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  • Teammates sitting together and looking at code

    Node Reference - Change Events

    The “Join” Problem Modern applications no longer exist in a silo. They need to integrate with other systems within the organization. In a microservice architecture, this is even more valid since very few business processes can be completed by involving only one service. Let us suppose that our product service...
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    Node Reference - Delete

    Prerequisites This article builds on the prior article: Node Reference - History. Deleting Humans make mistakes. Your users are humans, and sometimes they will create a product by mistake and will need to delete it. For that scenario, we need a DELETE REST endpoint. There are two main classes of...
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    Node Reference - History

    Prerequisites This article builds on the prior article: Patch. Tracking History The way our service is currently built, all modifications (PATCH requests) happen in-place to records in DynamoDB. It is common in most production applications that someone will want to know the history of a record. A business user may...
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    Node Reference - Patch Product

    Prerequisites This article builds on the prior article: Node Reference - Get Product by Id. Supporting Updates Sooner or later, there will be a need to modify a product. Except in the case of immutable data stores, rarely are there entities that are truely “insert only”. In order to support...
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    Node Reference - Get Product by Id

    Prerequisites This article builds on the prior article: Node Reference - Listing. Add Get By Id At this point, we have only one way to get Products. We have to list all products and page through them to find the one we want. However, a lot of the time, a...
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    Node Reference - List Products

    Prerequisites This article builds on the prior article: Node Reference - Monitoring. Add listing Clients of our service will need a way to find products. For that, we need a product listing service. DynamoDB provides an operation for listing the contents of a table called a ‘scan’. (As a table...
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    Node Reference - CloudWatch

    Monitoring How do we answer the question: “Is our application performing correctly?” With just one application server we could remotely log into the server, look at CPU and memory load, run grep on the log files and then determine that everything is fine. This approach is manual intensive and obviously...
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    Node Reference - Put Product

    Prerequisites This article builds on the prior article: Node Reference - DynamoDB. Create put test/endpoint First, lets write a spec for our POST /products endpoint. Create a file called products/createProduct.spec.js with the following contents: const proxyquire = require('proxyquire'); describe('products', function () { describe('createProduct', function () { beforeEach(function () { process.env.PRODUCTS_TABLE_NAME...
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    Node Reference - DynamoDB

    Prerequisites This article builds on the prior article: Node Reference - Authentication. Add DynamoDB Before we can start building out our product endpoints, we need a place to store them. For that, we are turning to DynamoDB. Tables are the main component, not a “database”, so we can create just...
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    Node Reference - Authentication

    Prerequisites This article builds on the prior article: Node Reference - Cognito. Adding authentication In order to leverage our new identity provider, we need to add a middleware into our Koa pipeline. This middleware will reject requests that do not contain valid tokens. We can accomplish this by using two...