fastavro.schema

parse_schema(schema, expand=False, _write_hint=True, _force=False)

Returns a parsed avro schema

It is not necessary to call parse_schema but doing so and saving the parsed schema for use later will make future operations faster as the schema will not need to be reparsed.

Parameters
  • schema (dict) – Input schema

  • expand (bool) –

    NOTE: This option should be considered a keyword only argument and may get enforced as such when Python 2 support is dropped.

    If true, named schemas will be fully expanded to their true schemas rather than being represented as just the name. This format should be considered an output only and not passed in to other reader/writer functions as it does not conform to the avro specification and will likely cause an exception

  • _write_hint (bool) – Internal API argument specifying whether or not the __fastavro_parsed marker should be added to the schema

  • _force (bool) – Internal API argument. If True, the schema will always be parsed even if it has been parsed and has the __fastavro_parsed marker

Example:

from fastavro import parse_schema
from fastavro import writer

parsed_schema = parse_schema(original_schema)
with open('weather.avro', 'wb') as out:
    writer(out, parsed_schema, records)
fullname(schema)

Returns the fullname of a schema

Parameters

schema (dict) – Input schema

Example:

from fastavro.schema import fullname

schema = {
    'doc': 'A weather reading.',
    'name': 'Weather',
    'namespace': 'test',
    'type': 'record',
    'fields': [
        {'name': 'station', 'type': 'string'},
        {'name': 'time', 'type': 'long'},
        {'name': 'temp', 'type': 'int'},
    ],
}

fname = fullname(schema)
assert fname == "test.Weather"
expand_schema(schema)

Returns a schema where all named types are expanded to their real schema

NOTE: The output of this function produces a schema that can include multiple definitions of the same named type (as per design) which are not valid per the avro specification. Therefore, the output of this should not be passed to the normal writer/reader functions as it will likely result in an error.

Parameters

schema (dict) – Input schema

Example:

from fastavro.schema import expand_schema

original_schema = {
    "name": "MasterSchema",
    "namespace": "com.namespace.master",
    "type": "record",
    "fields": [{
        "name": "field_1",
        "type": {
            "name": "Dependency",
            "namespace": "com.namespace.dependencies",
            "type": "record",
            "fields": [
                {"name": "sub_field_1", "type": "string"}
            ]
        }
    }, {
        "name": "field_2",
        "type": "com.namespace.dependencies.Dependency"
    }]
}

expanded_schema = expand_schema(original_schema)

assert expanded_schema == {
    "name": "com.namespace.master.MasterSchema",
    "type": "record",
    "fields": [{
        "name": "field_1",
        "type": {
            "name": "com.namespace.dependencies.Dependency",
            "type": "record",
            "fields": [
                {"name": "sub_field_1", "type": "string"}
            ]
        }
    }, {
        "name": "field_2",
        "type": {
            "name": "com.namespace.dependencies.Dependency",
            "type": "record",
            "fields": [
                {"name": "sub_field_1", "type": "string"}
            ]
        }
    }]
}