feat(target-factory): support declaration in the framework

python/cocoindex/flow.py

@@ -290,6 +290,12 @@ def export(self, name: str, target_spec: op.StorageSpec, /, *,
             name, _spec_kind(target_spec), dump_engine_object(target_spec),
             dump_engine_object(index_options), self._engine_data_collector, setup_by_user)
 
+    def declare(self, spec: op.DeclarationSpec):
+        """
+        Add a declaration to the flow.
+        """
+        self._flow_builder_state.engine_flow_builder.declare(dump_engine_object(spec))
+
 
 _flow_name_builder = _NameBuilder()
 

python/cocoindex/op.py

@@ -18,7 +18,7 @@ class OpCategory(Enum):
     FUNCTION = "function"
     SOURCE = "source"
     STORAGE = "storage"
-
+    DECLARATION = "declaration"
 @dataclass_transform()
 class SpecMeta(type):
     """Meta class for spec classes."""
@@ -41,6 +41,10 @@ class FunctionSpec(metaclass=SpecMeta, category=OpCategory.FUNCTION): # pylint:
 class StorageSpec(metaclass=SpecMeta, category=OpCategory.STORAGE): # pylint: disable=too-few-public-methods
     """A storage spec. All its subclass can be instantiated similar to a dataclass, i.e. ClassName(field1=value1, field2=value2, ...)"""
 
+class DeclarationSpec(metaclass=SpecMeta, category=OpCategory.DECLARATION): # pylint: disable=too-few-public-methods
+    """A declaration spec. All its subclass can be instantiated similar to a dataclass, i.e. ClassName(field1=value1, field2=value2, ...)"""
+    kind: str
+
 class Executor(Protocol):
     """An executor for an operation."""
     op_category: OpCategory

src/base/spec.rs

@@ -274,6 +274,9 @@ pub struct FlowInstanceSpec {
 
     #[serde(default = "Vec::new", skip_serializing_if = "Vec::is_empty")]
     pub export_ops: Vec<NamedSpec<ExportOpSpec>>,
+
+    #[serde(default = "Vec::new", skip_serializing_if = "Vec::is_empty")]
+    pub declarations: Vec<OpSpec>,
 }
 
 #[derive(Debug, Clone, Serialize, Deserialize)]

src/builder/analyzer.rs

@@ -930,6 +930,7 @@ impl AnalyzerContext<'_> {
         scope: &mut DataScopeBuilder,
         flow_inst: &FlowInstanceSpec,
         export_op_group: &AnalyzedExportTargetOpGroup,
+        declarations: Vec<serde_json::Value>,
         flow_setup_state: &mut FlowSetupState<DesiredMode>,
         existing_target_states: &HashMap<&ResourceIdentifier, Vec<&TargetSetupState>>,
     ) -> Result<Vec<impl Future<Output = Result<AnalyzedExportOp>> + Send>> {
@@ -1007,7 +1008,7 @@ impl AnalyzerContext<'_> {
         }
         let (data_collections_output, _) = export_op_group.target_factory.clone().build(
             collection_specs,
-            vec![],
+            declarations,
             self.flow_ctx.clone(),
         )?;
         if data_collections_output.len() != data_fields_infos.len() {
@@ -1162,37 +1163,49 @@ pub fn analyze_flow(
         RefList::Nil,
     )?;
 
-    let mut target_groups = IndexMap::<String, AnalyzedExportTargetOpGroup>::new();
+    #[derive(Default)]
+    struct TargetOpGroup {
+        export_op_ids: Vec<usize>,
+        declarations: Vec<serde_json::Value>,
+    }
+    let mut target_op_group = IndexMap::<String, TargetOpGroup>::new();
     for (idx, export_op) in flow_inst.export_ops.iter().enumerate() {
-        let target_kind = export_op.spec.target.kind.clone();
+        target_op_group
+            .entry(export_op.spec.target.kind.clone())
+            .or_default()
+            .export_op_ids
+            .push(idx);
+    }
+    for declaration in flow_inst.declarations.iter() {
+        target_op_group
+            .entry(declaration.kind.clone())
+            .or_default()
+            .declarations
+            .push(serde_json::Value::Object(declaration.spec.clone()));
+    }
+
+    let mut export_ops_futs = vec![];
+    let mut analyzed_target_op_groups = vec![];
+    for (target_kind, op_ids) in target_op_group.into_iter() {
         let export_factory = match registry.get(&target_kind) {
             Some(ExecutorFactory::ExportTarget(export_executor)) => export_executor,
             _ => {
-                return Err(anyhow::anyhow!(
-                    "Export target kind not found: {}",
-                    export_op.spec.target.kind
-                ))
+                bail!("Export target kind not found: {target_kind}");
             }
         };
-        target_groups
-            .entry(target_kind)
-            .or_insert_with(|| AnalyzedExportTargetOpGroup {
-                target_factory: export_factory.clone(),
-                op_idx: vec![],
-            })
-            .op_idx
-            .push(idx);
-    }
-
-    let mut export_ops_futs = vec![];
-    for group in target_groups.values() {
+        let analyzed_target_op_group = AnalyzedExportTargetOpGroup {
+            target_factory: export_factory.clone(),
+            op_idx: op_ids.export_op_ids,
+        };
         export_ops_futs.extend(analyzer_ctx.analyze_export_op_group(
             root_exec_scope.data,
             flow_inst,
-            group,
+            &analyzed_target_op_group,
+            op_ids.declarations,
             &mut setup_state,
             &target_states_by_name_type,
         )?);
+        analyzed_target_op_groups.push(analyzed_target_op_group);
     }
 
     let tracking_table_setup = setup_state.tracking_table.clone();
@@ -1215,7 +1228,7 @@ pub fn analyze_flow(
             import_ops,
             op_scope,
             export_ops,
-            export_op_groups: target_groups.into_values().collect(),
+            export_op_groups: analyzed_target_op_groups,
         })
     };
 

src/builder/flow_builder.rs

@@ -331,6 +331,8 @@ pub struct FlowBuilder {
     import_ops: Vec<NamedSpec<spec::ImportOpSpec>>,
     export_ops: Vec<NamedSpec<spec::ExportOpSpec>>,
 
+    declarations: Vec<spec::OpSpec>,
+
     next_generated_op_id: usize,
 }
 
@@ -370,6 +372,8 @@ impl FlowBuilder {
             direct_input_fields: vec![],
             direct_output_value: None,
 
+            declarations: vec![],
+
             next_generated_op_id: 0,
         };
         Ok(result)
@@ -612,6 +616,11 @@ impl FlowBuilder {
         Ok(())
     }
 
+    pub fn declare(&mut self, op_spec: py::Pythonized<spec::OpSpec>) -> PyResult<()> {
+        self.declarations.push(op_spec.into_inner());
+        Ok(())
+    }
+
     pub fn scope_field(
         &self,
         scope: DataScopeRef,
@@ -642,6 +651,7 @@ impl FlowBuilder {
             import_ops: self.import_ops.clone(),
             reactive_ops: self.reactive_ops.clone(),
             export_ops: self.export_ops.clone(),
+            declarations: self.declarations.clone(),
         };
         let flow_instance_ctx = build_flow_instance_context(
             &self.flow_instance_name,