Service Template Definitions

A registered service template definition is the foundation and initial building block to construct a service definition. Acting as a blueprint, a template definition will specify a framework for what a given registered service definition might look like. For example, a service template definition might want to specify a collection common settings and application policies for a given service type, such as attribute release and consent policies, to remove the need for those policies to be specified yet again in future service definitions that might stem from that blueprint. Concrete service definitions will automatically inherit from future improvements/changes to the template.

A few important considerations:

Concrete service definitions always have the ability to override the template definition and enforce their own policy and settings to allow for exceptions. Their version of the configuration and policy will always override the base template. The merging process is not exactly fine-tuned to pick out individual differences in configuration blocks.
Concrete service definitions may link up with a template definition using their template name and type. This design choice allows the CAS deployer to define multiple service definition blueprints and templates for the same type of CAS applications with different names.
Service definitions are not required to build and spin off of a blueprint and can remain and function in a standalone manner.
The relationship and inheritance hierarchy between a template definition and concrete definitions is fixed at one level or degree and is not recursive. However, composition is favored over inheritance and you may assign multiple template definition names to a concrete service in a comma-separated fashion.

Usage

Template service definitions work for and apply to all types of registered service definitions known to CAS and are not restricted to a specific type or protocol. The resulting service definition after the merge operation is always internal to CAS, and is not something you can manage and/or maintain separately.

The directory location of template service definitions needs to be taught to CAS via settings. This directory is expected to hold .json service definition files that structurally are no different than any given registered service in CAS. The directory is searched for template definitions recursively, and you may come up with your own directory structure to group definitions by type, application, etc.

Remember that a service template definition filename MUST match the template name itself. The formula for naming template definition files should be:

templateFileName = templateName + ".json"

Configuration

The following settings and properties are available from the CAS configuration catalog:

_{The configuration settings listed below are tagged as Required in the CAS configuration metadata. This flag indicates that the presence of the setting may be needed to activate or affect the behavior of the CAS feature and generally should be reviewed, possibly owned and adjusted. If the setting is assigned a default value, you do not need to strictly put the setting in your copy of the configuration, but should review it nonetheless to make sure it matches your deployment expectations.}

cas.service-registry.templates.directory.location=

The location of the resource. Resources can be URLs, or files found either on the classpath or outside somewhere in the file system.

In the event the configured resource is a Groovy script, specially if the script set to reload on changes, you may need to adjust the total number of inotify instances. On Linux, you may need to add the following line to /etc/sysctl.conf: fs.inotify.max_user_instances = 256.

You can check the current value via cat /proc/sys/fs/inotify/max_user_instances.

In situations and scenarios where CAS is able to automatically watch the underlying resource for changes and detect updates and modifications dynamically, you may be able to specify the following setting as either an environment variable or system property with a value of false to disable the resource watcher: org.apereo.cas.util.io.PathWatcherService.

org.apereo.cas.configuration.model.SpringResourceProperties.

_{How can I configure this property?}

Configuration properties can be included and activated using the following strategies.

Note

When possible, properties should be stored in lower-case kebab format, such as cas.property-name=value. The only possible exception to this rule is when naming actuator endpoints; The name of the actuator endpoints (i.e. ssoSessions) MUST remain in camelCase mode.

CAS properties can be specified using the Java configuration property syntax in any and all .properties files:

cas.service-registry.templates.directory.location=...

This is the most common form of property configuration that is recognized by CAS, regardless of the actual property source, which might in fact be managed separately outside the CAS environment, by another system or cloud framework.

CAS properties can be specified using the YAML syntax:

cas: 
  service-registry: 
    templates: 
      directory: 
        location: "..."

Note that YAML is very specific about structure and indentation. Be sure to verify the correctness of the final result with your YAML validator of choice.

CAS properties can be passed to the CAS web application as system properties, when the application is launched:

java -Dcas.service-registry.templates.directory.location="..." -jar build/libs/cas.war

The above example assumes that the CAS web application is packaged as cas.war with an embedded server container and can be found in the build/libs directory. Note the placement of the system property which must be specified before the CAS web application is launched.

CAS properties can specified as system environment variables before the CAS web application is launched:

export CAS_SERVICE_REGISTRY_TEMPLATES_DIRECTORY_LOCATION="..."

java -jar build/libs/cas.war

The above example assumes that the CAS web application is packaged as cas.war with an embedded server container and can be found in the build/libs directory.

CAS properties can be passed to the CAS web application as command-line arguments, when the application is launched:

java -jar build/libs/cas.war --cas.service-registry.templates.directory.location="..."

The above example assumes that the CAS web application is packaged as cas.war with an embedded server container and can be found in the build/libs directory.

_{The configuration settings listed below are tagged as Optional in the CAS configuration metadata. This
flag indicates that the presence of the setting
is not immediately necessary in the end-user CAS configuration, because a default value is assigned or
the activation of the feature is not conditionally controlled by the setting value. In other words, you should only include this field in your
configuration if you need to modify the default value or if you need to turn on the feature controlled by the setting.}

Configuration Metadata

The collection of configuration properties listed in this section are automatically generated from the CAS source and components that contain the actual field definitions, types, descriptions, modules, etc. This metadata may not always be 100% accurate, or could be lacking details and sufficient explanations.

Be Selective

This section is meant as a guide only. Do NOT copy/paste the entire collection of settings into your CAS configuration; rather pick only the properties that you need. Do NOT enable settings unless you are certain of their purpose and do NOT copy settings into your configuration only to keep them as reference. All these ideas lead to upgrade headaches, maintenance nightmares and premature aging.

YAGNI

Note that for nearly ALL use cases, declaring and configuring properties listed here is sufficient. You should NOT have to explicitly massage a CAS XML/Java/etc configuration file to design an authentication handler, create attribute release policies, etc. CAS at runtime will auto-configure all required changes for you. If you are unsure about the meaning of a given CAS setting, do NOT turn it on without hesitation. Review the codebase or better yet, ask questions to clarify the intended behavior.

Naming Convention

Property names can be specified in very relaxed terms. For instance cas.someProperty, cas.some-property, cas.some_property are all valid names. While all forms are accepted by CAS, there are certain components (in CAS and other frameworks used) whose activation at runtime is conditional on a property value, where this property is required to have been specified in CAS configuration using kebab case. This is both true for properties that are owned by CAS as well as those that might be presented to the system via an external library or framework such as Spring Boot, etc.

Note

Settings and properties that are controlled by the CAS platform directly always begin with the prefix cas. All other settings are controlled and provided to CAS via other underlying frameworks and may have their own schemas and syntax. BE CAREFUL with the distinction. Unrecognized properties are rejected by CAS and/or frameworks upon which CAS depends. This means if you somehow misspell a property definition or fail to adhere to the dot-notation syntax and such, your setting is entirely refused by CAS and likely the feature it controls will never be activated in the way you intend.

Validation

Configuration properties are automatically validated on CAS startup to report issues with configuration binding, specially if defined CAS settings cannot be recognized or validated by the configuration schema. Additional validation processes are also handled via Configuration Metadata and property migrations applied automatically on startup by Spring Boot and family.

Indexed Settings

CAS settings able to accept multiple values are typically documented with an index, such as cas.some.setting[0]=value. The index [0] is meant to be incremented by the adopter to allow for distinct multiple configuration blocks.

Please note that processing template service definitions requires scripting. To prepare CAS to support and integrate with Apache Groovy, please review this guide.

Examples

Consider the following base template service definition, stored in a AllLibraryApplications.json file, for a yet-to-be-registered CAS application:

{
  "@class": "org.apereo.cas.services.CasRegisteredService",
  "templateName": "AllLibraryApplications",
  "attributeReleasePolicy" : {
    "@class" : "org.apereo.cas.services.ReturnAllowedAttributeReleasePolicy",
    "allowedAttributes" : [ "java.util.ArrayList", [ "email", "username" ] ],
    "consentPolicy": {
      "@class": "org.apereo.cas.services.consent.DefaultRegisteredServiceConsentPolicy",
      "includeOnlyAttributes": ["java.util.LinkedHashSet", ["email", "username"]],
      "status": "TRUE"
    }    
  },
  "usernameAttributeProvider" : {
    "@class" : "org.apereo.cas.services.PrincipalAttributeRegisteredServiceUsernameProvider",
    "usernameAttribute" : "email",
    "canonicalizationMode" : "LOWER"
  },
  "properties" : {
      "@class" : "java.util.HashMap",
      "prop1": {
        "@class" : "org.apereo.cas.services.DefaultRegisteredServiceProperty",
        "values" : [ "java.util.HashSet", [ "false" ] ]
      },
      "prop2" : {
        "@class" : "org.apereo.cas.services.DefaultRegisteredServiceProperty",
        "values" : [ "java.util.HashSet", [ "hello-world" ] ]
      }
    }
  }

The following variations are possible:

A concrete service definition may link up with a template:

{
  "@class": "org.apereo.cas.services.CasRegisteredService",
  "serviceId": "^https://library.org/app/.+",
  "name": "Library",
  "templateName": "AllLibraryApplications",
  "id": 1,
  "description": "My application",
  "usernameAttributeProvider" : {
    "@class" : "org.apereo.cas.services.PrincipalAttributeRegisteredServiceUsernameProvider",
    "usernameAttribute" : "givenName",
  }
}

The final result, when processed and loaded internally by CAS would be the following definition:

{
  "@class": "org.apereo.cas.services.CasRegisteredService",
  "name": "Library",
  "templateName": "AllLibraryApplications",
  "serviceId": "^https://library.org/app/.+",
  "id": 1,
  "description": "My application",
  "attributeReleasePolicy" : {
    "@class" : "org.apereo.cas.services.ReturnAllowedAttributeReleasePolicy",
    "allowedAttributes" : [ "java.util.ArrayList", [ "email", "username" ] ],
    "consentPolicy": {
      "@class": "org.apereo.cas.services.consent.DefaultRegisteredServiceConsentPolicy",
      "includeOnlyAttributes": ["java.util.LinkedHashSet", ["email", "username"]],
      "status": "TRUE"
    }    
  },
  "usernameAttributeProvider" : {
    "@class" : "org.apereo.cas.services.PrincipalAttributeRegisteredServiceUsernameProvider",
    "usernameAttribute" : "givenName",
  },
  "properties" : {
      "@class" : "java.util.HashMap",
      "prop1": {
        "@class" : "org.apereo.cas.services.DefaultRegisteredServiceProperty",
        "values" : [ "java.util.HashSet", [ "false" ] ]
      },
      "prop2" : {
        "@class" : "org.apereo.cas.services.DefaultRegisteredServiceProperty",
        "values" : [ "java.util.HashSet", [ "hello-world" ] ]
      }
    }
  }

A concrete service definition may link up with a template:

{
  "@class": "org.apereo.cas.services.CasRegisteredService",
  "serviceId": "^https://library.org/app/.+",
  "name": "Library",
  "templateName": "AllLibraryApplications",
  "id": 1,
  "description": "My application"
}

The final result, when processed and loaded internally by CAS would be the following definition:

{
  "@class": "org.apereo.cas.services.CasRegisteredService",
  "name": "Library",
  "templateName": "AllLibraryApplications",
  "serviceId": "^https://library.org/app/.+",
  "id": 1,
  "description": "My application",
  "attributeReleasePolicy" : {
    "@class" : "org.apereo.cas.services.ReturnAllowedAttributeReleasePolicy",
    "allowedAttributes" : [ "java.util.ArrayList", [ "email", "username" ] ],
    "consentPolicy": {
      "@class": "org.apereo.cas.services.consent.DefaultRegisteredServiceConsentPolicy",
      "includeOnlyAttributes": ["java.util.LinkedHashSet", ["email", "username"]],
      "status": "TRUE"
    }    
  },
  "usernameAttributeProvider" : {
    "@class" : "org.apereo.cas.services.PrincipalAttributeRegisteredServiceUsernameProvider",
    "usernameAttribute" : "email",
    "canonicalizationMode" : "LOWER"
  },
  "properties" : {
      "@class" : "java.util.HashMap",
      "prop1": {
        "@class" : "org.apereo.cas.services.DefaultRegisteredServiceProperty",
        "values" : [ "java.util.HashSet", [ "false" ] ]
      },
      "prop2" : {
        "@class" : "org.apereo.cas.services.DefaultRegisteredServiceProperty",
        "values" : [ "java.util.HashSet", [ "hello-world" ] ]
      }
    }
  }

A concrete service definition may also specify multiple template names:

{
  "@class": "org.apereo.cas.services.CasRegisteredService",
  "serviceId": "^https://library.org/app/.+",
  "name": "Library",
  "templateName": "AllLibraryApplications,UnknownTemplate,AllGenericApplications",
  "id": 1,
  "description": "My application",
  "usernameAttributeProvider" : {
    "@class" : "org.apereo.cas.services.PrincipalAttributeRegisteredServiceUsernameProvider",
    "usernameAttribute" : "givenName",
  }
}

Template definitions will be applied in the same order as they are defined. Assuming both AllLibraryApplications and AllGenericApplications template definition files exist and have been loaded by CAS, the merge process will go through each assigned template sequentially, carrying the results of previous merge attempts and will also ignore unknown templates that cannot be found and resolved.

Service template definitions can be as designed Groovy templates, able to generate text and other constructs dynamically. The template framework in Groovy uses JSP style <% %> script and <%= %> expression syntax or GString style expressions. The variable out is bound to the writer that the template is being written to.

To prepare CAS to support and integrate with Apache Groovy, please review this guide.

For example consider the following GroovyTemplate template definition:

{
  "@class": "org.apereo.cas.services.CasRegisteredService",
  "name": "CAS",
  "description": "${GivenDescription}",
  "templateName": "GroovyTemplate",
  "usernameAttributeProvider" : {
    "@class" : "org.apereo.cas.services.PrincipalAttributeRegisteredServiceUsernameProvider",
    "usernameAttribute" : "${GivenUsernameAttribute}"
  },
  "attributeReleasePolicy" : {
    "@class" : "org.apereo.cas.services.ReturnAllowedAttributeReleasePolicy",
    "allowedAttributes" : [ "java.util.ArrayList", ${ AllowedAttributes.collect(it -> "\"$it\"") } ]
  }
}

The description, usernameAttribute and allowedAttributes fields will be dynamically constructed at the time of building a concrete service definition. The values for each of these fields is expected to be found from variables GivenDescription, GivenUsernameAttribute, and AllowedAttributes that are to be supplied by the concrete service definition in the form of service properties:

{
  "@class": "org.apereo.cas.services.CasRegisteredService",
  "serviceId": "^https://library.org/app/.+",
  "name": "Library",
  "templateName": "GroovyTemplate",
  "id": 1000,
  "properties": {
    "@class": "java.util.HashMap",
    "GivenDescription": {
      "@class": "org.apereo.cas.services.DefaultRegisteredServiceProperty",
      "values": [  "java.util.LinkedHashSet", [ "This is my description"  ] ]
    },
    "AllowedAttributes": {
      "@class": "org.apereo.cas.services.DefaultRegisteredServiceProperty",
      "values": [ "java.util.LinkedHashSet",  [ "email", "username" ] ]
    },
    "GivenUsernameAttribute": {
      "@class": "org.apereo.cas.services.DefaultRegisteredServiceProperty",
      "values": [ "java.util.LinkedHashSet",  [ "email" ] ]
    }
  }
}

After the merge process is completed, the final result would be similar to the following definition:

{
  "@class": "org.apereo.cas.services.CasRegisteredService",
  "name": "CAS",
  "templateName": "GroovyTemplate",
  "id": 1000,
  "description": "This is my description",
  "usernameAttributeProvider": {
    "@class": "org.apereo.cas.services.PrincipalAttributeRegisteredServiceUsernameProvider",
    "usernameAttribute": "email"
  },
  "attributeReleasePolicy": {
    "@class": "org.apereo.cas.services.ReturnAllowedAttributeReleasePolicy",
    "allowedAttributes": [ "java.util.ArrayList", [ "email",  "username" ] ]
  }
}