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Snap type:

Write

Description:

This Snap reads a binary data stream from the input view and writes it to a specified file destination. Possible file destinations include: SLDB, HTTP, S3, FTP, SFTP, FTPS, or HDFS. If File permissions for the file are provided, the Snap set those permissions to the file.

• Expected upstream Snaps: Any Snap with a binary output view can be connected upstream, such as CSV Formatter, JSON Formatter, XML Formatter, or File Reader.
• Expected downstream Snaps: Downstream Snap is optional. Any Snap with a document input view can be connected downstream.
• Expected input: Any binary data stream
• Expected output: The output view for this Snap is optional. If an output view is open and the file write action is successful, the output view provides a document with information on the filename, result, and original data. An example is:

{
        "filename": "ftp://ftp.Snaplogic.com/home/qatest/user_manual.pdf",
        "result": "overwritten",
        "original": {
            "content-type" : "application/json"
        }
    }

Files uploaded to SLFS have a 100-MB per file limit. 

This Snap uses account references created on the Accounts page of SnapLogic Manager to handle access to this endpoint. This Snap supports several account types, as listed in the table below, or no account. See Configuring Binary Accounts for information on setting up accounts that work with this Snap.

Account types supported by each protocol are as follows:

Required settings for account types are as follows:

Settings

Label

File name 

Required. This property specifies the URL for the destination file, which the binary data read from the input view is written to. It may start with one of the following protocols:

• http:
• https:
• s3:
• sftp:
• ftp:
• ftps:
• hdfs:
• sldb:
• smb:

• file: (only for use with a Groundplex)

• wasb:

• wasbs:

• gs:

• adl: 

For SLDB files, if you enter:

• just a file name, such as file.csv, then it writes the file to: /<org>/projects/<pipeline project>/file1.csv (where <org> is your organization name and <pipeline project> is the project where the pipeline is stored) if the pipeline is in a project other than the shared project.

• shared/file1.csv, then it writes the file to: /<org>/shared/file1.csv.

The Snap can write a file to its own project directory or the shared project, and cannot write it to another project directory.

For S3, your account must have full access.
The File property can be a JavaScript expression with the "=" button pressed.
For example, if the "File" property is:
                "sldb:///out_" + Date.now() + ".csv"
then the evaluated filename can be:

sldb:///out_2013-11-13T00:22:31.880Z.csv

Fields in the binary header can be also be accessed when computing a file name. For example, if a File Reader Snap was directly connected to a File Writer, you could access the "content-location" header field to get the original path to the file.

You could then compute a new file name based on the old one, for instance, to make a backup file:
    $['content-location'].match('/([^/]+)$')[1] + '.backup'

For http: and https: protocols, the Snap uses http PUT method only. This property should have the syntax:

        [protocol]://[host][:port]/[path]

Please note "://" is a separator between the file protocol and the rest of the URL and the host name and the port number should be between "://" and "/". If the port number is omitted, a default port for the protocol is used. The hostname and port number are omitted in the sldb and s3 protocols. 

The file:/// protocol is supported only on Groundplex. In Cloudplex configurations, please use sldb or other file protocols. When using the file:/// protocol, the file access is conducted using the permissions of the user in whose name the Snaplex is running (by default Snapuser). File system access is to be used with caution, and it is the customer's own responsibility to ensure that file system is cleaned up after use. 

For HDFS, if you want to be able to suggest information, use the HDFS Writer Snap. 

Examples: 

• s3:///<S3_bucket_name>@s3.<region_name>.amazonaws.com/<path>

  For region names and their details, see AWS Regions and Endpoints.
  Example: s3:///mybucket@s3.eu-west-1.amazonaws.com/test.json

• sftp://ftp.snaplogic.com:22/dir/filename
• smb://smb.Snaplogic.com:445/test_files/csv/input.csv
• _filename (A key/value pair with "filename" key should be defined as a pipeline parameter.)
• file:///D:/testFolder/  (if the Snap is executed in the Windows Groundplex and needs to access D: drive)
• wasb:///snaplogic/testDir/sampl/csv (to write 'sample.csv' file into the 'testDir' folder in the 'Snaplogic' container)
• gs:///mybucket/csv/test.csv (to read 'test.csv' file in the 'csv/' folder of the 'mybucket' bucket)
• adl://storename/folder/filename (to read the file from a location of the storage) 

Default value:  [None]

File action

Required. The action to perform if the file already exists. The available options include:

• Overwrite - If Overwrite is selected, the Snap attempts to write the file without checking for the file's existence for a better performance, and the "fileAction" field will be "overwritten" in the output view data.
• Append - Append is supported for file, FTP, FTPS and SFTP protocols only.
• Ignore - If Ignore, it will not overwrite the file and will do nothing but write the status and file name to its output view.
• Error -  If Error is selected, the error displays in the Pipeline Run Log. If an error view is defined, the error will be written there as well.

Default value: Overwrite

If selected, an empty file is written when the incoming binary document has empty data. If there is no incoming document at the input view of the Snap, no file is written regardless of the value of the property.

Default value: Not selected.

Write header file

The binary data stream in the input view may contain header information about the binary data in the form of a document with key-value-pair map data. If this property is checked, the Snap writes a header file whose name is generated by appending ".header" to the value of the File name property. The same header information is also included in the output view data, as shown in the "Expected output" section above, under the key "original". Note that if the header has no keys other than Content-Type or Content-Encoding, the .header file will not be written

Default value: Not selected 

Validate after write

If selected, the Snap checks if the file exists after the completion of the file write. This may delay a few more seconds for the validation.

Default value: Not selected 

Specifies the maximum number of retry attempts when the Snap fails to write. If the value is larger than 0, the Snap first stores the input data in a temporary local file before writing to the target file.

Minimum value: 0

Default value: 0

Specifies the minimum number of seconds for which the Snap must wait before attempting recovery from a network failure.

Example:  3

Minimum value: 1

Default value: 1

File permissions for various users

File permission sets to be assigned to the file.
Note:

• Supported for sftp, ftp, ftps, file, and hdfs protocols only.
• FTP/FTPS servers on Windows machines may not be supported.

User type

The user type to assign the permissions. This field is case-insensitive. Suggestible options are:

• owner
• group
• others

File permissions

Specify any combination of {read, write, execute}, separated by a plus sign (+).  This field is case-insensitive. Suggestible options are:

• read
• write
• execute
• read+write
• read+execute
• write+execute
• read+write+execute

Create directory if not present  

When selected, checks if the specified directory path exists and if it does not exist, creates a new directory. This property is not supported for HTTP, HTTPS, SLDB and SMB file protocols.

Default value: Not selected

Flush interval in kilobytes during the file upload. The Snap can flush a given size of data output stream written to the target file server. If the value is zero, the Snap flushes in maximum frequency after each byte block is written. Larger the value is, the less frequent flushes the Snap performs. Leave the property at default -1 for no flush during the upload. This property may help if the file upload experiences an intermittent failure. However, more frequent flushes will result in a slower file upload.

Example:   100

Default value:  -1

Examples

• For SFTP files, if you attempt to write a file into a directory where you do not have a write access right, the write operation will fail with "access denied" error. When you get an SFTP account credential, it is also important to know where your home directory is, for example, 

  sftp://ftp.snaplogic.com/home/mrtest for username "mrtest"
   

• HDFS Example

For HDFS file access, please use a SnapLogic on-premises Groundplex and make sure that its instance is within the Hadoop cluster and SSH authentication has already been established. You can access HDFS files in the same way as other file protocols in File Reader and File Writer Snaps. There is no need to use any account in the Snap.

hdfs://<hostname>:<port number>/<path to folder>/<filename>

hdfs://ec2-54-198-212-134.compute-1.amazonaws.com:8020/user/john/input/sample.csv

Common Error Messages

In this article

Overview

You can use the File Writer Snap to read a binary data stream from the input view and write it to a specified file destination. Possible file destinations include: SLDB, HTTP, S3, FTP, SFTP, FTPS, or HDFS. If you provide file permissions for the file, the Snap sets those permissions to the file.

Image Added

Snap Type

File Writer Snap is a Write-type Snap that writes data to the SnapLogic database or external target database.

Prerequisites

Support for Ultra Pipelines

Works in Ultra Pipelines.

Limitations

• Files uploaded to SLFS have a 100-MB per file limit. This limit does not apply when writing to external storage. 
• Do not use SLDB as a file system or storage. File Assets are intended only for specialized files that a pipeline uses to reference certain data, such as accounts, expressions, or JAR files. Use a Cloud storage provider to store production data. File Assets should not be used as a file source or as a destination in production pipelines. When you configure the Writer Snaps, set the file path to a cloud provider or external file system.
  

Known Issues

• This Snap does not create an output file when using the input from SAS Generator Snap configured with only the DELETE SAS permission. This is not the case when the target file exists.
• This Snap does not fail and turns green after execution despite providing an expired SAS URI. As a workaround, select Validate after write to fail the Snap in case of invalid credentials.
• This Snap Pack does not natively support SHA1-based algorithms to connect to SFTP endpoints. With the August 2023 GA release, you can now leverage the properties specified in the Configuration settings for Snaps to add support for ones that are disabled on your Snaplex. 

Snap Views

{
        "filename": "ftp://ftp.Snaplogic.com/home/qatest/user_manual.pdf",
        "result": "overwritten",
        "original": {
            "content-type" : "application/json"
        }
    }

Snap Settings

Video Demonstration

The following video helps to understand the new AWS canned ACL property.

Watch the following video to understand how to configure the File Writer Snap to write to the S3 Bucket.

Additional Information

Example

• For SFTP files, if you attempt to write a file into a directory where you do not have a write access right, the write operation will fail with "access denied" error. When you get an SFTP account credential, it is also important to know where your home directory is, for example, sftp://ftp.snaplogic.com/home/mrtest for username "mrtest"
• HDFS Example

For HDFS file access, please use a SnapLogic on-premises Groundplex and make sure that its instance is within the Hadoop cluster and SSH authentication has already been established. You can access HDFS files in the same way as other file protocols in File Reader and File Writer Snaps. There is no need to use any account in the Snap.

An example for HDFS is: 

hdfs://<hostname>:<port number>/<path to folder>/<filename>

hdfs://ec2-54-198-212-134.compute-1.amazonaws.com:8020/user/john/input/sample.csv

Troubleshooting

Downloads

Related Links

• Video: File Reader and Writer Demo
• Files
• Binary Snap Pack