Variables

Variables do not need to be declared first. Except predefined variables, other variables are defined at the first time they are assigned a value.

Variable names are case-sensitive. A variable name can be a string of any length that contains English letters, digits, underscore (_), or dot (.).

A variable can contain multiple values. Each variable value must be a string value. When a variable is assigned with more than one value, the values are saved as an ordered list.

Some variables are predefined to help with searching connection strings in command line or file system:

• scp.type: The connection type or protocol of the trigger service connection point.
• scp.ip: The IP address of the trigger service connection point.
• scp.port: The listening port of the trigger service connection point.
• scp.context: The context of the trigger service connection point.
• process.name: A list of process names of discovering running software.
• process.path: A list of process paths of discovering running software.
• process.<process name>.path: A list of process paths with specified name of discovering running software. For example, variable process.tomcat.path saves the paths of all Tomcat processes belong to current discovering running software.

A variable can be used in a file name, file path, file content, property key, XPath, or regular expression. The syntax to use a variable is ${<Variable name>}. For example, part of the connection string might be the IP address(es) of the provider. To save the IP address(es) in the configuration document, you can define a variable named IP_ADDRESS and use it in the expression in this way: ${IP_ADDRESS}.

The scope of all variables are inside an <Application> element.

Variables defined in the same element are grouped. For example, some variables are defined as the example below:

<CommandLine>
    <Regex expr="\s*(\S+)=\s*(\S+).*">
        <Variable name="name" group="1"/>
        <Variable name="value" group="2"/>
    </Regex>
    <SystemVariable name="oracle_home" environmentName="ORACLE_HOME"/>
    <SystemVariable name="tns_home" environmentName="TNS_ADMIN"/>
</CommandLine>

In this example, variable name and value are grouped. Variable oracle_home and tns_home are standalone variables.

When variables of the same group have more than one values, and the variables are used in the same element, they share the same iterator. Variables that are not in the same group use different iterators when the expression is being resolved.

For example, the following expression uses two variables (path and file) to express the full path, and each variable has multiple values.

<Path>${path}/${filename}</Path>

If the two variables are in the same variable group, this expression will be resolved to a string list as follows:

<path1>/<filename1>, <path2>/<filename2>, <path3>/<filename3> …

If the two variables are not in the same variable group, this expression will be resolved to the following:

<path1>/<filename1>, <path1>/<filename2>, <path1>/<filename3> …
<path2>/<filename1>, <path2>/<filename2>, <path2>/<filename3> …
<path3>/<filename1>, <path3>/<filename2>, <path3>/<filename3> …

Configuration signature supports several different ways to assign one or more values to a variable:

• Get value from the system environment variable: <SystemVariable>.
• Get value from a property file by specified property key: <Property> or <PropertyVariable>.
• Get values from an XML file by using XPath expression: <XPath> or <XPathVariable>.
• Get values from a string by using regular expression: <Regex>. Can be embedded in other sources of variables.

Variables can have default values. When the specified value is not found for a variable, the default value will be assigned. If the default value is not defined in this case, the signature processor ignores all ungrouped variables and assigns an empty string to grouped variables to make the lengths of their value lists consistent.