ConfigMerge

Web/App.config merge tool based on https://github.com/andreakn/ConfigStitcher

ConfigMerge lets you merge multiple config files without the need of xdt transforms. It also allows for independent local config files, typically for development environments, since nonexisting files are ignored. A developer would typically store his or her override settings in a file outside of (or ignored in) source control.

Example transformation

App.root.config:

<configuration>
    <appSettings>
        <add key="toBeOverridden" value="should be overridden"/>
        <add key="toBeDeleted" value="should be deleted"/>
        <add key="toBeleftAlone" value="unchanged"/>
    </appSettings>
    <connectionStrings>
        <add name="toBeOverridden" connectionString="should be overridden"/>
        <add name="toBeDeleted" connectionString="should be deleted"/>
        <add name="toBeleftAlone" connectionString="unchanged"/>
    </connectionStrings>
    <system.runtime.caching></system.runtime.caching>
</configuration>

App.override.config:

<configuration>
    <appSettings>
        <add key="added" value="added value"/>
        <add key="toBeOverridden" value="overridden"/>
        <add key="toBeDeleted"  DELETEME="true"/>
    </appSettings>
    <connectionStrings>
        <add name="added" connectionString="added connection string"/>
        <add name="toBeOverridden" connectionString="overridden"/>
        <add name="toBeDeleted" DELETEME="true"/>
    </connectionStrings>
    <assemblyBinding></assemblyBinding>
    <system.runtime.caching DELETEME="true"></system.runtime.caching>
</configuration>

Result:

<configuration>
  <appSettings>
    <add key="toBeOverridden" value="overridden" />
    <add key="toBeleftAlone" value="unchanged" />
    <add key="added" value="added value" />
  </appSettings>
  <connectionStrings>
    <add name="toBeOverridden" connectionString="overridden" />
    <add name="toBeleftAlone" connectionString="unchanged" />
    <add name="added" connectionString="added connection string" />
  </connectionStrings>
  <assemblyBinding></assemblyBinding>
</configuration>

Transformation recipies

A transformation is specified like this:

outputFile = [inputfile1, inputfile2, ...];

Last input file wins
Non-existing files are ignored

Simple usage (commandline argument):

C:\some\path\ConfigMerge.exe -recipe:App.config=[App.root.config,App.override.config];

Relative paths are relative the current directory. In this case: C:\some\path

Typical usage (recipe file):

Recipies can be specified in a recipe file:

ConfigMerge.exe -recipe:Web.config.recipe

Relative paths are relative to the recipe file's parent directory.

Example recipe file (Web.config.recipe):

# Folder "input/" stored in variable inputFolder
var inputFolder = input/;
var outputFolder = output/;


# Non-absolute file paths are relative to Web.config.recipe's parent folder
# Last file wins
# Non-existing files are ignored

# Create ./output/Web.test.config by merging ./input/Web.root.config, input/Web.test.override.config and input/Web.dev.config
# Web.dev.config might not be tracked by source control
outputFolder + Web.test.config = inputFolder + [Web.root.config, Web.test.override.config, Web.dev.config];

# Create ./output/Web.prod.config by merging ./input/Web.root.config and input/Web.prod.override.config
outputFolder + Web.prod.config = inputFolder + [Web.root.config, Web.prod.override.config];

# Create output based on input/Web.input1.config, input/Web.input2.config, etc.
Web.manyinputs.config = inputFolder + "Web." + [input1, input2, input3, input4] + .config;

String values may be enclosed in double quotes if they contain alphanumerics, '.', '/' or ''
String values MUST be enclosed in double quotes if they contain any other characters

Merge config files on build

Add a pre build event to your project:

path\to\ConfigMerge.exe -recipe:"$(ProjectDir)Web.config.recipe"

Be aware of

Some nuget packages add settings to Web/App.config when you install them. If Web.config is generated on build, these settings will be gone. When you install a nuget package, make sure the necessary settings are added to your input config files (e.g. Web.root.config).

Under the hood:

ConfigMerge parses the recipe and creates a lambda expression that is compiled and invoked with a ConfigTransformer. The ConfigTransformer then merges the given inputs, and writes the given outputs.

loftum/ConfigMerge