'yaml.parser.ParserError:预期'<document start>',但发现'<block mapping start>''是什么意思？

Question

我有以下 YAML 文件：

[mysqld]
user: "mysql"
pid-file: /var/run/mysqld/mysqld.pid
skip-external-locking
old_passwords: 1
skip-bdb
skip-innodb
create_key: yes
needs_agent: no
knows_oop: True
likes_emacs: TRUE
women:
    - Mary Smith
    - Susan Williams

以及以下Python代码：

#!/usr/bin/env python

import yaml


with open("config.yml") as f:
    sample_config = f.read()

print(yaml.load(sample_config))

但它给了我：

Traceback (most recent call last):
  File "/home/moose/Desktop/bla.py", line 9, in <module>
    print(yaml.load(sample_config))
  File "/usr/local/lib/python2.7/dist-packages/yaml/__init__.py", line 71, in load
    return loader.get_single_data()
  File "/usr/local/lib/python2.7/dist-packages/yaml/constructor.py", line 37, in get_single_data
    node = self.get_single_node()
  File "/usr/local/lib/python2.7/dist-packages/yaml/composer.py", line 39, in get_single_node
    if not self.check_event(StreamEndEvent):
  File "/usr/local/lib/python2.7/dist-packages/yaml/parser.py", line 98, in check_event
[Finished in 0.1s with exit code 1]
[shell_cmd: python -u "/home/moose/Desktop/bla.py"]
[dir: /home/moose/Desktop]
[path: /usr/local/texlive/2013/bin/x86_64-linux:/home/moose/google-cloud-sdk/bin:/home/moose/Downloads/google_appengine:/usr/local/texlive/2013/bin/x86_64-linux:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games]    self.current_event = self.state()
  File "/usr/local/lib/python2.7/dist-packages/yaml/parser.py", line 174, in parse_document_start
    self.peek_token().start_mark)
yaml.parser.ParserError: expected '<document start>', but found '<block mapping start>'
  in "<string>", line 2, column 1:
    user: "mysql"

我不知道什么

expected '<document start>', but found '<block mapping start>'

的含义以及如何修复它。什么是

<document start>

，什么是

<block mapping start>

？

Answer 1

您的文件不是有效的 YAML。它看起来像是 YAML 和 INI 文件 的混合。

• 您无法在 YAML 中定义类似

  [mysql]

  的块。如果要定义相关属性的集合，请使用带有嵌套键的列表：

  - service:
      name: mysql
      type: database
      port: 3306
  - service:
      name: ssh
      type: remote access
      port: 22
  

• 你不能有像

  skip-external-locking

  这样的裸词。每个属性都需要一个值。请改用

  skip-external-locking: true

  。

这是已修复语法错误的文档版本。我使用 YAMLLint 检查了这一点，这是一个用于验证 YAML 的便捷工具。

name: mysqld
user: mysql
pid-file: /var/run/mysqld/mysqld.pid
skip-external-locking: true
old_passwords: 1
skip-bdb: true
skip-innodb: true
create_key: yes
needs_agent: no
knows_oop: True
likes_emacs: TRUE
women:
    - Mary Smith
    - Susan Williams

Answer 2

对于 Java Spring 开发人员，您需要检查您的 yaml 文件。确保缩进正确。