---
last_modified_on: "2020-07-13"
delivery_guarantee: "at_least_once"
component_title: "File"
description: "The Vector `file` sink streams `log` events to a file."
event_types: ["log"]
function_category: "transmit"
issues_url: https://github.com/timberio/vector/issues?q=is%3Aopen+is%3Aissue+label%3A%22sink%3A+file%22
operating_systems: ["Linux","MacOS","Windows"]
sidebar_label: "file|[\"log\"]"
source_url: https://github.com/timberio/vector/tree/master/src/sinks/file
status: "prod-ready"
title: "File Sink"
unsupported_operating_systems: []
---

import Fields from '@site/src/components/Fields';
import Field from '@site/src/components/Field';
import Tabs from '@theme/Tabs';
import TabItem from '@theme/TabItem';

The Vector `file` sink
[streams](#streaming) [`log`][docs.data-model.log] events to a file.

<!--
     THIS FILE IS AUTOGENERATED!

     To make changes please edit the template located at:

     website/docs/reference/sinks/file.md.erb
-->

## Configuration

<Tabs
  block={true}
  defaultValue="common"
  values={[{"label":"Common","value":"common"},{"label":"Advanced","value":"advanced"}]}>
<TabItem value="common">

```toml title="vector.toml"
[sinks.my_sink_id]
  # General
  type = "file" # required
  inputs = ["my-source-or-transform-id"] # required
  healthcheck = true # optional, default
  path = "vector-%Y-%m-%d.log" # required

  # Encoding
  encoding.codec = "ndjson" # required
```

</TabItem>
<TabItem value="advanced">

```toml title="vector.toml"
[sinks.my_sink_id]
  # General
  type = "file" # required
  inputs = ["my-source-or-transform-id"] # required
  healthcheck = true # optional, default
  idle_timeout_secs = "30" # optional, default
  path = "vector-%Y-%m-%d.log" # required

  # Encoding
  encoding.codec = "ndjson" # required
  encoding.except_fields = ["timestamp", "message", "host"] # optional, no default
  encoding.only_fields = ["timestamp", "message", "host"] # optional, no default
  encoding.timestamp_format = "rfc3339" # optional, default
```

</TabItem>
</Tabs>

<Fields filters={true}>
<Field
  common={true}
  defaultValue={null}
  enumValues={null}
  examples={[]}
  groups={[]}
  name={"encoding"}
  path={null}
  relevantWhen={null}
  required={true}
  templateable={false}
  type={"table"}
  unit={null}
  warnings={[]}
  >

### encoding

Configures the encoding specific sink behavior.


<Fields filters={false}>
<Field
  common={true}
  defaultValue={null}
  enumValues={{"ndjson":"Each event is encoded into JSON and the payload is new line delimited.","text":"Each event is encoded into text via the `message` key and the payload is new line delimited."}}
  examples={["ndjson","text"]}
  groups={[]}
  name={"codec"}
  path={"encoding"}
  relevantWhen={null}
  required={true}
  templateable={false}
  type={"string"}
  unit={null}
  warnings={[]}
  >

#### codec

The encoding codec used to serialize the events before outputting.



</Field>
<Field
  common={false}
  defaultValue={null}
  enumValues={null}
  examples={[["timestamp","message","host"]]}
  groups={[]}
  name={"except_fields"}
  path={"encoding"}
  relevantWhen={null}
  required={false}
  templateable={false}
  type={"[string]"}
  unit={null}
  warnings={[]}
  >

#### except_fields

Prevent the sink from encoding the specified labels.



</Field>
<Field
  common={false}
  defaultValue={null}
  enumValues={null}
  examples={[["timestamp","message","host"]]}
  groups={[]}
  name={"only_fields"}
  path={"encoding"}
  relevantWhen={null}
  required={false}
  templateable={false}
  type={"[string]"}
  unit={null}
  warnings={[]}
  >

#### only_fields

Limit the sink to only encoding the specified labels.



</Field>
<Field
  common={false}
  defaultValue={"rfc3339"}
  enumValues={{"rfc3339":"Format as an RFC3339 string","unix":"Format as a unix timestamp, can be parsed as a Clickhouse DateTime"}}
  examples={["rfc3339","unix"]}
  groups={[]}
  name={"timestamp_format"}
  path={"encoding"}
  relevantWhen={null}
  required={false}
  templateable={false}
  type={"string"}
  unit={null}
  warnings={[]}
  >

#### timestamp_format

How to format event timestamps.



</Field>
</Fields>

</Field>
<Field
  common={true}
  defaultValue={true}
  enumValues={null}
  examples={[true,false]}
  groups={[]}
  name={"healthcheck"}
  path={null}
  relevantWhen={null}
  required={false}
  templateable={false}
  type={"bool"}
  unit={null}
  warnings={[]}
  >

### healthcheck

Enables/disables the sink healthcheck upon start.



</Field>
<Field
  common={false}
  defaultValue={"30"}
  enumValues={null}
  examples={["30"]}
  groups={[]}
  name={"idle_timeout_secs"}
  path={null}
  relevantWhen={null}
  required={false}
  templateable={false}
  type={"uint"}
  unit={null}
  warnings={[]}
  >

### idle_timeout_secs

The amount of time a file can be idle  and stay open. After not receiving any
events for this timeout, the file will be flushed and closed.



</Field>
<Field
  common={true}
  defaultValue={null}
  enumValues={null}
  examples={["vector-%Y-%m-%d.log","application-{{ application_id }}-%Y-%m-%d.log"]}
  groups={[]}
  name={"path"}
  path={null}
  relevantWhen={null}
  required={true}
  templateable={true}
  type={"string"}
  unit={null}
  warnings={[]}
  >

### path

File name to write events to.
 See [Template Syntax](#template-syntax) for more info.


</Field>
</Fields>


## How It Works

### Dynamic File And Directory Creation

Vector will attempt to create the entire directory structure and the file when
emitting events to the file sink. This requires that the Vector agent have
the correct permissions to create and write to files in the specified directories.

### Environment Variables

Environment variables are supported through all of Vector's configuration.
Simply add `${MY_ENV_VAR}` in your Vector configuration file and the variable
will be replaced before being evaluated.

You can learn more in the
[Environment Variables][docs.configuration#environment-variables] section.

### Streaming

The `file` sink streams data on a real-time
event-by-event basis. It does not batch data.

### Template Syntax

The [`path`](#path) options
support [Vector's template syntax][docs.reference.templating], enabling dynamic
values derived from the event's data. This syntax accepts
[strptime specifiers][urls.strptime_specifiers] as well as the
`{{ field_name }}` syntax for accessing event fields. For example:

```toml title="vector.toml"
[sinks.my_file_sink_id]
  # ...
  path = "vector-%Y-%m-%d.log"
  path = "application-{{ application_id }}-%Y-%m-%d.log"
  # ...
```

You can learn more about the complete syntax in the
[templating reference][docs.reference.templating].

[docs.configuration#environment-variables]: /docs/setup/configuration/#environment-variables
[docs.data-model.log]: /docs/about/data-model/log/
[docs.reference.templating]: /docs/reference/templating/
[urls.strptime_specifiers]: https://docs.rs/chrono/0.4.11/chrono/format/strftime/index.html#specifiers