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title description services author manager ms.service ms.component ms.custom ms.devlang ms.topic ms.date ms.author
Build an Azure Cosmos DB Node.js application by using Gremlin API | Microsoft Docs
Presents a Node.js code sample you can use to connect to and query Azure Cosmos DB
cosmos-db
luisbosquez
kfile
cosmos-db
cosmosdb-graph
quick start connect, mvc
nodejs
quickstart
01/08/2018
lbosq

Azure Cosmos DB: Build a Node.js application by using Gremlin API

[!div class="op_single_selector"]

Azure Cosmos DB is the globally distributed multimodel database service from Microsoft. You can quickly create and query document, key/value, and graph databases, all of which benefit from the global distribution and horizontal scale capabilities at the core of Azure Cosmos DB.

This quick start demonstrates how to create an Azure Cosmos DB Gremlin API account, database, and graph using the Azure portal. You then build and run a console app by using the open-source Gremlin Node.js driver.

Prerequisites

Before you can run this sample, you must have the following prerequisites:

[!INCLUDE quickstarts-free-trial-note]

Create a database account

[!INCLUDE cosmos-db-create-dbaccount-graph]

Add a graph

[!INCLUDE cosmos-db-create-graph]

Clone the sample application

Now let's clone a Gremlin API app from GitHub, set the connection string, and run it. You'll see how easy it is to work with data programmatically.

  1. Open a command prompt, create a new folder named git-samples, then close the command prompt.

    md "C:\git-samples"

  2. Open a git terminal window, such as git bash, and use the cd command to change to the new folder to install the sample app.

    cd "C:\git-samples"

  3. Run the following command to clone the sample repository. This command creates a copy of the sample app on your computer.

    git clone https://github.com/Azure-Samples/azure-cosmos-db-graph-nodejs-getting-started.git

  4. Open the solution file in Visual Studio.

Review the code

This step is optional. If you're interested in learning how the database resources are created in the code, you can review the following snippets. Otherwise, you can skip ahead to Update your connection string.

The following snippets are all taken from the app.js file.

  • The Gremlin client is created.

    const client = Gremlin.createClient(
    443, 
    config.endpoint, 
    { 
        "session": false, 
        "ssl": true, 
        "user": `/dbs/${config.database}/colls/${config.collection}`,
        "password": config.primaryKey
    });

    The configurations are all in config.js, which we edit in the following section.

  • A series of functions are defined to execute different Gremlin operations. This is one of them:

    function addVertex1(callback)
{
    console.log('Running Add Vertex1'); 
    client.execute("g.addV('person').property('id', 'thomas').property('firstName', 'Thomas').property('age', 44).property('userid', 1)", { }, (err, results) => {
      if (err) callback(console.error(err));
      console.log("Result: %s\n", JSON.stringify(results));
      callback(null)
    });
}

  • Each function executes a client.execute method with a Gremlin query string parameter. Here is an example of how g.V().count() is executed:

    console.log('Running Count'); 
client.execute("g.V().count()", { }, (err, results) => {
    if (err) return console.error(err);
    console.log(JSON.stringify(results));
    console.log();
});

  • At the end of the file, all methods are then invoked using the async.waterfall() method. This will execute them one after the other:

    try{
    async.waterfall([
        dropGraph,
        addVertex1,
        addVertex2,
        addEdge,
        countVertices
        ], finish);
} catch(err) {
    console.log(err)
}

Update your connection string

  1. Open the config.js file.

  2. In config.js, fill in the config.endpoint key with the Gremlin URI value from the Overview page of the Azure portal.

    config.endpoint = "GRAPHENDPOINT";

    View and copy an access key in the Azure portal, Keys blade

    If the Gremlin URI value is blank, you can generate the value from the Keys page in the portal. Use the URI value, remove https://, and change documents to gremlin.cosmosdb. If your graph account was created before December 20th, 2017, change documents to graphs.

    The Gremlin endpoint must be only the host name without the protocol/port number, like mygraphdb.gremlin.cosmosdb.azure.com (not https://mygraphdb.gremlin.cosmosdb.azure.com or mygraphdb.gremlin.cosmosdb.azure.com:433).

  3. In config.js, fill in the config.primaryKey value with the Primary Key value from the Keys page of the Azure portal.

    config.primaryKey = "PRIMARYKEY";

    Azure portal "Keys" blade

  4. Enter the database name, and graph (container) name for the value of config.database and config.collection.

Here's an example of what your completed config.js file should look like:

var config = {}

// Note that this must not have HTTPS or the port number
config.endpoint = "testgraphacct.gremlin.cosmosdb.azure.com";
config.primaryKey = "Pams6e7LEUS7LJ2Qk0fjZf3eGo65JdMWHmyn65i52w8ozPX2oxY3iP0yu05t9v1WymAHNcMwPIqNAEv3XDFsEg==";
config.database = "graphdb"
config.collection = "Persons"

module.exports = config;

Run the console app

  1. Open a terminal window and change (via cd command) to the installation directory for the package.json file that's included in the project.

  2. Run npm install to install the required npm modules, including gremlin.

  3. Run node app.js in a terminal to start your node application.

Browse with Data Explorer

You can now go back to Data Explorer in the Azure portal to view, query, modify, and work with your new graph data.

In Data Explorer, the new database appears in the Graphs pane. Expand the database, followed by the container, and then select Graph.

The data generated by the sample app is displayed in the next pane within the Graph tab when you select Apply Filter.

Try completing g.V() with .has('firstName', 'Thomas') to test the filter. Note that the value is case sensitive.

Review SLAs in the Azure portal

[!INCLUDE cosmosdb-tutorial-review-slas]

Clean up your resources

[!INCLUDE cosmosdb-delete-resource-group]

Next steps

In this article, you learned how to create an Azure Cosmos DB account, create a graph by using Data Explorer, and run an app. You can now build more complex queries and implement powerful graph traversal logic by using Gremlin.

[!div class="nextstepaction"] Query by using Gremlin