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Downloads objects within an Amazon S3 bucket, optionally filtered by a prefix, either by walking the items in the bucket or by streaming upload notifications in realtime.

# Common config fields, showing default values
label: ""
bucket: ""
prefix: ""
region: eu-west-1
codec: all-bytes
url: ""
key_path: Records.*.s3.object.key
bucket_path: Records.*
envelope_path: ""

Streaming Objects on Upload with SQS#

A common pattern for consuming S3 objects is to emit upload notification events from the bucket either directly to an SQS queue, or to an SNS topic that is consumed by an SQS queue, and then have your consumer listen for events which prompt it to download the newly uploaded objects. More information about this pattern and how to set it up can be found at:

Benthos is able to follow this pattern when you configure an sqs.url, where it consumes events from SQS and only downloads object keys received within those events. In order for this to work Benthos needs to know where within the event the key and bucket names can be found, specified as dot paths with the fields sqs.key_path and sqs.bucket_path. The default values for these fields should already be correct when following the guide above.

If your notification events are being routed to SQS via an SNS topic then the events will be enveloped by SNS, in which case you also need to specify the field sqs.envelope_path, which in the case of SNS to SQS will usually be Message.

When using SQS please make sure you have sensible values for sqs.max_messages and also the visibility timeout of the queue itself. When Benthos consumes an S3 object the SQS message that triggered it is not deleted until the S3 object has been sent onwards. This ensures at-least-once crash resiliency, but also means that if the S3 object takes longer to process than the visibility timeout of your queue then the same objects might be processed multiple times.

Downloading Large Files#

When downloading large files it's often necessary to process it in streamed parts in order to avoid loading the entire file in memory at a given time. In order to do this a codec can be specified that determines how to break the input into smaller individual messages.


By default Benthos will use a shared credentials file when connecting to AWS services. It's also possible to set them explicitly at the component level, allowing you to transfer data across accounts. You can find out more in this document.


This input adds the following metadata fields to each message:

- s3_key
- s3_bucket
- s3_last_modified_unix
- s3_last_modified (RFC3339)
- s3_content_type
- s3_content_encoding
- All user defined metadata

You can access these metadata fields using function interpolation. Note that user defined metadata is case insensitive within AWS, and it is likely that the keys will be received in a capitalized form, if you wish to make them consistent you can map all metadata keys to lower or uppercase using a Bloblang mapping such as meta = meta().map_each_key(key -> key.lowercase()).



The bucket to consume from. If the field sqs.url is specified this field is optional.

Type: string
Default: ""


An optional path prefix, if set only objects with the prefix are consumed when walking a bucket.

Type: string
Default: ""


The AWS region to target.

Type: string
Default: "eu-west-1"


Allows you to specify a custom endpoint for the AWS API.

Type: string
Default: ""


Optional manual configuration of AWS credentials to use. More information can be found in this document.

Type: object


A profile from ~/.aws/credentials to use.

Type: string
Default: ""

The ID of credentials to use.

Type: string
Default: ""


The secret for the credentials being used.

Type: string
Default: ""


The token for the credentials being used, required when using short term credentials.

Type: string
Default: ""


A role ARN to assume.

Type: string
Default: ""


An external ID to provide when assuming a role.

Type: string
Default: ""


Forces the client API to use path style URLs for downloading keys, which is often required when connecting to custom endpoints.

Type: bool
Default: false


Whether to delete downloaded objects from the bucket once they are processed.

Type: bool
Default: false


The way in which the bytes of a data source should be converted into discrete messages, codecs are useful for specifying how large files or contiunous streams of data might be processed in small chunks rather than loading it all in memory. It's possible to consume lines using a custom delimiter with the delim:x codec, where x is the character sequence custom delimiter. Codecs can be chained with /, for example a gzip compressed CSV file can be consumed with the codec gzip/csv.

Type: string
Default: "all-bytes"

autoEXPERIMENTAL: Attempts to derive a codec for each file based on information such as the extension. For example, a .tar.gz file would be consumed with the gzip/tar codec. Defaults to all-bytes.
all-bytesConsume the entire file as a single binary message.
chunker:xConsume the file in chunks of a given number of bytes.
csvConsume structured rows as comma separated values, the first row must be a header row.
delim:xConsume the file in segments divided by a custom delimiter.
gzipDecompress a gzip file, this codec should precede another codec, e.g. gzip/all-bytes, gzip/tar, gzip/csv, etc.
linesConsume the file in segments divided by linebreaks.
multipartConsumes the output of another codec and batches messages together. A batch ends when an empty message is consumed. For example, the codec lines/multipart could be used to consume multipart messages where an empty line indicates the end of each batch.
tarParse the file as a tar archive, and consume each file of the archive as a message.
# Examples
codec: lines
codec: "delim:\t"
codec: delim:foobar
codec: gzip/csv


Consume SQS messages in order to trigger key downloads.

Type: object


An optional SQS URL to connect to. When specified this queue will control which objects are downloaded.

Type: string
Default: ""


A custom endpoint to use when connecting to SQS.

Type: string
Default: ""


A dot path whereby object keys are found in SQS messages.

Type: string
Default: "Records.*.s3.object.key"


A dot path whereby the bucket name can be found in SQS messages.

Type: string
Default: "Records.*"


A dot path of a field to extract an enveloped JSON payload for further extracting the key and bucket from SQS messages. This is specifically useful when subscribing an SQS queue to an SNS topic that receives bucket events.

Type: string
Default: ""

# Examples
envelope_path: Message


An optional period of time to wait from when a notification was originally sent to when the target key download is attempted.

Type: string
Default: ""

# Examples
delay_period: 10s
delay_period: 5m


The maximum number of SQS messages to consume from each request.

Type: int
Default: 10