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Yandex Managed Service for YDB

Deploying a web application using the Java Servlet API

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Learn how to use serverless technologies and the Java Servlet API to create a simple web application for managing a task list.

To create a web application:

  1. Before you start.
  2. Prepare the environment.
  3. Create a Yandex Object Storage bucket.
  4. Create a YDB database.
  5. Create functions Yandex Cloud Functions.
  6. Create an API gateway.
  7. Test your application.

If you no longer need these resources, delete them.

Before you begin

Before working, you need to register in Yandex Cloud and create a billing account:

  1. Go to the management console. Then log in to Yandex Cloud or sign up if don't already have an account.
  2. On the billing page, make sure you linked a billing account, and it has the ACTIVE or TRIAL_ACTIVE status. If you don't have a billing account, create one.

If you have an active billing account, you can create or select a folder to run your VM in from the Yandex Cloud page.

Learn more about clouds and folders.

The cost of resources to support a web application includes:

Prepare the environment

  1. Download the archive with project files.
  2. Create a service account and assign it the viewer and editor roles for your folder.

Create a Object Storage bucket

Create a bucket and upload index.html there:

  1. In the management console, select the folder where you want to create a bucket.
  2. Select Object Storage.
  3. Click Create bucket.
  4. On the bucket creation page:
    1. Enter the bucket name, following the naming guidelines.
    2. If necessary, limit the maximum bucket size.
    3. Select the type of access.
    4. Select the default storage class.
    5. Click Create bucket to complete the operation.
  5. Select the created bucket.
  6. Click Upload.
  7. In the window that opens, in the project folder, select the src/main/resources/index.html file and click Open.
  8. Select the storage class for the file and click Upload.

Create a Managed Service for YDB database

  1. Create a database in Serverless mode:

    1. In the management console, select the folder where you created the bucket.

    2. Select Managed Service for YDB.

    3. Click Create database.

    4. Enter the database Name. Naming requirements:

      • The length can be from 3 to 63 characters.
      • It may contain lowercase Latin letters, numbers, and hyphens.
      • The first character must be a letter. The last character can't be a hyphen.

    5. Under Database type, select Serverless.

    6. Click Create database.

    7. Wait until the database starts. When a database is being created, it has the Provisioning status. When it's ready for use, the status changes to Running.

    8. Select the database created.

    9. Under Connection, find the Endpoint and Database location fields and save their values. You'll need them when creating functions.

  2. Create a table named Tasks:

    1. In the management console, select the folder where you created the database.

    2. Select Managed Service for YDB.

    3. Select a database on the Databases page.

    4. To open the DB root directory, go to the Navigation tab.

    5. To make a query to the database, click SQL query in the upper-right corner. The Query page opens.

    6. In the Query field, enter:

      CREATE TABLE Tasks (
  TaskId Utf8,
  Name Utf8,
  Description Utf8,
  CreatedAt Datetime,
  PRIMARY KEY (TaskId)
);

    7. Click Run.

    Run the query:

    ydb -e grpcs://<YDB endpoint> -d <database> \
scripting yql -s \
"CREATE TABLE Tasks
(
  TaskId Utf8,
  Name Utf8,
  Description Utf8,
  CreatedAt Datetime,
  PRIMARY KEY (TaskId)
);"

Create Cloud Functions functions

Create a function for each servlet:

  1. In the management console, go to the folder where you created the bucket and database.
  2. Select Cloud Functions.
  3. Click Create function.
  4. Enter the name add-task and a function description.
  5. Click Create.
  6. Under Editor, select the Java 11 runtime environment and click Continue.
  7. Prepare the function code. For this, in the Method field, select ZIP archive, and specify the path to the downloaded servlet.zip archive, then click Open.
  8. In the Entry point field, enter yandex.cloud.examples.serverless.todo.AddTaskServlet.
  9. In the Timeout, sec field, enter 5.
  10. In the Service account field, enter the account that you created when preparing the environment.
  11. Add environment variables:
  12. Click Create version.
  13. Repeat steps 3–12 and create a function named list-tasks with the entry point yandex.cloud.examples.serverless.todo.ListTasksServlet.
  14. Repeat steps 3–12 and create a function named delete-task with the entry point yandex.cloud.examples.serverless.todo.DeleteTaskServlet.

  1. Create a function named add-task:

    yc serverless function create --name=add-task

    Result:

    id: d4ejb1799eko6re4omb1
folder_id: aoek49ghmknnpj1ll45e
created_at: "2021-03-08T14:07:32.134Z"
name: add-task
log_group_id: eolm8aoq9vcppsieej6h
http_invoke_url: https://functions.yandexcloud.net/d4ejb1799eko6re4omb1
status: ACTIVE

  2. Create a version of the add-task function:

    yc serverless function version create \
  --function-name=add-task \
  --runtime java11 \
  --entrypoint yandex.cloud.examples.serverless.todo.AddTaskServlet \
  --memory 128m \
  --execution-timeout 5s \
  --source-path ./servlet.zip \
  --environment DATABASE=<database>,ENDPOINT=<YDB endpoint>

    Where:

    • function-name: The name of the function you want to create a version of.
    • runtime: The runtime environment.
    • entrypoint: The entry point specified in the <function file name>.<handler name> format.
    • memory: The amount of RAM.
    • execution-timeout: The maximum function execution time before the timeout is reached.
    • source-path: ZIP archive with the function code and required dependencies.
    • environment: Environment variables in key=value format.

    Result:

    done (1s)
id: d4evvn8obisajd51plaq
function_id: d4ejb1799eko6re4omb1
...
tags:
- $latest
log_group_id: ckg3qh8h363p40gmr9gn

  3. Repeat steps 1–2 and create a function named list-tasks with the entry point yandex.cloud.examples.serverless.todo.ListTasksServlet.

  4. Repeat steps 1–2 and create a function named delete-task with the entry point yandex.cloud.examples.serverless.todo.DeleteTaskServlet.

Use the create and the createVersion API methods.

You can create a function and its version using the Yandex Cloud Toolkit plugin for the IDE family on the IntelliJ platform from JetBrains.

Create an API gateway

To ensure interaction between services, create an API gateway:

  1. In the management console, select the folder where you created your bucket, database, and functions.

  2. Select API Gateway.

  3. Click Create API gateway.

  4. Enter a name and description of the gateway.

  5. In the Specification field, add the specification:

    openapi: 3.0.0
info:
  title: ToDo list
  version: 1.0.0
paths:
  /:
    get:
      x-yc-apigateway-integration:
        type: object-storage
        bucket: <bucket>
        object: index.html
        presigned_redirect: false
        service_account: <service account>
      operationId: static
  /add:
     post:
       x-yc-apigateway-integration:
         type: cloud-functions
         function_id: <add-task ID>
       operationId: addTask
  /list:
    get:
      x-yc-apigateway-integration:
        type: cloud-functions
        function_id: <list-tasks ID>
      operationId: listTasks
  /delete:
    delete:
      x-yc-apigateway-integration:
        type: cloud-functions
        function_id: <delete-task ID>
      operationId: deleteTask

    Where:

    • bucket: Name of the bucket containing index.html.
    • service_account: ID of the service account created when preparing the environment.
    • /add section, function_id parameter: ID of the add-task function.
    • /list section, function_id parameter: ID of the list-tasks function.
    • /delete section, function_id parameter: ID of the delete-task function.

  6. Click Create.

  1. Save the following specification to todo.yaml:

    openapi: 3.0.0
info:
  title: ToDo list
  version: 1.0.0
paths:
  /:
    get:
      x-yc-apigateway-integration:
        type: object-storage
        bucket: <bucket>
        object: index.html
        presigned_redirect: false
        service_account: <service account>
      operationId: static
  /add:
    post:
      x-yc-apigateway-integration:
        type: cloud-functions
        function_id: <add-task ID>
      operationId: addTask
  /list:
    get:
      x-yc-apigateway-integration:
        type: cloud-functions
        function_id: <list-tasks ID>
      operationId: listTasks
  /delete:
    delete:
      x-yc-apigateway-integration:
        type: cloud-functions
        function_id: <delete-task ID>
      operationId: deleteTask

    Where:

    • bucket: Name of the bucket containing index.html.
    • service_account: ID of the service account created when preparing the environment.
    • /add section, function_id parameter: ID of the add-task function.
    • /list section, function_id parameter: ID of the list-tasks function.
    • /delete section, function_id parameter: ID of the delete-task function.

  2. Create an API gateway:

    yc serverless api-gateway create \
  --name todo-list \
  --spec=todo.yaml \
  --description "simple todo list"

    Result:

    done (41s)
id: d5delqeel34qjjfcdj81
folder_id: b1g86q4m5vej8lkljme5
created_at: "2021-03-08T14:07:32.134Z"
name: todo-list
description: simple todo list
status: ACTIVE
domain: d5delqeel34qjjfcdj81.apigw.yandexcloud.net
log_group_id: ckg2hdmevnvcngprqvqb

You can create an API gateway using the Yandex Cloud Toolkit plugin for the family of IDEs on the IntelliJ platform from JetBrains.

Test the application

To open the app, follow the link in the Service domain field of the created API gateway.

How to delete created resources

To stop paying for the resources created:

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