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How to read/parse *only* the JSON schema from a file containing an avro message in binary format?

I have an avro message in binary format in a file.

Obj^A^D^Vavro.schemaÞ^B{"type":"record","name":"rec","namespace":"ns","fields":[{"name":"id","type":["int","null"]},{"name":"name","type":["string","null"]},{"name":"foo_id","type":["int","null"]}]}^Tavro.codec^Lsnappy^@¤²/n¹¼Bù<9b> à«_^NÌ^W

I'm just interested in the SCHEMA. Is there a way to read/parse just the schema from this file? I'm currently parsing this file by hand to extract the schema, but I was hoping avro would help me a standard way of doing that.

Solution

  • Avro does provide an API to get the schema from a file:

        File file = new File("myFile.avro")

    FileReader<?> reader = DataFileReader.openReader(file, new GenericDatumReader<>());
    Schema schema = reader.getSchema();
    System.out.println(schema);

    I think that it should match your definition of "just the schema", let me know if it doesn't.

    You could also use the getschema command from avro-tools if you have no reason to do it programmatically.