54 lines
1.8 KiB
Python
54 lines
1.8 KiB
Python
# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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import json
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def delta(previous, current, meta=False):
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product = {}
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seen = set()
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# Old keys
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for k, v in previous.items():
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if k not in current:
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continue
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newv = current[k]
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if type(v) is not type(newv):
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raise ValueError(
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'Type of key %s changed from %s to %s' % (k,
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type(v),
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type(newv)))
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if k == '__meta__':
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meta = True
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if meta and k == 'delta_seconds':
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continue
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elif meta and k == 'unixtime':
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product['delta_seconds'] = newv - v
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product[k] = newv
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elif isinstance(v, int) or isinstance(v, float):
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product[k] = newv - v
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elif isinstance(v, dict):
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product[k] = delta(v, newv, meta)
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else:
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raise ValueError('Only mappings of numbers are understood')
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seen.add(k)
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# New keys
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for k in set(current) - seen:
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product[k] = current[k]
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return product
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def delta_with_file(previous_path, current_data):
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with open(previous_path) as previous_file:
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previous_data = json.loads(previous_file.read())
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return delta(previous_data, current_data)
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