Question

我能够使用avro-tools-1.7.7.jar获取json数据和avro架构并输出二进制Avro文件，如下所示https://github.com/miguno/avro-cli-examples#json-to-avro。但是，我希望能够使用Avro python api https://avro.apache.org/docs/1.7.7/gettingstartedpython.html以编程方式执行此操作。

在他们的示例中，他们展示了如何将记录一次写入二进制avro文件。

    import avro.schema
    from avro.datafile import DataFileReader, DataFileWriter
    from avro.io import DatumReader, DatumWriter

    schema = avro.schema.parse(open("user.avsc").read())

    writer = DataFileWriter(open("users.avro", "w"), DatumWriter(), schema)
    writer.append({"name": "Alyssa", "favorite_number": 256})
    writer.append({"name": "Ben", "favorite_number": 7, "favorite_color": "red"})
    writer.close()

我的用例是像jro文件中的avro-tools jar一样编写所有记录，只是在python代码中。我不想炮轰并执行jar。如果重要的话，这将部署到Google App Engine。

Answer 1

这可以通过 fastavro 来完成。例如，给定链接中的架构：

twitter.avsc

{
  "type" : "record",
  "name" : "twitter_schema",
  "namespace" : "com.miguno.avro",
  "fields" : [ {
    "name" : "username",
    "type" : "string",
    "doc" : "Name of the user account on Twitter.com"
  }, {
    "name" : "tweet",
    "type" : "string",
    "doc" : "The content of the user's Twitter message"
  }, {
    "name" : "timestamp",
    "type" : "long",
    "doc" : "Unix epoch time in seconds"
  } ],
  "doc:" : "A basic schema for storing Twitter messages"
}

和json文件：

twitter.json

{"username":"miguno","tweet":"Rock: Nerf paper, scissors is fine.","timestamp": 1366150681 }
{"username":"BlizzardCS","tweet":"Works as intended.  Terran is IMBA.","timestamp": 1366154481 }

您可以使用类似于以下脚本的内容来写出一个 avro 文件：

import json
from fastavro import json_reader, parse_schema, writer

with open("twitter.avsc") as fp:
    schema = parse_schema(json.load(fp))

with open("twitter.avro", "wb") as avro_file:
    with open("twitter.json") as fp:
        writer(avro_file, schema, json_reader(fp, schema))

如何使用Python Avro api将JSON解析为二进制Avro文件？

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