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Added first draft of recovery logic

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This commit is contained in:
Martin Schett 2020-12-28 18:41:34 +01:00
parent 96b94f5c89
commit b98976a016
1 changed files with 55 additions and 14 deletions
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69
middleware/app_be/views/rest_api.py
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@ -51,27 +51,54 @@ class ImageEndpoint:
# get stored SHA512 hash
stored_hash = metadata.get('sha512', '')
logger.debug('Sorted SHA512: {}'.format(stored_hash))
service_image_bytes = None
# recovery code
recovery_has_image = {}
recovery_hash_matches = {}
valid_image_bytes = None
# check image existence and correctness for each service + retrieve valid image if possible
for service in ImageEndpoint.storageServiceList:
logger.debug('Checking hash for ' + service.name)
# get image bytes from Dropbox
logger.debug('Checking recovery for service ' + service.name)
print('Checking recovery for service ' + service.name)
service_image_bytes = service.read_file(metadata['filename'])
if service_image_bytes is None:
return JsonResponse({'Result': 'Error - could not find image in ' + service.name, 'id': identifier},
status=404, safe=False)
if service_image_bytes is not None:
recovery_has_image[service.name] = True
actual_service_hash = create_sha512(service_image_bytes)
if stored_hash == actual_service_hash:
recovery_hash_matches[service.name] = True
if valid_image_bytes is None:
valid_image_bytes = service_image_bytes
else:
recovery_hash_matches[service.name] = False
else:
recovery_has_image[service.name] = False
recovery_hash_matches[service.name] = False
# calc dropbox image hash
actual_service_hash = create_sha512(service_image_bytes)
logger.debug('Actual '+service.name+' SHA512: {}'.format(actual_service_hash))
if stored_hash != actual_service_hash:
return JsonResponse('Stored hash in service "'+service.name+'"does not match generated one! '
'stored: {} actual: {}'.format(stored_hash, actual_service_hash),
status=400, safe=False)
# TODO: after talking with tobias about updating => replace with older version if hash is wrong
# check if any service has the image saved
if not ImageEndpoint.combine_boolean_dict_or(recovery_has_image):
logger.debug('None of the storage services has the requested image saved')
MongoDBService.deleteSingle(identifier)
return JsonResponse({'Result': 'Error - image is not available on any storage service and was deleted',
'id': identifier}, status=404, safe=False)
# check if any service has a valid version of the image saved
if not ImageEndpoint.combine_boolean_dict_or(recovery_hash_matches) and valid_image_bytes is None:
logger.debug('None of the storage services has a valid image saved')
MongoDBService.deleteSingle(identifier)
return JsonResponse({'Result': 'Error - image is not available on any storage service and was deleted',
'id': identifier}, status=404, safe=False)
# at this point we know at least one valid image is available
for service in ImageEndpoint.storageServiceList:
if not recovery_has_image[service.name] or not recovery_hash_matches[service.name]:
if not service.create_file(metadata['filename'], valid_image_bytes):
logger.error('Error duplicating file in service ' + service.name)
payload = {
'id': identifier,
'metadata': metadata,
'image_data': WrapperService.wrap_file(service_image_bytes)
'image_data': WrapperService.wrap_file(valid_image_bytes)
}
return JsonResponse(payload, safe=False)
@ -175,6 +202,20 @@ class ImageEndpoint:
return JsonResponse({'id': identifier, 'filename': filename},
safe=False)
@staticmethod
def combine_boolean_dict_and(d: dict) -> bool:
result = True
for entry in d:
result = (result and d[entry])
return result
@staticmethod
def combine_boolean_dict_or(d: dict) -> bool:
result = False
for entry in d:
result = (result or d[entry])
return result
class HealthEndpoint: