Expose Spanner failIfPoolExhausted property

docs/src/main/asciidoc/spanner.adoc

@@ -87,6 +87,7 @@ The schema for the tables will be "ON DELETE NO ACTION" if `false`. | No | `true
 | `spring.cloud.gcp.spanner.maxIdleSessions` | Maximum number of idle sessions session pool will maintain | No | 0 - Determined by Cloud Spanner client library
 | `spring.cloud.gcp.spanner.writeSessionsFraction` | Fraction of sessions to be kept prepared for write transactions | No | 0.2 - Determined by Cloud Spanner client library
 | `spring.cloud.gcp.spanner.keepAliveIntervalMinutes` | How long to keep idle sessions alive | No | 30 - Determined by Cloud Spanner client library
+| `spring.cloud.gcp.spanner.failIfPoolExhausted` |  If all sessions are in use, fail the request by throwing an exception. Otherwise, by default, block until a session becomes available. | No | `false`
 |===
 
 ==== Repository settings

spring-cloud-gcp-autoconfigure/src/main/java/org/springframework/cloud/gcp/autoconfigure/spanner/GcpSpannerAutoConfiguration.java

@@ -95,6 +95,8 @@ static class CoreSpannerAutoConfiguration {
 
 		private final boolean createInterleavedTableDdlOnDeleteCascade;
 
+		private final boolean failIfPoolExhausted;
+
 		CoreSpannerAutoConfiguration(GcpSpannerProperties gcpSpannerProperties,
 				GcpProjectIdProvider projectIdProvider,
 				CredentialsProvider credentialsProvider) throws IOException {
@@ -116,6 +118,7 @@ static class CoreSpannerAutoConfiguration {
 					.getKeepAliveIntervalMinutes();
 			this.createInterleavedTableDdlOnDeleteCascade = gcpSpannerProperties
 					.isCreateInterleavedTableDdlOnDeleteCascade();
+			this.failIfPoolExhausted = gcpSpannerProperties.isFailIfPoolExhausted();
 		}
 
 		@Bean
@@ -158,6 +161,11 @@ public SessionPoolOptions sessionPoolOptions() {
 			if (this.keepAliveIntervalMinutes >= 0) {
 				builder.setKeepAliveIntervalMinutes(this.keepAliveIntervalMinutes);
 			}
+
+			if (this.failIfPoolExhausted) {
+				builder.setFailIfPoolExhausted();
+			}
+
 			return builder.build();
 		}
 

spring-cloud-gcp-autoconfigure/src/main/java/org/springframework/cloud/gcp/autoconfigure/spanner/GcpSpannerProperties.java

@@ -66,6 +66,10 @@ public class GcpSpannerProperties implements CredentialsSupplier {
 	// Default value is negative to indicate to use Cloud Spanner default number.
 	private int keepAliveIntervalMinutes = -1;
 
+	// When {@code true}, if all sessions are in use, fail the request by throwing an exception.
+	// Otherwise, by default, block until a session becomes available.
+	private boolean failIfPoolExhausted = false;
+
 	public Credentials getCredentials() {
 		return this.credentials;
 	}
@@ -159,4 +163,12 @@ public void setCreateInterleavedTableDdlOnDeleteCascade(
 		this.createInterleavedTableDdlOnDeleteCascade =
 				createInterleavedTableDdlOnDeleteCascade;
 	}
+
+	public boolean isFailIfPoolExhausted() {
+		return failIfPoolExhausted;
+	}
+
+	public void setFailIfPoolExhausted(boolean failIfPoolExhausted) {
+		this.failIfPoolExhausted = failIfPoolExhausted;
+	}
 }