Attribute Release Caching

By default, resolved attributes are cached to the length of the SSO session. If there are any attribute value changes since the commencement of SSO session, the changes are not reflected and returned back to the service upon release time.

Note: Remember that while the below policies are typically applied at release time on a per-service level, CAS automatically does create attribute release caching policies at a more global with configurable timeouts and durations.

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.

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.

  • cas.authn.attribute-repository.core.aggregation=MERGE
  • Indicates how the results of multiple attribute repositories should be aggregated together. Available values are as follows:

    • MERGE: Default. Designed to query multiple repositories in order and merge the results into a single result set.
    • CASCADE: Query multiple repositories in order and merge the results into a single result set. As each repository is queried the attributes from the first query in the result set are used as the query for the next repository.


  • cas.authn.attribute-repository.core.default-attributes-to-release=
  • CAS provides the ability to release a bundle of principal attributes to all services by default. This bundle is not defined on a per-service basis and is always combined with attributes produced by the specific release policy of the service, such that for instance, you can devise rules to always release givenName and cn to every application, and additionally allow other specific principal attributes for only some applications per their attribute release policy.


  • cas.authn.attribute-repository.core.expiration-time=30
  • Indicates the global cache expiration period, once attributes are fetched from the underlying attribute repository. A zero or negative value indicates that no attribute caching should take place where attributes must always be fetched from the source.


  • cas.authn.attribute-repository.core.expiration-time-unit=
  • Expiration caching time unit for attributes.


  • cas.authn.attribute-repository.core.maximum-cache-size=10000
  • Indicates the global cache size used to store attributes retrieved from the attribute repository.


  • cas.authn.attribute-repository.core.merger=REPLACE
  • Merging strategies can be used to resolve conflicts when the same attribute are found from multiple sources. Available values are as follows:

    • REPLACE: Replace attributes. Overwrites existing attribute values, if any.
    • ADD: Add attributes. Retains existing attribute values if any, and ignores values from subsequent sources in the resolution chain.
    • NONE: No merging. Doesn't merge attributes, ignores attributes from non-authentication attribute repositories.
    • MULTIVALUED: Multivalued attributes. Combines all values into a single attribute, essentially creating a multi-valued attribute.


  • cas.authn.attribute-repository.core.recover-exceptions=true
  • Recover from LDAP exceptions and continue with partial results. Otherwise, die and do not allow to log in.


  • cas.authn.attribute-repository.core.require-all-repository-sources=false
  • In the event that multiple attribute repositories are defined, setting this option to true forces all repositories to produce a person object. If any of the repositories fails to produce a person or person attributes, the resolution engine will halt to short-circuit the process, failing to resolve the person altogether.


    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.


    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. When possible, properties should be stored in lower-case kebab format, such as ettings 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.


    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. The validation process is on by default and can be skipped on startup using a special system property SKIP_CONFIG_VALIDATION that should be set to true. 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.

    The following settings are shared by all principal attribute repositories:

    Name Value
    mergingStrategy Indicate the merging strategy when combining attributes from multiple sources. Accepted values are MULTIVALUED, ADD, NONE, MULTIVALUED
    attributeRepositoryIds A Set of attribute repository identifiers to consult for attribute resolution at release time.
    ignoreResolvedAttributes Ignore the collection of attributes that may have been resolved during the principal resolution phase, typically via attribute repositories.


    The default relationship between a CAS Principal and the underlying attribute repository source, such that principal attributes are kept as they are