Go

Prerequisites

  • Go 1.13+

Initializing the project

Use the following command to initialize the Go module, replacing <project-url> with the URL of your project:

go mod init <project-url>

Code example

package main

import (
	"fmt"

	"github.com/neo4j/neo4j-go-driver/v4/neo4j"
)

func main() {
	// Aura requires you to use "neo4j+s" protocol
	// (You need to replace your connection details, username and password)
	uri := "neo4j+s://<Bolt url for Neo4j Aura instance>"
	auth := neo4j.BasicAuth("<Username for Neo4j Aura instance>", "<Password for Neo4j Aura instance>", "")
	// You typically have one driver instance for the entire application. The
	// driver maintains a pool of instance connections to be used by the sessions.
	// The driver is thread safe.
	driver, err := neo4j.NewDriver(uri, auth)
	if err != nil {
		panic(err)
	}
	// Don't forget to close the driver connection when you are finished with it
	defer driver.Close()
	// Create a session to run transactions in. Sessions are lightweight to
	// create and use. Sessions are NOT thread safe.
	session := driver.NewSession(neo4j.SessionConfig{})
	defer session.Close()
	// WriteTransaction retries the operation in case of transient errors by
	// invoking the anonymous function multiple times until it succeeds.
	records, err := session.WriteTransaction(
		func(tx neo4j.Transaction) (interface{}, error) {
			// To learn more about the Cypher syntax, see https://neo4j.com/docs/cypher-manual/current/
			// The Reference Card is also a good resource for keywords https://neo4j.com/docs/cypher-refcard/current/
			createRelationshipBetweenPeopleQuery := `
				MERGE (p1:Person { name: $person1_name })
				MERGE (p2:Person { name: $person2_name })
				MERGE (p1)-[:KNOWS]->(p2)
				RETURN p1, p2`
			result, err := tx.Run(createRelationshipBetweenPeopleQuery, map[string]interface{}{
				"person1_name": "Alice",
				"person2_name": "David",
			})
			if err != nil {
				// Return the error received from driver here to indicate rollback,
				// the error is analyzed by the driver to determine if it should try again.
				return nil, err
			}
			// Collects all records and commits the transaction (as long as
			// Collect doesn't return an error).
			// Beware that Collect will buffer the records in memory.
			return result.Collect()
		})
	if err != nil {
		panic(err)
	}
	for _, record := range records.([]*neo4j.Record) {
		firstPerson := record.Values[0].(neo4j.Node)
		fmt.Printf("First: '%s'\n", firstPerson.Props["name"].(string))
		secondPerson := record.Values[1].(neo4j.Node)
		fmt.Printf("Second: '%s'\n", secondPerson.Props["name"].(string))
	}

	// Now read the created persons. By using ReadTransaction method a connection
	// to a read replica can be used which reduces load on writer nodes in cluster.
	_, err = session.ReadTransaction(func(tx neo4j.Transaction) (interface{}, error) {
		// Code within this function might be invoked more than once in case of
		// transient errors.
		readPersonByName := `
			MATCH (p:Person)
			WHERE p.name = $person_name
			RETURN p.name AS name`
		result, err := tx.Run(readPersonByName, map[string]interface{}{
			"person_name": "Alice",
		})
		if err != nil {
			return nil, err
		}
		// Iterate over the result within the transaction instead of using
		// Collect (just to show how it looks...). Result.Next returns true
		// while a record could be retrieved, in case of error result.Err()
		// will return the error.
		for result.Next() {
			fmt.Printf("Person name: '%s' \n", result.Record().Values[0].(string))
		}
		// Again, return any error back to driver to indicate rollback and
		// retry in case of transient error.
		return nil, result.Err()
	})
	if err != nil {
		panic(err)
	}
}

Running the example

Follow the steps below to run the example code:

  1. Copy and paste the code above into a file named example.go.

  2. Enter the information for the AuraDB instance you want to connect to by replacing:

    • <Bolt url for Neo4j Aura instance> with the URI.

    • <Username for Neo4j Aura instance> with the username.

    • <Password for Neo4j Aura instance> with the password.

  3. Use the following command to update any unused or missing dependencies:

    go mod tidy
  4. Use the following command to run the example code:

    go run example.go

Example walkthrough

The example imports neo4j-go-driver to connect to the Neo4j AuraDB instance.

Within the main function, a write transaction creates two 'Person' nodes, Alice and David, and a 'KNOWS' relationship between them, and a read transaction finds Alice.

Developing with Neo4j Aura requires the use of Transaction Functions. Transaction Functions enable automatic recovery from transient network errors and enable load balancing.

Make sure to log queries and data sent from your application as it is useful when you encounter errors and can help with debugging.