使用pyparsing将lvm.conf转换为python dict

我正在尝试将lvm.conf转换为python（类似JSON）对象。 LVM（逻辑卷管理）配置文件如下所示：

# Configuration section config.
# How LVM configuration settings are handled.
config {

    # Configuration option config/checks.
    # If enabled, any LVM configuration mismatch is reported.
    # This implies checking that the configuration key is understood by
    # LVM and that the value of the key is the proper type. If disabled,
    # any configuration mismatch is ignored and the default value is used
    # without any warning (a message about the configuration key not being
    # found is issued in verbose mode only).
    checks = 1

    # Configuration option config/abort_on_errors.
    # Abort the LVM process if a configuration mismatch is found.
    abort_on_errors = 0

    # Configuration option config/profile_dir.
    # Directory where LVM looks for configuration profiles.
    profile_dir = "/etc/lvm/profile"
}


local {
}
log {
    verbose=0
    silent=0
    syslog=1
    overwrite=0
    level=0
    indent=1
    command_names=0
    prefix="  "
    activation=0
    debug_classes=["memory","devices","activation","allocation","lvmetad","metadata","cache","locking","lvmpolld","dbus"]
}

{ "section_name"": 
{"value1" : 1,
 "value2" : "some_string",
 "value3" : [list, of, strings]}... and so on.}

我想得到Python dict，如下所示：

# Configuration section config.
# How LVM configuration settings are handled.
config {

    # Configuration option config/checks.
    # If enabled, any LVM configuration mismatch is reported.
    # This implies checking that the configuration key is understood by
    # LVM and that the value of the key is the proper type. If disabled,
    # any configuration mismatch is ignored and the default value is used
    # without any warning (a message about the configuration key not being
    # found is issued in verbose mode only).
    checks = 1

    # Configuration option config/abort_on_errors.
    # Abort the LVM process if a configuration mismatch is found.
    abort_on_errors = 0

    # Configuration option config/profile_dir.
    # Directory where LVM looks for configuration profiles.
    profile_dir = "/etc/lvm/profile"
}


local {
}
log {
    verbose=0
    silent=0
    syslog=1
    overwrite=0
    level=0
    indent=1
    command_names=0
    prefix="  "
    activation=0
    debug_classes=["memory","devices","activation","allocation","lvmetad","metadata","cache","locking","lvmpolld","dbus"]
}

{ "section_name"": 
{"value1" : 1,
 "value2" : "some_string",
 "value3" : [list, of, strings]}... and so on.}

解析器函数：

def parseLvmConfig2(path="/etc/lvm/lvm.conf"):
    try:
        EQ, LBRACE, RBRACE, LQ, RQ = map(pp.Suppress, "={}[]")
        comment = pp.Suppress("#") + pp.Suppress(pp.restOfLine)
        configSection = pp.Word(pp.alphas + "_") + LBRACE
        sectionKey = pp.Word(pp.alphas + "_")
        sectionValue = pp.Forward()
        entry = pp.Group(sectionKey + EQ + sectionValue)
        real = pp.Regex(r"[+-]?\d+\.\d*").setParseAction(lambda x: float(x[0]))
        integer = pp.Regex(r"[+-]?\d+").setParseAction(lambda x: int(x[0]))
        listval = pp.Regex(r'(?:\[)(.*)?(?:\])').setParseAction(lambda x: eval(x[0]))

        pp.dblQuotedString.setParseAction(pp.removeQuotes)

        struct = pp.Group(pp.ZeroOrMore(entry) + RBRACE)
        sectionValue << (pp.dblQuotedString | real | integer | listval)
        parser = pp.ZeroOrMore(configSection + pp.Dict(struct))
        res = parser.parseFile(path)
        print(res)
    except (pp.ParseBaseException, ) as e:
        print("lvm.conf bad format {0}".format(e))

def parseLvmConfig2（path=“/etc/lvm/lvm.conf”）：
尝试：
等式，LBRACE，RBRACE，LQ，RQ=map（pp.Suppress，“={}[]”）
comment=pp.Suppress（“#”）和pp.Suppress（pp.restOfLine）
configSection=pp.Word（pp.alphas+“”）+LBRACE
sectionKey=pp.Word（pp.alphas+“389;”）
sectionValue=pp.Forward（）
条目=pp.Group（sectionKey+EQ+sectionValue）
real=pp.Regex（r“[+-]？\d+\.\d*”）.setParseAction（lambda x:float（x[0]））
整数=pp.Regex（r“[+-]？\d+”）.setParseAction（lambda x:int（x[0]））
listval=pp.Regex（r'（？：\[）（.*）（？：\]））.setParseAction（lambda x:eval（x[0]））
pp.dblQuotedString.setParseAction（pp.removeQuotes）
struct=pp.Group（pp.ZeroOrMore（条目）+RBRACE）
sectionValue步骤1应始终至少为您要解析的格式粗略绘制一个BNF。这确实有助于组织您的想法，并让您在开始编写实际代码之前考虑正在解析的结构和数据

下面是我为这个配置提供的一个BNF（它看起来像一个Python字符串，因为这样可以很容易地粘贴到代码中供将来参考-但是pyparsing不使用或需要这样的字符串，它们纯粹是一个设计工具）：

请注意，开始和结束{}和[]处于同一级别，而不是在一个表达式中有一个开始符，在另一个表达式中有一个结束符

这个BNF还允许嵌套在structs中的structs，这在您发布的示例文本中不是严格要求的，但是由于您的代码似乎支持这一点，所以我将其包括在内

从这里到pyparsing的转换非常简单，通过BNF自下而上：

EQ, LBRACE, RBRACE, LQ, RQ = map(pp.Suppress, "={}[]")
comment = "#" + pp.restOfLine

integer = ppc.integer  #pp.Regex(r"[+-]?\d+").setParseAction(lambda x: int(x[0]))
real = ppc.real  #pp.Regex(r"[+-]?\d+\.\d*").setParseAction(lambda x: float(x[0]))
pp.dblQuotedString.setParseAction(pp.removeQuotes)
scalar_value = real | integer | pp.dblQuotedString

# `delimitedList(expr)` is a shortcut for `expr + ZeroOrMore(',' + expr)`
list_value = pp.Group(LQ + pp.delimitedList(scalar_value) + RQ)

key = pp.Word(pp.alphas + "_", pp.alphanums + '_')
key_value = pp.Group(key + EQ + (scalar_value | list_value))

struct = pp.Forward()
entry = key_value | pp.Group(key + struct)
struct <<= (LBRACE + pp.ZeroOrMore(entry) + RBRACE)
parser = pp.ZeroOrMore(entry)
parser.ignore(comment)

提供此嵌套列表：

[['config',
  ['checks', 1],
  ['abort_on_errors', 0],
  ['profile_dir', '/etc/lvm/profile']],
 ['local'],
 ['log',
  ['verbose', 0],
  ['silent', 0],
  ['syslog', 1],
  ['overwrite', 0],
  ['level', 0],
  ['indent', 1],
  ['command_names', 0],
  ['prefix', '  '],
  ['activation', 0],
  ['debug_classes',
   ['memory',
    'devices',
    'activation',
    'allocation',
    'lvmetad',
    'metadata',
    'cache',
    'locking',
    'lvmpolld',
    'dbus']]]]

我认为您更喜欢的格式是，您可以在嵌套dict或层次对象中以键的形式访问值。Pyparsing有一个名为Dict的类，该类将在解析时执行此操作，以便自动为嵌套的子组分配结果名称。将这两行更改为自动口述其子条目：

struct <<= pp.Dict(LBRACE + pp.ZeroOrMore(entry) + RBRACE)
parser = pp.Dict(pp.ZeroOrMore(entry))

然后，您可以访问字段作为
res['config']['checks']
或
res.log.indent
您说“如何使
pyparsing
执行该工作”-确切地说，执行什么工作？我已经提到了它-作为输出Python dict对象，现在它是解析结果的列表，我不知道如何使用pyparsing将其与dict相结合（如果可能的话？）？
struct <<= pp.Dict(LBRACE + pp.ZeroOrMore(entry) + RBRACE)
parser = pp.Dict(pp.ZeroOrMore(entry))

[['config', ['checks', 1], ['abort_on_errors', 0], ['profile_dir', '/etc/lvm/profile']], ['local'], ['log', ['verbose', 0], ['silent', 0], ['syslog', 1], ['overwrite', 0], ['level', 0], ['indent', 1], ['command_names', 0], ['prefix', '  '], ['activation', 0], ['debug_classes', ['memory', 'devices', 'activation', 'allocation', 'lvmetad', 'metadata', 'cache', 'locking', 'lvmpolld', 'dbus']]]]
- config: [['checks', 1], ['abort_on_errors', 0], ['profile_dir', '/etc/lvm/profile']]
  - abort_on_errors: 0
  - checks: 1
  - profile_dir: '/etc/lvm/profile'
- local: ''
- log: [['verbose', 0], ['silent', 0], ['syslog', 1], ['overwrite', 0], ['level', 0], ['indent', 1], ['command_names', 0], ['prefix', '  '], ['activation', 0], ['debug_classes', ['memory', 'devices', 'activation', 'allocation', 'lvmetad', 'metadata', 'cache', 'locking', 'lvmpolld', 'dbus']]]
  - activation: 0
  - command_names: 0
  - debug_classes: ['memory', 'devices', 'activation', 'allocation', 'lvmetad', 'metadata', 'cache', 'locking', 'lvmpolld', 'dbus']
  - indent: 1
  - level: 0
  - overwrite: 0
  - prefix: '  '
  - silent: 0
  - syslog: 1
  - verbose: 0