mrtj · October 4, 2018 16:13 · Oct 4, 2018
diff --git a/ggcore_enable_sync.py b/ggcore_enable_sync.py
@@ -0,0 +1,84 @@
+import boto3
+import logging
+import json
+import re
+import uuid
+import argparse
+
+'''
+This script enables the IoT shadow syncing for your AWS Greengrass Core. 
+
+Call it with the ID of your Greengrass Group. 
+
+See also https://forums.aws.amazon.com/thread.jspa?messageID=831623
+'''
+
+logging.basicConfig(level=logging.INFO)
+
+ap = argparse.ArgumentParser(description='Enables shadow syncing for a Greengrass Core.')
+ap.add_argument('group_id', help='Greengrass group id')
+args = vars(ap.parse_args())
+
+def call_and_log(method, params):
+    logging.info('Calling greengrass.{} with params:\n{}'.format(method, json.dumps(params, indent=4)))
+    callable = getattr(client, method)
+    result = callable(**params)
+    del result['ResponseMetadata']
+    if result.get('NextToken') is not None:
+        del result['NextToken']
+    logging.info('Result of greengrass.{}:\n{}'.format(method, json.dumps(result, indent=4)))
+    return result
+
+client = boto3.client('greengrass')
+
+group_id = args['group_id']
+
+# Step 1 - Find the latest group version
+
+params = {
+    'GroupId':group_id,
+    'MaxResults':'2'
+}
+result = call_and_log('list_group_versions', params)
+
+group_version_obj = result['Versions'][0]
+
+params = {
+    'GroupId':group_id,
+    'GroupVersionId':group_version_obj['Version']
+}
+group_version_obj = call_and_log('get_group_version', params)
+
+# Step 2 - Get the latest core definition version to check shadow syncing
+
+core_definition_version_arn = group_version_obj['Definition']['CoreDefinitionVersionArn']
+matches = re.search(r'arn:aws:greengrass:.*:.*:/greengrass/definition/cores/(.*)/versions/(.*)', core_definition_version_arn)
+core_definition_id = matches.group(1)
+core_definition_version_id = matches.group(2)
+
+params = {
+    'CoreDefinitionId': core_definition_id,
+    'CoreDefinitionVersionId': core_definition_version_id
+}
+result = call_and_log('get_core_definition_version', params)
+core_definition_version = result['Definition']['Cores'][0]
+
+# Step 3 - Create a new core definition version to enable core shadow syncing
+
+core_definition_version['Id'] = str(uuid.uuid4())
+core_definition_version['SyncShadow'] = True    # this is the point of the whole script
+
+params = {
+    'CoreDefinitionId': core_definition_id,
+    'Cores': [core_definition_version]
+}
+core_definition_version_new = call_and_log('create_core_definition_version', params)
+
+# Step 4 - Create group definition version with new core definition version
+
+params = group_version_obj['Definition']
+params['GroupId'] = group_id
+params['CoreDefinitionVersionArn'] = core_definition_version_new['Arn']
+result = call_and_log('create_group_version', params)
+
+logging.info('A new version was created for your group, now you can deploy it from the Greengrass console.')
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