Adding expiry threshold and min renewal as properties.

We now allow configuration of expiry threshold and min renewal durations for lease renewal.

Original pull request: gh-278.

spring-cloud-vault-config/src/main/java/org/springframework/cloud/vault/config/VaultBootstrapPropertySourceConfiguration.java

@@ -95,6 +95,17 @@ public class VaultBootstrapPropertySourceConfiguration implements InitializingBe
 
 			SecretLeaseContainer secretLeaseContainer = secretLeaseContainerObjectFactory
 					.getObject();
+
+			if (vaultProperties.getConfig().getLifecycle().getMinRenewal() != null) {
+				secretLeaseContainer.setMinRenewal(
+						vaultProperties.getConfig().getLifecycle().getMinRenewal());
+			}
+
+			if (vaultProperties.getConfig().getLifecycle().getExpiryThreshold() != null) {
+				secretLeaseContainer.setMinRenewal(
+						vaultProperties.getConfig().getLifecycle().getExpiryThreshold());
+			}
+
 			secretLeaseContainer.start();
 
 			return new LeasingVaultPropertySourceLocator(vaultProperties, configuration,

spring-cloud-vault-config/src/main/java/org/springframework/cloud/vault/config/VaultProperties.java

@@ -483,6 +483,16 @@ public class VaultProperties implements EnvironmentAware {
 		 */
 		private boolean enabled = true;
 
+		/**
+		 * The amount of seconds that is at least required before renewing a lease.
+		 */
+		private Duration minRenewal;
+
+		/**
+		 * The expiry threshold. {@link Lease} is renewed the given seconds before it expires.
+		 */
+		private Duration expiryThreshold;
+
 	}
 
 }