August 15, 2023

tFileStreamInputJSON – Docs for ESB 6.x

tFileStreamInputJSON

Extracts JSON data from a file, then transfers the data to, for instance, a file or a
database table.

tFileStreamInputJSON properties for Apache Spark Streaming

These properties are used to configure tFileStreamInputJSON running in the Spark Streaming Job framework.

The Spark Streaming
tFileStreamInputJSON component belongs to the File family.

The streaming version of this component is available in the Palette of the Studio only if you have subscribed to Talend Real-time Big Data Platform or Talend Data
Fabric.

Basic settings

Define a storage configuration
component

Select the configuration component to be used to provide the configuration
information for the connection to the target file system such as HDFS.

If you leave this check box clear, the target file system is the local
system.

The configuration component to be used must be present in the same Job. For
example, if you have dropped a tHDFSConfiguration component in the Job, you can select it to write
the result in a given HDFS system.

Property type

Either Built-In or Repository.

 

Built-In: No property data stored centrally.

 

Repository: Select the repository file where the
properties are stored.

The fields that come after are pre-filled in using the fetched
data.

For further information about the File
Json
node, see the section about setting up a JSON file
schema in
Talend Studio

User Guide.

Schema et Edit
Schema

A schema is a row description. It defines the number of fields (columns) to
be processed and passed on to the next component. The schema is either Built-In or stored remotely in the Repository.

Click Edit schema to make changes to the schema.
If the current schema is of the Repository type, three
options are available:

  • View schema: choose this option to view the
    schema only.

  • Change to built-in property: choose this
    option to change the schema to Built-in for
    local changes.

  • Update repository connection: choose this
    option to change the schema stored in the repository and decide whether to propagate
    the changes to all the Jobs upon completion. If you just want to propagate the
    changes to the current Job, you can select No
    upon completion and choose this schema metadata again in the [Repository Content] window.

 

Built-In: You create and store the
schema locally for this component only. Related topic: see
Talend Studio

User Guide.

 

Repository: You have already created
the schema and stored it in the Repository. You can reuse it in various projects and
Job designs. Related topic: see
Talend Studio

User Guide.

Read by

Select a way of extracting the JSON data in the file.

  • Xpath: Extracts the JSON data based on
    the XPath query.

  • JsonPath: Extracts the JSON data based on
    the JSONPath query. Note that it is recommended to read the data by JSONPath in
    order to gain better performance.

Folder/File

Browse to, or enter the path pointing to the data to be used in the file system.

If the path you entered points to a folder, all files stored in
that folder will be read.

If the file to be read is a compressed one, enter the file name
with its extension; then tFileInputJSON automatically decompresses it at
runtime. The supported compression formats and their corresponding
extensions are:

  • DEFLATE: *.deflate

  • gzip: *.gz

  • bzip2: *.bz2

  • LZO: *.lzo

The button for browsing does not work with the Spark Local mode; if you are using the Spark Yarn or the Spark Standalone mode,
ensure that you have properly configured the connection in a configuration component in
the same Job, such as tHDFSConfiguration.

Die on error

Select the check box to stop the execution of the Job when an error
occurs.

Loop Jsonpath query

Enter the path pointing to the node within the JSON field, on which the loop is
based.

Note if you have selected Xpath from the Read
by
drop-down list, the Loop Xpath
query
field is displayed instead.

Mapping

Complete this table to map the columns defined in the schema to the
corresponding JSON nodes.

  • Column: The Column cells are automatically filled with the defined schema
    column names.

  • Json query/JSONPath query: Specify the JSONPath node that holds the
    desired data. For more information about JSONPath expressions, see http://goessner.net/articles/JsonPath/.

    This column is available only when JsonPath is selected from the Read
    By
    list.

  • XPath query: Specify the XPath node that
    holds the desired data.

    This column is available only when Xpath is selected from the Read
    By
    list.

  • Get Nodes: Select this check box to
    extract the JSON data of all the nodes or select the check box next to a
    specific node to extract the data of that node.

    This column is available only when Xpath is selected from the Read
    By
    list.

Advanced settings

Advanced separator (for number)

Select this check box to change the separator used for numbers. By default, the thousands separator is a comma (,) and the decimal separator is a period (.).

Encoding

You may encounter encoding issues when you process the stored data. In that
situation, select this check box to display the Encoding list.

Select the encoding from the list or select Custom and define it manually.

Usage

Usage rule

This component is used as a start component and requires an output link.

This component, along with the Spark Streaming component Palette it belongs to, appears
only when you are creating a Spark Streaming Job.

Note that in this documentation, unless otherwise explicitly stated, a scenario presents
only Standard Jobs, that is to say traditional
Talend
data
integration Jobs.

Spark Connection

You need to use the Spark Configuration tab in
the Run view to define the connection to a given
Spark cluster for the whole Job. In addition, since the Job expects its dependent jar
files for execution, you must specify the directory in the file system to which these
jar files are transferred so that Spark can access these files:

  • Yarn mode: when using Google
    Dataproc, specify a bucket in the Google Storage staging
    bucket
    field in the Spark
    configuration
    tab; when using other distributions, use a
    tHDFSConfiguration
    component to specify the directory.

  • Standalone mode: you need to choose
    the configuration component depending on the file system you are using, such
    as tHDFSConfiguration
    or tS3Configuration.

This connection is effective on a per-Job basis.

Related scenarios

No scenario is available for the Spark Streaming version of this component
yet.


Document get from Talend https://help.talend.com
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