Initial commit of a log capture and reporting feature

This adds a new section to the admin panel called "Activity", that
supplies charts, graphs and details about messages entering and leaving
the host.

A new daemon captures details of system mail activity by monitoring
the /var/log/mail.log file, summarizing it into a sqllite database
that's kept in user-data.

management/reporting/capture/mail/PostfixLogParser.py

@@ -0,0 +1,125 @@
+
+class PostfixLogParser(object):
+
+    @staticmethod
+    def split_host(str):
+        ''' split string in form HOST[IP] and return HOST and IP '''
+        ip_start = str.find('[')
+        ip_end = -1
+        if ip_start>=0:
+            ip_end = str.find(']', ip_start)
+            if ip_start<0 or ip_end<0:
+                return str, str
+            return str[0:ip_start], str[ip_start+1:ip_end]
+
+    @staticmethod
+    def strip_brackets(str, bracket_l='<', bracket_r='>'):
+        # strip enclosing '<>'
+        if len(str)>=2 and str[0]==bracket_l and str[-1]==bracket_r:
+            return str[1:-1]
+        return str
+
+
+    class SplitList(object):
+        ''' split a postfix name=value list. For example:
+
+        "delay=4.7, to=<alice@post.com>, status=sent (250 2.0.0 <user@domain.tld> YB5nM1eS01+lSgAAlWWVsw Saved)"
+
+        returns: {
+           "delay": {
+                "name": "delay",
+                "value": "4.7"
+           },
+           "to": {
+                "name": "to",
+                "value": "alice@post.com"
+           },
+           "status": {
+                "name": "status",
+                "value": "sent",
+                "comment": "250 2.0.0 <user@domain.tld> YB5nM1eS01+lSgAAlWWVsw Saved"
+           }
+        }
+
+        '''
+        def __init__(self, str, delim=',', strip_brackets=True):
+            self.str = str
+            self.delim = delim
+            self.strip_brackets = True
+            self.pos = 0
+
+        def asDict(self):
+            d = {}
+            for pair in self:
+                d[pair['name']] = pair
+            return d
+
+        def __iter__(self):
+            self.pos = 0
+            return self
+
+        def __next__(self):
+            if self.pos >= len(self.str):
+                raise StopIteration
+
+            # name
+            eq = self.str.find('=', self.pos)
+            if eq<0:
+                self.pos = len(self.str)
+                raise StopIteration
+
+            name = self.str[self.pos:eq].strip()
+
+            # value and comment
+            self.pos = eq+1
+            value = []
+            comment = []
+
+            while self.pos < len(self.str):
+                c = self.str[self.pos]
+                self.pos += 1
+
+                if c=='<':
+                    idx = self.str.find('>', self.pos)
+                    if idx>=0:
+                        value.append(self.str[self.pos-1:idx+1])
+                        self.pos = idx+1
+                        continue
+
+                if c=='(':
+                    # parens may be nested...
+                    open_count = 1
+                    begin = self.pos
+                    while self.pos < len(self.str) and open_count>0:
+                        c = self.str[self.pos]
+                        self.pos += 1
+                        if c=='(':
+                            open_count += 1
+                        elif c==')':
+                            open_count -= 1
+                    if open_count == 0:
+                        comment.append(self.str[begin:self.pos-1])
+                    else:
+                        comment.append(self.str[begin:len(self.str)])
+                    continue
+
+                if c==self.delim:
+                    break
+
+                begin = self.pos-1
+                while self.pos < len(self.str):
+                    lookahead = self.str[self.pos]
+                    if lookahead in [self.delim,'<','(']:
+                        break
+                    self.pos += 1
+
+                value.append(self.str[begin:self.pos])
+
+            if self.strip_brackets and len(value)==1:
+                value[0] = PostfixLogParser.strip_brackets(value[0])
+
+            return {
+                'name': name,
+                'value': ''.join(value),
+                'comment': None if len(comment)==0 else '; '.join(comment)
+            }