CLOUDLOC-2204: Перевод README-файлов в репозиториях примеров

README_en.md

@@ -0,0 +1,98 @@
+# Tutorial for deploying a small to-do list on a serverless stack using the Java Servlet API
+
+1. Create a `serverless` database. 
+To do this, select `Yandex Database` in the list of services, click **Create database**, and select `serverless` as the database type.
+Then, go to the **Navigation** tab and create the **Tasks** table. You can do this either from the UI or by running a simple SQL query:
+
+    ```sql
+    create table Tasks (
+        TaskId Utf8,
+        Name Utf8,
+        Description Utf8,
+        CreatedAt Datetime,
+        primary key (TaskId)
+    );
+    ```
+
+2. Create a service account in the current directory (to do this, go to the root directory and select **Service Accounts** on the left side of the menu), and then add the `viewer` and `editor` roles to that service account.
+
+3. Create three functions (one for each servlet), upload this project into each of them, set `java11` as the runtime environment and specify the entry point depending on the current servlet. 
+**Make sure to specify** the service account created at the previous step. For each function, add environment variables as follows:
+    * `DATABASE`: Value in the `Database` field of your database (e.g., `/ru-centralx/yyyyyyyyyy/zzzzzzzzzz`).
+    * `ENDPOINT`: Value in the `Endpoint` field of your database (e.g.,`ydb.serverless.yandexcloud.net:2135`).
+
+    Your function entry points should be as follows:
+    * yandex.cloud.examples.serverless.todo.AddTaskServlet
+    * yandex.cloud.examples.serverless.todo.ListTasksServlet
+    * yandex.cloud.examples.serverless.todo.DeleteTaskServlet
+
+    To deploy a function:
+    * Archive the project contents (e.g., `zip target.zip -r src pom.xml`).
+    * Run a simple command (for this, you need to have `yc` installed and configured; you can learn more info [here](https://yandex.cloud/docs/cli/quickstart#install)):
+
+   ```bash
+    yc serverless function version create \
+        --function-id=<current ID of the function> \
+        --runtime=java11 \
+        --entrypoint=<current entry point> \
+        --memory=128mb \
+        --execution-timeout=3s \
+        --source-path=target.zip \
+        --environment="DATABASE=<Database field value>;ENDPOINT=<Endpoint field value>"
+    ```
+
+    Run the command three times, each time specifying one of the entry points, the respective function ID, and values for the environment variables.
+
+    * Alternatively, you can create a version through the UI. To do this, go to the function, open the **Editor** tab; in the **Method** tab, select `ZIP`, and feed the zipped project there.
+
+    After that, set these parameters:
+      * Entry point: the current entry point (e.g., `yandex.cloud.examples.serverless.todo.AddTaskServlet` for the function associated with this servlet).
+      * Timeout, sec: 3.
+      * RAM: 128 MB.
+      * Service account: Select the service account created at step 2.
+      * Environment variables:
+        * DATABASE: `Database` field value.
+        * ENDPOINT: `Endpoint` field value.
+
+4. Create a bucket in `s3` and upload `index.html` (`src/main/resources/index.html`) to that bucket.
+
+5. Create `API Gateway`. In the specification, delete any contents in the `paths` field and provide the following instead:
+
+    ```openapi
+      /:
+        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_servlet_function>
+          operationId: addTask
+      /list:
+        get:
+          x-yc-apigateway-integration:
+            type: cloud-functions
+            function_id: <list_servlet_function>
+          operationId: listTasks
+      /delete:
+        delete:
+          x-yc-apigateway-integration:
+            type: cloud-functions
+            function_id: <delete_servlet_function>
+          operationId: deleteTask
+    ```
+
+    Replace `<bucket>` with the name of the bucket housing the `index.html` file, and `<service_account>`, with the the ID of the service account created at step 2. Replace all other parameter values with the IDs of the respective functions.
+
+That’s it! Your to-do list should now be displayed when you click on the link specified in `API Gateway`.
+
+Useful links:
+* [Cloud Functions documentation](https://yandex.cloud/docs/functions/)
+* [YDB documentation](https://yandex.cloud/docs/ydb/)
+* [API Gateway documentation](https://yandex.cloud/docs/api-gateway/)