Realtime Compute for Apache Flink:Manage variables

Reference a variable in an SQL draft

You can use variables when you develop an SQL draft. For example, you can use variables as the input parameters of a custom function. You can also modify the variable values when the deployment is started.

1. In the left-side navigation pane of the Realtime Compute for Apache Flink console, choose Development > ETL.

2. In the SQL editor of the draft that you want to develop, create variables in the ${Variable name} format. The following sample code provides an example.

   • If you reference a variable in the WITH clause, you must enclose the variable with a pair of single quotation marks ('), in the '${Variable name}' format.

   • If you reference a variable as a table name or field name in an SQL statement, you must enclose the variable with a pair of grave accents (`), in the `${Variable name}` format.

   create temporary table `${source_name}`(
       id varchar,
       name varchar
   ) with (
       'connector' = 'datagen'
   );
   
   
   create temporary table blackhole(
       id varchar,
       `${test_name}` varchar
   ) with (
       'connector' = '${blackhole}'
   );
   
   insert into blackhole select * from `${source_name}`;

3. Realtime Compute for Apache Flink automatically identifies variables in the required format in the draft. You need to use one of the following methods to configure the variable values:

   • Method 1: Enter a variable value in the Variables panel of the SQL editor.

     

   • Method 2: Click the Configurations tab on the right side of the SQL editor. In the Configurations panel, enter a variable value in the Variables section.

     

4. After the draft is deployed, view the variable that is referenced in the deployment on the Configuration tab of the Deployments page.

   

5. On the Deployments page, find the deployment that you want to start and click Start in the Actions column. You can change the variable value in the Start Job panel.

   Important

   The new variable values take effect only for the deployment to be started. The variable values in the statement of the SQL draft remain unchanged.

   

Reference a variable in a JAR or Python deployment

You can use variables as the input parameters in the Main function of a JAR or Python deployment.

1. In the development console of Realtime Compute for Apache Flink, choose O&M > Deployments. On the Deployments page, click Create Deployment.

2. Enter a variable name in the Entry Point Main Arguments field. Then, enter the variable value in the Variables section below the field.

   

   For more information about other deployment parameters, see Create a deployment.

3. Click Deploy.

4. On the Deployments page, find the deployment that you want to start and click Start in the Actions column. You can change the variable value in the Start Job panel.

   

Create a variable

1. Log on to the Realtime Compute for Apache Flink console. Find the workspace that you want to manage and click Console in the Actions column.

2. In the left-side navigation pane, choose Security > Variables. On the Variables page, click Add Variable.

   Parameter	Description
   Variable Name	Variable names must be unique in the same namespace and cannot be modified after the variables are created.
   Variable Value	Variable values are case-sensitive. Pay attention to the case when you enter letters in a variable value. You can change the value of a variable after it is created. For more information, see the Edit or delete a variable section in this topic.
   Type	You cannot modify the type of a variable after it is created. Valid values: Plaintext: You can directly view the variable value on the Variables page. Ciphertext: You cannot view the variable value.

3. Click OK.

Reference a variable

After you create a variable, you can reference the variable in the ${secret_values.Variable name} format. The following section provides examples for referencing a variable in different scenarios.

create temporary table `${secret_values.source_name}`(
    id varchar,
    name varchar
) with (
    'connector' = 'datagen'
);


create temporary table blackhole(
    id varchar,
    `${secret_values.test_name}` varchar
) with (
    'connector' = '${secret_values.blackhole}'
);

insert into blackhole select * from `${secret_values.source_name}`;

source:
  type: mysql
  name: Mysql Source
  hostname: localhost
  port: 3306
  username: test
  password: ${secret_values.mysqlpw}
  tables: app_db.\.*
  server-id: 5400-5404

···

USE CATALOG paimon;

CREATE DATABASE IF NOT EXISTS `${secret_values.test_name}`;

CREATE TABLE paimon.`${secret_values.test_name}`.ods_user_log
(
    item_id  int NOT NULL,
    `${secret_values.user}` varchar(50) NOT NULL,
    action  varchar(20)  NOT NULL,
    vtime   timestamp,
    ds      varchar(10) NOT NULL
)
PARTITIONED BY (ds);

SELECT * from paimon.`${secret_values.test_name}`.ods_user_log LIMIT 10;

Edit or delete a variable

1. Log on to the Realtime Compute for Apache Flink console. Find the workspace that you want to manage and click Console in the Actions column.

2. In the left-side navigation pane, choose Security > Variables. On the Variables page, find the variable that you want to edit or delete and click Edit or Delete in the Actions column.

   • Edit a variable

     You can change the value of a variable. Only members with the editor or higher permissions can edit variables.

   • Delete a variable

     Only members with the editor or higher permissions, or members with the variable deletion permission can delete variables.