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This component is mostly stable but breaking changes could still be made outside of major version releases if a fundamental problem with the component is found.

Downloads objects within an Azure Blob Storage container, optionally filtered by a prefix.

Introduced in version 3.36.0.

# Common config fields, showing default values
label: ""
storage_account: ""
storage_access_key: ""
storage_sas_token: ""
storage_connection_string: ""
container: ""
prefix: ""
codec: all-bytes

Downloads objects within an Azure Blob Storage container, optionally filtered by a prefix.

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.


This input adds the following metadata fields to each message:

- blob_storage_key
- blob_storage_container
- blob_storage_last_modified
- blob_storage_last_modified_unix
- blob_storage_content_type
- blob_storage_content_encoding
- All user defined metadata

You can access these metadata fields using function interpolation.



The storage account to download blobs from. This field is ignored if storage_connection_string is set.

Type: string
Default: ""


The storage account access key. This field is ignored if storage_connection_string is set.

Type: string
Default: ""


The storage account SAS token. This field is ignored if storage_connection_string or storage_access_key are set.

Type: string
Default: ""
Requires version 3.38.0 or newer


A storage account connection string. This field is required if storage_account and storage_access_key / storage_sas_token are not set.

Type: string
Default: ""


The name of the container from which to download blobs.

Type: string
Default: ""


An optional path prefix, if set only objects with the prefix are consumed.

Type: string
Default: ""


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


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

Type: bool
Default: false