{"id":12196,"date":"2020-11-27T12:56:40","date_gmt":"2020-11-27T11:56:40","guid":{"rendered":"https:\/\/www.codemotion.com\/magazine\/?p=12196"},"modified":"2022-01-05T20:06:46","modified_gmt":"2022-01-05T19:06:46","slug":"cloud-nimbella-aws","status":"publish","type":"post","link":"https:\/\/www.codemotion.com\/magazine\/devops\/cloud\/cloud-nimbella-aws\/","title":{"rendered":"Building a Stateful Cloud App on Nimbella or AWS"},"content":{"rendered":"\t\t\t\t
\n\t\t\t\t
\n\t\t\t\t\t\t
\n\t\t\t\t\t\t\tTable Of Contents\t\t\t\t\t\t<\/div>\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t
\n\t\t\t\t\t\t
  1. What sort of Stateful Serverless Cloud App am I going to build?<\/a>
  2. How should the code files be arranged?<\/a>
  3. How can an App be made Stateful for the Cloud?<\/a>
  4. Static Assets\u2026how can a Stateful App that has these be deployed to the Cloud?<\/a>
  5. So, what does that mean for me?<\/a><\/ol>\t\t\t\t\t<\/div>\n\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\n\n\n

    Building serverless<\/a> cloud applications<\/span>? There’s a simple way to do that! This article compares the user<\/span> experience of Nimbella<\/strong> and Amazon Web Services<\/a> when creating a voting app<\/span>, from a developer<\/span>‘s point of view.<\/p>\n\n\n\n

    What sort of Stateful Serverless Cloud App am I going to build?<\/h2>\n\n\n\n

    For the purposes of writing this article, I built a voting app<\/span> that allows users<\/span> to say whether they prefer cats or dogs. Because the data input by the user<\/span> needs to be saved between sessions<\/span> for later re-use, this needs to be a stateful<\/span> app<\/span>.<\/p>\n\n\n\n

    Building this app<\/span> requires two things.<\/p>\n\n\n\n

    1. A frontend that displays two voting buttons.<\/li>
    2. Two cloud functions that save the application\u2019s \u201cstate\u201d by calling on key-value storage<\/li><\/ol>\n\n\n\n
      \"A
      Dogs or Cats? Which do you prefer?<\/figcaption><\/figure><\/div>\n\n\n\n

      How should the code files be arranged?<\/h2>\n\n\n\n
      \"Code
      Code file arrangements for Nimbella and AWS<\/figcaption><\/figure><\/div>\n\n\n\n

      First things first: let\u2019s look at how to organise the code<\/span> before we look at the practical elements of launching the code<\/span> in the Cloud<\/span>.<\/p>\n\n\n\n

      Each of the systems<\/span> illustrated above includes two folders for this project<\/span>; one contains static content (Web) and the second stores cloud functions<\/span> (Packages). The primary difference between the two systems lies in how they arrange the cloud functions<\/span>.<\/p>\n\n\n\n

      In Nimbella<\/strong>, I simply create the cloud functions<\/span> as two files<\/span> (addVotes.js<\/em> and getVotes.js<\/em>).<\/p>\n\n\n\n

      If I use <\/em>Amazon Web Services<\/span><\/strong>, the process<\/span> is a little more complex. The first step is the creation of separate folders for each cloud function.  Next, the JS<\/span><\/a> files<\/span> are added, and their dependencies are included in each folder. Finally, the zip file<\/span> with its node-modules<\/span> folder, the JS file<\/span>, and the package.json are added to complete the process<\/span>.<\/p>\n\n\n\n

      How can an App be made Stateful for the Cloud?<\/h2>\n\n\n\n
      \"Making
      Making an app stateful: diagrams for Nimbella and AWS<\/figcaption><\/figure><\/div>\n\n\n\n

      Key-value<\/span> storage is necessary to make a stateful<\/span> app<\/span> – it saves the votes already cast, and presents the running totals when the page is refreshed. Again, Nimbella and AWS<\/span> achieve this in different ways.<\/p>\n\n\n\n

      Nimbella<\/h3>\n\n\n\n
      1. Add Redis<\/span> (key-value storage) to the project<\/strong>. To this end, create a new project template by running the following command:
        nim project create ProjectName<\/code><\/li>
      2. Call Redis from your functions<\/strong>. To this end, first import nim<\/strong>, and then import Redis from it within the function. Finally, add the code logic that makes Redis either update the vote totals, or return the current voting numbers (see image below)<\/li>
      3. Deploy stateful functions to the Cloud<\/strong>. Ensure your functions are properly located within the Packages folder, then run the following command:
        nim project deploy ProjectName<\/code><\/li><\/ol>\n\n\n\n

        The services<\/span> I need to achieve a stateful<\/span> app<\/span> are all readily available and in place in this system<\/span>. Because of this, there’s no service set-up to carry out \u2013 all I have to do is call the required services<\/span> using code logic.<\/p>\n\n\n\n

        To increment voting numbers, I used code<\/span> similar to the following:<\/p>\n\n\n\n

        \"Code
        Code used to increment voting numbers<\/figcaption><\/figure><\/div>\n\n\n\n

        Amazon Web Services<\/h3>\n\n\n\n

        Making a stateful<\/span> application<\/span> in AWS<\/span> involves a number of steps. Using this system<\/span>, I created stateful<\/span> key-value<\/span> storage<\/span> like this:<\/p>\n\n\n\n

        1. Deploy a Redis (key-value storage) cluster on Amazon Web Services<\/strong>:
          1. Select Redis from the AWS ElastiCache service<\/li>
          2. Input name, version, port, parameter group, node type, and the number of replicas desired in the Redis settings<\/li>
          3. Nominate the VPC your Redis cluster should be connected to<\/li>
          4. When this process is complete, keep the Primary Endpoint – it’s important in the next step<\/li><\/ol><\/li>
          5. Deploying EC2 on Amazon Web Services<\/strong>:
            1. Use the service tab to look for EC2. Don\u2019t forget to choose your region;<\/li>
            2. Open \u201cLaunch Instance\u201d<\/li>
            3. Select the type of instance you need<\/li>
            4. Configure your instance (N.B., always use the same VPC that you used for ElastiCache)<\/li>
            5. Add your Storage<\/li>
            6. Attach tags<\/li>
            7. Configure the Security Group & check what you have done so far<\/li>
            8. Connect the SSH to your EC2 instance before installing the Redis CLI<\/li>
            9. Connect the Redis instance via Redis CLI. Don’t forget to include the primary endpoint of Redis (as previously mentioned, this is important!)<\/li><\/ol><\/li>
            10. Deploy Lambda<\/span> functions on Amazon Web Services, then connect it to API Gateway:<\/strong>
              1. Find Lambda<\/span><\/a> by using the service tab. Ensure the correct region is identified<\/li>
              2. Create functions methodically. Working one by one, select \u201cAuthor from Scratch\u201d, the function\u2019s name, and what type of code it uses (NodeJS<\/span>, Python<\/span>, etc)<\/li>
              3. Using the same VPC as Redis, connect your functions. Check each one to be sure the correct ports have been chosen<\/li>
              4. Connect your functions to API<\/span> Gateway. Choose a trigger for the function, requesting an HTTP API as the trigger type. This will provide you with a URL that can be used to call your functions through your code<\/li><\/ol><\/li><\/ol>\n\n\n\n

                Static Assets\u2026how can a Stateful App that has these be deployed to the Cloud?<\/h2>\n\n\n\n
                \"Cloud
                Deployment to the Cloud with Nimbella or AWS<\/figcaption><\/figure><\/div>\n\n\n\n

                With your static web assets and cloud functions<\/span> complete, you can finally deploy the entire app<\/span> to the Cloud<\/span>!<\/p>\n\n\n\n

                Deploying to the Cloud with Nimbella<\/h3>\n\n\n\n

                If you\u2019re using Nimbella, there\u2019s no need to configure<\/span> cloud storage for any front-end<\/span> static assets, nor to configure<\/span> a content delivery network (CDN<\/span>) that will serve the app<\/span> from the Cloud<\/span>. This is because the configuration<\/span> will be done for you – just issue the instruction<\/span> that your code logic should be sent to the Cloud<\/span>, like this:<\/p>\n\n\n\n