feat(python): Execute with stdout / stderr

src/python/itkwasm/itkwasm/__init__.py

@@ -1,12 +1,14 @@
 """itkwasm: Python interface to itk-wasm WebAssembly modules."""
 
-__version__ = "1.0b1"
+__version__ = "1.0b2"
 
 from .image import Image, ImageType
 from .mesh import Mesh, MeshType
 from .pointset import PointSet, PointSetType
+from .pipeline import Pipeline
 
 __all__ = [
+  "Pipeline",
   "Image",
   "ImageType",
   "Mesh",

src/python/itkwasm/itkwasm/pipeline.py

@@ -0,0 +1,37 @@
+from pathlib import Path
+from typing import List, Union
+
+from wasmer import engine, wasi, Store, Module, ImportObject, Instance
+from wasmer_compiler_cranelift import Compiler
+
+
+class Pipeline:
+    """Run an itk-wasm WASI pipeline."""
+
+    def __init__(self, pipeline: Union[str, Path, bytes]):
+        """Compile the pipeline."""
+        self.engine = engine.Universal(Compiler)
+        if isinstance(pipeline, bytes):
+            wasm_bytes = pipeline
+        else:
+            with open(pipeline, 'rb') as fp:
+                wasm_bytes = fp.read()
+        self.store = Store(self.engine)
+        self.module = Module(self.store, wasm_bytes)
+        self.wasi_version = wasi.get_version(self.module, strict=True)
+
+    def run(self, args: List[str], outputs=[], inputs=[], preopen_directories=[], map_directories={}, environments={}):
+        """Run the itk-wasm pipeline."""
+
+        wasi_state = wasi.StateBuilder('itk-wasm-pipeline')
+        wasi_state.arguments(args)
+        wasi_state.environments(environments)
+        wasi_state.map_directories(map_directories)
+        wasi_state.preopen_directories(preopen_directories)
+        wasi_env = wasi_state.finalize()
+        import_object = wasi_env.generate_import_object(self.store, self.wasi_version)
+
+        instance = Instance(self.module, import_object)
+
+        start = instance.exports._start
+        start()

src/python/itkwasm/pyproject.toml

@@ -30,6 +30,8 @@ dynamic = ["version"]
 requires-python = ">=3.7"
 dependencies = [
     "numpy",
+    "wasmer",
+    "wasmer_compiler_cranelift",
 ]
 
 [project.urls]
@@ -39,7 +41,7 @@ Issues = "https://github.com/InsightSoftwareConsortium/itk-wasm/issues"
 
 [project.optional-dependencies]
 test = [
-    "itk>=5.3rc4.post3",
+    "itk>=5.3rc4.post2",
     "pytest >=2.7.3",
 ]
 doc = ["sphinx"]

src/python/itkwasm/test/test_pipeline.py

@@ -0,0 +1,17 @@
+from itkwasm import Pipeline
+
+from pathlib import Path
+
+test_input_dir = Path(__file__).resolve().parent / 'input'
+
+
+def test_stdout_stderr():
+    pipeline = Pipeline(test_input_dir / 'stdout-stderr-test.wasi.wasm')
+    pipeline.run([])
+
+def test_pipeline_bytes():
+    pipeline_path = test_input_dir / 'stdout-stderr-test.wasi.wasm'
+    with open(pipeline_path, 'rb') as fp:
+        wasm_bytes = fp.read()
+    pipeline = Pipeline(wasm_bytes)
+    pipeline.run([])