Database with MongoDB

Add a MongoDB integration to your backend service¶

Create a MongoDB instance¶

$ oc create secret generic --from-literal=MONGODB_HOST=<HOST> --from-literal=MONGODB_PORT=<PORT> --from-literal=MONGODB_USER=<USER> --from-literal=MONGODB_PASSWORD=<PASSWORD> --from-literal=MONGODB_DATABASE=<DATABASE> mongodb-access

Fill in the database with mock data¶

• To help create test JSON data we are going to supply a template to the JSON Generator tool, this helps when creating dummy data for testing. Navigate to the following link https://www.json-generator.com/.

• Replace the default template with following template. This will enable a 100 records of test data to be created to represent a products database. Click on the Generate button.

  [
     '{{repeat(100)}}',
     {
       _id: '{{objectId()}}',
       manufacturer: '{{company().toUpperCase()}}',
       name:  '{{lorem(3, "words")}}',
       price: '{{floating(10, 1000, 2, "0.00")}}',
       stock: '{{integer(1, 100)}}'
     }
   ]
  

• Connect to your MongoDB instance, create a new collection called stockItem in your database and insert the generated data.

Enable database in the solution¶

If you are starting from the solution, use the following steps to enable the Cloudant database

Update the gradle config to include mongodb dependencies

• Head over to the gradle and create the following build-mongodb.gradle file:
  gradle/build-mongodb.gradle

  dependencies {
    implementation group: 'org.springframework.boot', name: 'spring-boot-starter-data-mongodb', version: '2.7.1'
    implementation group: 'org.springframework.boot', name: 'spring-boot-starter-data-jpa', version: '2.7.1'
  }
  

• On the build.gradle file, add the following line :
  build.gradle

  apply from: 'gradle/build-mongodb.gradle'
  

• Run ./gradlew build --refresh-dependencies to validate the changes and load the libraries.

Update application configuration to connect to database

• On the src/main/resources/application.yml file, update the spring by adding the content as such.
  src/main/resources/application.yml

  spring:
    data:
     mongodb:
       username: "${MONGODB_USERNAME:<USERNAME>}"
       password: "${MONGODB_PASSWORD:<PASSWORD>}"
       database: "${MONGODB_DATABASE:<DATABASE>}"
       authentication-database: "${MONGODB_DATABASE:<DATABASE>}"
       port: "${MONGODB_PORT:<PORT>}"
       host: "${MONGODB_HOST:<HOST>}"
    autoconfigure:
     exclude: org.springframework.boot.autoconfigure.jdbc.DataSourceAutoConfiguration
  

  Replace the placeholders with your database instance values.

Update the configuration values in the Helm chart

• Open the values.yaml file and add the following value :

mongodbAccess=mongodb-access

env:
  - name: MONGODB_USERNAME
    valueFrom:
      secretKeyRef:
        name: {{ .Values.mongodbAccess | quote }}
        key: MONGODB_USERNAME
  - name: MONGODB_PASSWORD
    valueFrom:
      secretKeyRef:
        name: {{ .Values.mongodbAccess | quote }}
        key: MONGODB_PASSWORD
  - name: MONGODB_DATABASE
    valueFrom:
      secretKeyRef:
        name: {{ .Values.mongodbAccess | quote }}
        key: MONGODB_DATABASE
  - name: MONGODB_PORT
    valueFrom:
      secretKeyRef:
        name: {{ .Values.mongodbAccess | quote }}
        key: MONGODB_PORT
  - name: MONGODB_HOST
    valueFrom:
      secretKeyRef:
        name: {{ .Values.mongodbAccess | quote }}
        key: MONGODB_HOST

Update project files

• Update the StockItem.java file, add an @Id annotation on the id field.

  src/main/java/com/ibm/inventory_management/models/StockItem.java

  package com.ibm.inventory_management.models;
  
  import org.springframework.data.annotation.Id;
  
  import java.io.Serializable;
  
  public class StockItem implements Serializable {
    private String name;
    @Id
    private String id = null;
    private int stock = 0;
    private double price = 0.0;
    private String manufacturer = "";
  
    public StockItem() {
      super();
    }
  
    public StockItem(String id) {
      this.id = id;
    }
  
    public String getName() {
      return name;
    }
  
    public void setName(String name) {
      this.name = name;
    }
  
    public StockItem withName(String name) {
      this.setName(name);
      return this;
    }
  
    public String getId() {
      return id;
    }
  
    public void setId(String id) {
      this.id = id;
    }
  
    public StockItem withId(String id) {
      this.setId(id);
      return this;
    }
  
    public int getStock() {
      return stock;
    }
  
    public void setStock(int stock) {
      this.stock = stock;
    }
  
    public StockItem withStock(int stock) {
      this.setStock(stock);
      return this;
    }
  
    public double getPrice() {
      return price;
    }
  
    public void setPrice(double price) {
      this.price = price;
    }
  
    public StockItem withPrice(double price) {
      this.setPrice(price);
      return this;
    }
  
    public String getManufacturer() {
      return manufacturer;
    }
  
    public void setManufacturer(String manufacturer) {
      this.manufacturer = manufacturer;
    }
  
    public StockItem withManufacturer(String manufacturer) {
      this.setManufacturer(manufacturer);
      return this;
    }
  }
  

• Create a StockItemRepository.java interface to interact with the database, put it in a repositories directory.

  src/main/java/com/ibm/inventory_management/repositories/StockItemRepository.java

  package com.ibm.inventory_management.repositories;
  
  import com.ibm.inventory_management.models.StockItem;
  import org.springframework.data.mongodb.repository.MongoRepository;
  import org.springframework.stereotype.Repository;
  
  import java.util.Optional;
  
  @Repository
  public interface StockItemRepository extends MongoRepository<StockItem, String> {
      Optional<StockItem> findById(String id);
  }
  

• Update the StockItemApi.java interface to have CRUD operations.

  src/main/java/com/ibm/inventory_management/services/StockItemApi.java

  package com.ibm.inventory_management.services;
  
  import java.util.List;
  
  import com.ibm.inventory_management.models.StockItem;
  
  public interface StockItemApi {
    List<StockItem> listStockItems() throws Exception;
  
    void addStockItem(String name, Double price, Integer stock, String manufacturer) throws Exception;
  
    void updateStockItem(String id, String name, Double price, Integer stock, String manufacturer) throws Exception;
  
    void deleteStockItem(String id) throws Exception;
  }
  

• Update the StockItemService.java to implement the interface and use the repository.

  src/main/java/com/ibm/inventory_management/services/StockItemService.java

  package com.ibm.inventory_management.services;
  
  import java.util.List;
  
  import com.ibm.inventory_management.repositories.StockItemRepository;
  import org.bson.types.ObjectId;
  import org.springframework.beans.factory.annotation.Autowired;
  import org.springframework.stereotype.Service;
  
  import com.ibm.inventory_management.models.StockItem;
  
  @Service
  public class StockItemService implements StockItemApi {
        @Autowired
        private StockItemRepository stockItemRepository;
        @Override
        public List<StockItem> listStockItems() {
              return stockItemRepository.findAll();
        }
  
        @Override
        public void addStockItem(String name, Double price, Integer stock, String manufacturer) throws Exception {
              try {
                    stockItemRepository.save(
                            new StockItem(ObjectId.get().toString())
                                    .withName(name)
                                    .withManufacturer(manufacturer)
                                    .withStock(stock)
                                    .withPrice(price)
                    );
              } catch (Exception e) {
                    throw new Exception("",e);
              }
        }
  
        @Override
        public void updateStockItem(String id, String name, Double price, Integer stock, String manufacturer) throws Exception {
              try {
                    StockItem itemToUpdate = stockItemRepository.findById(id).get();
  
                    itemToUpdate.setName(name !=null ? name : itemToUpdate.getName());
                    itemToUpdate.setManufacturer(manufacturer != null ? manufacturer : itemToUpdate.getManufacturer());
                    itemToUpdate.setPrice(price != null ? price : itemToUpdate.getPrice());
                    itemToUpdate.setStock(stock != null ? stock : itemToUpdate.getStock());
  
                    stockItemRepository.save(itemToUpdate);
              } catch (Exception e) {
                    throw new Exception("",e);
              }
        }
  
        @Override
        public void deleteStockItem(String id) throws Exception {
              try {
                   stockItemRepository.deleteById(id);
              } catch (Exception e){
                   throw new Exception("",e);
              }
        }
  }
  

Running the application locally¶

• Start the application locally

  ./gradlew build
  ./gradlew bootrun
  

• Open a browser to http://localhost:9080/swagger-ui.html

• Once the application is up, go the Swagger UI and execute get stock-items.

• You should be able to see all the data you pushed to the database through ./dataload.sh

Prebuilt solution for this can be found here: Inventory Management Service MongoDB solution template