Validate API sample JSON files

We are maintaining these files by hand,
so errors are bound to creep in.

Change-Id: I1f5bbf8d5fcd396dfe63b9bf3ef95306c03765a4

tools/validate-json-files.py

@@ -0,0 +1,42 @@
+#!/usr/bin/env python
+# 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 json
+import os
+import sys
+
+if len(sys.argv) < 2:
+    print("Usage: %s <directory>" % sys.argv[0])
+    sys.exit(1)
+
+directory = sys.argv[1]
+
+invalid_json_files = []
+
+print("Validating JSON files in directory: ", directory)
+for dirpath, dirname, files in os.walk(directory):
+    json_files = [f for f in files if f.endswith('.json')]
+    for json_file in json_files:
+        path = os.path.join(dirpath, json_file)
+        with open(path) as json_file_content:
+            try:
+                content = json.load(json_file_content)
+            except ValueError as e:
+                print("File %s has invalid JSON: %s" % (path, e))
+                invalid_json_files.append(path)
+
+if invalid_json_files:
+    print("%d JSON files are invalid." % len(invalid_json_files))
+    sys.exit(1)
+else:
+    print("All JSON files are valid.")

tox.ini

@@ -129,6 +129,7 @@ basepython = python3
 whitelist_externals = rm
 commands =
   rm -rf api-ref/build
+  python {toxinidir}/tools/validate-json-files.py {toxinidir}/api-ref/source/samples/
   sphinx-build -W -b html -d api-ref/build/doctrees api-ref/source api-ref/build/html
 
 [testenv:dbrevision]