Supported File URL Formats for Writers

CloverDX Designer > Component Reference > Writers > Common Properties of Writers > Supported File URL Formats for Writers

The File URL attribute lets you type in the file URL directly, or open the URL File Dialog.

The URL shown below can also contain placeholders – a dollar sign or hash sign.

Dollar and hash signs serve for different purposes.

Dollar sign should be used when each of multiple output files contains only a specified number of records based on the Records per file attribute.
Hash sign should be used when each of multiple output files only contains records corresponding to the value of specified Partition key.

Note: hash signs in URL examples in this section serve to separate a compressed file (zip, gz) from its contents. These are not placeholders.

To ensure graph portability, forward slashes must be used when defining the path in URLs (even on Microsoft Windows).

Below are examples of possible URLs for Writers:

Writing to Local Files

/path/filename.out

Writes specified file on disk.
/path1/filename1.out;/path2/filename2.out

Writes two specified files on disk.
/path/filename$.out

Writes a number of files on disk. The dollar sign represents one digit. Thus, the output files can have the name range from filename0.out to filename9.out. The dollar sign is used when Records per file is set.
/path/filename$$.out

Writes a number of files on disk. Two dollar signs represent two digits. Thus, the output files can have the name range from filename00.out to filename99.out. The dollar sign is used when Records per file is set.
/path/filename#.out

Writes a number of files on disk. If Partition file tag is set to Key file tag, the hash sign in the file name is replaced with Partition key field value. Otherwise, the hash sign is replaced with number.
zip:(/path/file$.zip)

Writes a number of compressed files on disk. The dollar sign represents one digit. Thus, the compressed output files can have the names from file0.zip to file9.zip. The dollar sign is used when Records per file is set.
zip:(/path/file$.zip)#innerfolder/filename.out

Writes a specified file inside the compressed files on disk. The dollar sign represents one digit. Thus, the compressed output files containing the specified filename.out file can have the name range from file0.zip to file9.zip. The dollar sign is used when Records per file is set.
gzip:(/path/file$.gz)

Writes a number of compressed files on disk. The dollar sign represents one digit. Thus, the compressed output files can have the name ranges from file0.gz to file9.gz. The dollar sign is used when Records per file is set.

Although CloverDX can read data from a .tar file, writing to a .tar file is not supported.

Writing to Remote Files

ftp://user:password@server/path/filename.out

Writes a specified filename.out file on a remote server connected via an FTP protocol using username and password.
sftp://user:password@server/path/filename.out

Writes a specified filename.out file on a remote server connected via an SFTP protocol using a username and password.

If a certificate-based authentication is used, certificates are placed in the ${PROJECT}/ssh-keys/ directory. For more information, see SFTP Certificate in CloverDX.

Note, that only certificates without a password are currently supported. The certificate-based authentication has a URL without a password:

sftp://username@server/path/filename.txt
zip:(ftp://username:password@server/path/file.zip)#innerfolder/filename.txt

Writes a specified filename.txt file compressed in the file.zip file on a remote server connected via an FTP protocol using username and password.
zip:(ftp://username:password@server/path/file.zip)#innerfolder/filename.txt

Writes a specified filename.txt file compressed in the file.zip file on a remote server connected via an FTP protocol.
zip:(zip:(ftp://username:password@server/path/name.zip)#innerfolder/file.zip)#innermostfolder/filename.txt

Writes a specified filename.txt file compressed in a file.zip file that is also compressed in a name.zip file on a remote server connected via an FTP protocol using username and password.
gzip:(ftp://username:password@server/path/file.gz)

Writes the first file compressed in a file.gz file on a remote server connected via an FTP protocol.
http://username:password@server/filename.out

Writes a specified filename.out file on a remote server connected via a WebDAV protocol using username and password.
s3://access_key_id:secret_access_key@s3.amazonaws.com/bucketname/path/filename.out

Writes to path/filename.out object located in the Amazon S3 web storage service in a bucket bucketname using an access key ID and secret access key.

See Amazon S3 URL.

It is recommended to connect to S3 via a region-specific S3 URL: s3://s3.eu-central-1.amazonaws.com/bucket.name/. A region-specific URL have much better performance than a generic one (s3://s3.amazonaws.com/bucket.name/).

See recommendation on Amazon S3 URL.

s3:// URL protocol is available since CloverETL 4.1. More information about the deprecated http:// S3 protocol can be found in CloverDX 4.0 User Guide.
az-blob://account:account_key@account.blob.core.windows.net/containername/path/filename.txt

Writes to path/filename.out object located in the Azure Blob Storage service in the specified container.

Connects using the specified Account Key. See Azure Blob Storage for other authentication options.
hdfs://CONN_ID/path/filename.dat

Writes a file on a Hadoop distributed file system (HDFS). To which HDFS NameNode to connect to is defined in a Hadoop connection with CONN_ID. This example file URL writes a file with /path/filename.dat absolute HDFS path.
smb://domain%3Buser:password@server/path/filename.txt

Writes a file to a Windows share (Microsoft SMB version 1/CIFS protocol). The server part may be a DNS name, an IP address or a NetBIOS name. The Userinfo part of the URL (domain%3Buser:password) is not mandatory and any URL reserved character it contains should be escaped using the %-encoding similarly to the semicolon ; character with %3B in the example (the semicolon is escaped because it collides with the default CloverDX file URL separator). Also note that the dollar sign $ in the URL path (e.g. in the case of writing to an Administrative share) is reserved for the file partitioning feature so it too needs be escaped (with %24).

The SMB protocol is implemented in the JCIFS library which may be configured using Java system properties. For a list of all configurable properties, see Setting Client Properties in JCIFS documentation.
smb2://domain%3Buser:password@server/path/filename.txt

Writes a file to a Windows share (Microsoft SMB version 2 and 3).

The SMB version 2 and 3 protocol is implemented in the SMBJ library.

Writing to Output Port

port:$0.FieldName:discrete

If this URL is used, the output port of the Writer must be connected to another component. Output metadata must contain a FieldName of one of the following data types: string, byte or cbyte. Each data record that is received by the Writer through the input port is processed according to the input metadata, sent out through the optional output port, and written as the value of the specified field of the metadata of the output edge. Next records are parsed in the same way as described here.

Using Proxy in Writers

http:(direct:)//seznam.cz

Without proxy.
http:(proxy://user:password@212.93.193.82:443)//seznam.cz

Proxy setting for HTTP protocol.
ftp:(proxy://user:password@proxyserver:1234)//seznam.cz

Proxy setting for ftp protocol.
ftp:(proxy://proxyserver:443)//server/path/file.dat

Proxy setting for FTP protocol.
sftp:(proxy://66.11.122.193:443)//user:password@server/path/file.dat

Proxy setting for SFTP protocol.
s3:(proxy://user:password@66.11.122.193:443)//access_key_id:secret_access_key@s3.amazonaws.com/bucketname/path/filename.out

Proxy setting for S3 protocol.

Writing to Dictionary

dict:keyName:source

Writes data to a file URL specified in dictionary. Target file URL is retrieved from the specified dictionary entry.
dict:keyName:discrete^[1]

Writes data to dictionary. Creates ArrayList<byte[]>
dict:keyName:stream^[2]

Writes data to dictionary. Creates WritableByteChannel

Sandbox Resource as Data Source

A sandbox resource, whether it is a shared, local or partitioned sandbox, is specified in the graph under the fileURL attributes as a so called sandbox URL like:

sandbox://data/path/to/file/file.dat

where data is a code for sandbox and path/to/file/file.dat is the path to the resource from the sandbox root. The URL is evaluated by CloverDX Server during graph execution and a component (Reader or Writer) obtains the opened stream from the Server. This may be a stream to a local file or to some other remote resource. Thus, a graph does not have to run on the node which has local access to the resource. There may be more sandbox resources used in the graph and each of them may be on a different node. In such cases, CloverDX Server would choose the node with the most local resources to minimize remote streams.

The sandbox URL has a specific use for parallel data processing. When the sandbox URL with the resource in a partitioned sandbox is used, that part of graph/phase runs in parallel, according to the node allocation specified by the list of partitioned sandbox locations. Thus, each worker has its own local sandbox resource. CloverDX Server evaluates the sandbox URL on each worker and provides an open stream to a local resource to the component.