# AvroFileWriter

## class AvroFileWriter(file: IO[bytes])[source]

Bases: [`FileWriter`](https://dev.nominal.io/instro/ref/library/instro.lib.publishers.files.FileWriter.md#instro.lib.publishers.files.FileWriter "instro.lib.publishers.files.FileWriter")[[`bytes`](https://docs.python.org/3/builtins/stdtypes.html#bytes "(in Python v3.15)")]

Write snappy-compressed Avro records in the Nominal Core ingest schema.

Wrap the stream and write the Avro header.

Raises:
:   [**ValueError**](https://docs.python.org/3/builtins/exceptions.html#ValueError "(in Python v3.15)") – If the stream is not writable or is a text stream.

Attributes

| [`mode`](https://dev.nominal.io/instro/ref/library/instro.lib.publishers.files.AvroFileWriter.md#instro.lib.publishers.files.AvroFileWriter.mode "instro.lib.publishers.files.AvroFileWriter.mode") |  |
| --- | --- |
| [`newline`](https://dev.nominal.io/instro/ref/library/instro.lib.publishers.files.AvroFileWriter.md#instro.lib.publishers.files.AvroFileWriter.newline "instro.lib.publishers.files.AvroFileWriter.newline") |  |

Methods

| [`write`](https://dev.nominal.io/instro/ref/library/instro.lib.publishers.files.AvroFileWriter.md#instro.lib.publishers.files.AvroFileWriter.write "instro.lib.publishers.files.AvroFileWriter.write") | Append data as Avro records and flush them to the stream. |
| --- | --- |

### mode: str = 'a+b'

### write( data: Measurement | Command, ) → None[source]

Append data as Avro records and flush them to the stream.

### newline: str | None = None