Yaml Syntax

简略的过一下yaml语法

Syntax

键值对：并不像 json 需要括号，yaml 想 python 一样，仅用缩进就可以了，所以说 yaml 是一种适合人类阅读的标记语言

app: user-authentication
port: 9000
version: 1.7

字符串：我们可以用单引号，双括号或者不加引号。但是如果有转义符号，还是要加引号

str1: "string"
str2: 'string'
str3: string
str4: "Hello World\n"
long_string: |
    this is a single line string, thaat should be all one one line.
    some othher stuff.

注释：yaml 也是支持注释的，json 不支持

# 这是注释

对象：下面的microservice就是对象，app等等都是它的属性

microservice:
    app: user-authentication
    port: 9000
    version: 1.7

列表：加入横线，并列的就在一个列表里了。或者用[]也可以

microservice:
  - app: user-authentication
    port: 9000
    version: 1.7
  - app: shopping-cart
    port: 9002
    versions: [1.0, 2.0, 2.1]

布尔：true 或 false，yes 或 no，on 或 off

microservice:
  - app: user-authentication
    port: 9000
    version: 1.7
    deployed: true # false
    # deployed: yes / no
    # deployed: on / off

系统变量：$

command:
    - /bin/sh
    - -ec
    - >-
        mysql -h 127.0.0.1 -u root -p$MYSQL_ROT_PASSWORD$ -e 'SELECT 1'

占位符：{{}}，保留一个位置，让其他语言来进一步添加

app:
  name: My Application
  version: 1.0.0
  environment: {{ environment }}
  database:
    host: {{ db_host }}
    port: {{ db_port }}
    username: {{ db_username }}
    password: {{ db_password }}

api:
  base_url: {{ api_base_url }}
  timeout: {{ api_timeout }}

用 python 的 jinja2 动态地替换这些占位符：

from jinja2 import Template

# 读取 YAML 文件
with open("config.yaml", "r") as file:
    template_content = file.read()

# 创建模板
template = Template(template_content)

# 定义替换占位符的值
values = {
    "environment": "production",
    "db_host": "localhost",
    "db_port": "5432",
    "db_username": "admin",
    "db_password": "password123",
    "api_base_url": "https://api.example.com",
    "api_timeout": 30
}

# 渲染模板
rendered_content = template.render(values)

# 输出渲染后的内容
print(rendered_content)

app:
  name: My Application
  version: 1.0.0
  environment: production
  database:
    host: localhost
    port: 5432
    username: admin
    password: password123

api:
  base_url: https://api.example.com
  timeout: 30

文件分离（---）：比如 log 文件

---
Time: 2001-11-23 15:01:42 -5
User: ed
Warning:
  This is an error message
  for the log file
---
Time: 2001-11-23 15:02:31 -5
User: ed
Warning:
  A slightly different error
  message.
---
Date: 2001-11-23 15:03:17 -5
User: ed
Fatal:
  Unknown variable "bar"
Stack:
- file: TopClass.py
  line: 23
  code: |
    x = MoreObject("345\n")
- file: MoreClass.py
  line: 58
  code: |-
    foo = bar

Reference

[1] Yaml Tutorial | Learn YAML in 18 mins