Create CLI test utility

Add a CLI test program that can demonstrate how the parser can be used programattically
and iterated over parsed template. This is just a test program for example usage. The
correct way of using tosca parser is via tools like heat transaltor.

Change-Id: Idcce82ed986821c4f213dd13498da0af20f34d9d

doc/source/usage.rst

@@ -6,3 +6,7 @@ The TOSCA Parser can be used as a library by any client program, for example,
 OpenStack heat-translator uses it to translate TOSCA to Heat Orchestration
 Template (HOT).
 
+For an easy reference on how TOSCA Parser can be used programmatically, refer
+to the tosca_parser.py test program which is located at the root level of the
+project.
+

tosca_parser.py

@@ -0,0 +1,85 @@
+#    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
+#
+#         http://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 os
+import sys
+
+from toscaparser.tosca_template import ToscaTemplate
+from toscaparser.utils.gettextutils import _
+import toscaparser.utils.urlutils
+
+"""
+CLI test utility to show how TOSCA Parser can be used programmatically
+
+This is a basic command line test utility showing the entry point in the
+TOSCA Parser and how to iterate over parsed template. It can be extended
+or modified to fit an individual need.
+
+It can be used as,
+#python tosca_parser.py --template-file=<path to the YAML template>
+#python tosca_parser.py --template-file=<path to the CSAR zip file>
+#python tosca_parser.py --template-file=<URL to the template or CSAR>
+
+e.g.
+#python tosca_parser.py
+--template-file=toscaparser/tests/data/tosca_helloworld.yaml
+#python tosca_parser.py
+--template-file=toscaparser/tests/data/CSAR/csar_hello_world.zip
+"""
+
+
+def main():
+    if len(sys.argv) < 2:
+        msg = _("The program requires template or CSAR file as an argument. "
+                "Please refer to the usage documentation.")
+        raise ValueError(msg)
+    if "--template-file=" not in sys.argv[1]:
+        msg = _("The program expects --template-file as first argument. "
+                "Please refer to the usage documentation.")
+    path = sys.argv[1].split('--template-file=')[1]
+    if os.path.isfile(path):
+        parse(path)
+    elif toscaparser.utils.urlutils.UrlUtils.validate_url(path):
+        parse(path, False)
+    else:
+        raise ValueError(_("%(path)s is not a valid file.") % {'path': path})
+
+
+def parse(path, a_file=True):
+    output = None
+    tosca = ToscaTemplate(path, a_file)
+    version = tosca.version
+    if tosca.version:
+        print ("\nversion:\n" + version)
+    description = tosca.description
+    if description:
+        print ("\ndescription:\n" + description)
+    inputs = tosca.inputs
+    if inputs:
+        print ("\ninputs:")
+        for input in inputs:
+            print (input.name)
+    nodetemplates = tosca.nodetemplates
+    if nodetemplates:
+        print ("\nnodetemplates:")
+        for node in nodetemplates:
+            print (node.name)
+    outputs = tosca.outputs
+    if outputs:
+        print ("\noutputs:")
+        for output in outputs:
+            print (output.name)
+
+
+if __name__ == '__main__':
+    main()