refactor(instrumentation-build): use generic runtime types

crates/codegen/src/cxx_bridge.rs

@@ -530,7 +530,7 @@ fn emit_context_bridge(
             let (#(#build_fields,)*) = match opts {
                 None => (#(#build_wraps(#q::Observer::<#build_event_tys>::noop()),)*),
                 Some(options) => {
-                    let inner = #q::Context::try_new(id).map_err(|e| e.to_string())?;
+                    let inner = #q::ContextInner::try_new(id).map_err(|e| e.to_string())?;
                     #q::write_sidecar(
                         &options,
                         id,

crates/codegen/src/pyo3_bridge.rs

@@ -685,7 +685,7 @@ fn emit_context(
     quote! {
         #[pyclass(name = "Context")]
         pub struct PyContext {
-            inner: Option<#q::Context>,
+            inner: Option<#q::ContextInner>,
             #(#struct_fields,)*
             id: #q::uuid::Uuid,
         }
@@ -715,9 +715,9 @@ fn emit_context(
                 };
                 let id = #q::uuid::Uuid::now_v7();
                 let inner = match &opts {
-                    Some(_) => #q::Context::try_new(id)
+                    Some(_) => #q::ContextInner::try_new(id)
                         .map_err(|err| pyo3::exceptions::PyRuntimeError::new_err(err.to_string()))?,
-                    None => #q::Context::noop(id),
+                    None => #q::ContextInner::noop(id),
                 };
                 // Single sync/async bridge: build every entity's observer (each
                 // constructing its exporter from the options, bound to the id)

crates/instrumentation-build/example/src/main.rs

@@ -3,7 +3,7 @@
 
 use quent_instrumentation::{EventCallback, ExporterOptions};
 
-use crate::demo::{ConnectionHandle, ConnectionObserver, DemoContext, Uuid};
+use crate::demo::{Connection, Context, Demo, Handle, Observer, Query, Server, Uuid};
 
 #[allow(unused)]
 mod demo {
@@ -12,16 +12,16 @@ mod demo {
 
 fn main() -> Result<(), Box<dyn std::error::Error>> {
     // The context owns the exporter and exposes one observer per entity type.
-    let context: DemoContext = demo::DemoContext::try_new(Some(debug_printing_exporter()))?;
+    let context: Context<Demo> = Context::try_new(Some(debug_printing_exporter()))?;
 
     // `observer.handle()` creates a fresh entity instance to events emit for.
-    let mut server = context.server_observer().handle();
+    let mut server = context.observer::<Server>().handle();
     server.booted()?;
 
-    let observer: ConnectionObserver = context.connection_observer();
+    let observer: Observer<Connection> = context.observer::<Connection>();
     // Once-cardinality events take `&mut self` and may fire only once, tracked
     // by the handle, hence it is mut:
-    let mut conn: ConnectionHandle = observer.handle();
+    let mut conn: Handle<Connection> = observer.handle();
 
     // One method per entity event:
     conn.opened(
@@ -57,7 +57,7 @@ fn main() -> Result<(), Box<dyn std::error::Error>> {
     //
     // FSMs will get typestate pattern handles in the future, also see
     // https://github.com/rapidsai/quent/issues/416
-    let mut query = context.query_observer().handle();
+    let mut query = context.observer::<Query>().handle();
     query.submitted("select 1".to_owned(), conn.as_entity_ref())?;
     query.running(10)?;
     query.ready(true)?;

crates/instrumentation-build/src/lib.rs

@@ -143,6 +143,13 @@ pub enum GenerateError {
         /// The number of once-cardinality events the entity declares.
         count: usize,
     },
+    #[error("generated observer type `{generated}` conflicts with schema type `{schema_path}`")]
+    GeneratedTypeCollision {
+        /// The generated Rust type name.
+        generated: String,
+        /// The schema type whose generated name conflicts.
+        schema_path: Path,
+    },
     #[error("failed to write generated file")]
     Io(#[from] std::io::Error),
 }
@@ -180,8 +187,8 @@ pub fn generate(schema: &Schema, opts: &Options) -> Result<GenerateInfo, Generat
 /// # Errors
 ///
 /// Returns [`GenerateError`] if the schema contains a qualified type path, a
-/// derive entry is not a parseable Rust path, or the generated code is not a
-/// valid Rust file.
+/// generated observer type conflicts with a schema type, a derive entry is not
+/// a parseable Rust path, or the generated code is not a valid Rust file.
 pub fn generate_str(schema: &Schema, opts: &Options) -> Result<String, GenerateError> {
     ensure_unqualified_type_paths(schema)?;
 

crates/instrumentation-build/src/runtime/context.rs

@@ -1,107 +1,105 @@
 // SPDX-FileCopyrightText: Copyright (c) 2026, NVIDIA CORPORATION & AFFILIATES. All rights reserved.
 // SPDX-License-Identifier: Apache-2.0
 
-//! Generation of the schema context — builds every entity's observer on
-//! construction and hands out cheap clones.
+//! Generation of the schema model used by the generic instrumentation context.
 
 use convert_case::Case;
 use proc_macro2::TokenStream;
-use quent_schema::Schema;
+use quent_schema::{Entity, Schema};
 use quote::quote;
+use syn::Ident;
 
-use super::{event_ident, observer_ident};
+use super::{event_ident, marker_ident, model_ident};
+use crate::GenerateError;
 use crate::common::{raw_ident, to_case};
 
-/// Generate the declaration of an {Schema}Context and its impls.
-pub(super) fn schema_context(schema: &Schema) -> TokenStream {
-    let schema_pascal = to_case(schema.name(), Case::Pascal);
-    let context_ty = raw_ident(format!("{schema_pascal}Context"));
-    let model_name = schema.name().to_string();
+/// Generates the model's typed observer storage.
+pub(super) fn observer_storage(schema: &Schema) -> Result<TokenStream, GenerateError> {
+    let storage = observers_ident(schema);
+    let storage_name = storage.to_string();
+    if let Some(schema_path) = schema
+        .records()
+        .map(|record| record.path())
+        .chain(schema.entities().map(|entity| entity.path()))
+        .find(|path| to_case(path.name(), Case::Pascal) == storage_name)
+    {
+        return Err(GenerateError::GeneratedTypeCollision {
+            generated: storage_name,
+            schema_path: schema_path.clone(),
+        });
+    }
 
-    let fields: Vec<_> = schema
-        .entities()
-        .map(|e| raw_ident(to_case(e.path().name(), Case::Snake)))
-        .collect();
-    let observer_tys: Vec<_> = schema.entities().map(observer_ident).collect();
-    let event_tys: Vec<_> = schema.entities().map(event_ident).collect();
-    let accessors: Vec<_> = schema
-        .entities()
-        .map(|e| {
-            raw_ident(format!(
-                "{}_observer",
-                to_case(e.path().name(), Case::Snake)
-            ))
-        })
-        .collect();
-    let accessor_docs: Vec<String> = schema
+    let description = format!(
+        "Observers for the `{}` instrumentation model.",
+        schema.name()
+    );
+    let hidden_docs = "Hidden because the model context provides typed observer access.";
+    let entity_fields = schema.entities().map(|entity| {
+        let field = entity_observer_field(entity);
+        let entity_ty = marker_ident(entity);
+        quote! {
+            #field: ::quent_instrumentation::Observer<#entity_ty>
+        }
+    });
+
+    Ok(quote! {
+        #[doc = #description]
+        #[doc = ""]
+        #[doc = #hidden_docs]
+        #[doc(hidden)]
+        pub struct #storage {
+            #(#entity_fields,)*
+        }
+    })
+}
+
+/// Generates the model marker and its runtime integration.
+pub(super) fn schema_model(schema: &Schema) -> TokenStream {
+    let model = model_ident(schema);
+    let model_name = schema.name().to_string();
+    let observers = observers_ident(schema);
+    let active_observers = observer_storage_initializer(schema, true);
+    let noop_observers = observer_storage_initializer(schema, false);
+    let options_binding = if schema.entities().next().is_some() {
+        raw_ident("options".to_owned())
+    } else {
+        raw_ident("_options".to_owned())
+    };
+    let observer_impls = schema
         .entities()
-        .map(|e| {
-            format!(
-                "Observer for `{}` entities.",
-                to_case(e.path().name(), Case::Pascal)
-            )
-        })
-        .collect();
+        .map(|entity| observer_storage_impl(schema, entity));
 
-    let context_doc = format!(
-        "Instrumentation context for the `{model_name}` model. Construct it with \
-         [`Self::try_new`], then call a `*_observer()` accessor to get an entity's \
-         event observer, which creates the per-instance handles that emit events."
-    );
+    let model_doc = format!("The `{model_name}` instrumentation model.");
 
     quote! {
-        #[doc = #context_doc]
-        pub struct #context_ty {
-            #(#fields: #observer_tys,)*
-            _inner: ::quent_instrumentation::Context,
-        }
+        #[doc = #model_doc]
+        pub struct #model;
 
-        impl #context_ty {
-            /// Create a context, building every entity's exporter pipeline.
-            /// Pass `None` for a no-op context that discards events.
-            pub fn try_new(
-                exporter: ::core::option::Option<::quent_instrumentation::ExporterOptions>,
-            ) -> ::core::result::Result<Self, ::std::boxed::Box<dyn ::std::error::Error>> {
-                Self::try_with_id(::quent_instrumentation::Uuid::now_v7(), exporter)
-            }
+        #(#observer_impls)*
 
-            /// Create a context that adopts an existing `id` rather than
-            /// generating one.
-            pub fn try_with_id(
-                id: ::quent_instrumentation::Uuid,
-                exporter: ::core::option::Option<::quent_instrumentation::ExporterOptions>,
-            ) -> ::core::result::Result<Self, ::std::boxed::Box<dyn ::std::error::Error>> {
-                // With an exporter, build an active context, write the provenance
-                // sidecar, then build each entity's observer using the exporter
-                // options as its provider. `None` builds a no-op context and
-                // no-op observers.
-                let ( _inner, #(#fields,)* ) = match &exporter {
-                    ::core::option::Option::Some(options) => {
-                        let context = ::quent_instrumentation::Context::try_new(id)?;
-                        ::quent_instrumentation::write_sidecar(options, id, Self::model_info());
-                        let ( #(#fields,)* ) = context.block_on(async {
+        impl ::quent_instrumentation::Model for #model {
+            type Observers = #observers;
+
+            fn build_observers(
+                context: &::quent_instrumentation::ContextInner,
+                exporter: ::core::option::Option<&::quent_instrumentation::ExporterOptions>,
+            ) -> ::core::result::Result<
+                Self::Observers,
+                ::std::boxed::Box<dyn ::std::error::Error>,
+            > {
+                match exporter {
+                    ::core::option::Option::Some(#options_binding) => {
+                        context.block_on(async {
                             ::core::result::Result::<
                                 _,
                                 ::std::boxed::Box<dyn ::std::error::Error>,
-                            >::Ok((
-                                #(
-                                    context
-                                        .observer::<#event_tys>(::core::clone::Clone::clone(options))
-                                        .await?,
-                                )*
-                            ))
-                        })?;
-                        ( context, #(#fields,)* )
+                            >::Ok(#active_observers)
+                        })
                     }
-                    ::core::option::Option::None => (
-                        ::quent_instrumentation::Context::noop(id),
-                        #( ::quent_instrumentation::Observer::<#event_tys>::noop(), )*
-                    ),
-                };
-                ::core::result::Result::Ok(Self {
-                    #( #fields: #observer_tys { inner: ::std::sync::Arc::new(#fields) }, )*
-                    _inner,
-                })
+                    ::core::option::Option::None => {
+                        ::core::result::Result::Ok(#noop_observers)
+                    }
+                }
             }
 
             fn model_info() -> ::quent_instrumentation::build_info::ModelInfo {
@@ -123,18 +121,61 @@ pub(super) fn schema_context(schema: &Schema) -> TokenStream {
                     analyzer_package: ::core::option::Option::None,
                 }
             }
+        }
+    }
+}
 
-            /// Identity of this context.
-            pub fn id(&self) -> ::quent_instrumentation::Uuid {
-                self._inner.id()
+fn observer_storage_initializer(schema: &Schema, active: bool) -> TokenStream {
+    let storage = observers_ident(schema);
+    let entity_fields = schema.entities().map(|entity| {
+        let field = entity_observer_field(entity);
+        let entity_ty = marker_ident(entity);
+        let event_ty = event_ident(entity);
+        let observer = if active {
+            quote! {
+                context
+                    .observer::<#event_ty>(::core::clone::Clone::clone(options))
+                    .await?
             }
+        } else {
+            quote! {
+                ::quent_instrumentation::ObserverInner::<#event_ty>::noop()
+            }
+        };
+        quote! {
+            #field: ::quent_instrumentation::Observer::<#entity_ty>::new(
+                ::std::sync::Arc::new(#observer),
+            )
+        }
+    });
+    quote! {
+        #storage {
+            #(#entity_fields,)*
+        }
+    }
+}
 
-            #(
-                #[doc = #accessor_docs]
-                pub fn #accessors(&self) -> #observer_tys {
-                    ::core::clone::Clone::clone(&self.#fields)
-                }
-            )*
+fn observer_storage_impl(schema: &Schema, entity: &Entity) -> TokenStream {
+    let storage = observers_ident(schema);
+    let entity_ty = marker_ident(entity);
+    let field = entity_observer_field(entity);
+
+    quote! {
+        impl ::quent_instrumentation::ObserverProvider<#entity_ty> for #storage {
+            fn observer(&self) -> ::quent_instrumentation::Observer<#entity_ty> {
+                ::core::clone::Clone::clone(&self.#field)
+            }
         }
     }
 }
+
+fn observers_ident(schema: &Schema) -> Ident {
+    raw_ident(format!("{}Observers", to_case(schema.name(), Case::Pascal)))
+}
+
+fn entity_observer_field(entity: &Entity) -> Ident {
+    raw_ident(format!(
+        "{}_observer",
+        to_case(entity.path().name(), Case::Snake)
+    ))
+}