Quarkus meets Neo4j

I’m gonna first speak briefly about Neo4j itself, what’s the core product and why you might interested in it.
Give you an idea about my background (while this is often irrelevant or marketing, it may be of interest in the context of Quarkus)
Praise the Java community, which despite some other rumors manages to work closely together with great benefit for the whole ecosystem
We will than have a look at the building blocks of a Quarkus extension as well as the Neo4j database drivers
Quarkus calls itself „Supersonic subatomic Java“ and „a Kubernetes Native Java stack tailored for OpenJDK HotSpot and GraalVM“, meaning that applications build with it should be able to use GraalVM’s native-image tool to produce binary running GraalVMs SubstrateVM. For us this required changes to our Java driver which I would like to discuss as well.
And last but not least, I want to show you the resulting pieces in action

Transcript

1. About writing a natively compilable Quarkus extension
   Michael Simons, @rotnroll666
   Quarkus meets Neo4j
   

   View Slide

2. Quarkus meets Neo4j by @rotnroll666
   • About Neo4j
   • About me and Quarkus
   • Building blocks of…
   • … the Neo4j database driver
   • … a Quarkus extension
   • The search for the holy Graal(VM): AoT compiling a database driver.
   2
   Agenda
   

   View Slide

3. About Neo4j
   

   View Slide

4. Ecosystem
   Neo4j Professional Services
   300+ partners
   47,000 group members
   61,000 trained engineers
   3.5M downloads
   Mindset
   “Graph Thinking” is all about
   considering connections in
   data as important as the
   data itself.
   Native Graph Platform
   Neo4j is an internet-scale,
   native graph database which
   executes connected workloads
   faster than any other database
   management system.
   Neo4j
   4
   

   View Slide

5. The whiteboard model
   IS the physical model
   • Bands are founded in and
   solo artists are born in countries
   • Sometimes Artists are
   associated with other Artists
   and bands have member
   • Artists used to release
   Albums
   :Artist
   :Band
   :SoloArtist
   :Country
   :FOUNDED_IN
   :BORN_IN
   :ASSOCIATED_WITH
   :HAS_MEMBER
   :Album
   :RELEASED_BY
   5
   

   View Slide

6. Querying with Cypher
   • Cypher is to Neo4j what SQL is to RDBMS:
   A declarative, powerful query language
   • https://www.opencypher.org / The GQL Manifesto
   MATCH (a:Album) -[:RELEASED_BY]-# (b:Band),
   (c) $-[:FOUNDED_IN]- (b) -[:HAS_MEMBER]-# (m) -[:BORN_IN]-# (c2)
   WHERE a.name = 'Innuendo'
   RETURN b, m, c, c2
   6
   

   View Slide

7. About me and Quarkus
   

   View Slide

8. Quarkus meets Neo4j by @rotnroll666
   • Neo4j since July 2018
   • Java Champion
   • Co-Founder and current lead of Java User Group EuregJUG
   • Author (Spring Boot 2 und Arc42 by example)
   About me
   8
   First contact to Neo4j through
   

   View Slide

9. Quarkus meets Neo4j by @rotnroll666
   Graph Tour 2019
   9
   Now online:
   https://neo4j.com/graphtour/
   

   View Slide

10. Quarkus meets Neo4j by @rotnroll666
    Graph Tour 2019
    9
    Now online:
    https://neo4j.com/graphtour/
    

    View Slide

11. Quarkus meets Neo4j by @rotnroll666
    A Hibernate team lead appears…
    10
    With Sanne Grinovero,
    Hibernate Team Lead & Quarkus R&D
    

    View Slide

12. Building blocks
    

    View Slide

13. Quarkus meets Neo4j by @rotnroll666 12
    The Neo4j Java-Driver
    
    
    org.neo4j.driver#$groupId>
    
    neo4j-java-driver#$artifactId>
    
    4.1.1#$version>
    
    #$dependency>
    
    var driver = GraphDatabase.driver(
    
    "bolt:#%localhost:7687",
    
    AuthTokens.basic("neo4j", "secret"),
    
    Config.builder().withLogging(Logging.console(Level.INFO)).build()
    
    );
    
    

    View Slide

14. Quarkus meets Neo4j by @rotnroll666 13
    Imperative sessions
    Function getNameFromRecord =
    
    record #& record.get("name").asString();
    
    try (var session = driver.session()) {
    
    var names = session.readTransaction(
    
    tx #& tx
    
    .run("MATCH (n:Artist) RETURN n.name AS name")
    
    .stream().map(getNameFromRecord)
    
    .collect(toList())
    
    );
    
    names.forEach(System.out#'println);
    
    }
    

    View Slide

15. Quarkus meets Neo4j by @rotnroll666 14
    Reactive sessions with Project Reactor
    Function getNameFromRecord =
    
    record #& record.get("name").asString();
    
    RxTransactionWork
    tx #& tx.run("MATCH (n:Artist) RETURN n.name AS name").records();
    
    Flux.usingWhen(
    
    Mono.fromSupplier(driver#'rxSession),
    
    session #& session.readTransaction(txFunction),
    
    RxSession#'close
    
    )
    
    .map(getNameFromRecord)
    
    .doOnNext(System.out#'println)
    
    .blockLast(); !" Don't block at home
    
    

    View Slide

16. Quarkus meets Neo4j by @rotnroll666 15
    Reactive sessions with SmallRye Mutiny
    Function getNameFromRecord =
    
    record #& record.get("name").asString();
    
    RxTransactionWork
    tx #& tx.run("MATCH (n:Artist) RETURN n.name AS name").records();
    
    Uni.createFrom().item(driver#'rxSession).toMulti()
    
    .flatMap(session #& session.readTransaction(txFunction))
    
    .map(getNameFromRecord)
    
    .subscribe()
    
    .asStream()
    
    .forEach(System.out#'println);
    
    

    View Slide

17. Quarkus meets Neo4j by @rotnroll666 16
    The Quarkus extension system
    var driver = GraphDatabase.driver(
    
    "bolt:#%localhost:7687",
    
    AuthTokens.basic("neo4j", "secret"),
    
    Config.builder().withLogging(Logging.console(Level.INFO)).build()
    
    );
    
    

    View Slide

18. Quarkus meets Neo4j by @rotnroll666 16
    The Quarkus extension system
    quarkus.neo4j.uri = bolt:#%localhost:7687
    
    quarkus.neo4j.authentication.username = neo4j
    
    quarkus.neo4j.authentication.password = secret
    @Path("/hello")
    
    public class ExampleResource {
    
    private final Driver driver;
    
    @Inject
    
    public ExampleResource(Driver driver) {
    
    this.driver = driver;
    
    }
    
    }
    
    

    View Slide

19. Quarkus meets Neo4j by @rotnroll666
    • The runtime module which represents the capabilities the
    extension developer exposes to the application’s developer
    • The deployment module which is used during the
    augmentation phase of the build, it describes how to "deploy" a
    library following the Quarkus philosophy
    The deployment module often depends on the runtime
    module.
    17
    The Quarkus extension system
    A Quarkus extension consists of two parts:
    

    View Slide

20. Quarkus meets Neo4j by @rotnroll666
    • GraalVM restrictions
    • Dynamic class loading (Classes must be enumerated)
    • Reflection (Must be enumerated, too)
    • JCA (Java Cryptography Architecture) needs special treatment
    • Optimizing things (i.e. Replacing Service Loader with an index)
    • @BuildStep’s record byte code with @Recorder’s
    18
    The Quarkus extension system
    Three phases of bootstrapping: 1. Augmentation via build step processors
    

    View Slide

21. Quarkus meets Neo4j by @rotnroll666
    •@Record(STATIC_INIT)
    
    • Will run in a static init method on the main class during native
    build
    • Executed on the standard JVM during build
    • Objects will be directly serialized into the native executable
    19
    The Quarkus extension system
    Three phases of bootstrapping: 2. Static init
    

    View Slide

22. Quarkus meets Neo4j by @rotnroll666
    •@Record(RUNTIME_INIT)
    
    • Will run from the applications main method during native boot
    20
    The Quarkus extension system
    Three phases of bootstrapping: 3. Runtime init
    

    View Slide

23. Quarkus meets Neo4j by @rotnroll666
    •@Record(RUNTIME_INIT)
    
    • Will run from the applications main method during native boot
    21
    

    View Slide

24. Quarkus meets Neo4j by @rotnroll666
    •@Record(RUNTIME_INIT)
    
    • Will run from the applications main method during native boot
    21
    

    View Slide

25. Quarkus meets Neo4j by @rotnroll666
    •@Record(RUNTIME_INIT)
    
    • Will run from the applications main method during native boot
    21
    

    View Slide

26. Quarkus meets Neo4j by @rotnroll666
    •@Record(RUNTIME_INIT)
    
    • Will run from the applications main method during native boot
    21
    

    View Slide

27. Quarkus meets Neo4j by @rotnroll666
    •@Record(RUNTIME_INIT)
    
    • Will run from the applications main method during native boot
    21
    

    View Slide

28. Quarkus meets Neo4j by @rotnroll666
    •BUILD_TIME
    
    •BUILD_AND_RUN_TIME_FIXED
    
    •RUN_TIME
    22
    The Quarkus extension system
    Phases of configuration
    

    View Slide

29. Quarkus meets Neo4j by @rotnroll666 23
    Demo
    @Path("/artists")
    
    public class ArtistsResource {
    
    private final Driver driver;
    
    @Inject
    
    public ArtistsResource(Driver driver) {
    
    this.driver = driver;
    
    }
    
    private Multi executeArtistQuery(RxSession session) {
    
    return Multi.createFrom().publisher(
    
    session.readTransaction(tx #& tx.run("MATCH (n:Artist) RETURN n.name AS name").records())
    
    );
    
    }
    
    @GET
    
    @Produces(MediaType.APPLICATION_JSON)
    
    public Multi getArtists() {
    
    return Uni.createFrom().item(driver#'rxSession)
    
    .toMulti()
    
    .flatMap(this#'executeArtistQuery)
    
    .map(record #& record.get("name").asString());
    
    }
    
    }
    
    

    View Slide

30. The search for the holy Graal(VM):
    AoT compiling a database driver.
    

    View Slide

31. Quarkus meets Neo4j by @rotnroll666 25
    

    View Slide

32. Quarkus meets Neo4j by @rotnroll666
    • Neo4j: https://neo4j.com
    • Neo4j Quarkus Guide: https://quarkus.io/guides/neo4j
    • Neo4j Java Driver Manual:
    https://neo4j.com/docs/driver-manual/current/
    • The demo project:
    https://github.com/michael-simons/neo4j-sdn-ogm-tips/tree/master/
    examples/simple-quarkus
    • Neo4j Migrations: https://github.com/michael-simons/neo4j-migrations
    • Cypher-DSL: https://github.com/neo4j-contrib/cypher-dsl
    26
    Resources
    

    View Slide