When deploying web application to different environments you don’t want to re-build application package every time with different configurations, but you want to deploy the same package (artifact) with some environment-specific settings configured during deployment. When using Web Deploy the problem can be easily solved by Web Deploy parametrization.
Usage scenarios
Most common use cases for Web Deploy parametrization is updating node/attribute value in XML files or replacing a token in text files, for example:
- appSettings in
web.config - connection strings in
web.config - WCF endpoints
- Paths to log files
- Database name in SQL install script
Parameters.xml
To enable Web Deploy parametrization add parameters.xml file in the root of your web application.
Parameters.xml contains the list of parameters required (or supported) by your Web Deploy package. In the example below we introduce two parameters - one to update path to log file in appSettings section of web.config and another one to set database name in SQL script.
Parameter element describes the name, default value and the places where and how this parameter must be applied.
Parameters.xml for our example:
<?xml version="1.0" encoding="utf-8" ?>
<parameters>
<parameter name="LogsPath" defaultValue="logs">
<parameterEntry kind="XmlFile" scope="\\web.config$" match="/configuration/appSettings/add[@key='LogsPath']/@value" />
</parameter>
<parameter name="DatabaseName">
<parameterEntry kind="TextFile" scope="\\Database\\install_db.sql$" match="@@database_name@@" />
</parameter>
When Web Deploy package is built you can open it in the explorer and see parameters.xml in the root:
Resulting parameters.xml combines your custom parameters and system ones such as IIS Web Application Name. You don’t have to set IIS Web Application Name parameter explicitly - AppVeyor does that for you.
Read more about defining parameters: https://technet.microsoft.com/en-us/library/dd569084(v=ws.10).aspx
Setting parameters during deployment
Web Deploy provider in AppVeyor analyzes Web Deploy package and looks into environment variables to set parameter values with matching names.
When promoting specific build from Environment page you set variables on environment settings page:
When deploying during the build session environment variables are used instead. You can set build environment variables on Environment tab of project settings, appveyor.yml or programmatically during the build.
Variables defined during the build override those ones defined on Environment level.
Web Deploy parametrization is supported by Deployment Agent too when deploying from Web Deploy package.
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