Re: [keycloak-user] SPI with a third party database. Could not find any META-INF/persistence.xml file in the classpath

Hello there, I am using the standalone server distribution [1]. We need to extend the keycloak server [2] and we need to access a third party database to get some data. I developed a sample domain extension based on the keycloak example domain extension [3]. The deployment of this example one works at the first try, thanks!!! My sample domain extension access a third party database (mysql), so in wildfly... - I install the mysql driver - I create a datasource ... and in my sample I create a META-INF/persistence.xml <persistence version>     <persistence-unit name="JavaHelps" transaction-type="RESOURCE_LOCAL">         <non-jta-data-source>java:/MySqlDS</non-jta-data-source> <class>my.entity.Class</class> <properties>          <property name="hibernate.dialect" value="org.hibernate.dialect.MySQLDialect"/> </properties>     </persistence-unit> </persistence> I add my sample  $KEYCLOAK_HOME/bin/jboss-cli.sh --command="module add --name=... And it seems that wildfly likes evrything (from standard output), you can see below part of the wildfly output at startup time. However when I run it I get: Uncaught server error: java.lang.ExceptionInInitializerError.... Caused by: javax.persistence.PersistenceException: No Persistence provider for EntityManager named JavaHelps I found a workaround: having a deeper look at the standard output I saw this message... parse checking if "$KEYCLOAK_HOMEl/modules/system/layers/keycloak/org/keycloak/keycloak-server-subsystem/main/server-war/WEB-INF/classes/META-INF/persistence.xml" exists, result = false 10:59:55,279 TRACE [org.jboss.as.jpa] (MSC service thread 1-1) parsed persistence unit definitions for war server-war ... so if I copy my persistence.xml to that location my domain extension sample WORKS! My question is WHY??? Any thoughts on this? Thanks in advance, Luis [1] https://downloads.jboss.org/keycloak/4.6.0.Final/keycloak-4.6.0.Final.zip [2] https://www.keycloak.org/docs/latest/server_development/index.html#_exten... [3] https://github.com/keycloak/keycloak/tree/master/examples/providers/domai... 10:59:54,575 INFO  [org.jboss.as.connector.subsystems.datasources] (ServerService Thread Pool -- 28) WFLYJCA0005: Deploying non-JDBC-compliant driver class com.mysql.jdbc.Driver (version 5.1) 10:59:55,071 INFO  [org.jboss.as.connector.subsystems.datasources] (MSC service thread 1-8) WFLYJCA0001: Bound data source [java:/MySqlDS] 10:59:55,158 TRACE [org.jboss.as.jpa] (MSC service thread 1-7) parse checking if "/content/domain-extension-example.jar/META-INF/persistence.xml" exists, result = true 10:59:55,163 TRACE [org.jboss.as.jpa] (MSC service thread 1-7) parse persistence.xml: attribute value(0) = JavaHelps 10:59:55,163 TRACE [org.jboss.as.jpa] (MSC service thread 1-7) parse persistence.xml: attribute value(1) = RESOURCE_LOCAL 10:59:55,164 TRACE [org.jboss.as.jpa] (MSC service thread 1-7) parse persistence.xml: element=non-jta-data-source 10:59:55,164 TRACE [org.jboss.as.jpa] (MSC service thread 1-7) parse persistence.xml: element=class 10:59:55,164 TRACE [org.jboss.as.jpa] (MSC service thread 1-7) parse persistence.xml: element=properties 10:59:55,165 TRACE [org.jboss.as.jpa] (MSC service thread 1-7) parse persistence.xml: reached ending persistence-unit tag 10:59:55,165 INFO  [org.jboss.as.jpa] (MSC service thread 1-7) WFLYJPA0002: Read persistence.xml for JavaHelps 10:59:55,166 TRACE [org.jboss.as.jpa] (MSC service thread 1-7) PersistenceUnitMetadataImpl(version=2.1) [ name: JavaHelps jtaDataSource: null nonJtaDataSource: java:/MySqlDS transactionType: RESOURCE_LOCAL provider: org.hibernate.jpa.HibernatePersistenceProvider classes[ com.javahelps.jpa.Student ] packages[ ] mappingFiles[ ] jarFiles[ ] validation-mode: AUTO shared-cache-mode: UNSPECIFIED properties[ hibernate.dialect: org.hibernate.dialect.MySQLDialect ]] 10:59:55,167 TRACE [org.jboss.as.jpa] (MSC service thread 1-7) parsed persistence unit definitions for jar domain-extension-example.jar 10:59:55,168 TRACE [org.jboss.as.jpa] (MSC service thread 1-7) incrementing PU count for domain-extension-example.jar by 1 10:59:55,174 DEBUG [org.jboss.as.jpa] (MSC service thread 1-3) added javax.persistence.api dependency to domain-extension-example.jar 10:59:55,174 DEBUG [org.jboss.as.jpa] (MSC service thread 1-3) added org.hibernate.bytecodetransformer dependency to domain-extension-example.jar 10:59:55,175 DEBUG [org.jboss.as.jpa] (MSC service thread 1-3) added org.jboss.as.jpa dependency to domain-extension-example.jar 10:59:55,175 DEBUG [org.jboss.as.jpa] (MSC service thread 1-3) added org.jboss.as.jpa.spi dependency to domain-extension-example.jar 10:59:55,175 DEBUG [org.jboss.as.jpa] (MSC service thread 1-3) added (default provider) org.hibernate dependency to domain-extension-example.jar (since 1 PU(s) didn't specify jboss.as.jpa.providerModule) 10:59:55,175 DEBUG [org.jboss.as.jpa] (MSC service thread 1-3) added org.hibernate dependency to domain-extension-example.jar 10:59:55,196 TRACE [org.jboss.as.jpa] (MSC service thread 1-8) install persistence unit definition for jar domain-extension-example.jar 10:59:55,196 TRACE [org.jboss.as.jpa] (MSC service thread 1-8) adding 'vfs:/content/domain-extension-example.jar/' to annotation index map 10:59:55,196 TRACE [org.jboss.as.jpa] (MSC service thread 1-8) returning global (module) Persistence Provider org.hibernate.jpa.HibernatePersistenceProvider 10:59:55,199 DEBUG [org.jboss.as.jpa] (MSC service thread 1-8) loaded persistence provider adapter org.jboss.as.jpa.hibernate5.HibernatePersistenceProviderAdaptor from classloader ModuleClassLoader for Module "org.hibernate" version 5.3.6.Final from local module loader @400cff1a (finder: local module finder @275710fc (roots: /media/hdd/keycloak-4.6.0.Final/modules,/media/hdd/keycloak-4.6.0.Final/modules/system/layers/keycloak,/media/hdd/keycloak-4.6.0.Final/modules/system/layers/base)) 10:59:55,202 TRACE [org.jboss.as.jpa] (MSC service thread 1-8) add second level cache dependencies with properties '{caches=entity, container=hibernate}' 10:59:55,203 TRACE [org.jboss.as.jpa] (MSC service thread 1-8) added PersistenceUnitService (phase 1 of 2) for 'service jboss.persistenceunit."domain-extension-example.jar#JavaHelps".__FIRST_PHASE__'. PU is ready for injector action. 10:59:55,204 TRACE [org.jboss.as.jpa] (MSC service thread 1-8) returning global (module) Persistence Provider org.hibernate.jpa.HibernatePersistenceProvider 10:59:55,206 INFO [org.keycloak.subsystem.server.extension.KeycloakProviderDeploymentProcessor] (MSC service thread 1-4) Deploying Keycloak provider: domain-extension-example.jar 10:59:55,234 TRACE [org.jboss.as.jpa] (MSC service thread 1-6) install persistence unit definition for jar domain-extension-example.jar 10:59:55,234 TRACE [org.jboss.as.jpa] (MSC service thread 1-6) adding 'vfs:/content/domain-extension-example.jar/' to annotation index map 10:59:55,234 TRACE [org.jboss.as.jpa] (MSC service thread 1-6) returning global (module) Persistence Provider org.hibernate.jpa.HibernatePersistenceProvider 10:59:55,235 TRACE [org.jboss.as.jpa] (MSC service thread 1-6) add second level cache dependencies with properties '{caches=entity, container=hibernate}' 10:59:55,235 TRACE [org.jboss.as.jpa] (MSC service thread 1-6) added PersistenceUnitService (phase 2 of 2) for 'service jboss.persistenceunit."domain-extension-example.jar#JavaHelps"'.  PU is ready for injector action. 10:59:55,645 INFO  [org.jboss.as.jpa] (ServerService Thread Pool -- 57) WFLYJPA0010: Starting Persistence Unit (phase 1 of 2) Service 'domain-extension-example.jar#JavaHelps' 10:59:55,695 INFO  [org.hibernate.jpa.internal.util.LogHelper] (ServerService Thread Pool -- 57) HHH000204: Processing PersistenceUnitInfo [ name: JavaHelps ...] 10:59:56,038 INFO  [org.jboss.as.jpa] (ServerService Thread Pool -- 57) WFLYJPA0010: Starting Persistence Unit (phase 2 of 2) Service 'domain-extension-example.jar#JavaHelps'