Switch to python f-strings and autopep

pyheadermilter/__init__.py

@@ -13,7 +13,6 @@
 #
 
 __all__ = ["HeaderRule", "HeaderMilter"]
-name = "pyheadermilter"
 
 import Milter
 import argparse
@@ -34,7 +33,8 @@ from netaddr import IPAddress, IPNetwork, AddrFormatError
 class HeaderRule:
     """HeaderRule to implement a rule to apply on e-mail headers."""
 
-    def __init__(self, name, action, header, search="", value="", ignore_hosts=[], ignore_envfrom=None, only_hosts=[], log=True):
+    def __init__(self, name, action, header, search="", value="",
+                 ignore_hosts=[], ignore_envfrom=None, only_hosts=[], log=True):
         self.logger = logging.getLogger(__name__)
         self.name = name
         self.action = action
@@ -49,38 +49,46 @@ class HeaderRule:
         if action in ["del", "mod"]:
             # compile header regex
             try:
-                self.header = re.compile(header, re.MULTILINE + re.DOTALL + re.IGNORECASE)
+                self.header = re.compile(
+                    header, re.MULTILINE + re.DOTALL + re.IGNORECASE)
             except re.error as e:
-                raise RuntimeError("unable to parse option 'header' of rule '{}': {}".format(name, e))
+                raise RuntimeError(
+                    f"unable to parse option 'header' of rule '{name}': {e}")
 
             if action == "mod":
                 # compile search regex
                 try:
-                    self.search = re.compile(search, re.MULTILINE + re.DOTALL + re.IGNORECASE)
+                    self.search = re.compile(
+                        search, re.MULTILINE + re.DOTALL + re.IGNORECASE)
                 except re.error as e:
-                    raise RuntimeError("unable to parse option 'search' of rule '{}': {}".format(name, e))
+                    raise RuntimeError(
+                        f"unable to parse option 'search' of rule '{name}': {e}")
 
         if action in ["add", "mod"] and not value:
             raise RuntimeError("value of option 'value' is empty")
 
-        # replace strings in ignore_hosts and only_hosts with IPNetwork instances
+        # replace strings in ignore_hosts and only_hosts with IPNetwork
+        # instances
         try:
             for index, ignore in enumerate(ignore_hosts):
                 self.ignore_hosts[index] = IPNetwork(ignore)
         except AddrFormatError as e:
-            raise RuntimeError("unable to parse option 'ignore_hosts' of rule '{}': {}".format(name, e))
+            raise RuntimeError(
+                f"unable to parse option 'ignore_hosts' of rule '{name}': {e}")
 
         if self.ignore_envfrom:
             try:
                 self.ignore_envfrom = re.compile(ignore_envfrom, re.IGNORECASE)
             except re.error as e:
-                raise RuntimeError("unable to parse option 'ignore_envfrom' of rule '{}': {}".format(name, e))
+                raise RuntimeError(
+                    f"unable to parse option 'ignore_envfrom' of rule '{name}': {e}")
 
         try:
             for index, only in enumerate(only_hosts):
                 self.only_hosts[index] = IPNetwork(only)
         except AddrFormatError as e:
-            raise RuntimeError("unable to parse option 'only_hosts' of rule '{}': {}".format(name, e))
+            raise RuntimeError(
+                f"unable to parse option 'only_hosts' of rule '{name}': {e}")
 
     def ignore_host(self, host):
         ip = IPAddress(host)
@@ -101,7 +109,7 @@ class HeaderRule:
                     break
 
         if ignore:
-            self.logger.debug("host {} is ignored by rule {}".format(host, self.name))
+            self.logger.debug(f"host {host} is ignored by rule {self.name}")
         return ignore
 
     def ignore_from(self, envfrom):
@@ -110,7 +118,8 @@ class HeaderRule:
         if self.ignore_envfrom:
             if self.ignore_envfrom.search(envfrom):
                 ignore = True
-                self.logger.debug("envelope-from {} is ignored by rule {}".format(envfrom, self.name))
+                self.logger.debug(
+                    f"envelope-from {envfrom} is ignored by rule {self.name}")
         return ignore
 
     def execute(self, headers):
@@ -123,25 +132,26 @@ class HeaderRule:
         occurrences = {}
 
         # iterate headers
-        for name, hdr in headers:
-            # keep track of the occurrence of each header, needed by Milter.Base.chgheader
+        for name, header in headers:
+            # keep track of the occurrence of each header, needed by
+            # Milter.Base.chgheader
             if name not in occurrences.keys():
                 occurrences[name] = 1
             else:
                 occurrences[name] += 1
 
             # check if header line matches regex
-            value = hdr[name]
-            if self.header.search("{}: {}".format(name, value)):
+            value = header[name]
+            if self.header.search(f"{name}: {value}"):
                 if self.action == "del":
                     # set an empty value to delete the header
                     new_value = ""
                 else:
                     new_value = self.search.sub(self.value, value)
                 if value != new_value:
-                    hdr = EmailMessage(policy=default_policy)
-                    hdr.add_header(name, new_value)
-                    modified.append((name, hdr, index, occurrences[name]))
+                    header = EmailMessage(policy=default_policy)
+                    header.add_header(name, new_value)
+                    modified.append((name, header, index, occurrences[name]))
             index += 1
         return modified
 
@@ -161,7 +171,8 @@ class HeaderMilter(Milter.Base):
         self.rules = HeaderMilter._rules.copy()
 
     def connect(self, IPname, family, hostaddr):
-        self.logger.debug("accepted milter connection from {} port {}".format(*hostaddr))
+        self.logger.debug(
+            f"accepted milter connection from {hostaddr[0]} port {hostaddr[1]}")
         ip = IPAddress(hostaddr[0])
 
         # remove rules which ignore this host
@@ -170,7 +181,8 @@ class HeaderMilter(Milter.Base):
                 self.rules.remove(rule)
 
         if not self.rules:
-            self.logger.debug("host {} is ignored by all rules, skip further processing".format(hostaddr[0]))
+            self.logger.debug(
+                f"host {hostaddr[0]} is ignored by all rules, skip further processing")
             return Milter.ACCEPT
         return Milter.CONTINUE
 
@@ -181,14 +193,15 @@ class HeaderMilter(Milter.Base):
                 self.rules.remove(rule)
 
         if not self.rules:
-            self.logger.debug("mail from {} is ignored by all rules, skip further processing".format(mailfrom))
+            self.logger.debug(
+                f"mail from {mailfrom} is ignored by all rules, skip further processing")
             return Milter.ACCEPT
         return Milter.CONTINUE
 
     @Milter.noreply
     def data(self):
-        self.queueid = self.getsymval('i')
-        self.logger.debug("{}: received queue-id from MTA".format(self.queueid))
+        self.qid = self.getsymval('i')
+        self.logger.debug(f"{self.qid}: received queue-id from MTA")
         self.headers = []
         return Milter.CONTINUE
 
@@ -196,64 +209,89 @@ class HeaderMilter(Milter.Base):
     def header(self, name, value):
         # remove surrogates from value
         value = value.encode(errors="surrogateescape").decode(errors="replace")
-        self.logger.debug(f"{self.queueid}: received header: {name}: {value}")
-        hdr = HeaderParser(policy=default_policy).parsestr(f"{name}: {value}")
-        self.logger.debug(f"{self.queueid}: decoded header: {name}: {hdr[name]}")
-        self.headers.append((name, hdr))
+        self.logger.debug(f"{self.qid}: received header: {name}: {value}")
+        header = HeaderParser(
+            policy=default_policy).parsestr(f"{name}: {value}")
+        self.logger.debug(
+            f"{self.qid}: decoded header: {name}: {header[name]}")
+        self.headers.append((name, header))
         return Milter.CONTINUE
 
     def eom(self):
         try:
             for rule in self.rules:
-                self.logger.debug("{}: executing rule '{}'".format(self.queueid, rule.name))
+                self.logger.debug(f"{self.qid}: executing rule '{rule.name}'")
                 modified = rule.execute(self.headers)
 
-                for name, hdr, index, occurrence in modified:
-                    value = hdr[name]
+                for name, header, index, occurrence in modified:
+                    value = header[name]
                     # remove illegal characters, pymilter does not like them
-                    encoded_value = hdr.as_string().replace("\r", "").replace("\n", "").replace("\x00", "").split(":", 1)[1].strip()
-                    mod_header = "{}: {}".format(name, value)
+                    enc_value = header.as_string().replace(
+                        "\r", "").replace(
+                        "\n", "").replace(
+                        "\x00", "").split(
+                        ":", 1)[1].strip()
+                    mod_header = f"{name}: {value}"
                     if rule.action == "add":
                         if rule.log:
-                            self.logger.info("{}: add: header: {}".format(self.queueid, mod_header[0:70]))
+                            self.logger.info(
+                                f"{self.qid}: add: header: {mod_header[0:70]}")
                         else:
-                            self.logger.debug("{}: add: header: {}".format(self.queueid, mod_header))
-                        self.headers.insert(0, (name, hdr))
-                        self.addheader(name, encoded_value, 1)
+                            self.logger.debug(
+                                f"{self.qid}: add: header: {mod_header}")
+                        self.headers.insert(0, (name, header))
+                        self.addheader(name, enc_value, 1)
                     else:
                         if rule.action == "mod":
                             old_value = self.headers[index][1][name]
-                            old_header = "{}: {}".format(name, old_value)
+                            old_header = f"{name}: {old_value}"
                             if rule.log:
-                                self.logger.info("{}: modify: header: {}: {}".format(
-                                    self.queueid, old_header[0:70], mod_header[0:70]))
+                                self.logger.info(f"{self.qid}: modify: header: {old_header[0:70]}: {mod_header[0:70]}")
                             else:
-                                self.logger.debug("{}: modify: header (occ. {}): {}: {}".format(
-                                    self.queueid, occurrence, old_header, mod_header))
-                            self.headers[index] = (name, hdr)
+                                self.logger.debug(
+                                    f"{self.qid}: modify: header (occ. {occurrence}): {old_header}: {mod_header}")
+                            self.headers[index] = (name, header)
                         elif rule.action == "del":
                             if rule.log:
-                                self.logger.info("{}: delete: header: {}".format(self.queueid, mod_header[0:70]))
+                                self.logger.info(
+                                    f"{self.qid}: delete: header: {mod_header[0:70]}")
                             else:
-                                self.logger.debug("{}: delete: header (occ. {}): {}".format(self.queueid, occurrence, mod_header))
+                                self.logger.debug(
+                                    f"{self.qid}: delete: header (occ. {occurrence}): {mod_header}")
                             del self.headers[index]
 
-                        self.chgheader(name, occurrence, encoded_value)
+                        self.chgheader(name, occurrence, enc_value)
             return Milter.ACCEPT
         except Exception as e:
-            self.logger.exception("an exception occured in eom function: {}".format(e))
+            self.logger.exception(f"an exception occured in eom function: {e}")
             return Milter.TEMPFAIL
 
 
 def main():
     "Run PyHeader-Milter."
     # parse command line
-    parser = argparse.ArgumentParser(description="PyHeader milter daemon",
-            formatter_class=lambda prog: argparse.HelpFormatter(prog, max_help_position=45, width=140))
-    parser.add_argument("-c", "--config", help="Config file to read.", default="/etc/pyheader-milter.conf")
-    parser.add_argument("-s", "--socket", help="Socket used to communicate with the MTA.", required=True)
-    parser.add_argument("-d", "--debug", help="Log debugging messages.", action="store_true")
-    parser.add_argument("-t", "--test", help="Check configuration.", action="store_true")
+    parser = argparse.ArgumentParser(
+        description="PyHeader milter daemon",
+        formatter_class=lambda prog: argparse.HelpFormatter(
+            prog, max_help_position=45, width=140))
+    parser.add_argument(
+        "-c", "--config", help="Config file to read.",
+        default="/etc/pyheader-milter.conf")
+    parser.add_argument(
+        "-s",
+        "--socket",
+        help="Socket used to communicate with the MTA.",
+        required=True)
+    parser.add_argument(
+        "-d",
+        "--debug",
+        help="Log debugging messages.",
+        action="store_true")
+    parser.add_argument(
+        "-t",
+        "--test",
+        help="Check configuration.",
+        action="store_true")
     args = parser.parse_args()
 
     # setup logging
@@ -262,8 +300,8 @@ def main():
     syslog_name = logname
     if args.debug:
         loglevel = logging.DEBUG
-        logname = "{}[%(name)s]".format(logname)
-        syslog_name = "{}: [%(name)s] %(levelname)s".format(syslog_name)
+        logname = f"{logname}[%(name)s]"
+        syslog_name = f"{syslog_name}: [%(name)s] %(levelname)s"
 
     # set config files for milter class
     root_logger = logging.getLogger()
@@ -272,7 +310,7 @@ def main():
     # setup console log
     stdouthandler = logging.StreamHandler(sys.stdout)
     stdouthandler.setLevel(logging.DEBUG)
-    formatter = logging.Formatter("%(message)s".format(logname))
+    formatter = logging.Formatter("%(message)s")
     stdouthandler.setFormatter(formatter)
     root_logger.addHandler(stdouthandler)
     logger = logging.getLogger(__name__)
@@ -285,21 +323,25 @@ def main():
 
         # check if mandatory config options in global section are present
         if "global" not in parser.sections():
-            raise RuntimeError("mandatory section 'global' not present in config file")
+            raise RuntimeError(
+                "mandatory section 'global' not present in config file")
         for option in ["rules"]:
             if not parser.has_option("global", option):
-                raise RuntimeError("mandatory option '{}' not present in config section 'global'".format(option))
+                raise RuntimeError(
+                    f"mandatory option '{option}' not present in config section 'global'")
 
         # read global config section
         global_config = dict(parser.items("global"))
 
         # read active rules
-        active_rules = [ r.strip() for r in global_config["rules"].split(",") ]
+        active_rules = [r.strip() for r in global_config["rules"].split(",")]
         if len(active_rules) != len(set(active_rules)):
-            raise RuntimeError("at least one rule is specified multiple times in 'rules' option")
+            raise RuntimeError(
+                "at least one rule is specified multiple times in 'rules' option")
         if "global" in active_rules:
             active_rules.remove("global")
-            logger.warning("removed illegal rule name 'global' from list of active rules")
+            logger.warning(
+                "removed illegal rule name 'global' from list of active rules")
         if not active_rules:
             raise RuntimeError("no rules configured")
 
@@ -309,7 +351,8 @@ def main():
         for rule_name in active_rules:
             # check if config section exists
             if rule_name not in parser.sections():
-                raise RuntimeError("config section '{}' does not exist".format(rule_name))
+                raise RuntimeError(
+                    f"config section '{rule_name}' does not exist")
             config = dict(parser.items(rule_name))
 
             # check if mandatory option action is present in config
@@ -318,10 +361,12 @@ def main():
                     option in global_config.keys():
                 config[option] = global_config[option]
             if option not in config.keys():
-                raise RuntimeError("mandatory option '{}' not specified for rule '{}'".format(option, rule_name))
+                raise RuntimeError(
+                    f"mandatory option '{option}' not specified for rule '{rule_name}'")
             config["action"] = config["action"].lower()
             if config["action"] not in ["add", "del", "mod"]:
-                raise RuntimeError("invalid action specified for rule '{}'".format(rule_name))
+                raise RuntimeError(
+                    f"invalid action specified for rule '{rule_name}'")
 
             # check if mandatory options are present in config
             mandatory = ["header"]
@@ -334,7 +379,8 @@ def main():
                         option in global_config.keys():
                     config[option] = global_config[option]
                 if option not in config.keys():
-                    raise RuntimeError("mandatory option '{}' not specified for rule '{}'".format(option, rule_name))
+                    raise RuntimeError(
+                        f"mandatory option '{option}' not specified for rule '{rule_name}'")
 
             # check if optional config options are present in config
             defaults = {
@@ -350,19 +396,22 @@ def main():
                 if option not in config.keys():
                     config[option] = defaults[option]
             if config["ignore_hosts"]:
-                config["ignore_hosts"] = [ h.strip() for h in config["ignore_hosts"].split(",") ]
+                config["ignore_hosts"] = [h.strip()
+                                          for h in config["ignore_hosts"].split(",")]
             if config["only_hosts"]:
-                config["only_hosts"] = [ h.strip() for h in config["only_hosts"].split(",") ]
+                config["only_hosts"] = [h.strip()
+                                        for h in config["only_hosts"].split(",")]
             config["log"] = config["log"].lower()
             if config["log"] == "true":
                 config["log"] = True
             elif config["log"] == "false":
                 config["log"] = False
             else:
-                raise RuntimeError("invalid value specified for option 'log' for rule '{}'".format(rule_name))
+                raise RuntimeError(
+                    f"invalid value specified for option 'log' for rule '{rule_name}'")
 
             # add rule
-            logging.debug("adding rule '{}'".format(rule_name))
+            logging.debug(f"adding rule '{rule_name}'")
             rules.append(HeaderRule(name=rule_name, **config))
 
     except RuntimeError as e:
@@ -374,13 +423,16 @@ def main():
         sys.exit(0)
 
     # change log format for runtime
-    formatter = logging.Formatter("%(asctime)s {}: [%(levelname)s] %(message)s".format(logname), datefmt="%Y-%m-%d %H:%M:%S")
+    formatter = logging.Formatter(
+        f"%(asctime)s {logname}: [%(levelname)s] %(message)s",
+        datefmt="%Y-%m-%d %H:%M:%S")
     stdouthandler.setFormatter(formatter)
 
     # setup syslog
-    sysloghandler = logging.handlers.SysLogHandler(address="/dev/log", facility=logging.handlers.SysLogHandler.LOG_MAIL)
+    sysloghandler = logging.handlers.SysLogHandler(
+        address="/dev/log", facility=logging.handlers.SysLogHandler.LOG_MAIL)
     sysloghandler.setLevel(loglevel)
-    formatter = logging.Formatter("{}: %(message)s".format(syslog_name))
+    formatter = logging.Formatter(f"{syslog_name}: %(message)s")
     sysloghandler.setFormatter(formatter)
     root_logger.addHandler(sysloghandler)