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new f50e92dc1a Update getvariable.adoc
new 630b01d251 Merge pull request #3468 from Mattang-Dan/patch-59
f50e92dc1a is described below
commit f50e92dc1a774a383827948aa6c01cd085eddc5e
Author: Mattang-Dan <[email protected]>
AuthorDate: Wed Nov 29 11:05:47 2023 -0800
Update getvariable.adoc
---
.../pages/pipeline/transforms/getvariable.adoc | 33 ++++++++++++++++++----
1 file changed, 27 insertions(+), 6 deletions(-)
diff --git
a/docs/hop-user-manual/modules/ROOT/pages/pipeline/transforms/getvariable.adoc
b/docs/hop-user-manual/modules/ROOT/pages/pipeline/transforms/getvariable.adoc
index 92a7172516..d062583be1 100644
---
a/docs/hop-user-manual/modules/ROOT/pages/pipeline/transforms/getvariable.adoc
+++
b/docs/hop-user-manual/modules/ROOT/pages/pipeline/transforms/getvariable.adoc
@@ -27,6 +27,8 @@ under the License.
|
== Description
The Get Variables transform allows you to get the value of a variable and
create field(s) from it. You only need to use this transform if you need the
variable value in a field.
+
+TIP: If you need to refer to a previous pipeline’s data row(s) fields, then
use a Get rows from result transform.
|
== Supported Engines
[%noheader,cols="2,1a",frame=none, role="table-supported-engines"]
@@ -38,22 +40,41 @@ The Get Variables transform allows you to get the value of
a variable and create
!===
|===
+== 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: {openvar}myVariable{closevar},
for example from a previous pipeline. If you need to refer to a previous
pipeline’s data row(s) fields, then use a Get rows transform.
+Refer to parameters/variables using the syntax: {openvar}myVariable{closevar},
for example from a previous pipeline.
-For example, you can specify:
`{openvar}java.io.tmpdir{closevar}/hop/tempfile.txt` and it will be expanded to
`/tmp/hop/tempfile.txt` on Unix-like systems.
+*Two ways to pass fields, parameters to variables downstream:*
-You must always specify the data type or you will have errors like the
following:
+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.
-``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:``
+ * Use a pipeline executor transform or a Repeat action:
+ - Send: add fields on the Parameters tab (parameter name can be same as
field name) to send.
+ - Receive: in the immediate downstream pipeline, use Get variables to set
variables/fields from Parameters using format: ${myParam}
+ * Edit any upstream pipeline’s properties:
+ - 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.
+ - Receive: in the immediate downstream pipeline, use Get variables to set
variables/fields from Parameters using format: ${myParam}
+
+
+*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:
`{openvar}java.io.tmpdir{closevar}/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
[options="header"]
