import os
import sys
import re

sys.path.append('/home/users/jpa/remtemp/lib/python2.3/site-packages/')
import rrdtool

rrdpath = '/home/users/jpa/remtemp/rrds/'

def update(name, quantity, samples):
    'Samples is a list of tuples (time, value)'
    
    print 'U', name, quantity, samples

    if not samples:
        return
    
    if not quantity.isalnum():
        raise Exception('Invalid characters in quantity')
    path = rrdpath + os.path.basename(name) + '.rrd'
    
    try:
        rrdtool.update(path, "-t" + quantity, *['%d:%f' % s for s in samples])
    except rrdtool.error, info:
        print str(info)
        
        # Automatic recovery for the most common problem
        results = re.findall('illegal attempt to update using time ([0-9]+) when last update time is', str(info))
        
        if results:
            print "Filtering for", results
            oldsamples = len(samples)
            for r in results:
                time = int(r) # Timestamp of the duplicate entry
                samples = filter(lambda s: s[0] != time, samples)

            if oldsamples == len(samples):
                raise # Nothing was removed, so the message was false (don't recurse infinitely)
            
            update(name, quantity, samples)
        else:
            # Some other error
            raise