Services or capabilities described in Amazon Web Services documentation might vary by Region. To see the differences applicable to the China Regions, see Getting Started with Amazon Web Services in China (PDF).

Connecting to Amazon Neptune databases using IAM authentication with Gremlin Go

Overview

This guide demonstrates how to connect to a Amazon Neptune database with IAM authentication enabled using the Gremlin Go driver, with Signature Version 4 authentication and the Amazon SDK for GO v2.

Prerequisites

Create a basic connection

Use the following code example as guidance on how to establish a basic connection with IAM authentication using the Gremlin Go driver.

package main

import (
	"context"
	"fmt"
	"github.com/aws/aws-sdk-go-v2/config"
	"net/http"
	"strings"
	"time"

	gremlingo "github.com/apache/tinkerpop/gremlin-go/v3/driver"
	v4 "github.com/aws/aws-sdk-go-v2/aws/signer/v4"
)

const emptyStringSHA256 = `e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855`

func main() {
	neptuneEndpoint := "you.cluster.endpoint.neptune.amazonaws.com"
	connString := "wss://" + neptuneEndpoint + ":8182/gremlin"
	service := "neptune-db"
	defaultRegion := "us-east-1"

	// Create request to sign
	req, err := http.NewRequest(http.MethodGet, connString, strings.NewReader(""))
	if err != nil {
		fmt.Println(err)
		return
	}

	// Loads the default config with default credentials provider
	// See https://github.com/aws/aws-sdk-go-v2 for additional docs on API usage
	cfg, err := config.LoadDefaultConfig(context.TODO())
	if err != nil {
		fmt.Println(err)
		return
	}
	// Retrieve loaded credentials 
	cr, err := cfg.Credentials.Retrieve(context.TODO())
	if err != nil {
		fmt.Println(err)
		return
	}

	region := defaultRegion
	if cfg.Region != "" {
		// region set inside config profile, or via AWS_REGION or AWS_DEFAULT_REGION environment variable will be loaded
		region = cfg.Region
	}

	signer := v4.NewSigner()
	// Sign request
	err = signer.SignHTTP(context.TODO(), cr, req, emptyStringSHA256, service, "us-east-2", time.Now())
	if err != nil {
		fmt.Println(err)
		return
	}

	// Pass the signed request header into gremlingo.HeaderAuthInfo()
	driverRemoteConnection, err := gremlingo.NewDriverRemoteConnection(connString,
		func(settings *gremlingo.DriverRemoteConnectionSettings) {
			settings.TraversalSource = "g"
			settings.AuthInfo = gremlingo.HeaderAuthInfo(req.Header)
			// settings.TlsConfig = &tls.Config{InsecureSkipVerify: true} // Use this only if you're on a Mac running Go 1.18+ doing local dev. See https://github.com/golang/go/issues/51991
		})
	if err != nil {
		fmt.Println(err)
		return
	}

	// Cleanup
	defer driverRemoteConnection.Close()

	// Creating graph traversal
	g := gremlingo.Traversal_().WithRemote(driverRemoteConnection)

	// Query execution
	count, err := g.V().Limit(5).Count().Next()
	if err != nil {
		fmt.Println(err)
		return
	}
	fmt.Println("Vertex count:", *count)
}

Gremlin Go Dynamic Credential Refresh

Gremlin Go has DynamicAuth which allows the injection of a function pointer to retrieve credentials and generate the header, which prevents header expiry with long-running connections.

package main

import (
	"context"
	"crypto/tls"
	"fmt"
	"github.com/aws/aws-sdk-go-v2/config"
	"net/http"
	"strings"
	"time"

	gremlingo "github.com/apache/tinkerpop/gremlin-go/v3/driver"
	v4 "github.com/aws/aws-sdk-go-v2/aws/signer/v4"
)

const emptyStringSHA256 = `e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855`

func main() {
	neptuneEndpoint := "you.cluster.endpoint.neptune.amazonaws.com"
	connString := "wss://" + neptuneEndpoint + ":8182/gremlin"
	service := "neptune-db"
	defaultRegion := "us-east-1"

	//Create the request to sign
	req, err := http.NewRequest(http.MethodGet, connString, strings.NewReader(""))
	if err != nil {
		fmt.Println(err)
		return
	}

	// Loads the default config with default credentials provider
	// See https://github.com/aws/aws-sdk-go-v2 for additional docs on API usage
	cfg, err := config.LoadDefaultConfig(context.TODO())
	if err != nil {
		fmt.Println(err)
		return
	}

	region := defaultRegion
	if cfg.Region != "" {
		// region set inside config profile, or via AWS_REGION or AWS_DEFAULT_REGION environment variable will be loaded
		region = cfg.Region
	}
	
	signer := v4.NewSigner()

	// This is the function that will be used for dynamic refreseh of credentials and signed headers
	gen := func() gremlingo.AuthInfoProvider {
		// Retrieve loaded credentials 
		cr, err := cfg.Credentials.Retrieve(context.TODO())
		fmt.Println("AWS Credentials: ", cr)
		if err != nil {
			fmt.Println(err)
			return
		}
		// Sign request
		err = signer.SignHTTP(context.TODO(), cr, req, emptyStringSHA256, service, region, time.Now())
		if err != nil {
			fmt.Println(err)
			return
		}
		fmt.Println(req.Header)
		return gremlingo.HeaderAuthInfo(req.Header)
	}

	// Pass the function into gremlingo.NewDynamicAuth(), which will generate the AuthInfoProvider to pass into gremlingo.DriverRemoteConnectionSettings below
	auth := gremlingo.NewDynamicAuth(gen)

	driverRemoteConnection, err := gremlingo.NewDriverRemoteConnection(connString,
		func(settings *gremlingo.DriverRemoteConnectionSettings) {
			settings.TraversalSource = "g"
			settings.AuthInfo = auth
			// settings.TlsConfig = &tls.Config{InsecureSkipVerify: true} // Use this only if you're on a Mac running Go 1.18+ doing local dev. See https://github.com/golang/go/issues/51991

		})
	if err != nil {
		fmt.Println(err)
		return
	}

	// Cleanup
	defer driverRemoteConnection.Close()

	// Creating graph traversal
	g := gremlingo.Traversal_().WithRemote(driverRemoteConnection)

	// Query execution
	count, err := g.V().Limit(5).Count().Next()
	if err != nil {
		fmt.Println(err)
		return
	}
	fmt.Println("Vertex count:", *count)
}