FrameworkC++ userver

Framework reference

std::unique_ptr<Name> MakeName(servicelib::Context, servicelib::IServiceEnvironment&, const servicelib::config::<Config>&)

Extension model

C++ userver services use `cppservicelib`. Generated graph assembly owns runtime wiring; application code supplies typed business implementations through preserved maker functions.

When to use

Use this page while implementing a generated business function or endpoint handler.

Behavior

The runtime is C++20 on userver tasks and transport components.
Generated graph assembly calls the maker once and stores the returned callable or handler. The header and implementation files without generated in their names are user-owned.
The generated maker signature identifies the exact implementation and typed configuration required by the selected stream or endpoint.
Returning a construction error stops service startup instead of leaving a partially wired graph.

Regeneration contract

Function and endpoint implementation files are preserved by the merge script. Generated registries and graph assembly may change around them; make merge-validate detects a preserved maker whose generated signature is no longer compatible.

Choosing where state lives

Keep reusable clients and immutable dependencies on the implementation object. Keep request, record, RPC, or workflow invocation data in handler state. Use the runtime context for cancellation and correlation instead of inventing a parallel context channel.

Generated and user-owned boundaries

How generated services discover and run application code.

Type or methodRoleDescription

Generated graph assemblyFramework owned

Creates streams, links, connectors, endpoint consumers, serializers, stores, and runtime pools from the designer graph.

Maker functionUser entry point

std::unique_ptr<Name> MakeName(servicelib::Context, servicelib::IServiceEnvironment&, const servicelib::config::<Config>&)

Implementation objectUser owned

Contains business dependencies and reusable state for one generated function or endpoint.

Typed configGenerated contract

Matches the selected graph node and exposes its runtime configuration to the maker.

Service environmentFramework dependency

Provides configured observability and runtime services without requiring global variables.

Generated extension pattern

inline std::unique_ptr<ValidateOrder> MakeValidateOrder(
    servicelib::Context context,
    servicelib::IServiceEnvironment& environment,
    const servicelib::config::ProcessStreamConfig& config);