Google Cloud Storage Service Registry
Google Cloud Storage is a managed service for storing unstructured data. CAS takes advantage of Google Cloud Storage to store service and application definitions. Applications are grouped based on type and are stored in their own bucket, which are managed and/or created automatically.
Support is enabled by including the following dependency in the overlay:
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<dependency>
<groupId>org.apereo.cas</groupId>
<artifactId>cas-server-support-gcp-storage-service-registry</artifactId>
<version>${cas.version}</version>
</dependency>
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implementation "org.apereo.cas:cas-server-support-gcp-storage-service-registry:${project.'cas.version'}"
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dependencyManagement {
imports {
mavenBom "org.apereo.cas:cas-server-support-bom:${project.'cas.version'}"
}
}
dependencies {
implementation "org.apereo.cas:cas-server-support-gcp-storage-service-registry"
}
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dependencies {
/*
The following platform references are included automatically and are listed for reference only.
implementation enforcedPlatform("org.apereo.cas:cas-server-support-bom:${project.'cas.version'}")
implementation platform(org.springframework.boot.gradle.plugin.SpringBootPlugin.BOM_COORDINATES)
*/
implementation "org.apereo.cas:cas-server-support-gcp-storage-service-registry"
}
Integration support is backed by the Spring Cloud GCP project. Their reference documentation provides detailed information on how to integrate Google Cloud APIs with CAS.
To understand how to set up application default credentials, please review this page.
CAS Configuration
The following settings and properties are available from the CAS configuration catalog:
spring.cloud.gcp.storage.auto-create-files
spring.cloud.gcp.storage.credentials.default-scopes
spring.cloud.gcp.storage.enabledAuto-configure Google Cloud Storage components.
trueAuto-configure Google Cloud Storage components.
spring.cloud.gcp.storage.hostHost of the Storage client that is formatted as `https://${service}.
Host of the Storage client that is formatted as `https://${service}.${universeDomain}/`.
spring.cloud.gcp.storage.project-id
spring.cloud.gcp.storage.universe-domainUniverse domain of the client which is part of the host that is formatted as `https://${service}.
Universe domain of the client which is part of the host that is formatted as `https://${service}.${universeDomain}/`.
Required settings may be needed to activate or affect the feature; review them even when they have a default. Optional settings only need to be set to change a default or to turn on the behavior they control. Third party settings belong to libraries such as Spring Boot that CAS builds on; their own documentation may have more detail.
Notes on configuration
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
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, especially 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.
Google Cloud Storage with Pub/Sub Listener
CAS allows the Google Cloud Storage-backed service registry to listen for object-change events published through Google Pub/Sub. When a service definition or related registry object is created, updated, or deleted in the configured GCS bucket, the listener receives the notification and can refresh or invalidate the local registry state accordingly.
This is useful in clustered or cloud-native deployments where multiple CAS nodes may rely on the same GCS bucket as the source of truth. Instead of requiring restarts, polling, or manual refreshes, registry changes can be propagated to running nodes as events occur, helping keep service definitions synchronized across the deployment with lower latency and less operational overhead.
The subscription/topic name is set to be cas-service-regisry-gcp-storage. For the CAS listener to operate, the
required Pub/Sub infrastructure must exist ahead of time. The Cloud Storage service account for the project
must also have permission to publish messages to the topic. CAS only consumes messages from the configured
subscription; it does not automatically create the topic, subscription, bucket notification, or IAM bindings.
You may configure the bucket to emit supported events such as OBJECT_FINALIZE and OBJECT_DELETE.
Feature Activation
To activate this feature, the following feature toggle(s) must be turned on:
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CasFeatureModule.ServiceRegistry.gcp-storage-pubsub.enabled=true
To learn more about configuration feature toggles, please see this page.
Event payloads are expected to match the following structure:
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{
"eventType": "OBJECT_FINALIZE",
"bucketId": "...",
"objectId": "...",
"objectGeneration": "1710000000000000",
"eventTime": "2025-06-13T17:22:30.000Z",
"payloadFormat": "JSON_API_V1",
"notificationConfig": "..."
}
Troubleshooting
To enable additional logging, configure the log4j configuration file to add the following levels:
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...
<Logger name="com.google.cloud" level="debug" additivity="false">
<AppenderRef ref="casConsole"/>
<AppenderRef ref="casFile"/>
</Logger>
...
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.