Staying Ahead of the Curve with Spring and Cassandra 4 (SpringOne 2020)

Staying Ahead of the Curve
with Spring and Cassandra 4
2020-09-02 @ SpringOne
Alex Dutra, DataStax @alexdut
Mark Paluch, VMware @mp911de
Latest & Greatest in the Spring + Cassandra Ecosystem

What's new in...
1. Apache Cassandra™ 4.0 & DataStax Astra
2. Cassandra Driver 4.x
3. Spring Data Cassandra 3.0
4. Spring Boot 2.3
2 © 2020 Datastax, Inc. All rights reserved.

Apache Cassandra™ &
DataStax Astra
Latest & Greatest

Apache Cassandra™ 4.0 in a Nutshell
• Introducing Apache Cassandra 4.0 Beta
• Approaching GA
• First major release since 2016
• Large cross-industry effort
• Most stable Apache Cassandra version in history
© 2020 Datastax, Inc. All rights reserved.4

Apache Cassandra 4.0 Highlights
• Zero Copy Streaming
• Audit Logging
• Improved incremental repair
• Virtual tables
• Support for Java 11 and ZGC (experimental)
• Conﬁgurable ports per node

Try It Out!
• 4.0-beta2 released in September 2020
• No more API changes expected
• Already stable
docker run cassandra:4.0
cassandra.apache.org/download
or

DataStax Astra in a Nutshell
• Cloud-Native Cassandra as a Service
• Zero Lock-In: deploy on AWS or GCP
• REST and GraphQL endpoints
• Fully managed
• Auto-scaling
• Easy data modeling

Try It Out!
• astra.datastax.com/register
• 10GB free tier!!
• Spring Boot + Spring Data + Docker example app:
github.com/DataStax-Examples/spring-data-starter
• Try it on GitPod!

Cassandra Driver
Latest & Greatest

Cassandra Driver 4 in a Nutshell
• 4.0 released in 2019, latest release 4.9.0
• Major rewrite from 3.x
• Asynchronous, non-blocking engine
• Execution proﬁles
• Global timeouts
• Improved load balancing policy
• Improved metrics
• Improved Object Mapper
• Support for Cassandra 4 and DataStax Astra
www.datastax.com/blog/2019/03/introducing-java-driver-4

Upgrading to Cassandra Driver 4
• Maven coordinates changed
• Package names changed
com.datastax.driver -> com.datastax.oss.driver
• Having trouble migrating to driver 4? We can help!
• Follow the Upgrade guide:
docs.datastax.com/en/developer/java-driver/latest/upgrade_guide
• Ask questions at community.datastax.com
• Driver mailing list:
groups.google.com/a/lists.datastax.com/g/java-driver-user
New:
<dependency>
<groupId>com.datastax.oss</groupId>
<artifactId>java-driver-core</artifactId>
<version>4.8.0</version>
</dependency>
Old:
<dependency>
<groupId>com.datastax.cassandra</groupId>
<artifactId>cassandra-driver-core</artifactId>
<version>3.10.1</version>
</dependency>

• Cluster + Session = CqlSession
Cluster cluster = null;
try {
cluster = Cluster.builder()
.addContactPoints(...)
.build();
Session session = cluster.connect();
session.execute(...);
} finally {
if (cluster != null) cluster.close();
}
try (CqlSession session =
CqlSession
.builder()
.addContactPoint(...)
.build()) {
session.execute(...);
}
Old: New:

• No more Guava!
Futures.addCallback(
session.executeAsync(...), // Guava future
new FutureCallback<ResultSet>() {
public void onSuccess(ResultSet rs) {
Row row = rs.one();
process(row);
}
public void onFailure(Throwable t) {
t.printStackTrace();
}
});
session
.executeAsync(...) // Java 8 future
.thenApply(rs -> rs.one())
.whenComplete(
(row, error) -> {
if (error == null) {
process(row);
} else {
error.printStackTrace();
}
});
Old: New:
��

• Immutability by default, except for builders
PreparedStatement ps = ...;
BoundStatement bs = ps.bind();
bs.setInt("k", 42);
PreparedStatement ps = ...;
BoundStatement bs = ps.bind();
bs = bs.setInt("k", 42); // bs is immutable!!
Old: New:
⚠
BoundStatementBuilder builder =
ps.boundStatementBuilder();
builder.setInt("k", 42); // OK, mutable
bs = builder.build();
Alternatively, switch to builders (new):

• Conﬁgure your IDE to detect @CheckReturnValue!

• New asynchronous pagination API
ResultSetFuture rs = session.executeAsync(...);
ListenableFuture<Void> done =
Futures.transform(rs, process(1));
AsyncFunction<ResultSet, Void> process(int page) {
return rs -> {
// process current page
int remaining = rs.getAvailableWithoutFetching();
for (Row row : rs) {
...; if (--remaining == 0) break;
}
// process next page, if any
boolean hasMorePages =
rs.getExecutionInfo().getPagingState() != null;
return hasMorePages
? Futures.transform(
rs.fetchMoreResults(), process(page + 1))
: Futures.immediateFuture(null);
};
}
��
��
��
CompletionStage<AsyncResultSet> rs =
session.executeAsync(...);
CompletionStage<Void> done =
rs.thenCompose(this::process);
CompletionStage<Void> process(AsyncResultSet rs) {
// process current page
rs.currentPage().forEach(row -> ...);
// process next page, if any
return rs.hasMorePages()
? rs.fetchNextPage().thenCompose(this::process)
: CompletableFuture.completedFuture(null);
}
Old: New:
��
��
��

Cassandra Driver 4 Highlights
• New Reactive API
// ReactiveResultSet extends Publisher<ReactiveRow>
ReactiveResultSet rs = session.executeReactive("SELECT ...");
// Wrap with Reactor (or RxJava)
Flux.from(rs)
.doOnNext(System.out::println)
.blockLast(); // query execution happens here
docs.datastax.com/en/developer/java-driver/latest/manual/core/reactive

Cassandra 4 Support
• Multiple ports per node
• Contact points now must be entered with a port number
• Virtual tables
• Can be queried like normal tables
• New methods:
KeyspaceMetadata.isVirtual()
TableMetadata.isVirtual()

Spring Data Cassandra 3.0

Spring Data Cassandra 3.0
• Upgraded to Cassandra driver 4 in Neumann release train (3.0)
• Embedded Objects (@Embedded(prefix = …))
• @Value support for object creation
• Customizable NamingStrategy API

Upgrading to Spring Data Cassandra 3.0
• Your mileage varies depending on level of data access abstraction,
meaning:
• Repository vs. CassandraOperations usage
• Usage of CqlOperations and async CqlOperations Statement
API requires special attention
• Driver Statement objects are now immutable
• Migration guide shipped with reference documentation
• Lots of internal changes as consequence of driver design

Upgrade Tasks
• Dependency Upgrades (Driver, Spring Data)
• Adapt mapped entities to
• changed DATE type (com.datastax.driver.core.LocalDate ->
java.time.LocalDate)
• Changes in @CassandraType (CassandraType.Name enum)
• forceQuote in annotations deprecated now
• Review and adapt conﬁguration

Conﬁguration
• Recommended: Use Spring Boot
• Still using XML: cassandra:cluster and cassandra:session now
cassandra:session and cassandra:session-factory namespace
elements
• Programmatic conﬁguration mostly remains the same (YMMV!)

Execution Proﬁles
datastax-java-driver {
profiles {
oltp {
basic.request.timeout = 100 milliseconds
basic.request.consistency = ONE
}
olap {
basic.request.timeout = 5 seconds
basic.request.consistency = QUORUM
}
}
• Associate Statement with settings
• Driver conﬁguration referenced by Statement API objects

Execution Proﬁles (Code)
CqlTemplate template = new CqlTemplate();
SimpleStatement simpleStatement = QueryBuilder.….build();
SimpleStatement newStatement = simpleStatement.setExecutionProfileName("olap");
template.queryForList(newStatement);
CqlTemplate olapTemplate = new CqlTemplate();
olapTemplate.setExecutionProfile("olap");
CassandraTemplate cassandraTemplate = …
InsertOptions options = InsertOptions.builder().executionProfile("oltp").build();
cassandraTemplate.insert(person, options);

Embedded Objects
public class Customer {
@Id
UUID id;
@Embedded.Nullable(prefix = "billing_")
Address billing;
@Embedded.Nullable(prefix = "shipping_")
Address shipping;
static class Address {
String street;
String city;
String zip;
}
}

Embedded Objects
• Flattened when persisted
• Materialized as nested object
• Allow for namespacing through preﬁx
• Can be null or empty

Spring Boot 2.3

Spring Boot 2.3
• Upgraded to Cassandra driver 4 in 2.3
• Conﬁguration must be done either:
• In application.properties or application.yaml
• Under spring.data.cassandra preﬁx
• Or programmatically
• Changes to spring.data.cassandra properties:
• Some properties were renamed
• Contact points must now contain a port (host:port)
• Local datacenter is now required
• Except for Astra

Conﬁguration Upgrade Example
Old:
spring.data.cassandra:
cluster-name: prod1
contact-points: 127.0.0.1
port: 9042
keyspace-name: ks1
read-timeout: 10s
consistency-level: LOCAL_QUORUM
fetch-size: 1000
New:
session-name: prod1
contact-points: 127.0.0.1:9042
local-datacenter: dc1
keyspace-name: ks1
request:
timeout: 10s
consistency: LOCAL_QUORUM
page-size: 1000

Upgrading Application Properties
docs.spring.io/spring-boot/docs/current/reference/html/appendix-application-properties.html
Old property New property
spring.data.cassandra.cluster-name spring.data.cassandra.session-name
N/A spring.data.cassandra.local-datacenter
spring.data.cassandra.read-timeout
spring.data.cassandra.connect-timeout
spring.data.cassandra.request.timeout
spring.data.cassandra.connection.connect-timeout
spring.data.cassandra.connection.init-query-timeout
spring.data.cassandra.consistency-level
spring.data.cassandra.serial-consistency-level
spring.data.cassandra.request.consistency
spring.data.cassandra.request.serial-consistency
spring.data.cassandra.fetch-size spring.data.cassandra.request.page-size
spring.data.cassandra.jmx-enabled N/A (driver JMX conﬁg)

Customizing the Cassandra Session
• Avoid declaring your own CqlSession bean!
• You would lose Spring Boot's auto-conﬁguration support
• Customizers FTW!
• Callbacks that can be easily implemented by users
• Spring Boot 2.3+ customizers:
• SessionBuilderCustomizer (High-level)
• DriverConfigLoaderBuilderCustomizer (Low-level,
execution proﬁles)
• Declare as regular beans

Customizing the Cassandra Session
• Session customization examples
@Bean
public CqlSessionBuilderCustomizer sslCustomizer() {
return builder -> builder.withSslContext(…);
}
@Bean
public CqlSessionBuilderCustomizer credentialsCustomizer() {
return builder -> builder.withAuthCredentials(…);
}
@Bean
public DriverConfigLoaderBuilderCustomizer oltpProfile() {
return builder -> builder.startProfile("oltp"). … .endProfile();
}

Connecting to Astra
• Typical conﬁguration
username: <astra user>
password: <astra password>
keyspace-name: <astra keyspace>
# no contact-points and no local-datacenter for Astra!
datastax.astra:
secure-connect-bundle: </path/to/secure-connect-bundle.zip>
docs.datastax.com/en/developer/java-driver/latest/manual/cloud

Connecting to Astra
• Passing the secure connect bundle: with a customizer bean
@Value("${datastax.astra.secure-connect-bundle}")
private String astraBundle;
@Bean
public CqlSessionBuilderCustomizer sessionBuilderCustomizer() {
return builder ->
builder.withCloudSecureConnectBundle(Paths.get(astraBundle));
}
docs.datastax.com/en/developer/java-driver/latest/manual/cloud

Compatibility Matrix
Your driver version works with...
Cassandra Driver Spring Data Cassandra Spring Boot
3.x 2.2 and older 2.2 and older
4.x 3.0 and newer 2.3 and newer
• Can't mix versions from different lines

Thank You!

Staying Ahead of the Curve with Spring and Cassandra 4 (SpringOne 2020)

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