YML references other variables

Reference resources ：YAML file (.yml) The key (key) Set... By variable reference - i People in the Jianghu - Blog Garden

Set the configuration quantity through variable reference 【 value (value)】

stay YAML In file , A configuration quantity value You can set... By referring to another variable . for example ：

default-db:
  port: 3306

user-db:
  port: ${default-db.port}

however , If you want to set through variable reference key , adopt ${} It can't be done . for example ：

site:
  url:
    user: www.user.net
    shop: www.shop.net

site:
  slogan:
    ${site.url.user}: everyone is great!
    ${user.url.shop}: buy anything you want!

After reading the configuration into the program , You will find the above ${} quote , Not replaced with a real value .

Set the configuration amount through the anchor point reference 【 key (key)】

To replace keys , You need to use anchors . The anchor point is marked with “&” Definition , And use symbols “*” reference .
There are two ways to use anchors , One is to pass. “<<:” Introduce key value pairs into ：

default-db: &default-db-config
  host: 127.0.0.1
  port: 3306

user-db:
  <<: *default-db-config

The actual effect is as follows ：

default-db:
  host: 127.0.0.1
  port: 3306

user-db:
  host: 127.0.0.1
  port: 3306

explain ：& The following anchor name , You can define , It does not have to be the same as the key of the configuration quantity .

The other is Only the configured values are introduced ：

site:
  url:
    user: &site.user www.user.net
    shop: &site.shop www.shop.net

site:
  slogan:
    *site.user: everyone is great!
    *site.shop: buy anything you want!

The actual effect is as follows ：

site:
  url:
    user: www.user.net
    shop: www.shop.net

site:
  slogan:
    www.user.net: everyone is great!
    www.shop.net: buy anything you want!

explain ： use & When defining anchors , Notice the space before and after the anchor name .

Another example of introducing only values ：

color:
  - &red-color red
  - yellow
  - blue
  - *red-color
  - gray

The actual effect is as follows ：

color:
  - red
  - yellow
  - blue
  - red
  - gray

Reference documents ：

• YAML Language course
• yaml Of documents Anchor point & And quote *