Files

//tag::ref-doc[]
= Amazon S3 Source

This source app supports transfer of files using the Amazon S3 protocol.
Files are transferred from the `remote` directory (S3 bucket) to the `local` directory where the application is deployed.

Messages emitted by the source are provided as a byte array by default. However, this can be
customized using the `--mode` option:

- *ref* Provides a `java.io.File` reference
- *lines* Will split files line-by-line and emit a new message for each line
- *contents* The default. Provides the contents of a file as a byte array

When using `--mode=lines`, you can also provide the additional option `--withMarkers=true`.
If set to `true`, the underlying `FileSplitter` will emit additional _start-of-file_ and _end-of-file_ marker messages before and after the actual data.
The payload of these 2 additional marker messages is of type `FileSplitter.FileMarker`. The option `withMarkers` defaults to `false` if not explicitly set.

See also link:../../../functions/common/metadata-store-common/README.adoc[MetadataStore] options for possible shared persistent store configuration used to prevent duplicate messages on restart.


== mode = lines

=== Headers:

* `Content-Type: text/plain`
* `file_orginalFile: <java.io.File>`
* `file_name: <file name>`
* `correlationId: <UUID>` (same for each line)
* `sequenceNumber: <n>`
* `sequenceSize: 0` (number of lines is not know until the file is read)

=== Payload:

A `String` for each line.

The first line is optionally preceded by a message with a `START` marker payload.
The last line is optionally followed by a message with an `END` marker payload.

Marker presence and format are determined by the `with-markers` and `markers-json` properties.

== mode = ref

=== Headers:

None.

=== Payload:

A `java.io.File` object.

== Options

The `s3-source` has the following options:

//tag::configuration-properties[link-to-catalog=true]
https://github.com/spring-cloud/spring-functions-catalog/tree/main/supplier/spring-s3-supplier#configuration-options[See Spring Functions Catalog for configuration options].
//end::configuration-properties[]

== Amazon AWS common options

The Amazon S3 Source (as all other Amazon AWS applications) is based on the https://awspring.io/[Spring Cloud AWS] project as a foundation, and its auto-configuration classes are used automatically by Spring Boot.
Consult their documentation regarding required and useful auto-configuration properties.

== Examples

```
java -jar s3-source.jar --s3.remoteDir=/tmp/foo --file.consumer.mode=lines
```
//end::ref-doc[]