Conan was added, thanks to for the PR. CMake build flag `USERVERFEATUREUBOOST_CORO` can be used to use system boost::context. New scripts/uctl/uctl console script for administration of the running service was added. Improved compile times by removing multiple includes from userver headers including templating the serializers of different formats. Implemented ugrpc::server::HealthComponent handler, a gRPC alternative to server::handlers::Ping. gRPC server and clients now support middlewares - a customization plugins that could be shared by different handlers. Invalid implementations of CacheUpdateTrait::Update are now detected and logged. Optimizations: Significant improvements in HTTP handling due to new http::headers::HeaderMap usage instead of std::unordered_map. Improved performance of utils::TrivialBiMap by an order of magnitude for enum-to-enum mappings, thanks to for the bug report! utils::FromString now uses std::from_chars for better performance. TESTPOINT and other testpoint related macro now imply zero overhead if testpoints were disabled in static config. More functions of formats::json::ValueBuilder now accept std::string_view, resulting in less std::string constructions and better performance. TSKV escaping was optimized via SIMD, resulting in up to x10 speedup on long logs. `mlockdebuginfo` static configuration option of components::ManagerControllerComponent now allows to lock exception unwinding information in memory. It improves responsiveness of the service under heavy load on low memory and bad hard

Docs: Some metrics were documented, a human-readable format of metrics is now used in documentation. See @ref scripts/docs/en/userver/service_monitor.md. Custom @ref scripts/docs/en/userver/.md404 "404 page". New pages, including @ref scripts/docs/en/userver/faq.md, @ref scripts/docs/en/userver/periodics.md and @ref scripts/docs/en/userver/deploy_env.md. Build: Arch Linux instructions were improved, thanks to for the PR! Fixed Conan based builds, thanks to for the PR. Clickhouse-cpp version was raised to 2.4.0, thanks to for the PR! Fixed build on libstdc++ from GCC-13, thanks to for the PR! Fixed benchmarks build on non x86 targets. Rewrite of Protobuf and gRPC locating logic. MySQL driver was added, see @ref scripts/docs/en/userver/mysql/mysql_driver.md. Experimental support for HTTP "Baggage" header is implemented, including verification, forwarding from HTTP handlers to client, baggage manipulation. See baggage::BaggageManagerComponent for more info. Redis driver now supports non-queued variants for pubsub. Redis driver now supports read-only transactions. utils::FilterBloom was merged in along with initial SLRU cache implementations. The work is a part of the course project by , , , Egor Chistyakov from . HTTP request decompression is now ON by default in server::handlers::HandlerBase. dynamic_config::Source now allows subscribing to a particular dynamic config variable changes. Initial support for utils::statistics::Rate metrics type. Human-readable "pretty" format (utils::statistics::ToPrettyFormat) for metrics output was added to the server::handlers::ServerMonitor. Optimizations: Don't issue tail `writev` for empty `io_vec` on bulk socket writes. All the userver metrics are now written via the fast utils::statistics::Writer. x2-x50 faster serialization of unique maps into formats::json::ValueBuilder. utils::StrIcaseHash became slightly faster. engine::Task now does not have a virtual destructor. New engine::TaskBase based hierarchy does not use RTTI, resulting in smaller binaries. Mongo driver does not capture stack traces in release builds in case of errors. The error path become slightly faster, server is more responsive in case of Mongo problems. Build: Improved support for Conan 2.0, many thanks to for the PR. `.gitattributes` now handles line endings automatically for files detected as text. This simplifies WSL builds. Thanks to for the PR. PostgreSQL libs selection is now possible in CMake if the platform has multiple versions installed, see @ref POSTGRES_LIBS "PostgreSQL versions" for more info. Improved support for Arch Linux, many thanks to for the PR. Multiple improvements for docs, including mockserver clarifications from . Now logging of particular lines could be controlled by dynamic config. See @ref USERVERLOGDYNAMIC_DEBUG for more info. HTTP headers that contain the tracing context now could be customized, both for handlers and HttpClient, by feeding tracing::TracingManagerBase implementation into tracing::DefaultTracingManagerLocator (docs to come soon). User defined literals for different formats are now available at formats::literals Added crypto::CmsSigner and crypto::CmsVerifier as per RFC 5652. cache::LruMap and cache::LruSet now work with non-movable types. BSON<>JSON conversions now supported via json_value.ConvertTo<formats::bson::Value>() and bson_value.ConvertTo<formats::json::Value>(). engine::CancellableSemaphore was implemented. Optimizations: Mongo driver switched to a faster utils::statistics::Writer. utils::Async functions now make 1 dynamic allocation less, thanks to for the PR. Getting the default logger now takes only a single atomic read. LOG_ macro now do two RMW atomic operations less and do not use RCU, that could lead to a dynamic memory allocation in rare cases. PostgreSQL driver now does much less atomic operations due to wider usage of std::move on the internal std::shared_ptr. Added storages::postgres::Transaction::ExecuteDecomposeBulk function for fast insertion of C++ array of structures as arrays of values. Str[I]caseHash now uses a 5-10 times faster SipHash13 Redis driver now does an asynchronous DNS resolving, amount of heavy system calls dropped down

Build changes: CMake option `USERVEROPENSOURCE_BUILD` was removed as the build is always the same for in-house and public environments. CMake option `USERVERFEATURESPDLOGTCPSINK` was removed as now the implementation of the sink does not rely on spdlog implementation. Configuration step was made much faster. Makefile was simplified and only up-to-date targets were left. Added a script to prepare docker build, see @ref scripts/docker/Readme.md for more info. Scripts for generating CMakeLists were simplified and cleared from internal stuff. Added missing dependencies to @ref scripts/docs/en/depsubuntu.md20_04 and sorted all the dependencies, thanks to for the PR. Statistics and metrics now do additional lifetime checks in debug builds to catch improper usages. Push functions of concurrent::MpscQueue and other queues now have a `[[nodiscard]]` for compile time misuse detection. Significant improvement of Redis server-side errors diagnostic. Improved diagnostics for distributed locking. Fixed numerous typos in docs and samples. tracing::Span now logs the location where it was constructed. Now the string<>enum utils::TrivialBiMap mappings could be used within storages::postgres::io::CppToUserPg. See @ref pg_enum for more info. components::Logging now provides options for configuring the task processors to do the asynchronous logging. Redis driver now supports the `geosearch` and `unlink` commands. DNS resolvers were switched to asynchronous mode by default. UDP chaos proxy was implemented, see @ref pytest_userver.chaos.UdpGate "chaos.UdpGate" C++ Standard now could be explicitly controlled via the CMake flag `CMAKECXXSTANDARD`. Optimizations: Many metrics were moved to a faster utils::statistics::Writer. gRPC now allows concurrent execution of 1 Read and 1 Write on the same Bidirectional stream. Python dependencies for build are now automatically installed, thanks to for the PR! Added a Conan option to disable LTO, thanks to for the PR! Diagnostic messages and docs were improved, including: In case of a typo in static config name the fixed name is now reported `error-injection` static option for components::Postgres was documented Fixed typos, thanks to for the PR! Unknown/mistyped values in static configs are now reported by default. @ref static-configs-validation "Static configs validation" now could use `minimum` and `maximum`. gRPC clients now have ReadAsync() functions, that return a future and allow to request multiple results from different RPCs at the same moment. ugrpc::server::Server now can return a vector of gRPC service names. To aid in asynchronous drivers development the engine::io::FdPoller is now a part of the public API. Added a blazing fast utils::TrivialBiMap. HTTP Streaming is now considered production ready, see @ref scripts/docs/en/userver/http_server.md for docs. Testsuite fixtures were improved: Fixtures for detecting service readiness now work out of the box for services without server::handlers::Ping Known databases do no not require manual dependency registration any more Improved usage experience and testing of Metrics, see @ref TESTSUITEMETRICSTESTING "Testsuite metrics testing". Added fixtures to work with cache dumps. @ref pytestuserver.plugins.config.servicesecdistpath "servicesecdist_path" and `--service-secdist` options simplify setup of the components::Secdist in tests. Many fixtures were documented at @ref uservertestsuitefixtures, pytest plugins were documented in tutorials and at @ref scripts/docs/en/userver/functional_testing.md. Optimizations: Now the engine does less random number generator invocations for HTTP handling. Logging of tracing::Span became x2 faster IntrusiveMpscQueue is now used for engine internals, IO operations now schedule faster. Writing HTTP headers became faster, thanks to for the PR. utils::TrivialBiMap is now used wherever it is possible. Metrics: New interface for writing metrics utils::statistics::Writer is now considered stable. More metrics were moved to a faster utils::statistics::Writer, including utils::statistics::MetricTag. More metrics for Redis, including replica-syncing metrics. More tests for metrics. FreeBSD build fixes. Multiple documentation and diagnostics improvements. Added `ToStringView(HttpMethod)` function, thanks to for the PR. Added more engine::Yield tests, thanks to for the

Added logs colorization to the testsuite plugins, thanks to for the PR. Multiple big improvements in framework testing: improved unit tests re-entrance multiple new chaos and metrics tests improved testsuite diagnostics Added a @ref scripts/docs/en/userver/tutorial/auth_postgres.md sample. Added an option `settracingheaders` to disable HTTP tracing headers, thanks to for the PR. Fixed race in RabbitMQ sample, thanks to for the PR. Fixed PostgreSQL testing at GithubCI, thanks to for the PR. engine::SingleWaitingTaskMutex was added, many thanks to the for the PR! On-disk dumps were implemented for the LRU caches, many thanks to the and for the PR! Introduce metrics for ev-threads cpu load, thanks to the for the PR. AMQP optimized, thanks to the for the PR. Improved support for Conan packaging, many thanks to for the PR. Fixed GCC build, thanks to the for the PR. Fixed formats::yaml exception message typo, thanks to the for the PR. Added gRPC testsuite mock sample at @ref scripts/docs/en/userver/tutorial/grpc_service.md. Added engine::TaskCancellationToken to simplify async drivers development. Simplified build steps, in particular: Added `USERVERPYTHONPATH` to specify the path to the python3 binary for use in testsuite tests. Conan patches were merged into CMake scripts. Channelz support is now detected automatically. Experimental support for Conan packaging, many thanks to for the PR. Prometheus and Graphite metrics formats were added, see @ref scripts/docs/en/userver/service_monitor.md for details. Initial support for chaos testing was added, see @ref scripts/docs/en/userver/chaos_testing.md for more info. Generic Escape implementation for ranges was added to Clickhouse, thanks to for the PR. TLS/SSL support for Redis. Multiple optimizations from : utils::datetime::WallCoarseClock and its usage in the framework core; HTTP "Date" header caching; Significant reduction of syscalls count during any recv operations; Server::GetRequestsView not initialized if it is not required; utils::encoding::ToHex became faster; Marking response as ready became faster. Better diagnostics for CoroPool initialization failure, thanks to for the PR. New handler server::handlers::OnLogRotate. Multiple optimizations, including: Faster async cancellations for PostgreSQL; Avoid using dynamic_cast in multiple places; Avoid calling `std::chrono::steady_clock::now()` in multiple places. gRPC mockserver support (see @ref scripts/docs/en/userver/tutorial/grpc_service.md). gRPC now provides an efficient API for async execution of requests without additional `utils::Async` invocations. Build fixes for older platforms, thanks to for the PR. components::Logging now can output logs to UNIX sockets. Now the "help wanted" issues at github have additional tags "good first issue" and "big", to help you to choose between a good starting issue and a big feature. See @ref scripts/docs/en/userver/development/releases.md for more info. implemented the RabbitMQ driver. Added navigation to the next and previous page in docs, thanks to multiple feature requests in . Improved Task::Detach docs and added recommendation to use concurrent::BackgroundTaskStorage instead, thanks to for the bugreport. Added `start-` targets for the samples, to simplify experimenting with them. Docs now support dark theme out of the box. Fixed CMake issue with `-DUSERVERFEATURETESTSUITE=0`, thanks to for the bugreport. Fixed build on Arch Linux, thanks to for the bugreport. Fixed building in virtual environment on Windows, thanks to for the bug report. Fixed building with `-std=gnu++20`, thanks to for the PR. Improved package version detection in CMake via `pkg-config`. Added a `USERVERFEATUREUTEST` flag for disabling utest and ubench target builds, thanks to for the PR. Simplified gRPC component registration and usage. Added an ability to turn on gRPCs ChannelZ. Added evalsha/script load commands for Redis driver. Added server::handlers::HttpHandlerStatic handler to serve static pages. Added navigation to previous and next page in

Optimized internals: WaitListLight now never calls std::this_thread::yield(). More lightweight queues are now used in HTTP server. Smaller critical section in TaskContext::Sleep(), improved performance for many the synchronization primitives. std::unique_ptr now holds the payload in engine::Task, rather than std::shared_ptr. Thanks to the for the idea and draft PR. Simplified and optimized FdControl, resulting in less CPU and memory usage for sockets, pipes and TLS. Fixed typos in tests, thanks to for the PR. Removed suspicious operator, thanks to the for the bugreport. Fixed CentOS 7.8 builds, many thanks to for the bugreport and fix ideas. Fixed Gentoo builds, many thanks to for the PR. Fixed default DB values in , many thanks to for the bugreport. Added engine::io::WritableBase and engine::io::RwBase, thanks to for the idea. Added components::TcpAcceptorBase with new tutorials @ref scripts/docs/en/userver/tutorial/tcpservice.md and @ref scripts/docs/en/userver/tutorial/tcpfull.md, thanks to for the idea and usage samples at https://github.com/szvyagin-gj/unetwork. Fixed comparison operator for UserScope, thanks to for the PR. Add CryptoPP version download during CryptoPP installation, thanks to for the PR. Added more documentation on Non FIFO queues, thanks to for the report. Added missing std::atomic into TaskProcessor, thanks to for the report. Fixed Boost version detection on MacOs, thanks to for the PR. Added Fedora 36 support, thanks to for the PR. Improved statistics for gRPC. Vector versions of engine::io::Socket::SendAll were added and used to optimize CPU and memory consumption during HTTP response sends. Fixed engine::io::TlsWrapper retries, thanks to for the report. Fixed missing `const` in utils::DaemonMain function, thanks to for the PR. Cmake function `uservertestsuiteadd` now can pass arguments to `virtualenv`, thanks to for the PR. Improved hello_service run instruction, thanks to for the PR. Better Python3 detection, thanks to for the PR. Task processors now have an `os-scheduling` static config option and @mdenuservertaskprocessors_guide "a usage guide". Added a service template that uses userver the userver framework with PostgreSQL In template services, it is now possible to deploy the environment and run the service in one command: `make service-start-debug` or `make service-start-release`. Added userver::os_signals::Component, which is used for handling OS signals. You can now allow skipping the component in the static config file by specializing the components::kConfigFileMode, see @ref scripts/docs/en/userver/component_system.md "the documentation". The PostgreSQL driver now requires explicit serialization methods when working with enum. Optimized CPU consumption for handlers that do not log requests or responses. utils::Async() now can be invoked from non-coroutine thread (in that case do not forget to use engine::Task::BlockingWait() to wait for it). tracing::Span construction became faster. Thanks to for the report. Improved MacOS support, thanks to . Docker support: , docker-compose.yaml for the userver with build and test targets. See @ref scripts/docs/en/userver/tutorial/build.md Docs improved: removed internal links; added @ref scripts/docs/en/userver/framework_comparison.md, @ref scripts/docs/en/userver/supported_platforms.md, @ref scripts/docs/en/userver/security_changelog.md, @ref scripts/docs/en/userver/profilecontextswitches.md, @ref scripts/docs/en/userver/driver_guide.md, @mdenuservertaskprocessors_guide, @ref scripts/docs/en/userver/ossignals.md and @ref scripts/docs/en/userver/roadmapand_changelog.md. AArch64 build supported. Tests pass successfully HTTP headers hashing not vulnerable to HashDOS any more, thanks to Ivan Trofimov for the report. engine::WaitAny now can wait for engine::Future, including futures that are signaled by engine::Promise from non-coroutine environment. Optimized the PostgreSql driver, thanks to Dmitry Sokolov for the idea. Arch Linux is now properly supported, thanks to and . Published a service to manage of other userver-based services. Now it is possible to enable logging a particular LOG_XXX by its source location, see server::handlers::DynamicDebugLog for more details. Added a wrapper class utils::NotNull and aliases utils::UniqueRef and utils::SharedRef. LTSV-format is now available for logs via components::Logging static option @htmlonly <div class="bottom-nav"> @endhtmlonly @ref scripts/docs/en/userver/development/releases.md | @ref scripts/docs/en/userver/faq.md @htmlonly </div> @endhtmlonly