task-9

bff-service/.env.example

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+CART_URL=https://CART_URL/
+PRODUCT_URL=https://PRODUCT_URL/
+CACHE_TTL=120

bff-service/.eslintrc.js

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+module.exports = {
+  parser: '@typescript-eslint/parser',
+  parserOptions: {
+    project: 'tsconfig.json',
+    sourceType: 'module',
+  },
+  plugins: ['@typescript-eslint/eslint-plugin'],
+  extends: [
+    'plugin:@typescript-eslint/recommended',
+    'plugin:prettier/recommended',
+  ],
+  root: true,
+  env: {
+    node: true,
+    jest: true,
+  },
+  ignorePatterns: ['.eslintrc.js'],
+  rules: {
+    '@typescript-eslint/interface-name-prefix': 'off',
+    '@typescript-eslint/explicit-function-return-type': 'off',
+    '@typescript-eslint/explicit-module-boundary-types': 'off',
+    '@typescript-eslint/no-explicit-any': 'off',
+  },
+};

bff-service/.gitignore

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+# compiled output
+/dist
+/node_modules
+
+# Logs
+logs
+*.log
+npm-debug.log*
+yarn-debug.log*
+yarn-error.log*
+lerna-debug.log*
+
+# OS
+.DS_Store
+
+# Tests
+/coverage
+/.nyc_output
+
+# IDEs and editors
+/.idea
+.project
+.classpath
+.c9/
+*.launch
+.settings/
+*.sublime-workspace
+
+# IDE - VSCode
+.vscode/*
+!.vscode/settings.json
+!.vscode/tasks.json
+!.vscode/launch.json
+!.vscode/extensions.json

bff-service/.prettierrc

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+{
+  "singleQuote": true,
+  "trailingComma": "all"
+}

bff-service/README.md

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+# Task 9 (Backend For Frontend)
+
+**After Lecture 8 "Docker. AWS Elastic Beanstalk"**
+
+## Prerequisites
+---
+
+- The task is a continuation of **Homework 8**
+- The task should be done in the backend repo - the same repo with **product-service** and **import-service** services
+- **product-service** and **CART** services should exist and work in your application
+
+## TASK 9.1
+---
+
+Create a folder for the **bff-service** in the same level as for other services in the repo. Create an **express** application in this folder, that listens for all requests and redirects those requests to the appropriate services based on variables provided by the **.env** file.
+
+**bff-service** workflow example:
+* Call **bff-service** by the URL: **{bff-service-url}**/**{recipient-service-name}**?var1=someValue
+    * **{bff-service-url}** - for example, http://localhost:3000
+    * **{recipient-service-name}** - ‘cart’ or ‘product’ (you can use any other mapping of your choice)
+    * ?var1=someValue - query string
+* Get **recipientURL** from the env variables using **{recipient-service-name}** as a key
+* Get request **method** (GET, POST, etc.)
+* Make a new request to the needed service using the appropriate **method** and **recipientURL**
+* **bff-service** should return the result of the recipient’s request
+
+If **bff-service** cannot find **recipientURL** by the **{recipient-service-name}**, return a 'Cannot process request’ error message with status 502.  
+**bff-service** should return the same status code and error message that the recipient service returns to the **bff-service** in case of any error on the recipient service side.
+
+## TASK 9.2
+---
+
+Deploy **bff-service** with Elastic Beanstalk.
+* Platform should be **node.js**
+* Application name must follow the following convention **{yours_github_account_login}-bff-api**
+* Use the **--cname** option **{yours_github_account_login}-bff-api-{environment_name}**
+* Use the **--single** option
+
+**bff-service** should work only with requests from the **product-service** and **CART** services.  
+All **product-service** and **CART** services methods should work correctly if requested via **bff-service**
+
+## Evaluation criteria (each mark includes previous mark criteria)
+---
+
+Provide your reviewers with the following information:
+- link to the repo
+- **product-service** service API endpoint URL
+- example of the **create product** API call with all needed information: URL, payload, headers, etc.
+- **CART** service API endpoint URL
+- **bff-service** service URL
+- example how to call **product-service** and **CART** services via **bff-service** service URL
+---
+* **3** - A working and correct **express** application should be in the **bff-service** folder. Reviewer can start this application locally with any valid configuration in the **.env** file and this application should works as described in the task 9.1
+* **5** - The **bff-service** should be deployed with Elastic Beanstalk. The **bff-service** call should be redirected to the appropriate service : **product-service** or **CART**. The response from the **bff-service** should be the same as if **product-service** or **CART** services were called directly.
+
+## Additional (optional) tasks
+---
+* **+1** - Add a cache at the **bff-service** level for a request to the **getProductsList** function of the **product-service**. The cache should expire in 2 minutes.  
+  How to test:
+    * Get products list
+    * Create new product
+    * Get products list - result shouldn’t have new product
+    * Wait more than 2 minutes
+    * Get products list - result should have new product
+* **+1** - Use **NestJS** to create **bff-service** instead of **express**

bff-service/nest-cli.json

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+{
+  "collection": "@nestjs/schematics",
+  "sourceRoot": "src"
+}