feat: Error Details Improvement

google-cloud-spanner/src/main/java/com/google/cloud/spanner/SpannerException.java

@@ -16,6 +16,8 @@
 
 package com.google.cloud.spanner;
 
+import com.google.api.gax.rpc.ApiException;
+import com.google.api.gax.rpc.ErrorDetails;
 import com.google.cloud.grpc.BaseGrpcServiceException;
 import com.google.common.base.Preconditions;
 import com.google.protobuf.util.Durations;
@@ -24,6 +26,7 @@
 import io.grpc.Metadata;
 import io.grpc.Status;
 import io.grpc.protobuf.ProtoUtils;
+import java.util.Map;
 import javax.annotation.Nullable;
 
 /** Base exception type for all exceptions produced by the Cloud Spanner service. */
@@ -51,6 +54,7 @@ public String getResourceName() {
       ProtoUtils.keyForProto(RetryInfo.getDefaultInstance());
 
   private final ErrorCode code;
+  private final ApiException apiException;
 
   /** Private constructor. Use {@link SpannerExceptionFactory} to create instances. */
   SpannerException(
@@ -59,10 +63,23 @@ public String getResourceName() {
       boolean retryable,
       @Nullable String message,
       @Nullable Throwable cause) {
-    super(message, cause, code.getCode(), retryable);
+    super(
+        message,
+        // If the cause is instance of APIException then using its cause to avoid the breaking
+        // change, because earlier we were passing APIException's cause to constructor.
+        cause instanceof ApiException ? cause.getCause() : cause,
+        code.getCode(),
+        retryable);
+
     if (token != DoNotConstructDirectly.ALLOWED) {
       throw new AssertionError("Do not construct directly: use SpannerExceptionFactory");
     }
+
+    if (cause instanceof ApiException) {
+      this.apiException = (ApiException) cause;
+    } else {
+      this.apiException = null;
+    }
     this.code = Preconditions.checkNotNull(code);
   }
 
@@ -95,4 +112,67 @@ static long extractRetryDelay(Throwable cause) {
     }
     return -1L;
   }
+
+  /**
+   * Checks the underlying reason of the exception and if it's {@link ApiException} then return the
+   * reason otherwise null.
+   *
+   * @see <a
+   *     href="https://github.com/googleapis/googleapis/blob/master/google/rpc/error_details.proto#L117">Reason</a>
+   * @return the reason of an error.
+   */
+  public String getReason() {
+    if (this.apiException != null) {
+      return this.apiException.getReason();
+    }
+    return null;
+  }
+
+  /**
+   * Checks the underlying reason of the exception and if it's {@link ApiException} then return the
+   * specific domain otherwise null.
+   *
+   * @see <a
+   *     href="https://github.com/googleapis/googleapis/blob/master/google/rpc/error_details.proto#L125">Domain</a>
+   * @return the logical grouping to which the "reason" belongs.
+   */
+  public String getDomain() {
+    if (this.apiException != null) {
+      return this.apiException.getDomain();
+    }
+    return null;
+  }
+
+  /**
+   * Checks the underlying reason of the exception and if it's {@link ApiException} then return a
+   * map of key-value pairs otherwise null.
+   *
+   * @see <a
+   *     href="https://github.com/googleapis/googleapis/blob/master/google/rpc/error_details.proto#L135">Metadata</a>
+   * @return the map of additional structured details about an error.
+   */
+  public Map<String, String> getMetadata() {
+    if (this.apiException != null) {
+      return this.apiException.getMetadata();
+    }
+    return null;
+  }
+
+  /**
+   * Checks the underlying reason of the exception and if it's {@link ApiException} then return the
+   * ErrorDetails otherwise null.
+   *
+   * @see <a
+   *     href="https://github.com/googleapis/googleapis/blob/master/google/rpc/status.proto">Status</a>
+   * @see <a
+   *     href="https://github.com/googleapis/googleapis/blob/master/google/rpc/error_details.proto">Error
+   *     Details</a>
+   * @return An object containing getters for structured objects from error_details.proto.
+   */
+  public ErrorDetails getErrorDetails() {
+    if (this.apiException != null) {
+      return this.apiException.getErrorDetails();
+    }
+    return null;
+  }
 }

google-cloud-spanner/src/main/java/com/google/cloud/spanner/SpannerExceptionFactory.java

@@ -295,12 +295,8 @@ private static SpannerException fromApiException(ApiException exception) {
       code = Status.Code.UNKNOWN;
     }
     ErrorCode errorCode = ErrorCode.fromGrpcStatus(Status.fromCode(code));
-    if (exception.getCause() != null) {
-      return SpannerExceptionFactory.newSpannerException(
-          errorCode, exception.getMessage(), exception.getCause());
-    } else {
-      return SpannerExceptionFactory.newSpannerException(errorCode, exception.getMessage());
-    }
+    return SpannerExceptionFactory.newSpannerException(
+        errorCode, exception.getMessage(), exception);
   }
 
   private static boolean isRetryable(ErrorCode code, @Nullable Throwable cause) {