Why is the placeholder not set properly in hikari.data-source-properties

Question

I am setting the hikari.data-source-properties with a placeholder, but the placeholder value does not get substituted. It is a spring-boot 2.1.4.RELEASE based application. My intention is to set the Session properties so the DBAs can identify my application. Currently I get a default JDBC Thin Client for my connection when I run SELECT PROGRAM FROM V$SESSION from the DB

Below is what I have in my application.yml file

spring:
    datasource:
        url: "jdbc:oracle:thin:@machine:1521:service_name"
        driver-class-name: "oracle.jdbc.driver.OracleDriver"
        hikari.data-source-properties:
            v$session.program:${spring.application.name}

Below is what I have in my bootstrap.yml file

spring:
    application:
        name: ms-db-service

When I query the Oracle DB, I notice that the value for program is literally ${spring.application.name}, instead of the expected value ms-db-service

I have tried the below, with same logical result:

• Tried redefining the spring.application.name again in the application.yml
• Tried using a different locally defined key ${name}
• Added the following bean

public static PropertySourcesPlaceholderConfigurer propertySourcesPlaceholderConfigurer() {
    return new PropertySourcesPlaceholderConfigurer();
}

• Tried specifying the property as such: spring.datasource.hikari.data-source-properties: v$session.program=${spring.application.name}

I tried the below items to gain more knowledge of the situation:

• I tried using a placeholder for spring.datasource.url and that worked fine
• I tried to read the value manually using the below code, and that shows the correct values: @Value("${spring.datasource.hikari.data-source-properties}") String propVal;

My conclusion is that HikariCp reads these values before the placeholder substitution is done. I don't understand the relative timing of when the substitution and datasource bean creation happen in the spring-boot bean life-cycle

I am trying to avoid using a bean for hikaricp datasource (not sure if that will even solve the issue), as I don't want to manually build the whole datasource as hikari supports huge number of properties.

So, how can I set the spring.datasource.hikari.data-source-properties in application.yml using a placeholder. And, is there any other way to assign spring.application.name to identify my current db connection?

Answer 1

You have to use it like this:

spring:
  datasource:
    hikari:
      data-source-properties:
        "[v$session.program]": ${spring.application.name}