jazzparser.utils.config

82 """ 83 A really simple interface to options stored in config files. 84 Can also process a string as if read from the contents of a file. 85 86 """

87 - def __init__(self, filename, string=False):

88 self.options = [] 89 self.flags = [] 90 self.arguments = [] 91 self.required_options = [] 92 93 if string: 94 # Take the config lines as a string directly 95 self.filename = None 96 self.lines = filename.split("\n") 97 else: 98 # Read config lines from a file 99 self.filename = filename 100 with open(self.filename, 'r') as cfile: 101 self.lines = cfile.readlines() 102 self.parse_lines()

103 104 @staticmethod

105 - def from_string(string):

106 return ConfigFile(string, string=True)

107

108 - def parse_lines(self):

109 """ 110 Parses the lines stored in self.lines. Called by initialization. 111 You can call this straight off if you've instantiated with a string. 112 113 """ 114 from jazzparser import settings 115 import os 116 117 conf_lines = self.lines 118 119 numbered_args = {} 120 defined_variables = {} 121 122 def _do_substitutions(value, full_line): 123 # Look for any placeholders in the value and perform the 124 # appropriate substitution 125 while "%{" in value: 126 opener = value.index("%{") 127 closer = value.find("}", opener) 128 if closer == -1: 129 # No matching close brace 130 raise ConfigFileReadError, "no matching close brace (}) found in %s" % full_line 131 const_name = value[opener+2:closer] 132 133 if const_name in defined_variables: 134 # First check whether a value is defined for this name 135 sub_value = defined_variables[const_name] 136 elif hasattr(settings, const_name): 137 # Try getting a constant from the settings file 138 sub_value = getattr(settings, const_name) 139 else: 140 raise ConfigFileReadError, "no setting or variable "\ 141 "'%s' found to make substitution in: %s" % \ 142 (const_name, full_line.strip()) 143 # Replace every occurrence of this placeholder with the value 144 value = value.replace("%{"+const_name+"}", sub_value) 145 return value

146 147 # Preprocess the lines 148 def _preprocess_lines(lines, included=False): 149 _proc_lines = [] 150 151 # Remove line breaks from the end 152 lines = [l.rstrip("\n") for l in lines] 153 # Concatenate lines where a \ precedes the line break 154 joined_lines = [] 155 to_join = [] 156 for line in lines: 157 if line.endswith("\\"): 158 to_join.append(line[:-1].lstrip()) 159 else: 160 if len(to_join) > 0: 161 to_join.append(line.lstrip()) 162 joined_lines.append("".join(to_join)) 163 to_join = [] 164 else: 165 joined_lines.append(line) 166 167 for line in joined_lines: 168 use_line = True 169 # Ignore anything after a # 170 if "#" in line: 171 line = line[:line.index("#")] 172 line = line.strip() 173 174 # Check for directives 175 if line.startswith("%%"): 176 # Eliminate this line from the preprocessed set 177 use_line = False 178 179 line = _do_substitutions(line[2:], line) 180 # Pull out the first word and make it case insensitive 181 directive = line.split()[0].strip().lower() 182 args = line.split()[1:] 183 # Check what the directive is a process the lines accordingly 184 if directive == "include": 185 if len(args) != 1: 186 raise ConfigFileReadError, "INCLUDE directive "\ 187 "requires a filename argument" 188 # Include another config file 189 if self.filename is None: 190 # Can't make paths relative to filename 191 filename = args[0] 192 else: 193 filename = os.path.join( 194 os.path.dirname(self.filename), 195 args[0]) 196 filename = os.path.abspath(filename) 197 try: 198 file = open(filename, 'r') 199 except IOError: 200 raise ConfigFileReadError, "could not open "\ 201 "included config file %s" % filename 202 203 try: 204 # Replace this line with the lines of the other file 205 file_lines = _preprocess_lines(file.readlines(), included=True) 206 _proc_lines.extend(file_lines) 207 finally: 208 file.close() 209 elif directive == "arg": 210 if len(args) != 2: 211 raise ConfigFileReadError, "ARG directive "\ 212 "requires an argument number and a value" 213 arg_num = int(args[0]) 214 numbered_args[arg_num] = args[1] 215 elif directive == "def": 216 if len(args) != 2: 217 raise ConfigFileReadError, "DEF directive "\ 218 "requires a variable name and a value" 219 defined_variables[args[0]] = args[1] 220 elif directive == "abstract": 221 if not included: 222 # The file isn't being read because it's included 223 # in another, but it's marked as abstract, so 224 # shouldn't be used directly 225 raise ConfigFileReadError, "encountered ABSTRACT "\ 226 "directive in a non-included file. You should "\ 227 "not use this file directly, but as an include "\ 228 "in another config file." 229 elif directive == "require": 230 if len(args) != 1: 231 raise ConfigFileReadError, "REQUIRE directive "\ 232 "needs an option name" 233 self.required_options.append(args[0]) 234 # Define any more directives here 235 else: 236 raise ConfigFileReadError, "unknown directive: %s" % directive 237 238 if use_line and len(line) > 0: 239 _proc_lines.append(line) 240 return _proc_lines

280 """ 281 An alternative to calling parser.parse_args() which adds a --config 282 option to the parser's options and uses it to read in a config 283 file if it's given. 284 285 The args will potentially get parsed twice: once to get the config 286 file and then again to incorporate options from the file. 287 288 @return: (options, arguments) tuple, as given by parser.parse_args(). 289 290 """ 291 import sys 292 # Add the config file option 293 parser.add_option("--%s" % option_name, dest="%s" % option_name, action="store", help="read options in from a config file.") 294 # Do the initial (standard) parse 295 options,arguments = parser.parse_args() 296 297 conf_file = getattr(options, option_name) 298 if conf_file is not None: 299 # Read in options from the config file 300 conf = ConfigFile(conf_file) 301 # Check that any options the file requires the user to give are there 302 for required in conf.required_options: 303 if not hasattr(options, required): 304 raise ConfigFileReadError, "config file requires non-existent "\ 305 "command line option '%s'" % required 306 elif getattr(options, required) is None: 307 print "Error: config file requires that you "\ 308 "give the option '%s' on the command line" % required 309 sys.exit(1) 310 # Produce arguments that incorporate the file and cmd-line opts 311 conf_strings = conf.get_strings() 312 if len(conf_strings) > 0: 313 # Parse the opts and args from the config file first 314 options, file_arguments = parser.parse_args(args=conf_strings) 315 # Reparse the command line options so that values given there 316 # override those in the file 317 options, cl_arguments = parser.parse_args(values=options) 318 # Include arguments from both sources, file first 319 arguments = file_arguments + cl_arguments 320 return options,arguments

Source Code for Module jazzparser.utils.config