python3 读取avro文件

官网示例文档：http://avro.apache.org/docs/current/gettingstartedpython.html#download_install

需要注意的是，官网给出的是py2.x的示例代码。

py3 需要做一些改动：

1. 首先你需要下载avro_python3 而不是avro
2. 然后对代码做以下调整(黄底部分)

   import avro.schema
   from avro.datafile import DataFileReader, DataFileWriter
   from avro.io import DatumReader, DatumWriter
   
   schema = avro.schema.Parse(open("user.avsc", "rb").read())
   
   writer = DataFileWriter(open("users.avro", "wb"), DatumWriter(), schema)
   writer.append({"name": "Alyssa", "favorite_number": 256})
   writer.append({"name": "Ben", "favorite_number": 7, "favorite_color": "red"})
   writer.close()
   
   reader = DataFileReader(open("users.avro", "rb"), DatumReader())
   for user in reader:
       print(user)
   reader.close()

3. user.avsc 文件哪来?

直接将文章中的以下内容存到文件中就行了。

{"namespace": "example.avro",
 "type": "record",
 "name": "User",
 "fields": [
     {"name": "name", "type": "string"},
     {"name": "favorite_number",  "type": ["int", "null"]},
     {"name": "favorite_color", "type": ["string", "null"]}
 ]
}