Feature gates (#2361)

Feature gates

Author: rjeberhard

json-schema-generator/src/main/java/oracle/kubernetes/json/Feature.java

@@ -0,0 +1,23 @@
+// Copyright (c) 2021, Oracle and/or its affiliates.
+// Licensed under the Universal Permissive License v 1.0 as shown at https://oss.oracle.com/licenses/upl.
+
+package oracle.kubernetes.json;
+
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+
+import static java.lang.annotation.ElementType.FIELD;
+
+/** Specifies that this field is related to the named feature. */
+@Retention(RetentionPolicy.RUNTIME)
+@Target(FIELD)
+public @interface Feature {
+
+  /**
+   * Feature name.
+   *
+   * @return feature name
+   */
+  String value();
+}

json-schema-generator/src/main/java/oracle/kubernetes/json/SchemaGenerator.java

@@ -64,6 +64,8 @@ public class SchemaGenerator {
   private final Collection<String> suppressDescriptionForPackages = new ArrayList<>();
   private final Map<Class<?>, String> additionalPropertiesTypes = new HashMap<>();
 
+  private final Collection<String> enabledFeatures = new ArrayList<>();
+
   /**
    * Returns a pretty-printed string corresponding to a generated schema.
    *
@@ -195,7 +197,7 @@ void generateFieldIn(Map<String, Object> map, Field field) {
   }
 
   private boolean includeInSchema(Field field) {
-    return !isStatic(field) && !isVolatile(field);
+    return !isStatic(field) && !isVolatile(field) && !isDisabledFeature(field);
   }
 
   private boolean isStatic(Field field) {
@@ -210,6 +212,11 @@ private boolean isDeprecated(Field field) {
     return field.getAnnotation(Deprecated.class) != null;
   }
 
+  private boolean isDisabledFeature(Field field) {
+    Feature feature = field.getAnnotation(Feature.class);
+    return feature != null && !enabledFeatures.contains(feature.value());
+  }
+
   private String getPropertyName(Field field) {
     SerializedName serializedName = field.getAnnotation(SerializedName.class);
     if (serializedName != null && serializedName.value().length() > 0) {
@@ -502,6 +509,10 @@ public void defineAdditionalProperties(Class<?> forClass, String additionalPrope
     additionalPropertiesTypes.put(forClass, additionalPropertyType);
   }
 
+  public void defineEnabledFeatures(Collection<String> enabledFeatures) {
+    this.enabledFeatures.addAll(enabledFeatures);
+  }
+
   private class SubSchemaGenerator {
     final Field field;
 

json-schema-generator/src/test/java/oracle/kubernetes/json/SchemaGeneratorTest.java

@@ -7,6 +7,7 @@
 import java.lang.reflect.Field;
 import java.net.URL;
 import java.util.HashMap;
+import java.util.List;
 import java.util.Map;
 
 import org.junit.jupiter.api.BeforeEach;
@@ -215,6 +216,22 @@ public void doNotGenerateSchemaForStatics() {
     assertThat(schema, hasJsonPath("$.required", not(arrayContaining("staticInt"))));
   }
 
+  @Test
+  public void generateSchemaForEnabledFeature() throws NoSuchFieldException {
+    generator.defineEnabledFeatures(List.of("Binding"));
+    Object schema = generator.generate(SimpleObject.class);
+
+    assertThat(schema, hasJsonPath("$.properties.fieldAssociatedWithBindingFeature"));
+  }
+
+  @Test
+  public void doNotGenerateSchemaForDisabledFeature() {
+    Object schema = generator.generate(SimpleObject.class);
+
+    assertThat(schema, hasNoJsonPath("$.properties.fieldAssociatedWithMountFeature"));
+    assertThat(schema, hasJsonPath("$.required", not(arrayContaining("fieldAssociatedWithMountFeature"))));
+  }
+
   @SuppressWarnings("unused")
   @Test
   public void generateSchemaForSimpleObject() {

json-schema-generator/src/test/java/oracle/kubernetes/json/SimpleObject.java

@@ -23,4 +23,10 @@ class SimpleObject {
   private float aaFloat;
 
   private Map<String,Integer> keys;
+
+  @Feature("Mount")
+  private String fieldAssociatedWithMountFeature;
+
+  @Feature("Binding")
+  private String fieldAssociatedWithBindingFeature;
 }

kubernetes/charts/weblogic-operator/templates/_operator-cm.tpl

@@ -34,6 +34,9 @@ data:
   {{- if .dns1123Fields }}
   dns1123Fields: {{ .dns1123Fields | quote }}
   {{- end }}
+  {{- if .featureGates }}
+  featureGates: {{ .featureGates | quote }}
+  {{- end }}
   {{- if .introspectorJobNameSuffix }}
   introspectorJobNameSuffix: {{ .introspectorJobNameSuffix | quote }}
   {{- end }}

kubernetes/charts/weblogic-operator/values.yaml

@@ -117,6 +117,13 @@ elasticSearchHost: "elasticsearch.default.svc.cluster.local"
 # This parameter is ignored if 'elkIntegrationEnabled' is false.
 elasticSearchPort: 9200
 
+# featureGates specifies a set of key=value pairs separated by commas that describe whether a given
+# operator feature is enabled. You enable a feature by including a key=value pair where the key is the
+# feature name and the value is "true". This will allow the operator team to release features that
+# are not yet ready to be enabled by default, but that are ready for testing by customers. Once a feature is
+# stable then it will be enabled by default and can not be disabled using this configuration.
+# featureGates: "...,CommonMounts=true"
+
 # javaLoggingLevel specifies the Java logging level for the operator. This affects the operator pod's
 # log output and the contents of log files in the container's /logs/ directory.
 # Valid values are: "SEVERE", "WARNING", "INFO", "CONFIG", "FINE", "FINER", and "FINEST".

operator/src/main/java/oracle/kubernetes/operator/Main.java

@@ -175,6 +175,8 @@ private static String getBuildProperty(Properties buildProps, String key) {
 
     private void logStartup(LoggingFacade loggingFacade) {
       loggingFacade.info(MessageKeys.OPERATOR_STARTED, buildVersion, operatorImpl, operatorBuildTime);
+      Optional.ofNullable(TuningParameters.getInstance().getFeatureGates().getEnabledFeatures())
+          .ifPresent(ef -> loggingFacade.info(MessageKeys.ENABLED_FEATURES, ef));
       loggingFacade.info(MessageKeys.OP_CONFIG_NAMESPACE, getOperatorNamespace());
       loggingFacade.info(MessageKeys.OP_CONFIG_SERVICE_ACCOUNT, serviceAccountName);
       Optional.ofNullable(Namespaces.getConfiguredDomainNamespaces())

operator/src/main/java/oracle/kubernetes/operator/TuningParameters.java

@@ -3,6 +3,8 @@
 
 package oracle.kubernetes.operator;
 
+import java.util.Collection;
+import java.util.Collections;
 import java.util.Map;
 import java.util.concurrent.ScheduledExecutorService;
 
@@ -29,6 +31,8 @@ static TuningParameters getInstance() {
 
   PodTuning getPodTuning();
 
+  FeatureGates getFeatureGates();
+
   class MainTuning {
     public final int initializationRetryDelaySeconds;
     public final int domainPresenceFailureRetrySeconds;
@@ -314,4 +318,48 @@ public boolean equals(Object o) {
           .isEquals();
     }
   }
+
+  class FeatureGates {
+    public final Collection<String> enabledFeatures;
+
+    public FeatureGates(Collection<String> enabledFeatures) {
+      this.enabledFeatures = Collections.unmodifiableCollection(enabledFeatures);
+    }
+
+    public Collection<String> getEnabledFeatures() {
+      return enabledFeatures;
+    }
+
+    public boolean isFeatureEnabled(String featureName) {
+      return enabledFeatures.contains(featureName);
+    }
+
+    @Override
+    public String toString() {
+      return new ToStringBuilder(this)
+          .append("enabledFeatures", enabledFeatures)
+          .toString();
+    }
+
+    @Override
+    public int hashCode() {
+      return new HashCodeBuilder()
+          .append(enabledFeatures)
+          .toHashCode();
+    }
+
+    @Override
+    public boolean equals(Object o) {
+      if (o == null) {
+        return false;
+      }
+      if (!(o instanceof FeatureGates)) {
+        return false;
+      }
+      FeatureGates fg = (FeatureGates) o;
+      return new EqualsBuilder()
+          .append(enabledFeatures, fg.enabledFeatures)
+          .isEquals();
+    }
+  }
 }

operator/src/main/java/oracle/kubernetes/operator/TuningParametersImpl.java

@@ -3,9 +3,13 @@
 
 package oracle.kubernetes.operator;
 
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collection;
 import java.util.concurrent.ScheduledExecutorService;
 import java.util.concurrent.locks.ReadWriteLock;
 import java.util.concurrent.locks.ReentrantReadWriteLock;
+import java.util.stream.Collectors;
 
 import oracle.kubernetes.operator.helpers.ConfigMapConsumer;
 import oracle.kubernetes.operator.logging.LoggingFacade;
@@ -23,6 +27,7 @@ public class TuningParametersImpl extends ConfigMapConsumer implements TuningPar
   private CallBuilderTuning callBuilder = null;
   private WatchTuning watch = null;
   private PodTuning pod = null;
+  private FeatureGates featureGates = null;
 
   private TuningParametersImpl(ScheduledExecutorService executorService) {
     super(executorService);
@@ -82,23 +87,40 @@ private void update() {
             (int) readTuningParameter("livenessProbePeriodSeconds", 45),
             readTuningParameter("introspectorJobActiveDeadlineSeconds", 120));
 
+    FeatureGates featureGates =
+        new FeatureGates(generateFeatureGates(get("featureGates")));
+
     lock.writeLock().lock();
     try {
       if (!main.equals(this.main)
           || !callBuilder.equals(this.callBuilder)
           || !watch.equals(this.watch)
-          || !pod.equals(this.pod)) {
+          || !watch.equals(this.pod)
+          || !pod.equals(this.featureGates)) {
         LOGGER.info(MessageKeys.TUNING_PARAMETERS);
       }
       this.main = main;
       this.callBuilder = callBuilder;
       this.watch = watch;
       this.pod = pod;
+      this.featureGates = featureGates;
     } finally {
       lock.writeLock().unlock();
     }
   }
 
+  private Collection<String> generateFeatureGates(String featureGatesProperty) {
+    Collection<String> enabledGates = new ArrayList<>();
+    if (featureGatesProperty != null) {
+      Arrays.stream(
+          featureGatesProperty.split(","))
+          .filter(s -> s.endsWith("=true"))
+          .map(s -> s.substring(s.indexOf('=')))
+          .collect(Collectors.toCollection(() -> enabledGates));
+    }
+    return enabledGates;
+  }
+
   @Override
   public MainTuning getMainTuning() {
     lock.readLock().lock();
@@ -138,4 +160,14 @@ public PodTuning getPodTuning() {
       lock.readLock().unlock();
     }
   }
+
+  @Override
+  public FeatureGates getFeatureGates() {
+    lock.readLock().lock();
+    try {
+      return featureGates;
+    } finally {
+      lock.readLock().unlock();
+    }
+  }
 }

operator/src/main/java/oracle/kubernetes/operator/logging/MessageKeys.java

@@ -11,6 +11,7 @@ public class MessageKeys {
   public static final String OPERATOR_STARTED = "WLSKO-0000";
   public static final String CREATING_API_CLIENT = "WLSKO-0001";
   public static final String K8S_MASTER_URL = "WLSKO-0002";
+  public static final String ENABLED_FEATURES = "WLSKO-0003";
   public static final String OPERATOR_SHUTTING_DOWN = "WLSKO-0005";
   public static final String EXCEPTION = "WLSKO-0006";
   public static final String CREATING_CRD = "WLSKO-0012";
@@ -19,11 +20,9 @@ public class MessageKeys {
   public static final String SECRET_DATA_NOT_FOUND = "WLSKO-0020";
   public static final String WLS_CONFIGURATION_READ = "WLSKO-0021";
   public static final String JSON_PARSING_FAILED = "WLSKO-0026";
-  public static final String SERVICE_URL = "WLSKO-0027";
   public static final String NO_WLS_SERVER_IN_CLUSTER = "WLSKO-0028";
   public static final String VERIFY_ACCESS_START = "WLSKO-0029";
   public static final String VERIFY_ACCESS_DENIED = "WLSKO-0030";
-  public static final String NAMESPACE_IS_DEFAULT = "WLSKO-0031";
   public static final String STARTING_LIVENESS_THREAD = "WLSKO-0034";
   public static final String COULD_NOT_CREATE_LIVENESS_FILE = "WLSKO-0035";
   public static final String REST_AUTHENTICATION_MISSING_ACCESS_TOKEN = "WLSKO-0037";
@@ -138,7 +137,6 @@ public class MessageKeys {
   public static final String CLUSTER_PDB_PATCHED = "WLSKO-0185";
   public static final String BEGIN_MANAGING_NAMESPACE = "WLSKO-0186";
   public static final String END_MANAGING_NAMESPACE = "WLSKO-0187";
-  public static final String MII_DOMAIN_DYNAMICALLY_UPDATED = "WLSKO-0188";
   public static final String HTTP_REQUEST_GOT_THROWABLE = "WLSKO-0189";
 
   // domain status messages