Add json-to-Workfow function

python_workflow_definition/src/python_workflow_definition/pyiron_workflow.py

@@ -1,9 +1,10 @@
 from inspect import isfunction
 from importlib import import_module
-from typing import Optional
+from typing import Any, Optional
 
 import numpy as np
 from pyiron_workflow import function_node, Workflow
+from pyiron_workflow.api import Function
 
 from python_workflow_definition.models import PythonWorkflowDefinitionWorkflow
 from python_workflow_definition.shared import (
@@ -312,3 +313,62 @@ def load_workflow_json(file_name: str, workflow: Optional[Workflow] = None):
         total_dict=total_dict,
         node_conversion_dict=node_conversion_dict,
     )
+
+
+def import_from_string(library_path: str) -> Any:
+    # Copied from bagofholding
+    split_path = library_path.split(".", 1)
+    if len(split_path) == 1:
+        module_name, path = split_path[0], ""
+    else:
+        module_name, path = split_path
+    obj = import_module(module_name)
+    for k in path.split("."):
+        obj = getattr(obj, k)
+    return obj
+
+
+def build_function_dag_workflow(file_name: str) -> Workflow:
+    content = remove_result(
+        PythonWorkflowDefinitionWorkflow.load_json_file(file_name="workflow.json")
+    )
+
+    input_values: dict[int, object] = (
+        {}
+    )  # Type is actually more restrictive, must be jsonifyable object
+    nodes: dict[int, Function] = {}
+    wf = Workflow(file_name.split(".")[0])
+    for node_dict in content[NODES_LABEL]:
+        if node_dict["type"] == "function":
+            fnc = import_from_string(node_dict["value"])
+            n = function_node(
+                fnc,
+                output_labels=fnc.__name__  # Strictly force single-output
+            )
+            nodes[node_dict["id"]] = n
+            wf.add_child(n)
+        elif node_dict["type"] == "input":
+            input_values[node_dict["id"]] = node_dict["value"]
+
+    for edge_dict in content[EDGES_LABEL]:
+        target_id = edge_dict["target"]
+        target_port = edge_dict["targetPort"]
+        source_id = edge_dict["source"]
+        source_port = edge_dict["sourcePort"]
+
+        if source_port is None:
+            if source_id in input_values.keys():  # Parent input value
+                upstream = input_values[source_id]
+            else:  # Single-output sibling
+                upstream = nodes[source_id]
+        else:  # Dictionary-output sibling
+            injected_attribute_access = nodes[source_id].__getitem__(source_port)
+            upstream = injected_attribute_access
+        downstream = nodes[target_id]
+        setattr(
+            downstream.inputs, target_port, upstream
+        )  # Exploit input panel magic
+        # Warning: edge setup routine is bespoke for an environment where all nodes return
+        # a single value or a dictionary
+
+    return wf