# Custom Addon

    # Application Scenarios

    • Non-platform deployed addons (for example, MySQL deployed on a separately purchased machine, etc.)
    • Public third-party services (such as SMS channel configuration, etc.)

    # Set Entrance

    Go to DevOps Platform > Projects > App Center > Environments > Addons, click Add, and select Custom for Third service.

    Fill in the configuration.

    Tips

    After modifying the addon parameters, all associated applications need to be restarted, which may affect these applications. Please operate with caution.

    # Use Entrance

    Go to Apps > Code, edit the erda.yml and select the previously created addon.

    After editing, rebuild and redeploy the pipeline to make the configuration take effect.

    # How to Use

    The application can obtain configuration through system environment variables. Taking the Spring Boot application as an example, the configuration can be obtained by ${MYSQL_HOST} in application.yml.

    server:
  port: 8080

spring:
  datasource:
    driver-class-name: com.mysql.jdbc.Driver
    url: jdbc:mysql://${MYSQL_HOST:127.0.0.1}:${MYSQL_PORT:3306}/${MYSQL_DATABASE}?useUnicode=true&characterEncoding=UTF-8
    username: ${MYSQL_USERNAME:root}
    password: ${MYSQL_PASSWORD:}

    # Import and Export

    # Export

    Go to DevOps Platform > Projects > App Center > Environments > Addons, and click View Config in Custom to view the JSON configuration of all custom addons under the current project.

    # Import

    Go to DevOps platform > Projects > App Center > Environments > Addons > Add, select Custom for third service and Import Configuration for creation method to paste the exported JSON mentioned above (modify the configuration parameters if necessary), then the custom addon is imported from other projects to the current one.

    # Switch Similar Addons Smoothly

    In the development phase, developers mostly use the low-cost and out-of-the-box addons on Erda, while in the delivery phase, they want to smoothly switch to a more stable third-party similar addon without modifying the artifact. The similar addon is suitable for such scenarios.

    A similar addon is a different presentation of the same function. If you need to use MySQL, you can choose either the third-party addon Alicloud-RDS, or the out-of-the-box erda mysql of Erda. Here the Alicloud-RDS and erda mysql are both for MySQL implementation, and the relationship between the two is similar addon.

    When using an out-of-the-box addon of Erda for deployment, the deployed service will preferentially reference the similar addon if there is one under the project with the same name.

    Erda supports the following similar addons:

    Type Third-party Erda
    MySQL alicloud-rds erda mysql
    Elasticsearch alicloud-es terminus-elasticsearch
    RocketMQ alicloud-ons erda rocketmq
    Redis alicloud-redis erda redis

    # Example

    You can define the addon in dice.yml or in the artifact. An example of dice.yml is as follows:

    addons:
  demo-mysql:
    plan: "mysql:basic"
  demo-es:
    plan: "terminus-elasticsearch:basic"
  demo-mq:
    plan: "rocketmq:basic"
  demo-redis:
    plan: "redis:basic"

    A similar addon with the same name is added to the Addons page, which will be referenced preferentially for service deployment.

    Tips

    If the service runtime already exists, and you want to switch from an Erda addon to a third-party similar addon (or from a third-party similar addon to an Erda addon), you should first delete the runtime, add (or delete) the third-party similar addon with the same name, and then redeploy it.

    ← Database Migration →