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https://github.com/meistermeier/spring-graphql-neo4j

Example project using Spring Data Neo4j and Spring GraphQL
https://github.com/meistermeier/spring-graphql-neo4j

java spring-boot spring-graphql

Last synced: 2 months ago
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Example project using Spring Data Neo4j and Spring GraphQL

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README 

        
== Spring GraphQL with Spring Data Neo4j



This example project shows how to combine https://docs.spring.io/spring-graphql/docs/1.2.0/reference/html/[Spring GraphQL 1.2.0] with https://docs.spring.io/spring-data/neo4j/docs/current/reference/html/#reference[Spring Data Neo4j 7.1.0].

The project itself is based on Spring Boot 3.1 to make use of some very nice improvements.



=== Planned features / tasks for this example



* Support for Scroll/Pagination https://docs.spring.io/spring-graphql/docs/current/reference/html/#data.pagination.scroll

** Need to https://github.com/spring-projects/spring-data-neo4j/issues/2726[implement some functionality] in Spring Data Neo4j first

* Native image support without additional definitions

** Spring Data Neo4j https://github.com/spring-projects/spring-data-neo4j/issues/2725[misses some hints] to compile out-of-the-box with Spring GraphQL



=== Some features and libraries used in this example



==== New Testcontainers support features



* `@ServiceConnection`: https://docs.spring.io/spring-boot/docs/3.1.x/reference/htmlsingle/#features.testing.testcontainers.service-connections

* Testcontainers at development time: https://docs.spring.io/spring-boot/docs/3.1.x/reference/htmlsingle/#features.testing.testcontainers.at-development-time

* `@ImportTestcontainers`: https://docs.spring.io/spring-boot/docs/3.1.x/reference/htmlsingle/#features.testing.testcontainers.at-development-time.importing-container-declarations



==== Neo4j-Migrations for test data creation



Starting the application from the tests or running integration tests, the project will use https://github.com/michael-simons/neo4j-migrations[Neo4j-Migrations] to create the initial dataset.



==== Neo4j Java driver metrics / health



===== Micrometer metrics



Although the current version of the Neo4j Java driver is 5.7.,

the Spring Boot autoconfiguration is backwards compatible to the whole 4.x versions.

As a consequence, it cannot configure the metrics provider automatically and we need to provide a `ConfigBuilderCustomizer`

to set `Micrometer` as the adapter.



[source,java]

----

@Bean

ConfigBuilderCustomizer configBuilderCustomizer() {

    return configBuilder -> configBuilder.withMetricsAdapter(MetricsAdapter.MICROMETER);

}

----



This will provide following metrics to consume.

Accessible via http://localhost:8080/actuator/metrics/



[source,text]

.Overview of available Neo4j driver metrics

----

neo4j.driver.connections.acquiring

neo4j.driver.connections.acquisition

neo4j.driver.connections.acquisition.timeout

neo4j.driver.connections.closed

neo4j.driver.connections.creating

neo4j.driver.connections.creation

neo4j.driver.connections.failed

neo4j.driver.connections.idle

neo4j.driver.connections.in.use

neo4j.driver.connections.usage

----



===== Health



The health endpoint is enriched with the information about the connection to the running Neo4j instance

and can be queried at http://localhost:8080/actuator/health/neo4j.



Please be aware that both, metrics and health endpoints, are configured without any security mechanisms in this project's configuration.

Always check the information you are exposing before deploying an application to the public.



=== Try it out



==== With a temporary test database



The project provides a Neo4j testcontainer instance if it gets started from the tests. (Docker needed)



[source,shell]

----

./mvnw spring-boot:test-run

----



==== With a "production" database



If you want to connect to a running instance, you have to start the application with the matching environment variables



[source,shell]

----

SPRING_NEO4J_AUTHENTICATION_PASSWORD= \\

SPRING_NEO4j_URI= \\

./mvnw spring-boot:run

----



Please keep in mind that the application is focused on using the movie dataset.

If not happen yet, please run the `:play movies` guide and the Cypher query to populate the database.



==== Compile native



This requires you to have GraalVM (Java 17 based) installed and included your _$PATH_ on your machine.

There is a pre-configured profile (_native_) that will invoke the GraalVM's native maven plugin.



[source,shell]

.invoke native compile

----

./mvnw -Pnative clean package

----



After it has successfully compiled, you can invoke the executable similar to the command above.



[source,shell]

.start the application

----

SPRING_NEO4J_AUTHENTICATION_PASSWORD= \\

SPRING_NEO4j_URI= \\

target/spring-neo4j-graphql

----



=== What to explore



The current schema looks like this:



[source,graphql endpoint]

.schema.graphqls

----

type Query {

    movies : [Movie]

    movie(title : String!) : Movie

}



type Movie {

    id: ID!

    title: String!

    description : String!

    "Random number 0 - 100 as an example for aggregation of data"

    rating: Int

    actors: [Person]

    directors: [Person]

}



"A person is either an actor or a director"

type Person {

    id: ID!

    name: String!

    yearOfBirth: Int

}

----



Example queries as you can see above are:



[source,graphql]

.Query all movies

----

{movies {title, actors {name, yearOfBirth}}}

----

will return:



[source, json]

----

{

  "data": {

    "movies": [

      {

        "title": "The Matrix",

        "actors": [

          {

            "name": "Gloria Foster",

            "yearOfBirth": null

          },

          {

            "name": "Hugo Weaving",

            "yearOfBirth": 1960

          },

          {

            "name": "Keanu Reeves",

            "yearOfBirth": 1964

          },

          {

            "name": "Emil Eifrem",

            "yearOfBirth": 1978

          }, ...

     ]},

     {

        "title": "The Matrix Reloaded",

        "actors": [

          {

            "name": "Gloria Foster",

            "yearOfBirth": null

          }, ....

        ]}

    ]}

}

----



[source,graphql]

.Query one particular movie

----

{movie (title: "The Matrix") {title, description}}

----



will return:



[source, json]

----

{

  "data": {

    "movie": {

      "title": "The Matrix",

      "description": "Welcome to the Real World"

    }

  }

}

----



==== Multiple sources



It is possible to aggregate the data from different sources.

For example the `rating` field of the `Movie` will be a random generated number between 0 and 100.



[source,graphql]

.Query movie with field from other source

----

{movie (title: "The Matrix") {title, rating}}

----



returns



[source, json]

----

{

  "data": {

    "movie": {

      "title": "The Matrix",

      "rating": 99

    }

  }

}

----