I'm trying to convert lvm.conf to python (JSON like) object. LVM (Logical Volume Management) configuration file looks like this:
# 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"]
}
I'd like to get Python dict, like this:
{ "section_name"":
{"value1" : 1,
"value2" : "some_string",
"value3" : [list, of, strings]}... and so on.}
The parser function:
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))
The result is messy and the question is, how to make pyparsing do the job, without additional logic?
UPDATE(SOLVED):
For anyone who wants to understand pyparsing better, please check @PaulMcG explanation below. (Thanks for pyparsing, Paul! )
import pyparsing as pp
def parseLvmConf(conf="/etc/lvm/lvm.conf", res_type="dict"):
EQ, LBRACE, RBRACE, LQ, RQ = map(pp.Suppress, "={}[]")
comment = "#" + pp.restOfLine
integer = pp.nums
real = pp.Word(pp.nums + "." + pp.nums)
pp.dblQuotedString.setParseAction(pp.removeQuotes)
scalar_value = real | integer | pp.dblQuotedString
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 <<= pp.Dict(LBRACE + pp.ZeroOrMore(entry) + RBRACE)
parser = pp.Dict(pp.ZeroOrMore(entry))
parser.ignore(comment)
try:
#return lvm.conf as dict
if res_type == "dict":
return parser.parseFile(conf).asDict()
# return lvm.conf as list
elif res_type == "list":
return parser.parseFile(conf).asList()
else:
#return lvm.conf as ParseResults
return parser.parseFile(conf)
except (pp.ParseBaseException,) as e:
print("lvm.conf bad format {0}".format(e))
