Configuration variables and system variables
Often when you deploy your app, you need access to configuration or system settings for your script. That way you don’t have to hardcode values in multiple locations when the values may change depending on a configuration, build, server, or release. To avoid hardcoded values, with Release Management for Visual Studio 2013 Update 4 you can use configuration and system variables within your scripts for vNext releases.
Configuration variables provide reusable and customizable settings that are available during action execution. You can set configuration variables and default values on servers, components and globally, and then use those values in your PowerShell scripts and configuration scripts. And, if you don’t want to use a default value during a deployment, you can override it. An example for using configuration variables is setting the user name and password used for deploying your app on the server.
Configuration variables can be set at the global, server, component, and action levels.
Global configuration variables: Set via Administration > Settings > Configuration Variables. Available everywhere.
Server configuration variables: Set via Configure Paths > Server, selecting a server, Configuration Variables. Available to actions that deploy your app to the server. Use for server-specific variables, such as for a UserName and a Password.
Component configuration variables: Set via Configure Apps > Component, selecting a component, Configuration Variables. Available to actions that use the component.
Action configuration variables: Set within the Release Template designer, available to the actions.
The order of precedence, from highest to lowest, when a configuration variable name is used in more than one level is Configuration Script file>Action>Component>Server>Global.
To manage configuration variables, in the bottom left corner of the Release Templates and Releases views are tabs named Configuration variables and Resource variables.
The Configuration variables tab shows the configuration variables in effect for the action, for each stage.
The Resource variables tab shows the configuration variables and values that are set globally, for servers, and for components. (These are current values, not a snapshot from a previous time.) Changes to resource variables will be in effect by in-flight releases that start a new deployment.
To add a configuration variable within an action, in the Release Templates Designer, open an activity, click the dropdown arrow in the Custom configuration section, and specify Standard or Encrypted for the type of configuration variable. (If using Encrypted, ensure the HTTPS listener is configured on the server where you deploy your app.)
Type in the name of the new variable, and provide its value.
To override a value in a resource variable, click the + sign and then click the dropdown arrow in the Custom configuration section. Select the variable to customize and provide a value.
In addition to configuration settings, your script might also need access to system settings. For example, if your script needs to perform special action when you deploy your app to a Production environment, the script can examine the Environment variable. The following system variables are available:
ApplicationPath Destination path, including the component name, where the component is copied.
ApplicationPathRoot Destination path where the component is copied. The default is C:\Windows\dtlDownloads. You can over-ride this value to specify an alternative destination path.
BuildDefinition Build definition for the component.
BuildNumber Build number for the component.
Environment The environment for the release.
PackageLocation The source path from which the component is copied. For builds dropped to a Standard server, the path points to the container-id. For builds dropped to Azure, the path points to the storage blob GUID.
ReleaseId The ID of the release; this is assigned by Release Management.
ReleaseNumber The number of the release.
Stage The stage of the release.
Tag Tag used to group the server which is running the action.
TeamProject Team project for the component.
TFSUrl TFS URL for the component.
When using configuration or system variables in scripts, prefix a $ to the variable name. For example: $Stage.
Note a value could be unassigned. For example, if you are deploying your app to a server that wasn’t grouped by a tag, the value of the $Tag variable will be unassigned.