chore: start adding cache support

src/main/java/com/aws/greengrass/clientdevices/auth/configuration/RuntimeConfiguration.java

@@ -7,6 +7,8 @@
 
 import com.aws.greengrass.clientdevices.auth.connectivity.HostAddress;
 import com.aws.greengrass.clientdevices.auth.iot.dto.CertificateV1DTO;
+import com.aws.greengrass.clientdevices.auth.iot.dto.ThingAssociationV1DTO;
+import com.aws.greengrass.clientdevices.auth.iot.dto.ThingDescriptionV1DTO;
 import com.aws.greengrass.clientdevices.auth.iot.dto.ThingV1DTO;
 import com.aws.greengrass.config.Node;
 import com.aws.greengrass.config.Topic;
@@ -204,6 +206,22 @@ public void removeCertificateV1(String certificateId) {
         }
     }
 
+    public void putThingAssociationV1(ThingAssociationV1DTO thingAssociationV1DTO) {
+        // TODO
+    }
+
+    public ThingAssociationV1DTO getThingAssociationV1() {
+        return null; // TODO
+    }
+
+    public void putThingDescriptionV1(ThingDescriptionV1DTO thingDescriptionV1DTO) {
+        // TODO
+    }
+
+    public ThingDescriptionV1DTO getThingDescriptionV1(String thingName) {
+        return null; // TODO
+    }
+
     private Topics getOrRepairTopics(Topics root, String... path) {
         try {
             return root.lookupTopics(path);

src/main/java/com/aws/greengrass/clientdevices/auth/iot/IotCoreClient.java

@@ -12,6 +12,7 @@
 import software.amazon.awssdk.services.iot.IotClient;
 import software.amazon.awssdk.services.iot.model.DescribeThingRequest;
 
+import java.util.Collections;
 import java.util.Map;
 import javax.inject.Inject;
 
@@ -38,10 +39,11 @@ class Default implements IotCoreClient {
         @SuppressWarnings("PMD.AvoidCatchingGenericException")
         public Map<String, String> getThingAttributes(String thingName) throws CloudServiceInteractionException {
             try (IotClient client = iotClientFactory.getClient()) {
-                return client.describeThing(DescribeThingRequest.builder()
+                Map<String, String> attributes = client.describeThing(DescribeThingRequest.builder()
                                 .thingName(thingName)
                                 .build())
                         .attributes();
+                return attributes == null ? Collections.emptyMap() : attributes;
             } catch (DeviceConfigurationException e) {
                 throw new CloudServiceInteractionException("Failed to construct IoT Core client", e);
             } catch (Exception e) {

src/main/java/com/aws/greengrass/clientdevices/auth/iot/ThingAttributesCache.java

@@ -5,12 +5,16 @@
 
 package com.aws.greengrass.clientdevices.auth.iot;
 
+import com.aws.greengrass.clientdevices.auth.configuration.RuntimeConfiguration;
 import com.aws.greengrass.clientdevices.auth.exception.CloudServiceInteractionException;
 import com.aws.greengrass.clientdevices.auth.infra.NetworkStateProvider;
+import com.aws.greengrass.clientdevices.auth.iot.dto.ThingAssociationV1DTO;
+import com.aws.greengrass.clientdevices.auth.iot.dto.ThingDescriptionV1DTO;
 import com.aws.greengrass.logging.api.Logger;
 import com.aws.greengrass.logging.impl.LogManager;
 import software.amazon.awssdk.services.greengrassv2.model.AssociatedClientDevice;
 
+import java.time.LocalDateTime;
 import java.util.List;
 import java.util.Map;
 import java.util.Optional;
@@ -28,6 +32,13 @@ public class ThingAttributesCache {
 
     private static final Logger logger = LogManager.getLogger(ThingAttributesCache.class);
 
+    private static final long DEFAULT_REFRESH_DELAY_SECONDS =
+            TimeUnit.MINUTES.toSeconds(1);
+    private static final long DEFAULT_THING_ASSOCIATION_TRUST_DURATION_SECONDS =
+            TimeUnit.MINUTES.toSeconds(5);
+    private static final long DEFAULT_THING_DESCRIPTION_TRUST_DURATION_SECONDS =
+            TimeUnit.MINUTES.toSeconds(10);
+
     // set once during component install
     private static final AtomicReference<ThingAttributesCache> INSTANCE = new AtomicReference<>();
     private final AtomicReference<CountDownLatch> initialized = new AtomicReference<>();
@@ -41,6 +52,8 @@ public class ThingAttributesCache {
     private final NetworkStateProvider networkStateProvider;
     private ScheduledFuture<?> refreshTask;
 
+    private final RuntimeConfiguration runtimeConfiguration;
+
     public static Optional<ThingAttributesCache> instance() {
         return Optional.ofNullable(INSTANCE.get());
     }
@@ -55,16 +68,19 @@ public static void setInstance(ThingAttributesCache cache) {
      * @param iotCoreClient        iot core client
      * @param iotAuthClient        iot auth client
      * @param networkStateProvider network state provider
+     * @param runtimeConfiguration runtime configuration
      * @param ses                  scheduled executor service
      */
     @Inject
     public ThingAttributesCache(IotCoreClient iotCoreClient,
                                 IotAuthClient iotAuthClient,
                                 NetworkStateProvider networkStateProvider,
+                                RuntimeConfiguration runtimeConfiguration,
                                 ScheduledExecutorService ses) {
         this.iotCoreClient = iotCoreClient;
         this.iotAuthClient = iotAuthClient;
         this.networkStateProvider = networkStateProvider;
+        this.runtimeConfiguration = runtimeConfiguration;
         this.ses = ses;
     }
 
@@ -102,8 +118,9 @@ private void markAsInitialized() {
      */
     public void startPeriodicRefresh() {
         stopPeriodicRefresh();
-        // TODO configurable delay
-        refreshTask = ses.scheduleWithFixedDelay(this::refresh, 0L, 1L, TimeUnit.MINUTES);
+        // TODO pull from configuration
+        refreshTask = ses.scheduleWithFixedDelay(this::refresh, 0L,
+                DEFAULT_REFRESH_DELAY_SECONDS, TimeUnit.SECONDS);
     }
 
     /**
@@ -117,46 +134,91 @@ public void stopPeriodicRefresh() {
     }
 
     private void refresh() {
-        if (networkStateProvider.getConnectionState() == NetworkStateProvider.ConnectionState.NETWORK_DOWN) {
-            // TODO cache attributes on disk and load here, handle case if device restarts while offline
-            logger.atTrace().log("network down, unable to refresh thing-attribute cache");
-            return;
-        }
         logger.atTrace().log("beginning thing-attribute cache refresh");
         getAssociatedThingNames().ifPresent(thingNames -> {
             for (String thingName : thingNames) {
                 if (Thread.currentThread().isInterrupted()) {
                     return;
                 }
-                fetchDeviceAttributes(thingName).ifPresent(attrs -> {
+                getThingAttributes(thingName).ifPresent(attrs -> {
                     logger.atInfo().kv("thing", thingName).log("attributes refreshed for device");
                     attributesByThing.put(thingName, new ConcurrentHashMap<>(attrs));
                 });
             }
-            // TODO handle case where some fetches fail
+            // TODO it's currently possible that not all thing attributes were successfully
+            //      fetched at this point, meaning that CDA will have started and devices
+            //      will be rejected until subsequent refreshes as executed successfully.
             markAsInitialized();
         });
     }
 
-    @SuppressWarnings("PMD.AvoidCatchingGenericException")
     private Optional<Set<String>> getAssociatedThingNames() {
+        // use cached value, provided it's not stale
+        ThingAssociationV1DTO dto = runtimeConfiguration.getThingAssociationV1();
+        // TODO pull from configuration
+        if (dto != null && dto.getLastFetched().plusSeconds(DEFAULT_THING_ASSOCIATION_TRUST_DURATION_SECONDS)
+                .isBefore(LocalDateTime.now())) {
+            logger.atTrace().log("Using locally cached thing associations");
+            return Optional.ofNullable(dto.getAssociatedThingNames());
+        }
+
+        if (networkStateProvider.getConnectionState() == NetworkStateProvider.ConnectionState.NETWORK_DOWN) {
+            logger.atTrace().log("Network down, unable to fetch thing associations from cloud");
+            return Optional.empty();
+        }
+
+        // otherwise fetch new associations from cloud and write to cache
+        logger.atTrace().log("Fetching thing associations from cloud");
+        Optional<Set<String>> associatedThingNames = fetchAssociatedThingNames();
+        associatedThingNames.ifPresent(names ->
+                runtimeConfiguration.putThingAssociationV1(new ThingAssociationV1DTO(names, LocalDateTime.now())));
+        return associatedThingNames;
+    }
+
+    @SuppressWarnings("PMD.AvoidCatchingGenericException")
+    private Optional<Set<String>> fetchAssociatedThingNames() {
         try {
             return Optional.of(iotAuthClient.getThingsAssociatedWithCoreDevice()
                     .flatMap(List::stream)
                     .map(AssociatedClientDevice::thingName)
                     .collect(Collectors.toSet()));
         } catch (Exception e) {
             logger.atWarn()
+                    .cause(e)
                     .log("Unable to find associated things");
             return Optional.empty();
         }
     }
 
-    private Optional<Map<String, String>> fetchDeviceAttributes(String thingName) {
+    private Optional<Map<String, String>> getThingAttributes(String thingName) {
+        // use cached value, provided it's not stale
+        ThingDescriptionV1DTO dto = runtimeConfiguration.getThingDescriptionV1(thingName);
+        // TODO pull from configuration
+        if (dto != null && dto.getLastFetched().plusSeconds(DEFAULT_THING_DESCRIPTION_TRUST_DURATION_SECONDS)
+                .isBefore(LocalDateTime.now())) {
+            logger.atTrace().log("Using locally cached thing description");
+            return Optional.ofNullable(dto.getAttributes());
+        }
+
+        if (networkStateProvider.getConnectionState() == NetworkStateProvider.ConnectionState.NETWORK_DOWN) {
+            logger.atTrace().log("Network down, unable to fetch thing description from cloud");
+            return Optional.empty();
+        }
+
+        // otherwise fetch new description from cloud and write to cache
+        logger.atTrace().log("Fetching thing description from cloud");
+        Optional<Map<String, String>> attributes = fetchThingAttributes(thingName);
+        attributes.ifPresent(attrs ->
+                runtimeConfiguration.putThingDescriptionV1(new ThingDescriptionV1DTO(thingName, attrs, LocalDateTime.now())));
+        return attributes;
+    }
+
+    private Optional<Map<String, String>> fetchThingAttributes(String thingName) {
         try {
-            return Optional.ofNullable(iotCoreClient.getThingAttributes(thingName));
+            return Optional.of(iotCoreClient.getThingAttributes(thingName));
         } catch (CloudServiceInteractionException e) {
             logger.atWarn()
+                    .cause(e)
                     .kv("thing", thingName)
                     .log("Unable to get thing attributes");
             return Optional.empty();

src/main/java/com/aws/greengrass/clientdevices/auth/iot/dto/ThingAssociationV1DTO.java

@@ -0,0 +1,19 @@
+/*
+ * Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package com.aws.greengrass.clientdevices.auth.iot.dto;
+
+import lombok.AllArgsConstructor;
+import lombok.Value;
+
+import java.time.LocalDateTime;
+import java.util.Set;
+
+@Value
+@AllArgsConstructor
+public class ThingAssociationV1DTO {
+    Set<String> associatedThingNames;
+    LocalDateTime lastFetched;
+}

src/main/java/com/aws/greengrass/clientdevices/auth/iot/dto/ThingDescriptionV1DTO.java

@@ -0,0 +1,20 @@
+/*
+ * Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package com.aws.greengrass.clientdevices.auth.iot.dto;
+
+import lombok.AllArgsConstructor;
+import lombok.Value;
+
+import java.time.LocalDateTime;
+import java.util.Map;
+
+@Value
+@AllArgsConstructor
+public class ThingDescriptionV1DTO {
+    String thingName;
+    Map<String, String> attributes;
+    LocalDateTime lastFetched;
+}