feat: Improvements to the S3 API

extensions/parquet/table/src/test/java/io/deephaven/parquet/table/S3ParquetRemoteTest.java

@@ -75,16 +75,43 @@ public void readSampleParquetFilesFromPublicS3Part1() {
     @Test
     public void readSampleParquetFilesFromPublicS3Part2() {
         Assume.assumeTrue("Skipping test because s3 testing disabled.", ENABLE_REMOTE_S3_TESTING);
-        final S3Instructions s3Instructions = S3Instructions.builder()
-                .regionName("eu-west-3")
-                .readTimeout(Duration.ofSeconds(60))
-                .credentials(Credentials.anonymous())
-                .build();
-        final ParquetInstructions readInstructions = new ParquetInstructions.Builder()
-                .setSpecialInstructions(s3Instructions)
-                .build();
-        readTable("s3://datasets-documentation/pypi/2023/pypi_66_7_29.snappy.parquet", readInstructions)
-                .head(10).select();
+        {
+            final S3Instructions s3Instructions = S3Instructions.builder()
+                    .regionName("eu-west-3")
+                    .readTimeout(Duration.ofSeconds(60))
+                    .credentials(Credentials.anonymous())
+                    .build();
+            final ParquetInstructions readInstructions = new ParquetInstructions.Builder()
+                    .setSpecialInstructions(s3Instructions)
+                    .build();
+            readTable("s3://datasets-documentation/pypi/2023/pypi_66_7_29.snappy.parquet", readInstructions)
+                    .head(10).select();
+        }
+
+        // Now read the same file without a region
+        {
+            final S3Instructions s3Instructions = S3Instructions.builder()
+                    .readTimeout(Duration.ofSeconds(60))
+                    .credentials(Credentials.anonymous())
+                    .build();
+            final ParquetInstructions readInstructions = new ParquetInstructions.Builder()
+                    .setSpecialInstructions(s3Instructions)
+                    .build();
+            readTable("s3://datasets-documentation/pypi/2023/pypi_66_7_29.snappy.parquet", readInstructions)
+                    .head(10).select();
+        }
+
+        // Now read the same file with credentials not set as anonymous
+        {
+            final S3Instructions s3Instructions = S3Instructions.builder()
+                    .readTimeout(Duration.ofSeconds(60))
+                    .build();
+            final ParquetInstructions readInstructions = new ParquetInstructions.Builder()
+                    .setSpecialInstructions(s3Instructions)
+                    .build();
+            readTable("s3://datasets-documentation/pypi/2023/pypi_66_7_29.snappy.parquet", readInstructions)
+                    .head(10).select();
+        }
     }
 
     @Test

extensions/parquet/table/src/test/java/io/deephaven/parquet/table/S3ParquetTestBase.java

@@ -29,6 +29,7 @@
 import java.io.IOException;
 import java.net.URI;
 import java.time.Duration;
+import java.util.Optional;
 import java.util.concurrent.ExecutionException;
 import java.util.concurrent.TimeoutException;
 
@@ -91,22 +92,28 @@ public final void readSingleParquetFile()
 
     @Test
     public final void readWriteSingleParquetFile() {
-        readWriteSingleParquetFileHelper(0); // Empty table
-        readWriteSingleParquetFileHelper(5_000);
-        readWriteSingleParquetFileHelper(50_000);
-        readWriteSingleParquetFileHelper(500_000);
+        readWriteSingleParquetFileHelper(0, true); // Empty table
+        readWriteSingleParquetFileHelper(0, false);
+        readWriteSingleParquetFileHelper(5_000, true);
+        readWriteSingleParquetFileHelper(5_000, false);
+        readWriteSingleParquetFileHelper(50_000, true);
+        readWriteSingleParquetFileHelper(500_000, true);
     }
 
-    private void readWriteSingleParquetFileHelper(final int numRows) {
+    private void readWriteSingleParquetFileHelper(final int numRows, boolean withRegion) {
         final Table table = getTable(numRows);
         final URI uri = uri("table.parquet");
+        S3Instructions s3Instructions = s3Instructions(
+                S3Instructions.builder()
+                        .writePartSize(5 << 20)
+                        .numConcurrentWriteParts(5)
+                        .readTimeout(Duration.ofSeconds(10)))
+                .build();
+        if (!withRegion) {
+            s3Instructions = s3Instructions.withRegionName(Optional.empty());
+        }
         final ParquetInstructions instructions = ParquetInstructions.builder()
-                .setSpecialInstructions(s3Instructions(
-                        S3Instructions.builder()
-                                .writePartSize(5 << 20)
-                                .numConcurrentWriteParts(5)
-                                .readTimeout(Duration.ofSeconds(10)))
-                        .build())
+                .setSpecialInstructions(s3Instructions)
                 .build();
 
         // Write the table to S3 using ParquetTools write API

extensions/s3/src/main/java/io/deephaven/extensions/s3/Credentials.java

@@ -3,13 +3,15 @@
 //
 package io.deephaven.extensions.s3;
 
+import software.amazon.awssdk.auth.credentials.DefaultCredentialsProvider;
+
 public interface Credentials {
 
     /**
-     * The default credentials.
+     * Default credentials provider that looks for credentials at a number of locations as described in
+     * {@link DefaultCredentialsProvider} and falls back to anonymous credentials if no credentials are found.
      *
-     * @see <a href="https://docs.aws.amazon.com/sdk-for-java/latest/developer-guide/credentials-chain.html">Default
-     *      credentials provider chain</a>
+     * @see DefaultCredentialsProvider
      */
     static Credentials defaultCredentials() {
         return DefaultCredentials.DEFAULT_CREDENTIALS;

extensions/s3/src/main/java/io/deephaven/extensions/s3/DefaultCredentials.java

@@ -3,18 +3,36 @@
 //
 package io.deephaven.extensions.s3;
 
+import software.amazon.awssdk.auth.credentials.AnonymousCredentialsProvider;
+import software.amazon.awssdk.auth.credentials.AwsCredentials;
 import software.amazon.awssdk.auth.credentials.AwsCredentialsProvider;
+import software.amazon.awssdk.auth.credentials.AwsCredentialsProviderChain;
 import software.amazon.awssdk.auth.credentials.DefaultCredentialsProvider;
 
 /**
  * Default AWS credentials provider that looks for credentials at a number of locations as described in
- * {@link DefaultCredentialsProvider}
+ * {@link DefaultCredentialsProvider} and falls back to anonymous credentials if no credentials are found.
+ *
+ * @see DefaultCredentialsProvider
  */
-enum DefaultCredentials implements AwsSdkV2Credentials {
+enum DefaultCredentials implements AwsSdkV2Credentials, AwsCredentialsProvider {
     DEFAULT_CREDENTIALS;
 
+    private static final AwsCredentialsProviderChain PROVIDER_CHAIN = AwsCredentialsProviderChain.builder()
+            .reuseLastProviderEnabled(true)
+            .credentialsProviders(new AwsCredentialsProvider[] {
+                    DefaultCredentialsProvider.create(),
+                    AnonymousCredentialsProvider.create()
+            })
+            .build();
+
     @Override
     public final AwsCredentialsProvider awsV2CredentialsProvider() {
-        return DefaultCredentialsProvider.create();
+        return DEFAULT_CREDENTIALS;
+    }
+
+    @Override
+    public AwsCredentials resolveCredentials() {
+        return PROVIDER_CHAIN.resolveCredentials();
     }
 }

extensions/s3/src/main/java/io/deephaven/extensions/s3/S3AsyncClientFactory.java

@@ -9,10 +9,8 @@
 import software.amazon.awssdk.core.client.config.ClientOverrideConfiguration;
 import software.amazon.awssdk.core.client.config.SdkAdvancedAsyncClientOption;
 import software.amazon.awssdk.core.retry.RetryMode;
-import software.amazon.awssdk.http.SdkHttpClient;
 import software.amazon.awssdk.http.async.SdkAsyncHttpClient;
 import software.amazon.awssdk.http.crt.AwsCrtAsyncHttpClient;
-import software.amazon.awssdk.http.crt.AwsCrtHttpClient;
 import software.amazon.awssdk.regions.Region;
 import software.amazon.awssdk.services.s3.S3AsyncClient;
 import software.amazon.awssdk.services.s3.S3AsyncClientBuilder;
@@ -41,6 +39,25 @@ class S3AsyncClientFactory {
     private static volatile ScheduledExecutorService scheduledExecutor;
 
     static S3AsyncClient getAsyncClient(@NotNull final S3Instructions instructions) {
+        S3AsyncClient s3AsyncClient;
+        try {
+            s3AsyncClient = getAsyncClientBuilder(instructions).build();
+        } catch (final RuntimeException e) {
+            if (instructions.regionName().isEmpty() && e.getMessage().contains("region")) {
+                // We might have failed because region was not provided and could not be determined by the SDK.
+                // We will try again with a default region.
+                s3AsyncClient = getAsyncClientBuilder(instructions).region(Region.US_EAST_2).build();
+            } else {
+                throw e;
+            }
+        }
+        if (log.isDebugEnabled()) {
+            log.debug().append("Building S3AsyncClient with instructions: ").append(instructions).endl();
+        }
+        return s3AsyncClient;
+    }
+
+    private static S3AsyncClientBuilder getAsyncClientBuilder(@NotNull final S3Instructions instructions) {
         final S3AsyncClientBuilder builder = S3AsyncClient.builder()
                 .asyncConfiguration(
                         b -> b.advancedOption(SdkAdvancedAsyncClientOption.FUTURE_COMPLETION_EXECUTOR,
@@ -58,13 +75,15 @@ static S3AsyncClient getAsyncClient(@NotNull final S3Instructions instructions)
                         .scheduledExecutorService(ensureScheduledExecutor())
                         .build())
                 .credentialsProvider(instructions.awsV2CredentialsProvider());
-        instructions.regionName().map(Region::of).ifPresent(builder::region);
-        instructions.endpointOverride().ifPresent(builder::endpointOverride);
-        final S3AsyncClient s3AsyncClient = builder.build();
-        if (log.isDebugEnabled()) {
-            log.debug().append("Building S3AsyncClient with instructions: ").append(instructions).endl();
+        if (instructions.regionName().isPresent()) {
+            builder.region(Region.of(instructions.regionName().get()));
+        } else {
+            // If region is not provided, we enable cross-region access to allow the SDK to determine the region
+            // based on the bucket location and cache it for future requests.
+            builder.crossRegionAccessEnabled(true);
         }
-        return s3AsyncClient;
+        instructions.endpointOverride().ifPresent(builder::endpointOverride);
+        return builder;
     }
 
     private static class HttpClientConfig {

extensions/s3/src/main/java/io/deephaven/extensions/s3/S3Instructions.java

@@ -6,6 +6,7 @@
 import io.deephaven.annotations.CopyableStyle;
 import io.deephaven.base.log.LogOutput;
 import io.deephaven.base.log.LogOutputAppendable;
+import io.deephaven.util.annotations.VisibleForTesting;
 import org.immutables.value.Value.Check;
 import org.immutables.value.Value.Default;
 import org.immutables.value.Value.Immutable;
@@ -51,7 +52,9 @@ public static Builder builder() {
     /**
      * The region name to use when reading or writing to S3. If not provided, the region name is picked by the AWS SDK
      * from 'aws.region' system property, "AWS_REGION" environment variable, the {user.home}/.aws/credentials or
-     * {user.home}/.aws/config files, or from EC2 metadata service, if running in EC2.
+     * {user.home}/.aws/config files, or from EC2 metadata service, if running in EC2. If no region name is derived from
+     * the above chain or derived the region name derived is incorrect for the bucket accessed, the correct region name
+     * will be derived internally, at the cost of one additional request.
      */
     public abstract Optional<String> regionName();
 
@@ -177,6 +180,9 @@ default Builder endpointOverride(String endpointOverride) {
 
     abstract S3Instructions withReadAheadCount(int readAheadCount);
 
+    @VisibleForTesting
+    public abstract S3Instructions withRegionName(Optional<String> regionName);
+
     @Lazy
     S3Instructions singleUse() {
         final int readAheadCount = Math.min(DEFAULT_READ_AHEAD_COUNT, readAheadCount());

py/server/deephaven/experimental/s3.py

@@ -51,10 +51,13 @@ def __init__(self,
             region_name (str): the region name for reading parquet files. If not provided, the default region will be
                 picked by the AWS SDK from 'aws.region' system property, "AWS_REGION" environment variable, the
                 {user.home}/.aws/credentials or {user.home}/.aws/config files, or from EC2 metadata service, if running
-                in EC2.
+                in EC2. If no region name is derived from the above chain or the derived region name is incorrect for
+                the bucket accessed, the correct region name will be derived internally, at the cost of one additional
+                request.
             max_concurrent_requests (int): the maximum number of concurrent requests for reading files, default is 256.
-            read_ahead_count (int): the number of fragments to send asynchronous read requests for while reading the current
-                fragment. Defaults to 32, which means fetch the next 32 fragments in advance when reading the current fragment.
+            read_ahead_count (int): the number of fragments to send asynchronous read requests for while reading the
+                current fragment. Defaults to 32, which means fetch the next 32 fragments in advance when reading the
+                current fragment.
             fragment_size (int): the maximum size of each fragment to read, defaults to 64 KiB. If there are fewer bytes
                 remaining in the file, the fetched fragment can be smaller.
             connection_timeout (DurationLike):
@@ -65,8 +68,8 @@ def __init__(self,
                 the amount of time to wait when reading a fragment before giving up and timing out, can be expressed as
                 an integer in nanoseconds, a time interval string, e.g. "PT00:00:00.001" or "PT1s", or other time
                 duration types. Default to 2 seconds.
-            access_key_id (str): the access key for reading files. Both access key and secret access key must be provided
-                to use static credentials, else default credentials will be used.
+            access_key_id (str): the access key for reading files. Both access key and secret access key must be
+                provided to use static credentials, else default credentials will be used.
             secret_access_key (str): the secret access key for reading files. Both access key and secret key must be
                 provided to use static credentials, else default credentials will be used.
             anonymous_access (bool): use anonymous credentials, this is useful when the S3 policy has been set to allow