Note: This post uses the the Couchbase Analytics Data Definition Language as of the version 5.5 preview release.  For updates and information on breaking changes in newer versions, please refer to Changes to the Couchbase Analytics Service.

The application built for the Couchbase Connect Silicon Valley conference last fall incorporates dynamic N1QL queries, offline mobile, IoT sensors, ad hoc queries with analytics, cross-data center replication, failover, fuzzy text matching, and a slew of other features.

You can watch the keynote demonstration here, find out about the high-level architecture here, and watch a full walk-through of how to set up the demo here.

In this post, I’ll go through all the steps to configure and run the demo. We’ll do this through the command line. (Some steps require the cURL tool.)

Throughout I include direct links to video that goes over similar material.

Clone Repository and Set Working Directory

You can find the code for the demo on GitHub. Clone the repo and change directories to the top level.

Configuring Couchbase Server

The demo project depends on new capabilities slated for Couchbase 5.5. As of this writing, 5.5 is in beta. Download and install Couchbase 5.5 for your platform here. Start a node running.

Preparing

The following assumes you’re running on localhost. You can adjust to a remote host as necessary. The command executables are included in your Couchbase installation. You may want to add the tools directory to your command path. For example, on a Mac, you can do something like this.

Initialize the Node

To initialize the first node, we need three steps.

  • Basic setup of the administrative user, services to run, and memory allocations
  • Creation of the main application bucket
  • Adding a separate user for role-based access control.

Run the following commands to perform these steps.

Most of the parameters for these commands should be fairly straight-forward to figure out.

Couchbase Server nodes can be dedicated to running a subset of all available services, part of what’s referred to as Multidimensional Scaling. Here, we’re configuring the node with all the services needed by the application.

The RAM allocations are all set to their minimum values. These aren’t typically what you’d use in production, but are plenty for data included here.

Note the cluster specification uses a custom URL, couchbase://127.0.0.1. There are other ways to specify it, but this is the easiest. This is telling the commands to connect to Couchbase Server on the local machine.

After running these commands, it will typically take a few moments to warm the node up. Give it a short pause before proceeding with the next steps.

Related video:

Data

We generated realistic synthetic patient data using the Synthea tool (Copyright © 2018 The MITRE Corporation). Synthea is open source and free to use. The full demo at Connect 2017 used hundreds of millions of records. A dataset more suitable for running on a single machine has been included in the demo source repository. To load it, execute the following.

The options tell cbimport to expect one record per line, and to auto-generate the document key from the id field of each record.

Related video:

Eventing Service

The Couchbase Eventing Service is one of the new features being added in release 5.5. It allows you to monitor changes in the database and run JavaScript functions in response.

In this application we use it to monitor incoming patient data. This lets us push the data to the web app, rather than relying on polling. This happens using the cURL capabilities built into N1QL.

To do this, we need to set up a JavaScript function that watches changes in the database. Currently the Eventing Service needs its own meta-data bucket as well. Configure this part with the following commands.

Here’s the actual JavaScript.

This function only processes “Observation” documents. It extracts a few elements we want to display on in the web console. It then uses a cURL call to post that data to a REST endpoint on the web server.

Related video:

Query Indexes

The application relies on a number of N1QL queries. These would run if you define a primary index, but they would be slow. Instead, add three Global Secondary Indexes.

The data used in the application follows the FHIR specification. Records include a resourceType field. For example, “Observation”, “Condition”, and “Practitioner” are all resource types. The first index optimizes queries against this field.

In the dashboard we show graphs of temperatures. The are recorded as “Observation” documents. The second index pulls out the main information we care about displaying. (Compare the fields here with what gets pushed by the Eventing code.) This makes lookups and retrieval of the relevant data fast, since everything we need is stored in the index.

The last index is built against “Location” records. This is used to allow us to connect patients with their nearest hospital.

Related video:

Analytics

The application can examine some case history data. This kind of free-form analysis is better suited to the new Couchbase Analytics Service (currently in preview).

The Analytics Service works by automatically importing data from the operational database buckets into its own special-purpose buckets. You then define what are known as shadow datasets. Finally, you must issue an instruction to connect the analytics to your operational data. After that, queries are done using SQL++, an superset of SQL similar to N1QL. You can read more in this tutorial.

All the configuration is done by issuing commands through the analytics query engine. Configure the necessary pieces for the demo with the following command.

Here are the actual commands being run.

You could do this just as well from the query interface on the Couchbase Server web console, using the lines exactly as shown above.

Related video:

Couchbase Server Full-Text Search allows language aware matching based both on indexed fields and the input search terms. It provides a great deal of power when searching free-form text. For this application, we use it to pull out records based on just that: entries in FHIR documents set aside for unstructured notes.

Configure the needed indexes as follows.

The index is too complicated to go through here in full. I’ll just touch on some main points.

Most importantly, we’re doing language aware analysis of the note field of an “Observation” document, and the reason field of an “Encounter” document. These are the fields where a care provider might enter free form text.

Other entries are there to pull data in simply to display or for use in faceting. Faceting lets a user restrict and refine searches. It’s a powerful way to allow structured drilling down into data.

Look for a future post going through the index and the FTS code for more details.

Related video:

cURL Access Restrictions

N1QL queries can include cURL-style network calls. We use these for pushing updates to the web app, and for obtaining geomapping data via Google.

Since these calls originate from a query service node, they have important security implications. Therefore, by default, it’s turned off.

We need to authorize calls to the Google endpoint and to an api on the web server. Do that with the following command.

Related video:

Sync Gateway

Sync Gateway provides the glue between Couchbase Server and the mobile application. It also provides some of the business logic. In this case, we simply need to connect to Coucbase Server, configure basic authentication, and create a channel for our primary user.

Run Sync Gateway directly as follows.

We’re not using a filtered document import here, so this can take a little while the first time to create all the needed meta-data.

Related video:

Web Client and Server

Install Node.js. The server requires version 7 or higher. I recommend using nvm to manage Node versions if you have an existing installation. (The nvm installation guide can be found here.)

Configuring the Web Client

The web client code is under web/client. Under src/config in the client code, update serverURI in the index.jsfile to point to your web server. This is the host the web server is running on. This may be different from where you run Couchbase. By default it uses localhost, so if you plan to run everything on one machine you can just leave it as is.

Building the Client

Change directories to web/client. Install the Node packages.

You can run in one of two modes, development or production. Development allows easier debugging, and supports hot reloading, but is more complicated to set up. This mode requires running separate servers, one that serves the client pages and the other to expose the API we need.

Here I’m only going to describe running in production mode. For the client, this just means running a build.

When finished, this will copy the final client files over to a subdirectory of the server directory. The Node server will pull app content from there.

Configuring and Running the Web Server

Change directories to web/server. Install the Node packages.

The server has a few parameters that need setting. I included a package that will pull these either from environment variables or a file named .env in the server directory. The parameters break into two groups, those needed for Urban Airship push notifications, and those needed to connect to Couchbase.

The parameters are

  • An Urban Airship application key
  • An Urban Airship master secret
  • The Couchbase Server cluster URL
  • The username and password of a user on the CB Server cluster with appropriate privileges
  • A URL for connecting to a Couchbase Server Analytics Service node.

This set of Bash shell commands will create a template for you.

Alternatively, you can just set environment variables. For example, you could leave the Urban Airship parameters out, and configure them like this instead.

If you don’t want to use the Urban Airship push notification feature, set the UA keys to something arbitrary.

You can now run the server.

Open a browser and navigate to localhost:8080. You should see the web console.

Related video:

Android Mobile Application

Open mobile/android/CBCHealth in Android Studio to build the application.

The Android mobile app uses Urban Airship for push notifications. If you want to include this feature, you must fill out the Urban Airship configuration with your own keys. See mobile/android/CBCHealth/app/src/main/assets/airshipconfig.properties.sample.

If you don’t want to include push notifications, remove the following line from the application’s AndroidManifest.xml file.

By default, this builds a version of the application for use with the Android emulator. There’s a soft entry dialog for entering temperature readings.

If you want to use the actual patch with a real device, you need to make two changes.

  1. In mobile/android/CBCHealth/app/build.gradle change def parameters = ".EMULATOR" to def parameters = ".DEFAULT" (See mobile/android/CBCHealth/app/src/main/java/com/couchbase/mobile/app/launch/Parameters.java for definitions of these entries)
  2. In mobile/android/CBCHealth/app/src/main/resources/META-INF/services/com.couchbase.mobile.collectors.Collector change com.couchbase.mobile.collectors.temperature.ManualEntry to com.couchbase.mobile.collectors.temperature.RF430_TMPSNS_EVM

Related video:

Wrapping up

There’s a lot going on here. The purpose of this post is primarily to get you up and running with a full-featured app you can use to try various aspects of Couchbase out.

Look for deeper dives into the code and configuration coming up.

Postscript

Couchbase is open source and free to try out.
Get started with sample code, example queries, tutorials, and more.
Find other resources on our developer portal.
Follow us on Twitter @CouchbaseDev.
You can post questions on our forums.
We actively participate on Stack Overflow.
Hit me up on Twitter with any questions, comments, topics you’d like to see, etc. @HodGreeley

Posted by Hod Greeley, Developer Advocate, Couchbase

Hod Greeley is a Developer Advocate for Couchbase, living in Silicon Valley. He has over two decades of experience as a software engineer and engineering manager. He has worked in a variety of software fields, including computational physics and chemistry, computer and network security, finance, and mobile. Prior to joining Couchbase in 2016, Hod led developer relations for mobile at Samsung. Hod holds a Ph.D. in chemical physics from Columbia University.

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