Remove numeric identifier from PolarisPrincipal

This change removes the requirement for Polaris principals to have a numeric identifier, by removing the only sites where such an identifier was required:

- In the `Resolver`. Instead, the `Resolver` now performs a lookup by principal name.
- In  `PolarisAdminService`. Instead, the code now compares the principal name against the entity name.

Note: the lookup in the `Resolver` is still necessary, because the `Resolver` also needs to fetch the grant records.

Author: adutra

polaris-core/src/main/java/org/apache/polaris/core/auth/PolarisPrincipal.java

@@ -39,43 +39,31 @@ public interface PolarisPrincipal extends Principal {
    * @param roles the set of roles associated with the principal
    */
   static PolarisPrincipal of(PrincipalEntity principalEntity, Set<String> roles) {
-    return of(
-        principalEntity.getId(),
-        principalEntity.getName(),
-        principalEntity.getInternalPropertiesAsMap(),
-        roles);
+    return of(principalEntity.getName(), principalEntity.getInternalPropertiesAsMap(), roles);
   }
 
   /**
    * Creates a new instance of {@link PolarisPrincipal} with the specified ID, name, roles, and
    * properties.
    *
-   * @param id the unique identifier of the principal
    * @param name the name of the principal
    * @param properties additional properties associated with the principal
    * @param roles the set of roles associated with the principal
    */
-  static PolarisPrincipal of(
-      long id, String name, Map<String, String> properties, Set<String> roles) {
+  static PolarisPrincipal of(String name, Map<String, String> properties, Set<String> roles) {
     return ImmutablePolarisPrincipal.builder()
-        .id(id)
         .name(name)
         .properties(properties)
         .roles(roles)
         .build();
   }
 
   /**
-   * Returns the unique identifier of the principal.
+   * Returns the set of activated principal role names.
    *
-   * <p>This identifier is used to uniquely identify the principal within a Polaris realm.
-   */
-  long getId();
-
-  /**
-   * Returns the set of activated principal role names. Activated role names are the roles that were
-   * explicitly requested by the client when authenticating, through JWT claims or other means. It
-   * may be a subset of the roles that the principal has in the system.
+   * <p>Activated role names are the roles that were explicitly requested by the client when
+   * authenticating, through JWT claims or other means. It may be a subset of the roles that the
+   * principal has in the system.
    */
   Set<String> getRoles();
 

polaris-core/src/main/java/org/apache/polaris/core/persistence/resolver/Resolver.java

@@ -755,11 +755,7 @@ private ResolverStatus resolveCallerPrincipalAndPrincipalRoles(
 
     // resolve the principal, by name or id
     this.resolvedCallerPrincipal =
-        this.resolveById(
-            toValidate,
-            PolarisEntityType.PRINCIPAL,
-            PolarisEntityConstants.getNullId(),
-            polarisPrincipal.getId());
+        this.resolveByName(toValidate, PolarisEntityType.PRINCIPAL, polarisPrincipal.getName());
 
     // if the principal was not found, we can end right there
     if (this.resolvedCallerPrincipal == null

runtime/service/src/main/java/org/apache/polaris/service/admin/PolarisAdminService.java

@@ -251,11 +251,8 @@ private void authorizeBasicTopLevelEntityOperationOrThrow(
     PolarisResolvedPathWrapper topLevelEntityWrapper =
         resolutionManifest.getResolvedTopLevelEntity(topLevelEntityName, entityType);
 
-    // TODO: If we do add more "self" privilege operations for PRINCIPAL targets this should
-    // be extracted into an EnumSet and/or pushed down into PolarisAuthorizer.
-    if (topLevelEntityWrapper.getResolvedLeafEntity().getEntity().getId()
-            == polarisPrincipal.getId()
-        && (op.equals(PolarisAuthorizableOperation.ROTATE_CREDENTIALS))) {
+    PolarisEntity entity = topLevelEntityWrapper.getResolvedLeafEntity().getEntity();
+    if (isSelfEntity(entity) && isSelfOperation(op)) {
       LOGGER
           .atDebug()
           .addKeyValue("principalName", topLevelEntityName)
@@ -270,6 +267,29 @@ private void authorizeBasicTopLevelEntityOperationOrThrow(
         null /* secondary */);
   }
 
+  /**
+   * Returns true if the target entity is the same as the current authenticated {@link
+   * PolarisPrincipal}.
+   */
+  private boolean isSelfEntity(PolarisEntity entity) {
+    // Entity name is unique for (realm_id, catalog_id, parent_id, type_code),
+    // which is reduced to (realm_id, type_code) for top-level entities;
+    // so there can be only one principal with a given name inside any realm.
+    return entity.getType() == PolarisEntityType.PRINCIPAL
+        && entity.getName().equals(polarisPrincipal.getName());
+  }
+
+  /**
+   * Returns true if the operation is a "self" operation, that is, an operation that is being
+   * performed by the principal on itself.
+   *
+   * <p>TODO: If we do add more "self" privilege operations for PRINCIPAL targets this should be
+   * extracted into an EnumSet and/or pushed down into PolarisAuthorizer.
+   */
+  private static boolean isSelfOperation(PolarisAuthorizableOperation op) {
+    return op.equals(PolarisAuthorizableOperation.ROTATE_CREDENTIALS);
+  }
+
   private void authorizeBasicCatalogRoleOperationOrThrow(
       PolarisAuthorizableOperation op, String catalogName, String catalogRoleName) {
     resolutionManifest =

runtime/service/src/main/java/org/apache/polaris/service/auth/PersistedPolarisPrincipal.java

@@ -52,12 +52,6 @@ public String getName() {
     return getEntity().getName();
   }
 
-  @Value.Derived
-  @Override
-  public long getId() {
-    return getEntity().getId();
-  }
-
   @Value.Lazy
   @Override
   public Map<String, String> getProperties() {

runtime/service/src/test/java/org/apache/polaris/service/admin/PolarisAuthzTestBase.java

@@ -399,9 +399,8 @@ protected static void assertSuccess(BaseResult result) {
   protected @Nonnull Set<String> loadPrincipalRolesNames(PolarisPrincipal p) {
     PolarisBaseEntity principal =
         metaStoreManager
-            .loadEntity(
-                callContext.getPolarisCallContext(), 0L, p.getId(), PolarisEntityType.PRINCIPAL)
-            .getEntity();
+            .findPrincipalByName(callContext.getPolarisCallContext(), p.getName())
+            .orElseThrow();
     return metaStoreManager
         .loadGrantsToGrantee(callContext.getPolarisCallContext(), principal)
         .getGrantRecords()