4ee3db80b0
Summary: Updated the feature specs, the changelog and added a new section in user technical. Reviewers: mferencevic, mculinovic, buda, ipaljak Reviewed By: ipaljak Subscribers: pullbot Differential Revision: https://phabricator.memgraph.io/D1534
35 lines
1019 B
Markdown
35 lines
1019 B
Markdown
# Kafka - data transform
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The transform script is a user defined script written in Python. The script
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should be aware of the data format in the Kafka message.
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Each Kafka message is byte length encoded, which means that the first eight
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bytes of each message contain the length of the message.
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A sample code for a streaming transform script could look like this:
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```python
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def create_vertex(vertex_id):
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return ("CREATE (:Node {id: $id})", {"id": vertex_id})
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def create_edge(from_id, to_id):
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return ("MATCH (n:Node {id: $from_id}), (m:Node {id: $to_id}) "\
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"CREATE (n)-[:Edge]->(m)", {"from_id": from_id, "to_id": to_id})
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def stream(batch):
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result = []
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for item in batch:
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message = item.decode('utf-8').strip().split()
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if len(message) == 1:
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result.append(create_vertex(message[0])))
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else:
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result.append(create_edge(message[0], message[1]))
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return result
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```
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The script should output openCypher query strings based on the type of the
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records.
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