Managing multiline xml attributes with augeas

[Francois Herbert]

I'm trying to use the augeas resource type to manage a multiline attribute in an xml file. It looks like this:

<resolver:AttributeResolver

        xmlns:resolver="urn:mace:shibboleth:2.0:resolver" 

        xmlns:pc="urn:mace:shibboleth:2.0:resolver:pc"

        xmlns:ad="urn:mace:shibboleth:2.0:resolver:ad" 

        xmlns:dc="urn:mace:shibboleth:2.0:resolver:dc"

        xmlns:enc="urn:mace:shibboleth:2.0:attribute:encoder" 

        xmlns:sec="urn:mace:shibboleth:2.0:security"

        xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 

        xsi:schemaLocation="urn:mace:shibboleth:2.0:resolver http://shibboleth.net/schema/idp/shibboleth-attribute-resolver.xsd

                            urn:mace:shibboleth:2.0:resolver:pc http://shibboleth.net/schema/idp/shibboleth-attribute-resolver-pc.xsd

                            urn:mace:shibboleth:2.0:resolver:ad http://shibboleth.net/schema/idp/shibboleth-attribute-resolver-ad.xsd

                            urn:mace:shibboleth:2.0:resolver:dc http://shibboleth.net/schema/idp/shibboleth-attribute-resolver-dc.xsd

                            urn:mace:shibboleth:2.0:attribute:encoder http://shibboleth.net/schema/idp/shibboleth-attribute-encoder.xsd

                            urn:mace:shibboleth:2.0:security http://shibboleth.net/schema/idp/shibboleth-security.xsd">

 As you can see, the xsi:schemaLocation is a multine value attribute. Using augtool, I can manually update this attribute using the Xml.lns lens and running:

set /files/attribute-resolver.xml/resolver:AttributeResolver/#attribute/xsi:schemaLocation 'urn:mace:shibboleth:2.0:resolver http://shibboleth.net/schema/idp/shibboleth-attribute-resolver.xsd\n        urn:mace:shibboleth:2.0:resolver:pc http://shibboleth.net/schema/idp/shibboleth-attribute-resolver-pc.xsd'

But using the augeas resource type I can't seem to get it right. Any of my '\n' are escaped so what ends up in the xml file is '\\n' which is incorrect. My manifest looks like this:

$changes = 'set resolver:AttributeResolver/#attribute/xsi:schemaLocation "urn:mace:shibboleth:2.0:resolver http://shibboleth.net/schema/idp/shibboleth-attribute-resolver.xsd\n        urn:mace:shibboleth:2.0:resolver:pc http://shibboleth.net/schema/idp/shibboleth-attribute-resolver-pc.xsd"

augeas { "attributeresolver_attributes_${name}":

    lens    => 'Xml.lns',

    incl    => $configfile,

    changes => $changes,

  }

I've tried changing the double quotes around to single quotes but still can't get it to write the '\n' correctly.

Any ideas?