Get variables
Usage
Note that workflow/environment variables are set only once. A pipeline needs to start to get any new variables. A running or sequential or nested (nested pipelines are technically the same pipeline) pipeline can’t fetch new variable values. A pipeline is considered started when a pipeline starts for every row in a pipeline executor.
Refer to parameters/variables using the syntax: ${myVariable}, for example from a previous pipeline.
Two ways to pass fields, parameters to variables downstream:
Parameters must be unique per pipeline (case is not a differentiator). The pipeline executor parameter value takes precedence over the pipeline’s properties parameter value. The sending parameter value takes precedence over the default value of the receiving pipeline’s properties parameter.
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Use a pipeline executor transform or a Repeat action:
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Send: add fields on the Parameters tab (parameter name can be same as field name) to send.
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Receive: in the immediate downstream pipeline, use Get variables to set variables/fields from Parameters using format: ${myParam}
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Edit any upstream pipeline’s properties:
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Send: Add a parameter on the parameters tab of a pipeline’s properties (Edit pipeline icon), and optionally give it a default value. The parameter value can be set in a pipeline using various transforms.
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Receive: in the immediate downstream pipeline, use Get variables to set variables/fields from Parameters using format: ${myParam}
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Other:
See also the Set Variables transform.
To convert the Variable into a data type other than String use Select Values - Meta Data tab.
To get system values, including command line arguments, use the Get System Info transform.
For example, in the variable column, you can specify: ${java.io.tmpdir}/hop/tempfile.txt and it will be evaluated as /tmp/hop/tempfile.txt on Unix-like systems.
Troubleshooting
You must always specify the data type or you will have errors like the following:
2023/07/21 09:30:23 - REST client.0 - ERROR: Because of an error, this transform can’t continue: 2023/07/21 09:30:23 - REST client.0 - TOKEN_URL None : Unknown type 0 specified. 2023/07/21 09:30:23 - REST client.0 - ERROR: org.apache.hop.core.exception.HopValueException:
Options
| Option | Description | ||
|---|---|---|---|
transform Name | The name of this transform as it appears in the pipeline workspace. | ||
Name | Name of the field. | ||
Variable | Allows you to enter variables as complete strings to return rows or add values to input rows. For example, you can specify: $${java.io.tmpdir}/hop/tempfile.txt and it will be expanded to /tmp/hop/tempfile.txt on Unix-like systems.
| ||
Type | Specifies the field type: String, Date, Number, Boolean, Integer, BigNumber, Serializable, or Binary. | ||
Format | Allows you to specify the format of the field after the type has been determined. | ||
Length | For Number: Total number of significant figures in a number; For String: total length of string; For Date: length of printed output of the string (for example, entering 4 would only return the year). | ||
Precision | For Number: Number of floating point digits. Not used for String, Date, or Boolean. | ||
Currency | Used to interpret numbers with currency symbols. For example, $10,000.00 or E5.000,00. | ||
Decimal | Used to indicate whether to use a period (".") or comma (",") for number values. | ||
Group | Used to indicate whether to use a period (".") or comma (",") for number values. | ||
TrimType | Type trim this field before processing: select either none, left, right, or both (left and right). |