CASSSIDECAR-162: Sidecar endpoint to GET sstable's preemptive interval value

adapters/base/src/main/java/org/apache/cassandra/sidecar/adapters/base/CassandraStorageOperations.java

@@ -20,6 +20,7 @@
 
 import java.io.IOException;
 import java.net.UnknownHostException;
+import java.security.InvalidParameterException;
 import java.util.Arrays;
 import java.util.Collections;
 import java.util.List;
@@ -29,8 +30,10 @@
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
+import org.apache.cassandra.sidecar.common.response.GetPreemptiveOpenIntervalResponse;
 import org.apache.cassandra.sidecar.common.response.RingResponse;
 import org.apache.cassandra.sidecar.common.response.TokenRangeReplicasResponse;
+import org.apache.cassandra.sidecar.common.server.DataStorageUnit;
 import org.apache.cassandra.sidecar.common.server.JmxClient;
 import org.apache.cassandra.sidecar.common.server.StorageOperations;
 import org.apache.cassandra.sidecar.common.server.cluster.locator.Partitioners;
@@ -213,4 +216,17 @@ public void outOfRangeDataCleanup(@NotNull String keyspace, @NotNull String tabl
         jmxClient.proxy(StorageJmxOperations.class, STORAGE_SERVICE_OBJ_NAME)
                  .forceKeyspaceCleanup(concurrency, keyspace, table);
     }
+
+    @Override
+    public GetPreemptiveOpenIntervalResponse getSSTablePreemptiveOpenInterval(DataStorageUnit unit)
+    {
+        if (unit != DataStorageUnit.MEBIBYTES)
+        {
+            throw new InvalidParameterException("Unsupported data storage unit: " + unit);
+        }
+
+        int preemptiveOpenInterval = jmxClient.proxy(StorageJmxOperations.class, STORAGE_SERVICE_OBJ_NAME)
+                                              .getSSTablePreemptiveOpenIntervalInMB();
+        return new GetPreemptiveOpenIntervalResponse(preemptiveOpenInterval);
+    }
 }

adapters/base/src/main/java/org/apache/cassandra/sidecar/adapters/base/GossipDependentStorageJmxOperations.java

@@ -159,4 +159,10 @@ public void ensureGossipIsEnabled()
         LOGGER.warn("Gossip is disabled and unavailable for the operation");
         throw OperationUnavailableException.GOSSIP_DISABLED;
     }
+
+    @Override
+    public int getSSTablePreemptiveOpenIntervalInMB()
+    {
+        return delegate.getSSTablePreemptiveOpenIntervalInMB();
+    }
 }

adapters/base/src/main/java/org/apache/cassandra/sidecar/adapters/base/StorageJmxOperations.java

@@ -159,4 +159,10 @@ public interface StorageJmxOperations
      * @throws InterruptedException it does not really throw but declared in MBean
      */
     int forceKeyspaceCleanup(int jobs, String keyspaceName, String... tables) throws IOException, ExecutionException, InterruptedException;
+
+    /**
+     * Invokes C* StorageServiceMBean's JMX function getSSTablePreemptiveOpenIntervalInMB
+     * @return the same value returned by the JMX operation
+     */
+    int getSSTablePreemptiveOpenIntervalInMB();
 }

client-common/src/main/java/org/apache/cassandra/sidecar/common/ApiEndpointsV1.java

@@ -118,6 +118,11 @@ public final class ApiEndpointsV1
 
     public static final String CONNECTED_CLIENT_STATS_ROUTE = API_V1 + CASSANDRA + "/stats/connected-clients";
 
+    // Endpoint to retrieve sstable's preemptiveOpenInterval value.
+    // Value returned is in MB, may return negative value when disabled
+    private static final String SSTABLE = "/sstable";
+    public static final String SSTABLE_PREEMPTIVE_OPEN_INTERVAL_ROUTE = API_V1 + CASSANDRA + SSTABLE +
+                                                                        "/preemptive-open-interval";
     private ApiEndpointsV1()
     {
         throw new IllegalStateException(getClass() + " is a constants container and shall not be instantiated");

client-common/src/main/java/org/apache/cassandra/sidecar/common/request/GetPreemptiveOpenIntervalRequest.java

@@ -0,0 +1,55 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.cassandra.sidecar.common.request;
+
+import io.netty.handler.codec.http.HttpMethod;
+import org.apache.cassandra.sidecar.common.ApiEndpointsV1;
+import org.apache.cassandra.sidecar.common.response.GetPreemptiveOpenIntervalResponse;
+
+/**
+ * Request to get preemptive open interval value
+ */
+public class GetPreemptiveOpenIntervalRequest extends JsonRequest<GetPreemptiveOpenIntervalResponse>
+{
+    /**
+     * Constructs a request to GET preemptive open interval value
+     */
+    public GetPreemptiveOpenIntervalRequest()
+    {
+        super(ApiEndpointsV1.SSTABLE_PREEMPTIVE_OPEN_INTERVAL_ROUTE);
+    }
+
+    /**
+     * Constructs a request to GET preemptive open interval value with query param 'unit'
+     * @param unit query param, data storage units of preemptive open interval value
+     */
+    public GetPreemptiveOpenIntervalRequest(String unit)
+    {
+        super(ApiEndpointsV1.SSTABLE_PREEMPTIVE_OPEN_INTERVAL_ROUTE + "?unit=" + unit);
+    }
+
+    /**
+     * {@inheritDoc}
+     */
+    @Override
+    public HttpMethod method()
+    {
+        return HttpMethod.GET;
+    }
+}

client-common/src/main/java/org/apache/cassandra/sidecar/common/response/GetPreemptiveOpenIntervalResponse.java

@@ -0,0 +1,46 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.cassandra.sidecar.common.response;
+
+import com.fasterxml.jackson.annotation.JsonInclude;
+import com.fasterxml.jackson.annotation.JsonProperty;
+
+/**
+ * Response for GET preemptive open interval API
+ */
+@JsonInclude(JsonInclude.Include.NON_NULL)
+public class GetPreemptiveOpenIntervalResponse
+{
+    private final int sstablePreemptiveOpenInterval;
+
+    /**
+     * Constructs a response with preemptive open interval value
+     * @param sstablePreemptiveOpenInterval value of preemptive open interval
+     */
+    public GetPreemptiveOpenIntervalResponse(@JsonProperty("SSTablePreemptiveOpenInterval") int sstablePreemptiveOpenInterval)
+    {
+        this.sstablePreemptiveOpenInterval = sstablePreemptiveOpenInterval;
+    }
+
+    @JsonProperty("SSTablePreemptiveOpenInterval")
+    public int sstablePreemptiveOpenInterval()
+    {
+        return sstablePreemptiveOpenInterval;
+    }
+}

client/src/main/java/org/apache/cassandra/sidecar/client/RequestContext.java

@@ -33,6 +33,7 @@
 import org.apache.cassandra.sidecar.common.request.ClearSnapshotRequest;
 import org.apache.cassandra.sidecar.common.request.ConnectedClientStatsRequest;
 import org.apache.cassandra.sidecar.common.request.CreateSnapshotRequest;
+import org.apache.cassandra.sidecar.common.request.GetPreemptiveOpenIntervalRequest;
 import org.apache.cassandra.sidecar.common.request.GossipInfoRequest;
 import org.apache.cassandra.sidecar.common.request.ImportSSTableRequest;
 import org.apache.cassandra.sidecar.common.request.ListSnapshotFilesRequest;
@@ -486,6 +487,28 @@ public Builder connectedClientStatsRequest()
             return request(new ConnectedClientStatsRequest());
         }
 
+        /**
+         * Sets the {@code request} to be a {@link GetPreemptiveOpenIntervalRequest} and returns a reference to this builder
+         * enabling method chaining
+         * @return a reference to this builder
+         */
+        public Builder getPreemptiveOpenIntervalRequest()
+        {
+            return request(new GetPreemptiveOpenIntervalRequest());
+        }
+
+        /**
+         * Sets the {@code request} to be a {@link GetPreemptiveOpenIntervalRequest} with query param 'unit' and
+         * returns a reference to this builder enabling method chaining
+         * @param unit query param, data storage units of preemptive open interval value
+         * @return a reference to this builder
+         */
+        public Builder getPreemptiveOpenIntervalRequest(String unit)
+        {
+            return request(new GetPreemptiveOpenIntervalRequest(unit));
+        }
+
+
         /**
          * Sets the {@code retryPolicy} to be an
          * {@link org.apache.cassandra.sidecar.client.retry.ExponentialBackoffRetryPolicy} configured with

client/src/main/java/org/apache/cassandra/sidecar/client/SidecarClient.java

@@ -49,6 +49,7 @@
 import org.apache.cassandra.sidecar.common.request.data.RestoreJobProgressRequestParams;
 import org.apache.cassandra.sidecar.common.request.data.UpdateRestoreJobRequestPayload;
 import org.apache.cassandra.sidecar.common.response.ConnectedClientStatsResponse;
+import org.apache.cassandra.sidecar.common.response.GetPreemptiveOpenIntervalResponse;
 import org.apache.cassandra.sidecar.common.response.GossipInfoResponse;
 import org.apache.cassandra.sidecar.common.response.HealthResponse;
 import org.apache.cassandra.sidecar.common.response.ListSnapshotFilesResponse;
@@ -593,6 +594,30 @@ public CompletableFuture<ConnectedClientStatsResponse> connectedClientStats()
                                    .build());
     }
 
+    /**
+     * Executes GET preemptive open interval request using the default retry policy and configured selection policy
+     * @return a completable future with {@link GetPreemptiveOpenIntervalResponse}
+     */
+    public CompletableFuture<GetPreemptiveOpenIntervalResponse> getPreemptiveOpenInterval()
+    {
+        return executeRequestAsync(requestBuilder()
+                                   .getPreemptiveOpenIntervalRequest()
+                                   .build());
+    }
+
+    /**
+     * Executes GET preemptive open interval request using the default retry policy and configured selection policy and
+     * with query param 'unit'
+     * @param unit query param, data storage units of preemptive open interval value
+     * @return a completable future with {@link GetPreemptiveOpenIntervalResponse}
+     */
+    public CompletableFuture<GetPreemptiveOpenIntervalResponse> getPreemptiveOpenInterval(String unit)
+    {
+        return executeRequestAsync(requestBuilder()
+                                   .getPreemptiveOpenIntervalRequest(unit)
+                                   .build());
+    }
+
     /**
      * Returns a copy of the request builder with the default parameters configured for the client.
      *

client/src/testFixtures/java/org/apache/cassandra/sidecar/client/SidecarClientTest.java

@@ -67,6 +67,7 @@
 import org.apache.cassandra.sidecar.common.request.data.MD5Digest;
 import org.apache.cassandra.sidecar.common.request.data.XXHash32Digest;
 import org.apache.cassandra.sidecar.common.response.ConnectedClientStatsResponse;
+import org.apache.cassandra.sidecar.common.response.GetPreemptiveOpenIntervalResponse;
 import org.apache.cassandra.sidecar.common.response.GossipInfoResponse;
 import org.apache.cassandra.sidecar.common.response.HealthResponse;
 import org.apache.cassandra.sidecar.common.response.ListSnapshotFilesResponse;
@@ -1440,6 +1441,32 @@ public void testConnectedClientStats() throws Exception
         validateResponseServed(ApiEndpointsV1.CONNECTED_CLIENT_STATS_ROUTE);
     }
 
+    @Test
+    public void testGetPreemptiveOpenInterval() throws Exception
+    {
+        String responseAsString = "{\"SSTablePreemptiveOpenInterval\":30}";
+
+        MockResponse response = new MockResponse().setResponseCode(OK.code()).setBody(responseAsString);
+        enqueue(response);
+        GetPreemptiveOpenIntervalResponse result = client.getPreemptiveOpenInterval().get();
+
+        assertThat(result).isNotNull();
+        assertThat(result.sstablePreemptiveOpenInterval()).isNotNull().isEqualTo(30);
+    }
+
+    @Test
+    public void testGetPreemptiveOpenIntervalWithUnit() throws Exception
+    {
+        String responseAsString = "{\"SSTablePreemptiveOpenInterval\":40}";
+
+        MockResponse response = new MockResponse().setResponseCode(OK.code()).setBody(responseAsString);
+        enqueue(response);
+        GetPreemptiveOpenIntervalResponse result = client.getPreemptiveOpenInterval("MiB").get();
+
+        assertThat(result).isNotNull();
+        assertThat(result.sstablePreemptiveOpenInterval()).isNotNull().isEqualTo(40);
+    }
+
     private void enqueue(MockResponse response)
     {
         for (MockWebServer server : servers)

server-common/src/main/java/org/apache/cassandra/sidecar/common/server/DataStorageUnit.java

@@ -0,0 +1,24 @@
+package org.apache.cassandra.sidecar.common.server;
+
+/**
+ * Enum for data storage units, resembles same unit names as C* is using
+ */
+public enum DataStorageUnit
+{
+    BYTES("B"),
+    KIBIBYTES("KiB"),
+    MEBIBYTES("MiB"),
+    GIBIBYTES("GiB");
+
+    private final String unit;
+
+    DataStorageUnit(String unit)
+    {
+        this.unit = unit;
+    }
+
+    public String getValue()
+    {
+        return unit;
+    }
+}

server-common/src/main/java/org/apache/cassandra/sidecar/common/server/StorageOperations.java

@@ -24,6 +24,7 @@
 import java.util.Map;
 import java.util.concurrent.ExecutionException;
 
+import org.apache.cassandra.sidecar.common.response.GetPreemptiveOpenIntervalResponse;
 import org.apache.cassandra.sidecar.common.response.RingResponse;
 import org.apache.cassandra.sidecar.common.response.TokenRangeReplicasResponse;
 import org.apache.cassandra.sidecar.common.server.data.Name;
@@ -102,4 +103,10 @@ default void outOfRangeDataCleanup(@NotNull String keyspace, @NotNull String tab
     {
         outOfRangeDataCleanup(keyspace, table, 1);
     }
+
+    /**
+     * @param unit preemptive open interval value unit, only allowed value is "MiB"
+     * @return sstable's preemptive open interval value
+     */
+    GetPreemptiveOpenIntervalResponse getSSTablePreemptiveOpenInterval(DataStorageUnit unit);
 }

server/src/main/java/org/apache/cassandra/sidecar/routes/AbstractHandler.java

@@ -35,6 +35,7 @@
 import org.apache.cassandra.sidecar.cluster.CassandraAdapterDelegate;
 import org.apache.cassandra.sidecar.cluster.instance.InstanceMetadata;
 import org.apache.cassandra.sidecar.common.server.MetricsOperations;
+import org.apache.cassandra.sidecar.common.server.StorageOperations;
 import org.apache.cassandra.sidecar.common.server.data.Name;
 import org.apache.cassandra.sidecar.common.server.data.QualifiedTableName;
 import org.apache.cassandra.sidecar.common.server.exceptions.JmxAuthenticationException;
@@ -331,4 +332,16 @@ public static String extractHostAddressWithoutPort(String address)
         }
         return address;
     }
+
+    protected StorageOperations getStorageOperations(String host)
+    {
+        CassandraAdapterDelegate delegate = this.metadataFetcher.delegate(host);
+        StorageOperations storageOperations = delegate == null ? null : delegate.storageOperations();
+        if (storageOperations == null)
+        {
+            throw cassandraServiceUnavailable();
+        }
+
+        return storageOperations;
+    }
 }