bin/mtail.py

   1 #!/usr/bin/env python
   2
   3 '''
   4 Does tail -f on log files in a given directory.
   5 The display is in chronological order of the logged lines,
   6 given that the first column of log files is timestamp.
   7 It can be altered to fit other formats too
   8 '''
   9
  10 import os, sys, time
  11 import select
  12 import sys, tty, termios
  13
  14 from optparse import OptionParser
  15
  16 class mtail:
  17
  18     default_time_format = "%H:%M:%S"
  19
  20     def __init__ (self, args ):
  21
  22         # internal structure for tracking changes
  23         self.files = {}
  24         # parse command-line args : will set options and args
  25         self.parse_args(args)
  26         # initialize
  27         self.scan_files()
  28
  29     def parse_args (self, args):
  30         usage = """usage: %prog [options] file-or-dir ...
  31 example:
  32 # %prog -e '*access*' /var/log"""
  33         parser=OptionParser(usage=usage)
  34         # tail_period
  35         parser.add_option("-p","--period", type="int", dest="tail_period", default=1,
  36                           help="Files check period in seconds")
  37         # rescan_period
  38         parser.add_option("-d","--dir-period", type="int", dest="rescan_period", default=5,
  39                           help="Directories rescan period in seconds")
  40         # time format
  41         parser.add_option("-f","--format", dest="time_format", default=mtail.default_time_format,
  42                           help="Time format, defaults to " + mtail.default_time_format)
  43         # show time
  44         parser.add_option("-r","--raw", action="store_true", dest="show_time", default=True,
  45                           help="Suppresses time display")
  46
  47         # note for exclusion patterns
  48         parser.add_option("-e","--exclude", action="append", dest="excludes", default=[],
  49                           help="Exclusion pattern  -- can be specified multiple times applies on files not explicitly mentioned on the command-line")
  50
  51         parser.add_option("-u","--usual",action="store_true",dest="plc_mode",default=False,
  52                           help="Shortcut for watching /var/log with default settings")
  53         parser.add_option("-s","--sfa",action="store_true",dest="sfa_mode",default=False,
  54                           help="Shortcut for monitoring server-side SFA log files")
  55
  56         # verbosity
  57         parser.add_option("-v","--verbose", action="store_true", dest="verbose", default=False,
  58                           help="Run in verbose mode")
  59
  60         (self.options, self.args) = parser.parse_args(args)
  61         self.option_parser = parser
  62
  63         ### plc shortcuts
  64         if self.options.plc_mode:
  65             # monitor all files in /var/log with some exceptions
  66             self.options.excludes.append('*access_log')
  67             self.options.excludes.append('*request_log')
  68             self.options.excludes.append('*.swp')
  69             self.args.append('/var/log')
  70             # watch the postgresql logs as well
  71             self.args.append('/var/lib/pgsql/data/pg_log')
  72
  73         if self.options.sfa_mode:
  74             self.args.append("/var/log/sfa.log")
  75             self.args.append("/var/log/sfa_import.log")
  76             self.args.append("/var/log/httpd/sfa_access_log")
  77
  78         if self.options.verbose:
  79             print 'Options:',self.options
  80             print 'Arguments:',self.args
  81
  82     def file_size (self,filename):
  83         try:
  84             return os.stat(filename)[6]
  85         except:
  86             print "WARNING: file %s has vanished"%filename
  87             return 0
  88
  89     def number_files (self):
  90         return len(self.files)
  91
  92     # scans given arguments, and updates files accordingly
  93     # can be run several times
  94     def scan_files (self) :
  95
  96         if self.options.verbose:
  97             print 'entering scan_files, files=',self.files
  98
  99         # mark entries in files as pre-existing
 100         for key in self.files:
 101             self.files[key]['old-file']=True
 102
 103         # refreshes the proper set of filenames
 104         filenames = []
 105         for arg in self.args:
 106             if self.options.verbose:
 107                 print 'scan_files -- Considering arg',arg
 108             if os.path.isfile (arg):
 109                 filenames += [ arg ]
 110             elif os.path.isdir (arg) :
 111                 filenames += self.walk (arg)
 112             else:
 113                 print "mtail : no such file or directory %s -- ignored"%arg
 114
 115         # updates files
 116         for filename in filenames :
 117             # known file
 118             if self.files.has_key(filename):
 119                 size = self.file_size(filename)
 120                 offset = self.files[filename]['size']
 121                 if size > offset:
 122                     self.show_file_end(filename,offset,size)
 123                     self.files[filename]['size']=size
 124                 elif size < offset:
 125                     self.show_file_when_size_decreased(filename,offset,size)
 126                 try:
 127                     del self.files[filename]['old-file']
 128                 except:
 129                     pass
 130             else:
 131                 # enter file with current size
 132                 # if we didn't set format yet, it's because we are initializing
 133                 try:
 134                     self.format
 135                     self.show_now()
 136                     print self.format%filename,"new file"
 137                     self.show_file_end(filename,0,self.file_size(filename))
 138                 except:
 139                     pass
 140                 self.files[filename]={'size':self.file_size(filename)}
 141
 142         # cleanup
 143         # avoid side-effects on the current loop basis
 144         read_filenames = self.files.keys()
 145         for filename in read_filenames:
 146             if self.files[filename].has_key('old-file'):
 147                 self.show_now()
 148                 print self.format%filename,"file has gone"
 149                 del self.files[filename]
 150
 151         # compute margin and format
 152         if not filenames:
 153             print sys.argv[0],": WARNING : no file in scope"
 154             self.format="%s"
 155         else:
 156             if len(filenames)==1:
 157                 self.margin=len(filenames[0])
 158             else:
 159                 # this stupidly fails when there's only 1 file
 160                 self.margin=max(*[len(f) for f in filenames])
 161             self.format="%%%ds"%self.margin
 162             if self.options.verbose:
 163                 print 'Current set of files:',filenames
 164
 165     def tail_files (self):
 166
 167         if self.options.verbose:
 168             print 'tail_files'
 169         for filename in self.files:
 170             size = self.file_size(filename)
 171             offset = self.files[filename]['size']
 172             if size != offset:
 173                 self.show_file_end(filename,offset,size)
 174                 self.files[filename]['size']=size
 175
 176     def show_now (self):
 177         if self.options.show_time:
 178             label=time.strftime(self.options.time_format,time.localtime())
 179             print label,
 180
 181     def show_file_end (self, filename, offset, size):
 182         try:
 183             file = open(filename,"r")
 184         # file has vanished
 185         except:
 186             return
 187         file.seek(offset)
 188         line=file.read(size-offset)
 189         self.show_now()
 190         print self.format%filename,'----------------------------------------'
 191         print line
 192         file.close()
 193
 194     def show_file_when_size_decreased (self, filename, offset, size):
 195         print self.format%filename,'---------- file size decreased ---------',
 196         if self.options.verbose:
 197             print 'size during last check',offset,'current size',size
 198         else:
 199             print ''
 200
 201     # get all files under a directory
 202     def walk ( self, root ):
 203         import fnmatch, os, string
 204
 205         # initialize
 206         result = []
 207
 208         # must have at least root folder
 209         try:
 210             names = os.listdir(root)
 211         except os.error:
 212             return result
 213
 214         # check each file
 215         for name in names:
 216             fullname = os.path.normpath(os.path.join(root, name))
 217
 218             # a file : check for excluded, otherwise append
 219             if os.path.isfile(fullname):
 220                 try:
 221                     for exclude in self.options.excludes:
 222                         if fnmatch.fnmatch(name, exclude):
 223                             raise Exception('excluded')
 224                     result.append(fullname)
 225                 except:
 226                     pass
 227             # a dir : let's recurse - avoid symlinks for anti-loop
 228             elif os.path.isdir(fullname) and not os.path.islink(fullname):
 229                 result = result + self.walk( fullname )
 230
 231         return result
 232
 233     def run (self):
 234
 235         if len(self.args) == 0:
 236             self.option_parser.print_help()
 237             sys.exit(1)
 238         counter = 0
 239
 240         fdin = sys.stdin.fileno()
 241         while True:
 242             ## hit the period ?
 243             # dont do this twice at startup
 244             if (counter !=0 and counter % self.options.rescan_period == 0):
 245                 self.scan_files()
 246
 247             if (counter % self.options.tail_period == 0):
 248                 self.tail_files()
 249
 250             time.sleep(1)
 251             counter += 1
 252             # react on some keys - rough but convenient
 253             if os.isatty(fdin):
 254                 # read stdin
 255                 typed=[]
 256                 while select.select([sys.stdin,],[],[],0.0)[0]:
 257                     typed.append(sys.stdin.read(1))
 258 #                print 'found chars',typed
 259                 for char in typed:
 260                     if char.lower() in ['l']: os.system("clear")
 261                     elif char.lower() in ['m']:
 262                         for i in range(3) : print 60 * '='
 263                     elif char.lower() in ['q']: sys.exit(0)
 264                     elif char.lower() in ['h']:
 265                         print """l: refresh page
 266 m: mark
 267 q: quit
 268 h: help"""
 269
 270 ###
 271 if __name__ == '__main__':
 272     mtail (sys.argv[1:]).run()