Teaching how to use Bitnami to deploy any Image into Oracle Public Cloud

Recently, I was challenged at work, to make my drone take off, using a simple voice command via “Alexa”. Given this challenge came from my boss, I decided to happily accept it. I ended up writing some simple NodeJS code that interfaces with my drone and used a series of new Echo skills and a Home Assistant bridge to easily command my drone to take off and follow simple orders, something like “Alexa, please take off my drone and make it back flip twice“.

After some hours and many coffees, I got to the point that I was done and ready to show my working demo. However, I needed to take my NodeJS code and put it somewhere in the cloud to run it. I had a few options, like deploying my code into Oracle Application Container Cloud Service, which runs NodeJS natively over docker containers, but given that I have done this in the past and I was in an “adventurous mode”, I decided to try something new.

I wondered how simple would it be to use Bitnami to spin up a new NodeJS VM in Oracle Public Cloud… Well, I was amazed how pleasant the experience was, so I decided to capture this excitement in a quick blog for you to try as well.

Continue reading “Teaching how to use Bitnami to deploy any Image into Oracle Public Cloud”

Teaching how to use MongoDB and expose it via NodeJS APIs

 

Hi, we are starting to use different technologies to build complex scenarios around APIs. It’s getting common to use popular NoSQL DBs like MongoDB.

For this reason, I decided to build this very easy to follow blog that will help you get started with MongoDB and build simple REST APIs using NodeJS via the Express module.

The use case is simple, we are going to build a MongoDB to store users information that eventually (in a future blog) we are going to use to send SMS and Voice call notifications… But for now we are keeping things simple, we are starting by demystifying the use of MongoDB with NodeJS.

The code that sends the SMS/Voice call notifications in NodeJS via Twilio is out of the scope of this blog, but if you want to use it, you can find it here.

Pre-requisites

 

This blog is about simplicity, so we are going to build a simple HelloWorld sample that starts from scratch and interacts (GET and POST) with a MongoDB via Express APIs.

 

Installing and playing with MongoDB

 

In this section, I am going to show you how to install and get your MongoDB up and running. This is going to be the DB that we are going to use in a future blog to send SMS and voice call notifications to people.

Note: I am using Ubuntu, adjust if using other OS (e.g. yum if using OEL/RH):

sudo apt-get install mongodb

  • Validate the installation by running mongo client – This should connect to the running MongoDB Server

  • In the mongo client prompt, create a simple test database called myTestDB:

    use myTestDB


  • The database doesn’t really exist until we add some data. The best thing of MongoDB is that you store JSON payloads into it. This makes it very friendly when interacting with APIs.

     

    In our case, we want to build a notification service and we want to store the contact details of the recipients. Something like:

     

    {“name”:”Carlos”, “mobile”:”+615550505″, “msg”:”Hello World”}

     

    Note that we are not defining ids, mongoDB will take care of it.

     

  • Still within the mongo client db type the following inserts each followed by ab enter:

     

    db.usercollection.insert({ “name” : “Carlos”, “mobile” : “+615550505”, “msg” : “+Hello World”})

    db.usercollection.insert({ “name” : “Dave”, “mobile” : “+616660606”, “msg” : “+Hello World again”})

    db.usercollection.insert({ “name” : “Serene”, “mobile” : “+617770707”, “msg” : “+Hello World once more”})

     

     

  • Now, simply retrieve the inserted collection

    db.usercollection.find().pretty()


  • You can also add a JSON array of JSON payloads, so that you can insert a bulk of entries to MongoDB. For example:

     

    users = [{“name”:”Callan”, “mobile”:”+618880808″, “msg”:”More stuff”},{“name”:”Alessia”, “mobile”:”+612220202″, “msg”:”Stuff plus stuff”}]

     

    db.usercollection.insert(users);

     

  • Once again, retrieve the inserted collection:

    db.usercollection.find().pretty()


  • You can also use the usercollection object to remove individual entries by _id:

    db.usercollection.remove( {“_id”: ObjectId(“ID_GOES_HERE”)});

  • To completely clean up all your entries, you can simply use:

    db.usercollection.remove()

     

  • If you only want to use mong client to switch to a MongoDB and print a specific collection you can do this:

     

    • From Linux shell:             mongo [db_name]
    • Then, from within the mongo client:

      c = db.[collection_name];

      c.find().pretty()

  • To list all Collections in current db:

    db.getCollectionNames()

  • If you are using a MongoDB that requires authentication, you might need to create a specific user(s) under specific databases. For this follow the next steps:

     

  1. Using mongo client, login to admin db as administrator:

     

    mongo admin –username root –password [GIVEN_PASSWORD]

     

    Note: If using Bitnami, [GIVEN_PASSWORD] is the same as the OS root password.

     

  2. Switch to your MongoDB database:

     

    use [DATABASE]

     

  3. Create a new user(s)

     

    db.createUser(

    {

    user: “USER-GOES-HERE”,

    pwd: “PASSWORD-GOES-HERE”,

    roles: [ “readWrite”, “dbAdmin” ]

    }

    )

     

    Note: Substitute USER-GOES-HERE and PASSWORD-GOES-HERE with your own values.

     

  4. That’s it, you can now use that username and password to authenticate and grant read and write access to your db. If using monk in NodeJS as shown below in this blog, make sure to add the credentials in the connection string. A simple way to achieve this is by adding “USER:PASSWD@” before the server name.

     

    For example:

     

    var db = monk(USER + ‘:’ + PASSWD + ‘@’ + MONGODB_SERVER + ‘:’ + MONGODB_PORT + ‘/’ + DB_NAME);

 

 

For more information: https://docs.mongodb.com/manual/reference/mongo-shell/

 

Ok, our MongoDB is behaving well. Let’s run it together with our Express NodeJS code.

 

Building a simple Express JS API that interacts with a MongoDB

 

Now that we have a running MongoDB server running, let’s build a simple NodeJS code that will expose simple Express REST APIs to interact with your MongoDB.

I am going to explain below those snippets that require explanation, however before continuing make sure that you have downloaded/cloned the NodeJS project found here: https://github.com/barackd222/s2v-iia-nodejs-mongodb-crud-demo

The bits that you need to pay special attention from the NodeJS code:

  • app.js – This is a very standard Express JS code that starts a service listening in a specific port. In terms of MongoDB, notice the following snippets:

     

    • You need to require mongodb module, as well as monk.

  • Monk is going to give you the ability to connect to a MongoDB running somewhere. Think of it as a JDBC connection, in the relational database world, if you like.

  • Configuring the Express app to add the Monk db as part of it, so that it can be accessed within the request variable in each REST API.

 

  • The rest is just adding the right headers for the requests and starting the listening service.

 

  • mongoDBCrudAPIs.js – This file is where I define my REST APIs. At the time of writing this blog I just added 2 APIs, one that GET all Users in the MongoDB and the other that POST a new user.

     

    • GET /users – This is a very
      typical Express GET API. Inside the body though that’s where we:
      • Retrieve the monk DB connection that points to the MongoDB
      • Builds the Collection object as we did in the MongoDB console before
      • Runs a Find ALL function on the collections object that it built in the previous step
      • Sends back the resulting JSON payload as the API response. Notice that you can iterate and do whatever you want with this result

  • POST /user – Once again, this is a very typical POST Express API that retrieves some JSON body elements from the request. In terms of MongoDB, the bits that are worthwhile showing are:
    • Retrieve the monk DB connection that points to the MongoDB

  • Builds the Collection object as we did in the MongoDB console before
  • Uses the collection to insert the new user in a JSON format
  • Then it just handles errors if any. Otherwise return a successful response


  • Package.json – Make sure to add the right modules, so that you can run your NodeJS Application without having to manually install dependencies. In this case I am using:
    • express – To build the REST APIs
    • mongodb – To bring internal MongoDB libraries
    • monk – To help establish the MongoDB db connection
    • body-parser – To parse the incoming JSON requests

 

Let’s test our NodeJS Application

If you have been following this blog, at this point you have a few users in your “myTestDB” MongoDB, that you enter via the mongo client command line earlier.

  • I am using Postman to call the APIs, you can use your preferred test REST client. Let’s first try to retrieve these users.

  • Great job, now invoke your POST API to create a new one. In my case this is the JSON that I am sending:

{“name”:”Jason”,

“mobile”:”+6115791010101″,

“msg”:”Hi. This message comes from POSTMAN “}

 

Note: Make sure to add your header Content-type set to application/json

 

 

  • Now call the GET
    /users API again and make sure your new user is retrieved

Congratulations, you just managed to do very basic, yet powerful tasks using MongoDB as the backstore and NodeJS to expose interactive REST APIs via Express JS

 

If you have any comment, feel free to contact any of the authors of solutionsanz.blog – We are here to help you!

Thanks,

 

 

 

 

 

 

 

 

 

 

 

Developing with ACCS Caching Services

Try though we might to shift everything to a glorious set of stateless services, there are still plenty of scenarios in which an application might need to store some state, commonly to track some information about a user and that user’s session. In these cases, an in-memory cache is a powerful addition to an application, and is nearly indispensable to an elastic cloud architected app which is expected to be able to scale horizontally on-demand, to allow information to be shared between application instances, avoiding the need for load balancer complexity to implement sticky-sessions. Application Container Cloud Service added the ability for applications to add a Caching Service binding in the 17.1.1 drop, and in this blog post we will explore how to leverage this capability in a Node.js application.

Continue reading “Developing with ACCS Caching Services”

Teaching how to integrate with Twilio APIs

In this section we are going to build a simple REST API that calls a “Programmable Voice call and SMS” via using Twilio APIs.

This example is based in one of the samples provided by Twilio (see below).

Original Calling clicktocall-node NodeJS project.

Continue reading “Teaching how to integrate with Twilio APIs”

Teaching how to connect to Sphero2 and Parrot Drones with ACCS

This section shows you how to use the Sphero 2 JS APIs to connect and interact with it.

For more information refer to: https://github.com/orbotix

Install NodeJS

Continue reading “Teaching how to connect to Sphero2 and Parrot Drones with ACCS”

Teaching how to setup your Raspberry Pi 3

Installing VNC Server on your Raspberry Pi 3

Source: https://www.raspberrypi.org/documentation/remote-access/vnc/

  • Install the TightVNC Package

Continue reading “Teaching how to setup your Raspberry Pi 3”

Teaching how to use NodeJS in your local environment

Installing NodeJS

This section assumes that you are using the Xubuntu development environment that was built in this document. If using other environment, you will have to adapt the commands/paths accordingly.

  • Run the following commands:

Continue reading “Teaching how to use NodeJS in your local environment”