Realtime Compute for Apache Flink:Manage variables

Reference a variable in an SQL draft

Use variables in SQL drafts to avoid hardcoding values—for example, as input parameters for a custom function. After the deployment starts, you can update variable values without modifying the draft.

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

2. In the SQL editor, define variables in the ${Variable name} format. Follow these rules: Example:

   • Variables in a WITH clause: wrap in single quotation marks — '${Variable name}'

   • Variables as a table name or field name: wrap in grave accents — ` ${Variable name} `

   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 detects variables in the draft. Set values using either method:

   • Variables panel: enter values directly in the Variables panel of the SQL editor.

   • Configurations tab: click the Configurations tab on the right side of the SQL editor, then enter values in the Variables section.

4. After deploying the draft, verify the referenced variables on the Configuration tab of the Deployments page.

   

5. On the Deployments page, find the target deployment and click Start in the Actions column. In the Start Job panel, update variable values as needed.

   Important

   Updated values apply only to this particular job start. The values defined in the SQL draft remain unchanged.

   

Reference a variable in a JAR or Python deployment

Use deployment variables as entry point arguments in the Main function of a JAR or Python deployment. Two methods are available.

Create a variable

Only members with editor or higher permissions, or members with the variable creation permission, can create variables.

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

2. In the left-side navigation pane, choose Security > Variables, then click Add Variable and configure the following parameters:

   Parameter	Description
   Variable name	Must be unique within the namespace. Cannot be changed after creation.
   Variable value	Case-sensitive. Can be updated after creation. For details, see Edit or delete a variable.
   Type	Cannot be changed after creation. Plaintext: the value is visible on the Variables page. Ciphertext: the value is hidden.

3. Click OK.

Reference a variable

After creating a variable, reference it in the ${secret_values.Variable name} format. The following examples show how to reference namespace variables 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 and click Console in the Actions column.

2. In the left-side navigation pane, choose Security > Variables. Find the target variable and click Edit or Delete in the Actions column.

   • Edit: change the variable value. Only members with editor or higher permissions can edit variables.

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