metayaml-ng 1.2

安装

Meta Yaml在PyPI中，因此可以直接使用以下命令安装

$ pip install metayaml

或从BitBucket

$ git clone https://bitbucket.org/atagunov/metayaml
$ cd metayaml
$ python setup.py install

文档

文档（如有）可在以下网址找到：https://bitbucket.org/atagunov/metayaml

使用方法

from metayaml import read
read(["config.yaml",
      "test.yaml"],
     {'join': os.path.join, # allows get right os specific path in yaml file
      'env': os.environ}  # allows use system environments from yaml file
    )

config.yaml

extend:
  - ${join(env["HOME"], ".metayaml", "localconfig.yaml")} # added reading local config from $HOME
user_name: ${env["USER"]}
email: ${user_name + "@example.com"}
debug: false

test.yaml

debug: true

替换顺序

替换是按照文件中的值进行的。例如，以下示例将失败

B: ${A+1}     <--- A is not defined here
AA: ${B}
A: 1

但以下结果正常

A: 1
B: ${A+1}
AA: ${B}

更改合并行为

默认情况下，可以在字典中添加新键并替换列表。在某些情况下，需要从基本文件中删除键或向列表中添加一些值。例如

base.yaml:

main:
    iso_3166:
      China: CN
      Honduras: HN
      Madagascar: MG

    country_codes:
      - CN
      - HN
      - MG

    country_codes_3:
      - CHN
      - HND
      - MDG

last.yaml:

extend:
  - base.yaml
main:
  iso_3166:
     China: ${__del__}  #  key 'China' will be removed from the result
     Liberia: LR  # add new key

  country_codes:
     - LR         # after merge country_codes contains only one element.

  country_codes_3:
    ${__extend__}:
      - LBR       # the result list is ["CHN", "HND", "MDG", "LBR"]

代码的结果

d = read("last.yaml")
print d

{
    "main": {
        "iso_3166": {
            "Honduras": "HN",
            "Madagascar": "MG",
            "Liberia": "LR"
        },
        "country_codes": [
            "LR"
        ],
        "country_codes_3": [
            "CHN",
            "HND",
            "MDG",
            "LBR"
        ]
    }
}

复制方法

存在一个名为‘cp’的方法，可以扩展性地复制字典/列表

cron:
  daily:
    min: 0
    hour: 0

  monthly:
    min: 0
    hour: 0
    day: 1

schedule:
  nighttask: ${cp(cron.daily, min=5)}  # min will be replaced to 5
  #  min: 5
  #  hour: 0
  daytask: ${cp(cron.daily, min=7, hour=13)} # min and hour are replaced
  #  min: 7
  #  hour: 13
  monthtask: ${cp(cron.monthly, day=2)}
  #  min: 0
  #  hour: 0
  #  day: 2

deploy:
  subnets:
    - 1.1.1.1
    - 2.2.2.2

  base_elb:
    - 4.4.4.4
    - 5.5.5.5

  elb: ${cp(deploy.subnets, "3.3.3.3", *deploy.base_elb)}
  # - 1.1.1.1
  # - 2.2.2.2
  # - 3.3.3.3
  # - 4.4.4.4
  # - 5.5.5.5

继承方法

还有另一种复制现有字典并更新一些字段的方法

foo:
  bar:
    baz: 1
    buz: 2
    foobar: 3
  foobar: [4, 5]

bar:
  ${__inherit__}: foo.bar  # bar will be replaces by content of for.bar
  buz: 33

# the result value of 'bar' will be
#    baz: 1
#    buz: 33
#    foobar: 3

许可证

MetaYaml是在MIT许可证下发布的。