JSON Service Registry

This registry reads services definitions from JSON configuration files at the application context initialization time. JSON files are expected to be found inside a configured directory location and this registry will recursively look through the directory structure to find relevant JSON files.

Support is enabled by adding the following module into the overlay:



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<dependency>
    <groupId>org.apereo.cas</groupId>
    <artifactId>cas-server-support-json-service-registry</artifactId>
    <version>${cas.version}</version>
</dependency>





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implementation "org.apereo.cas:cas-server-support-json-service-registry:${project.'cas.version'}"





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dependencyManagement {
    imports {
        mavenBom "org.apereo.cas:cas-server-support-bom:${project.'cas.version'}"
    }
}

dependencies {
    implementation "org.apereo.cas:cas-server-support-json-service-registry"
}





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dependencies {
    /*
        The following platform references should be included automatically and are listed here for reference only.

        implementation enforcedPlatform("org.apereo.cas:cas-server-support-bom:${project.'cas.version'}")
        implementation platform(org.springframework.boot.gradle.plugin.SpringBootPlugin.BOM_COORDINATES)
        
    */
    implementation "org.apereo.cas:cas-server-support-json-service-registry"
}

A sample JSON file follows:



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{
  "@class" : "org.apereo.cas.services.CasRegisteredService",
  "serviceId" : "testId",
  "name" : "testJsonFile",
  "id" : 103935657744185,
  "evaluationOrder" : 10
}

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.json.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.support.services.json.JsonServiceRegistryProperties.

    How can I configure this property?

    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.

  • cas.service-registry.json.watcher-enabled=true

    • Flag indicating whether a background watcher thread is enabled for the purposes of live reloading of service registry data changes from persistent data store.

    org.apereo.cas.configuration.model.support.services.json.JsonServiceRegistryProperties.

    How can I configure this property?

    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.

    :information_source: 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.

    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.

    :warning: Clustering Services

    You MUST consider that if your CAS server deployment is clustered, each CAS node in the cluster must have access to the same set of JSON configuration files as the other, or you may have to devise a strategy to keep changes synchronized from one node to the next.

    The JSON service registry is also able to auto detect changes to the specified directory. It will monitor changes to recognize file additions, removals and updates and will auto-refresh CAS so changes do happen instantly.

    :information_source: Escaping Characters

    Please make sure all field values in the JSON blob are correctly escaped, specially for the service id. If the service is defined as a regular expression, certain regex constructs such as . and \d need to be doubly escaped.

    Naming Conventions

    The naming convention for new JSON files is recommended to be the following:

    

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    JSON fileName = serviceName + "-" + serviceNumericId + ".json"

    Based on the above formula, for example the above JSON snippet shall be named: testJsonFile-103935657744185.json. Remember that because files are created based on the serviceName, you will need to make sure characters considered invalid for file names are not used as part of the name. Furthermore, note that CAS MUST be given full read/write permissions on directory which contains service definition files.

    The registry is able to auto-organize service definition files into dedicated directories based on the service type. If any of the following subdirectories exist inside the base services directory for a CAS service, CAS would auto-choose the appropriate directory by type:

    Service Type Subdirectories
    CAS CAS Client, cas-client
    OpenID Connect OpenID Connect Relying Party, openid-connect-relying-party
    OAuth2 OAuth2 Client, oauth2-client
    SAML2 SAML2 Service Provider, saml2-service-provider
    WS-Federation WS Federation Relying Party, ws-federation-relying-party

    If no subdirectory for a service type is found, the base services directory would be used.

    :warning: Duplicate Services

    As you add more files to the directory, you need to be absolutely sure that no two service definitions would have the same numeric id. If this happens, loading one definition will stop loading the other. While service ids can be chosen arbitrarily, make sure all service numeric identifiers are unique. CAS will also output warnings if duplicate data is found.

    JSON Syntax

    CAS uses a version of the JSON syntax that provides a much more relaxed syntax with the ability to specify comments.

    • A given JSON file for instance could be formatted as such in CAS:

      

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      {
  /*
    Generic service definition that applies to https/imaps urls
    that wish to register with CAS for authentication.
  */
  "@class" : "org.apereo.cas.services.CasRegisteredService",
  "serviceId" : "^(https|imaps)://.*",
  "name" : "HTTPS and IMAPS",
  # "description": "This is commented out"
  "id" : 10000001,
}

      Note the trailing comma at the end. See the above link for more info on the alternative syntax.

    • Multiline strings with proper whitespace handling should also be supported:

      

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      {
  "@class": "org.apereo.cas.services.CasRegisteredService",
  "serviceId": "^https://app.example.org/.*",
  "id": 1,
  "name": "Sample",
  "description": 
    '''
    This is the description
    of this application here
    ```
}

    Clustering & Replication

    If CAS is deployed in a cluster, the service definition files must be kept in sync for all CAS nodes. Please review this guide to learn more about available options.

    You might be wondering: but, is using the file system with JSON (or YAML) files a good solution for CAS deployments?

    Like almost everything else in life, it depends.

    If you have a single CAS server, packaging the JSON files with the CAS web application is easy. You just have to remember (which might be the downside) to redeploy and rebuild CAS every time you add, remove or make changes to any of the files. Your build then becomes immutable which may or may not be a good thing. You may alternatively decide to not package these files with the CAS web application and instead move them outside to a different location, removing the need for rebuilding. You then have to worry about where that location might be, and what permissions it should be given to the process that reads data from it etc, and how are changes to files in that directory tracked and managed by source control.

    If you have N CAS server nodes in a cluster, you should consider the following:

    • If the JSON files are packaged with the CAS web application, you have to rebuild and redeploy CAS N times.
    • If the JSON files are outside the CAS web application, you need to make sure N CAS servers in the cluster have access to the same shared location, or you may look at replication options outlined here. Managing files in an external location not tied to the CAS build might make it challenging for you to track such changes in source control.

    You may alternatively decide to not use the filesystem and instead opt for a proper external data store. Then, you would of course remove issues regarding rebuilds and keeping files in sync across CAS nodes because the database must be centralized and shared by all nodes. Instead, you add the extra overhead of managing, updating and maintaining a separate database which generally should remain available as much as CAS itself.

    Auto Initialization

    Upon startup and configuration permitting, the registry is able to auto initialize itself from default JSON service definitions available to CAS. See this guide for more info.