System Nexus payload handling from WIT

pyproject.toml

@@ -99,14 +99,17 @@ format = [
   { cmd = "cargo fmt", cwd = "temporalio/bridge" },
 ]
 gen-docs = "uv run scripts/gen_docs.py"
+gen-nexus-system-api = "uv run scripts/gen_nexus_system_api.py"
 gen-protos = [
   { cmd = "uv run scripts/gen_protos.py" },
+  { ref = "gen-nexus-system-api" },
   { cmd = "uv run scripts/gen_payload_visitor.py" },
   { cmd = "uv run scripts/gen_bridge_client.py" },
   { ref = "format" },
 ]
 gen-protos-docker = [
   { cmd = "uv run scripts/gen_protos_docker.py" },
+  { ref = "gen-nexus-system-api" },
   { cmd = "uv run scripts/gen_payload_visitor.py" },
   { cmd = "uv run scripts/gen_bridge_client.py" },
   { ref = "format" },
@@ -170,7 +173,7 @@ exclude = [
 [tool.pydocstyle]
 convention = "google"
 # https://github.com/PyCQA/pydocstyle/issues/363#issuecomment-625563088
-match_dir = "^(?!(docs|scripts|tests|api|proto|\\.)).*"
+match_dir = "^(?!(docs|scripts|tests|api|proto|system|\\.)).*"
 add_ignore = [
   # We like to wrap at a certain number of chars, even long summary sentences.
   # https://github.com/PyCQA/pydocstyle/issues/184

scripts/gen_nexus_system_api.py

@@ -0,0 +1,170 @@
+import os
+import shutil
+import subprocess
+import sys
+import tempfile
+from importlib.util import module_from_spec, spec_from_file_location
+from pathlib import Path
+from typing import cast
+
+import gen_protos
+
+base_dir = Path(__file__).parent.parent
+sys.path.insert(0, str(base_dir))
+wit_input_dir = (
+    base_dir
+    / "temporalio"
+    / "bridge"
+    / "sdk-core"
+    / "crates"
+    / "protos"
+    / "protos"
+    / "api_upstream"
+    / "nexus"
+)
+wit_path = wit_input_dir / "workflow-service.wit"
+wit_deps_dir = wit_input_dir / "deps"
+python_support_path = (
+    base_dir
+    / "temporalio"
+    / "nexus"
+    / "system"
+    / "_generation_support"
+    / "temporal_model_converters.py"
+)
+output_dir = base_dir / "temporalio" / "nexus" / "system" / "workflow_service"
+workflow_init_path = base_dir / "temporalio" / "workflow" / "__init__.py"
+workflowservice_request_response_proto = (
+    gen_protos.api_proto_dir
+    / "temporal"
+    / "api"
+    / "workflowservice"
+    / "v1"
+    / "request_response.proto"
+)
+
+
+def nex_gen_command() -> list[str]:
+    if bin_path := os.environ.get("NEX_GEN_BIN"):
+        return [bin_path]
+
+    if shutil.which("nex-gen") is None:
+        subprocess.check_call(["cargo", "install", "--locked", "nex-gen", "--force"])
+    return ["nex-gen"]
+
+
+def build_descriptor_set(descriptor_path: Path) -> None:
+    subprocess.check_call(
+        [
+            sys.executable,
+            "-mgrpc_tools.protoc",
+            f"--proto_path={gen_protos.api_proto_dir}",
+            f"--proto_path={gen_protos.proto_dir}",
+            "--include_imports",
+            f"--descriptor_set_out={descriptor_path}",
+            str(workflowservice_request_response_proto),
+        ]
+    )
+
+
+def generate_workflow_exports() -> None:
+    spec = spec_from_file_location(
+        "temporalio_nexus_system_workflow_service_exports",
+        output_dir / "__init__.py",
+        submodule_search_locations=[str(output_dir)],
+    )
+    if spec is None or spec.loader is None:
+        raise RuntimeError(f"Cannot load generated workflow service from {output_dir}")
+    module = module_from_spec(spec)
+    sys.modules[spec.name] = module
+    spec.loader.exec_module(module)
+    exports = cast(list[str], module.__all__)
+
+    import_block = [
+        "# BEGIN GENERATED NEXUS SYSTEM EXPORTS\n",
+        "from temporalio.nexus.system.workflow_service import (\n",
+        *[f"    {export},\n" for export in exports],
+        ")\n",
+        "# END GENERATED NEXUS SYSTEM EXPORTS\n",
+    ]
+    all_block = [
+        "    # BEGIN GENERATED NEXUS SYSTEM __ALL__\n",
+        *[f'    "{export}",\n' for export in exports],
+        "    # END GENERATED NEXUS SYSTEM __ALL__\n",
+    ]
+    content = workflow_init_path.read_text()
+    start = content.index("# BEGIN GENERATED NEXUS SYSTEM EXPORTS")
+    end = content.index("# END GENERATED NEXUS SYSTEM EXPORTS", start)
+    end = content.index("\n", end) + 1
+    content = content[:start] + "".join(import_block) + content[end:]
+    start = content.index("    # BEGIN GENERATED NEXUS SYSTEM __ALL__")
+    end = content.index("    # END GENERATED NEXUS SYSTEM __ALL__", start)
+    end = content.index("\n", end) + 1
+    workflow_init_path.write_text(content[:start] + "".join(all_block) + content[end:])
+
+
+def generate_nexus_system_api() -> None:
+    if not wit_path.exists():
+        raise RuntimeError(f"missing WIT source: {wit_path}")
+    if not wit_deps_dir.exists():
+        raise RuntimeError(f"missing WIT dependency directory: {wit_deps_dir}")
+    if not python_support_path.exists():
+        raise RuntimeError(f"missing Python support source: {python_support_path}")
+
+    with tempfile.TemporaryDirectory(dir=base_dir) as temp_dir:
+        descriptor_path = Path(temp_dir) / "temporal_api.bin"
+        build_descriptor_set(descriptor_path)
+        command = nex_gen_command()
+
+        shutil.rmtree(output_dir, ignore_errors=True)
+        output_dir.parent.mkdir(parents=True, exist_ok=True)
+        subprocess.check_call(
+            [
+                *command,
+                "generate",
+                "--lang",
+                "python",
+                "--input",
+                str(wit_path),
+                "--input",
+                str(wit_deps_dir),
+                "--support-file",
+                str(python_support_path),
+                "--descriptors",
+                str(descriptor_path),
+                "--output",
+                str(output_dir),
+            ]
+        )
+
+    (output_dir.parent / "__init__.py").touch()
+    generate_workflow_exports()
+    subprocess.check_call(
+        [
+            sys.executable,
+            "-m",
+            "ruff",
+            "check",
+            "--select",
+            "I",
+            "--fix",
+            str(output_dir),
+            str(workflow_init_path),
+        ]
+    )
+    subprocess.check_call(
+        [
+            sys.executable,
+            "-m",
+            "ruff",
+            "format",
+            str(output_dir),
+            str(workflow_init_path),
+        ]
+    )
+
+
+if __name__ == "__main__":
+    print("Generating Nexus system API...", file=sys.stderr)
+    generate_nexus_system_api()
+    print("Done", file=sys.stderr)