Make synthtool an executable (#74)

setup.py

@@ -19,14 +19,17 @@
 version = '0.8.0'
 release_status = 'Development Status :: 3 - Alpha'
 dependencies = [
+    "click",
     "colorlog",
     "jinja2",
     "packaging",
     "requests",
 ]
 
 packages = setuptools.find_packages()
-
+scripts = [
+    'synthtool=synthtool.__main__:main'
+]
 
 setuptools.setup(
     name=name,
@@ -50,4 +53,7 @@
     install_requires=dependencies,
     include_package_data=True,
     zip_safe=False,
+    entry_points={
+        'console_scripts': scripts,
+    },
 )

synthtool/__main__.py

@@ -0,0 +1,35 @@
+# Copyright 2018 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import importlib
+import os
+
+import click
+
+from synthtool import log
+
+
+@click.command()
+@click.version_option(message="%(version)s")
+def main():
+    synth_file = os.path.join(os.getcwd(), "synth.py")
+
+    if os.path.lexists(synth_file):
+        log.debug(f"Executing {synth_file}.")
+        # https://docs.python.org/3/library/importlib.html#importing-a-source-file-directly
+        spec = importlib.util.spec_from_file_location("synth", synth_file)
+        synth_module = importlib.util.module_from_spec(spec)
+        spec.loader.exec_module(synth_module)
+    else:
+        log.exception(f"{synth_file} not found.")