Runtime Values

Runtime values are values that you define outside of the pipeline and use for stage and pipeline properties. You can change the values for each pipeline run without having to edit the pipeline.

You can use runtime values for any pipeline property that allows the use of the expression language. You can, for example, use runtime values to represent batch sizes, timeouts, directories, and URI. You cannot use runtime values to represent fields.

You can use the following methods of passing runtime values to pipelines:

Runtime parameters: Use runtime parameters when you want to define runtime values for a single pipeline.; You define runtime parameters when you configure the pipeline, and then you call the parameters from within that pipeline. When you start the pipeline, you can optionally override the parameters defined in the pipeline.; Runtime parameters are defined for a single pipeline - only that pipeline can call them.
Runtime properties: Use runtime properties when you want to define values for multiple pipeline properties in a single file.; You define runtime properties in a file local to the Data Collector, and then you call the properties from within a pipeline. At runtime, Data Collector loads the property values from the file. A runtime properties file can contain multiple properties.; Runtime properties are defined for the entire Data Collector - any pipeline can call them.
Runtime resources: Use runtime resources when you want to store common pipeline configuration properties in files with restricted permissions.; You define runtime resources in a file local to the Data Collector, and then you call the resources from within a pipeline. You can restrict the permissions for the resource files, but any user who can create a pipeline can access the data stored in the files. Data Collector loads the property values from the files each time it processes a new batch. A runtime resource file can contain a single piece of information.; Runtime resources are defined for the entire Data Collector - any pipeline can call them.; Tip: Runtime resources can impact pipeline performance because Data Collector loads runtime resource files for each batch. Consider using runtime parameters or runtime properties instead. Or, to more securely define sensitive values, consider using credential stores. For more information, see Credential Stores in the Data Collector documentation.

Note: When configuring runtime values for pipelines run by StreamSets Control Hub, all Data Collector that run the pipeline must have the values locally defined in the expected locations.

Runtime Parameters

Runtime parameters are parameters that you define in a pipeline and then call from within that same pipeline. When the pipeline runs, the value replaces the name of the runtime parameter. Use runtime parameters to define values for stage and pipeline properties.

When you start the pipeline, you can override the default parameter values. For example, you can define a directory parameter that points to a directory on a production system and override it during testing to point to a directory on a test system.

Note: If you shut down and then restart Data Collector without stopping the pipeline, the pipeline continues running with the last set of parameter values.

To implement runtime parameters, perform the following steps:

Define runtime parameters.
Use an expression in the pipeline to call a runtime parameter.

Step 1. Define Runtime Parameters

Define runtime parameters when you configure the pipeline.

In the pipeline properties, click the Parameters tab.
Using simple or bulk edit mode, click the Add icon and define the name and the default value for each parameter.
For example, define a parameter named JDBCConnectionString with the default value of jdbc:mysql://localhost:3306/sample.

Step 2. Call the Runtime Parameters

Use an expression in the pipeline to call a runtime parameter.

You can use runtime parameters to represent any stage or pipeline property that allows the use of the StreamSets expression language, including properties that display as text boxes, checkboxes, drop-down menus. You can also call a runtime parameter in the code developed for a scripting processor.

Calling from Text Boxes

To call a runtime parameter in a stage or pipeline property that displays as a text box, use the following syntax:

${<parameter name>}

For example, to use the JDBCConnectionString runtime parameter for the JDBC Multitable Consumer origin, enter the following syntax for the JDBC Connection String property:

${JDBCConnectionString}

You can call a runtime parameter from within an expression language function by simply entering the parameter name. For example, the following expression returns the value of the JDBCConnectionString runtime parameter:

 ${record:value(JDBCConnectionString)}

You can use a runtime parameter to represent a part of a property. For example, you could use a RootDir runtime parameter and append the rest of the directory in the property as follows:

${RootDir}/logfiles

Calling from Checkboxes and Drop-Down Menus

To call a runtime parameter in a stage or pipeline property that displays as a checkbox or drop-down menu, you first must convert the property to a text box.

Click the Use Parameter icon (

) next to the checkbox or drop-down menu to convert the property to a text box, and then call the parameter using the required syntax:

${<parameter name>}

For example, the following image shows that the Delivery Guarantee property that displays as a drop-down menu has been converted to a text box so that a parameter can be called from the property:

The parameter must evaluate to a valid option for the property type:

Checkboxes: Parameters called from properties that display as checkboxes must evaluate to true or false.
Drop-down menus: Parameters called from properties that display as drop-down menus must evaluate to a valid key value. Each option in the menu has an associated key value.; For example, to use a parameter for the Delivery Guarantee property that displays as a drop-down menu, the parameter must evaluate to one of the valid key values, AT_LEAST_ONCE or AT_MOST_ONCE, and not to one of the menu options, At Least Once or At Most Once.; To view the valid keys for a menu, configure the pipeline with the desired option, then export the pipeline and view the exported pipeline JSON file.

Calling from Scripting Processors

You can call a runtime parameter in the code developed for a scripting processor.

The method you use to call the runtime parameter depends on the following scripting processor types:

JavaScript Evaluator processor

Use the following syntax in any of the processor scripts: ${<parameter name>}. For example, the following line of JavaScript code assigns the value of the NewFieldValue parameter to a map field:

records[i].value.V= ${NewFieldValue}

Jython Evaluator processor

You can use either of the following methods:

Use the following syntax in any of the processor scripts: '${<parameter name>}'. For example, the following line of Jython code assigns the value of the NewFieldValue parameter to a map field:
```
records[i].value = '${NewFieldValue}'
```
Use the sdc.pipelineParameters() method in any of the processor scripts to return a map of all runtime parameters defined for the pipeline. For example, the following line of Jython code assigns the value of the NewFieldValue parameter to a map field:
```
records[i].value = sdc.pipelineParameters()['NewFieldValue']
```

Groovy Evaluator processor

Use the sdc.pipelineParameters() method in any of the processor scripts to return a map of all runtime parameters defined for the pipeline. For example, the following line of Groovy code assigns the value of the CompanyParam parameter to the Company Name field:

record.value['Company Name'] = sdc.pipelineParameters()['CompanyParam']

Runtime Resources

Similar to runtime properties, runtime resources are values that you define in a file local to the Data Collector and call from within a pipeline. But with runtime resources, you can restrict the permissions for the files to secure information.

Use runtime resources to store common configuration properties for multiple pipelines, like URLs for external systems. Note that any user who can create a pipeline can access the data stored in the resource files.

Tip: Runtime resources can impact pipeline performance because Data Collector loads runtime resource files for each batch. Consider using runtime parameters or runtime properties instead. Or, to more securely define sensitive values, use credential stores. For more information, see Credential Stores in the Data Collector documentation.

To implement runtime resources, perform the following steps:

Define each runtime resource.
Use an expression in the pipeline to call a runtime resource.

Step 1. Define Runtime Resources

Use the following steps to define runtime resources:

For each resource, create a text file and save it in the $SDC_RESOURCES directory. This directory should be defined outside of $SDC_DIST, the Data Collector runtime directory.
A file must contain one piece of information to be used when the resource is called.
Optionally, restrict the permissions for the file.
Generally, anyone can read a file. To restrict permissions, configure the file so only the owner has read or write permissions for the file - in octals, that's 600 or 400. And the owner must be the system user that runs the Data Collector.
When you use the resource in the pipeline, you specify whether the file is restricted.

Step 2. Call the Runtime Resource

Use the runtime:loadResource or runtime:loadResourceRaw function to call a runtime resource. You can use runtime resources to represent information in any stage or pipeline property that allows the use of the expression language.

Note: In most cases, you'll use the runtime:loadResource function which trims any leading or trailing whitespace characters from the file. However, if needed, you can also use the runtime:loadResourceRaw function which includes any leading or trailing whitespace characters in the file.

To call a runtime resource, use the following syntax:

${runtime:loadResource(<file name>, <restricted: true | false>)}

For example, the following expression returns the contents of the JDBC.txt file, trimming any leading or trailing whitespace characters. The file contains a connection string and is restricted so only the owner can read the file:

${runtime:loadResource("JDBC.txt", true)}

Runtime Properties

Runtime properties are properties that you define in a file local to the Data Collector and call from within a pipeline.

With runtime properties, you can define different sets of values for different Data Collectors. Runtime properties allow you to easily update the property definitions without editing the pipeline.

For example, you might define a set of runtime properties that points to test systems for pipeline development. When you move to production, you simply update the runtime property definitions in the file. This effectively updates every pipeline that uses those runtime properties without having to edit the pipelines.

When defining a runtime property, you can use a static value or an environment variable.

When calling the runtime property, you can use it as part of a larger property definition. For example, you can set a runtime property to the HOME environment variable, which would differ on different machines, and then call the runtime property as a base directory for a longer directory.

To implement runtime properties, perform the following steps:

Define runtime properties.
Use an expression in the pipeline to call a runtime property.

Step 1. Define Runtime Properties

You can define runtime properties in the Data Collector configuration file, $SDC_CONF/sdc.properties, or in a separate runtime properties file. If you define the properties in a separate runtime properties file, use the required procedure for your installation type.

Data Collector configuration file

Use the following steps to define runtime properties in the Data Collector configuration file:

In the Data Collector configuration file, $SDC_CONF/sdc.properties, configure the runtime.conf.location property as follows:
```
runtime.conf.location=embedded
```
To define the runtime properties in the Data Collector configuration file, use either of the following formats:
- To define a static value for a runtime property, use the following format:
```
runtime.conf_<property name>=<value>
```
  For example, the following runtime property defines a Hadoop FS directory template:
```
runtime.conf_HDFSDirTemplate=/HDFS/DirectoryTemplate
```
- To define an environment variable for a runtime property, use the following format:
```
runtime.conf_<property name>=${env("<environment_variable>")}
```
  For example, the following runtime property defines a base directory, setting it to the HOME environment variable:
```
runtime.conf_BaseDir=${env("HOME")}
```
To enable the changes, restart Data Collector.

Separate runtime properties file for tarball and RPM

Use the following steps to define runtime properties in a separate runtime properties file for a tarball or RPM installation:

Create a text file and save it in a directory relative to the $SDC_CONF directory.
To define runtime properties in a separate text file, use either of the following formats:
- To define a static value for a runtime property, use the following format:
```
<property name>=<value>
```
  For example, the following runtime property defines a Hadoop FS directory template:
```
HDFSDirTemplate=/HDFS/DirectoryTemplate
```
- To define an environment variable for a runtime property, use the following format:
```
<property name>=${env("<environment_variable>")}
```
  For example, the following runtime property defines a base directory, setting it to the HOME environment variable:
```
BaseDir=${env("HOME")}
```
In the Data Collector configuration file, $SDC_CONF/sdc.properties, configure the runtime.conf.location property to point to the location of the separate runtime properties file. Specify a relative path for a file inside the $SDC_CONF directory or an absolute path for a file outside the $SDC_CONF directory.
For example, the following separate runtime properties file is located in a runtime directory that is inside the $SDC_CONF directory:
runtime.conf.location=runtime/test-runtime.properties
To enable the changes, restart Data Collector.

Separate runtime properties file for Cloudera Manager

Use the following steps to define runtime properties in a separate runtime properties file for a Cloudera Manager installation:

Create a text file and define the runtime properties in the text file using either of the following formats:
- To define a static value for a runtime property, use the following format:
```
<property name>=<value>
```
  For example, the following runtime property defines a Hadoop FS directory template:
```
HDFSDirTemplate=/HDFS/DirectoryTemplate
```
- To define an environment variable for a runtime property, use the following format:
```
<property name>=${env("<environment_variable>")}
```
  For example, the following runtime property defines a base directory, setting it to the HOME environment variable:
```
BaseDir=${env("HOME")}
```
Save the text file in the same directory on every node that runs Data Collector.
In Cloudera Manager, select the StreamSets service and click Configuration.
On the Configuration page, in the Data Collector Advanced Configuration Snippet (Safety Valve) for sdc-env.sh field, add the following line to define the runtime properties file directory:
```
ln -sf /<directory>/runtime.properties "${CONF_DIR}/runtime.properties"
```
For example:
```
ln -sf /opt/sdc-runtime/runtime.properties "${CONF_DIR}/runtime.properties"
```
In the Data Collector Advanced Configuration Snippet (Safety Valve) for sdc.properties field, configure the runtime.conf.location property to point to the separate runtime properties file by adding the following line:
```
runtime.conf.location=runtime.properties 
```
Restart Data Collector to enable the changes.

For more information, see Configuring Data Collector in the Data Collector documentation.

Step 2. Call the Runtime Property

Use the runtime:conf function to call a runtime property. You can use runtime properties to represent any stage or pipeline property that allows the use of the expression language.

To call a runtime property, use the following syntax:

${runtime:conf(<property name>)}

For example, to call the HDFSDirTemplate runtime property to provide the directory template value for the Hadoop FS destination, enter the following syntax for the Directory Template property:

${runtime:conf('HDFSDirTemplate')}

You can call a runtime property to represent a part of a property value. For example, you can call the RootDir runtime property and append the rest of the directory, as follows:

${runtime:conf('RootDir')}/logfiles