chore: cleanup `len' usage (canonical#5956)

In most cases there is no need to calculate length of list of string
values to do something else, just ensuring list or string is not empty
is enough. This will also give a slight performance gain.

Signed-off-by: Shreenidhi Shedi <shreenidhi.shedi@broadcom.com>

cloudinit/config/cc_apt_configure.py

@@ -241,7 +241,7 @@ def apply_debconf_selections(cfg):
     LOG.debug("pkgs_cfgd: %s", pkgs_cfgd)
     need_reconfig = pkgs_cfgd.intersection(pkgs_installed)
 
-    if len(need_reconfig) == 0:
+    if not need_reconfig:
         LOG.debug("no need for reconfig")
         return
 

cloudinit/config/cc_byobu.py

@@ -28,7 +28,7 @@
 
 
 def handle(name: str, cfg: Config, cloud: Cloud, args: list) -> None:
-    if len(args) != 0:
+    if args:
         value = args[0]
     else:
         value = util.get_cfg_option_str(cfg, "byobu_by_default", "")

cloudinit/config/cc_disk_setup.py

@@ -377,7 +377,7 @@ def check_partition_mbr_layout(device, layout):
     found_layout = []
     for line in out.splitlines():
         _line = line.split()
-        if len(_line) == 0:
+        if not _line:
             continue
 
         if device in _line[0]:
@@ -500,7 +500,7 @@ def get_partition_mbr_layout(size, layout):
         # Create a single partition, default to Linux
         return ",,83"
 
-    if (len(layout) == 0 and isinstance(layout, list)) or not isinstance(
+    if ((not layout) and isinstance(layout, list)) or not isinstance(
         layout, list
     ):
         raise RuntimeError("Partition layout is invalid")

cloudinit/config/cc_final_message.py

@@ -38,7 +38,7 @@
 def handle(name: str, cfg: Config, cloud: Cloud, args: list) -> None:
 
     msg_in = ""
-    if len(args) != 0:
+    if args:
         msg_in = str(args[0])
     else:
         msg_in = util.get_cfg_option_str(cfg, "final_message", "")

cloudinit/config/cc_locale.py

@@ -27,7 +27,7 @@
 
 
 def handle(name: str, cfg: Config, cloud: Cloud, args: list) -> None:
-    if len(args) != 0:
+    if args:
         locale = args[0]
     else:
         locale = util.get_cfg_option_str(cfg, "locale", cloud.get_locale())

cloudinit/config/cc_mounts.py

@@ -548,7 +548,7 @@ def handle(name: str, cfg: Config, cloud: Cloud, args: list) -> None:
     if swapfile:
         updated_cfg.append([swapfile, "none", "swap", "sw", "0", "0"])
 
-    if len(updated_cfg) == 0:
+    if not updated_cfg:
         # This will only be true if there is no mount configuration at all
         # Even if fstab has no functional changes, we'll get past this point
         # as we remove any 'comment=cloudconfig' lines and then add them back

cloudinit/config/cc_ntp.py

@@ -427,18 +427,14 @@ def write_ntp_config_template(
     if not peers:
         peers = []
 
-    if len(servers) == 0 and len(pools) == 0 and distro_name == "cos":
+    if not servers and not pools and distro_name == "cos":
         return
-    if (
-        len(servers) == 0
-        and distro_name == "alpine"
-        and service_name == "ntpd"
-    ):
+    if not servers and distro_name == "alpine" and service_name == "ntpd":
         # Alpine's Busybox ntpd only understands "servers" configuration
         # and not "pool" configuration.
         servers = generate_server_names(distro_name)
         LOG.debug("Adding distro default ntp servers: %s", ",".join(servers))
-    elif len(servers) == 0 and len(pools) == 0:
+    elif not (servers) and not (pools):
         pools = generate_server_names(distro_name)
         LOG.debug(
             "Adding distro default ntp pool servers: %s", ",".join(pools)

cloudinit/config/cc_phone_home.py

@@ -47,7 +47,7 @@
 
 
 def handle(name: str, cfg: Config, cloud: Cloud, args: list) -> None:
-    if len(args) != 0:
+    if args:
         ph_cfg = util.read_conf(args[0])
     else:
         if "phone_home" not in cfg:

cloudinit/config/cc_resizefs.py

@@ -249,7 +249,7 @@ def maybe_get_writable_device_path(devpath, info):
 
 
 def handle(name: str, cfg: Config, cloud: Cloud, args: list) -> None:
-    if len(args) != 0:
+    if args:
         resize_root = args[0]
     else:
         resize_root = util.get_cfg_option_str(cfg, "resize_rootfs", True)

cloudinit/config/cc_rh_subscription.py

@@ -330,7 +330,7 @@ def addPool(self, pools):
         """
 
         # An empty list was passed
-        if len(pools) == 0:
+        if not pools:
             self.log.debug("No pools to attach")
             return True
 
@@ -379,7 +379,7 @@ def update_repos(self):
             return False
 
         # Bail if both lists are not populated
-        if (len(erepos) == 0) and (len(drepos) == 0):
+        if not (erepos) and not (drepos):
             self.log.debug("No repo IDs to enable or disable")
             return True
 

cloudinit/config/cc_ssh_import_id.py

@@ -47,7 +47,7 @@ def handle(name: str, cfg: Config, cloud: Cloud, args: list) -> None:
         return
 
     # import for "user: XXXXX"
-    if len(args) != 0:
+    if args:
         user = args[0]
         ids = []
         if len(args) > 1:

cloudinit/config/cc_timezone.py

@@ -27,7 +27,7 @@
 
 
 def handle(name: str, cfg: Config, cloud: Cloud, args: list) -> None:
-    if len(args) != 0:
+    if args:
         timezone = args[0]
     else:
         timezone = util.get_cfg_option_str(cfg, "timezone", False)

cloudinit/distros/aosc.py

@@ -135,7 +135,7 @@ def update_locale_conf(sys_path, locale_cfg):
         if v is None:
             continue
         v = str(v)
-        if len(v) == 0:
+        if not v:
             continue
         contents[k] = v
         updated_am += 1

cloudinit/distros/parsers/ifconfig.py

@@ -102,7 +102,7 @@ def parse(self, text: str) -> Dict[str, Union[Ifstate, List[Ifstate]]]:
         ifs_by_mac = defaultdict(list)
         dev = None
         for line in text.splitlines():
-            if len(line) == 0:
+            if not line:
                 continue
             if line[0] not in ("\t", " "):
                 # We hit the start of a device block in the ifconfig output

cloudinit/distros/parsers/sys_conf.py

@@ -65,7 +65,7 @@ def __str__(self):
     def _quote(self, value, multiline=False):
         if not isinstance(value, str):
             raise ValueError('Value "%s" is not a string' % (value))
-        if len(value) == 0:
+        if not value:
             return ""
         quot_func = None
         if value[0] in ['"', "'"] and value[-1] in ['"', "'"]:

cloudinit/distros/rhel_util.py

@@ -26,7 +26,7 @@ def update_sysconfig_file(fn, adjustments, allow_empty=False):
         if v is None:
             continue
         v = str(v)
-        if len(v) == 0 and not allow_empty:
+        if (not v) and (not allow_empty):
             continue
         contents[k] = v
         updated_am += 1

cloudinit/net/__init__.py

@@ -828,7 +828,7 @@ def find_entry(mac, driver, device_id):
         "up": Iproute2.link_up,
     }
 
-    if len(ops) + len(ups) == 0:
+    if not (ops) and not (ups):
         if len(errors):
             LOG.warning(
                 "Unable to rename interfaces: %s due to errors: %s",

cloudinit/net/dhcp.py

@@ -237,7 +237,7 @@ def parse_leases(lease_content: str) -> List[Dict[str, Any]]:
         """
         lease_regex = re.compile(r"lease {(?P<lease>.*?)}\n", re.DOTALL)
         dhcp_leases: List[Dict] = []
-        if len(lease_content) == 0:
+        if not lease_content:
             return []
         for lease in lease_regex.findall(lease_content):
             lease_options = []

cloudinit/net/sysconfig.py

@@ -938,7 +938,7 @@ def _render_networkmanager_conf(network_state, templates=None):
         ):
             content.set_section_keypair("main", "dns", "none")
 
-        if len(content) == 0:
+        if not content:
             return None
         out = "".join([_make_header(), "\n", "\n".join(content.write()), "\n"])
         return out

cloudinit/netinfo.py

@@ -189,7 +189,7 @@ def _netdev_info_ifconfig_netbsd(ifconfig_data):
     # fields that need to be returned in devs for each dev
     devs = {}
     for line in ifconfig_data.splitlines():
-        if len(line) == 0:
+        if not line:
             continue
         if line[0] not in ("\t", " "):
             curdev = line.split()[0]
@@ -237,7 +237,7 @@ def _netdev_info_ifconfig(ifconfig_data):
     # fields that need to be returned in devs for each dev
     devs = {}
     for line in ifconfig_data.splitlines():
-        if len(line) == 0:
+        if not line:
             continue
         if line[0] not in ("\t", " "):
             curdev = line.split()[0]
@@ -587,7 +587,8 @@ def netdev_pformat():
         fields = ["Device", "Up", "Address", "Mask", "Scope", "Hw-Address"]
         tbl = SimpleTable(fields)
         for dev, data in sorted(netdev.items()):
-            for addr in data.get("ipv4"):
+            ipv4_addrs = data.get("ipv4")
+            for addr in ipv4_addrs:
                 tbl.add_row(
                     (
                         dev,
@@ -598,7 +599,9 @@ def netdev_pformat():
                         data["hwaddr"],
                     )
                 )
-            for addr in data.get("ipv6"):
+
+            ipv6_addrs = data.get("ipv6")
+            for addr in ipv6_addrs:
                 tbl.add_row(
                     (
                         dev,
@@ -609,7 +612,7 @@ def netdev_pformat():
                         data["hwaddr"],
                     )
                 )
-            if len(data.get("ipv6")) + len(data.get("ipv4")) == 0:
+            if not (ipv4_addrs) and not (ipv6_addrs):
                 tbl.add_row(
                     (dev, data["up"], empty, empty, empty, data["hwaddr"])
                 )

cloudinit/reporting/handlers.py

@@ -345,7 +345,7 @@ def _break_down(self, key, meta_data, description):
             result_array.append(self._encode_kvp_item(subkey, value))
             i += 1
             des_in_json = des_in_json[room_for_desc:]
-            if len(des_in_json) == 0:
+            if not des_in_json:
                 break
         return result_array
 

cloudinit/sources/DataSourceAzure.py

@@ -1733,15 +1733,18 @@ def can_dev_be_reformatted(devpath, preserve_ntfs):
     # devpath of /dev/sd[a-z] or /dev/disk/cloud/azure_resource
     # where partitions are "<devpath>1" or "<devpath>-part1" or "<devpath>p1"
     partitions = _partitions_on_device(devpath)
-    if len(partitions) == 0:
+    if not partitions:
         return False, "device %s was not partitioned" % devpath
-    elif len(partitions) > 2:
+
+    partition_len = len(partitions)
+    if partition_len > 2:
         msg = "device %s had 3 or more partitions: %s" % (
             devpath,
             " ".join([p[1] for p in partitions]),
         )
         return False, msg
-    elif len(partitions) == 2:
+
+    if partition_len == 2:
         cand_part, cand_path = partitions[1]
     else:
         cand_part, cand_path = partitions[0]

cloudinit/sources/DataSourceEc2.py

@@ -895,7 +895,7 @@ def _build_nic_order(
     @return: Dictionary with macs as keys and nic orders as values.
     """
     nic_order: Dict[str, int] = {}
-    if len(macs_to_nics) == 0 or len(macs_metadata) == 0:
+    if (not macs_to_nics) or (not macs_metadata):
         return nic_order
 
     valid_macs_metadata = filter(

cloudinit/sources/DataSourceMAAS.py

@@ -197,7 +197,7 @@ def get_id_from_ds_cfg(ds_cfg):
 def read_maas_seed_dir(seed_d):
     if seed_d.startswith("file://"):
         seed_d = seed_d[7:]
-    if not os.path.isdir(seed_d) or len(os.listdir(seed_d)) == 0:
+    if not os.path.isdir(seed_d) or not os.listdir(seed_d):
         raise MAASSeedDirNone("%s: not a directory")
 
     # seed_dir looks in seed_dir, not seed_dir/VERSION
@@ -283,7 +283,7 @@ def check_seed_contents(content, seed):
         else:
             ret[dpath] = content[spath]
 
-    if len(ret) == 0:
+    if not ret:
         raise MAASSeedDirNone("%s: no data files found" % seed)
 
     if missing:

cloudinit/sources/DataSourceNoCloud.py

@@ -167,7 +167,7 @@ def _pp2d_callback(mp, data):
 
         # There was no indication on kernel cmdline or data
         # in the seeddir suggesting this handler should be used.
-        if len(found) == 0:
+        if not found:
             return False
 
         # The special argument "seedfrom" indicates we should

cloudinit/sources/DataSourceOVF.py

@@ -78,7 +78,7 @@ def _get_data(self):
                 found.append(name)
 
         # There was no OVF transports found
-        if len(found) == 0:
+        if not found:
             return False
 
         if "seedfrom" in md and md["seedfrom"]:
@@ -372,7 +372,7 @@ def get_properties(contents):
         dom.documentElement, lambda n: n.localName == "PropertySection"
     )
 
-    if len(propSections) == 0:
+    if not propSections:
         raise XmlError("No 'PropertySection's")
 
     props = {}

cloudinit/sources/DataSourceSmartOS.py

@@ -438,7 +438,7 @@ def as_ascii():
         while True:
             try:
                 byte = self.fp.read(1)
-                if len(byte) == 0:
+                if not byte:
                     raise JoyentMetadataTimeoutException(msg % as_ascii())
                 if byte == b"\n":
                     return as_ascii()

cloudinit/sources/DataSourceVMware.py

@@ -500,7 +500,7 @@ def get_none_if_empty_val(val):
     # simplify the rest of this function's logic.
     val = util.decode_binary(val)
     val = val.rstrip()
-    if len(val) == 0 or val == GUESTINFO_EMPTY_YAML_VAL:
+    if (not val) or (val == GUESTINFO_EMPTY_YAML_VAL):
         return None
     return val
 

cloudinit/sources/DataSourceWSL.py

@@ -237,14 +237,14 @@ def merge_agent_landscape_data(
     cloud-init to merge separate parts.
     """
     # Ignore agent_data if None or empty
-    if agent_data is None or len(agent_data.raw) == 0:
-        if user_data is None or len(user_data.raw) == 0:
+    if (agent_data is None) or (not agent_data.raw):
+        if (user_data is None) or (not user_data.raw):
             return None
         return user_data.raw
 
     # Ignore user_data if None or empty
-    if user_data is None or len(user_data.raw) == 0:
-        if agent_data is None or len(agent_data.raw) == 0:
+    if (user_data is None) or (not user_data.raw):
+        if (agent_data is None) or (not agent_data.raw):
             return None
         return agent_data.raw
 

cloudinit/sources/helpers/azure.py

@@ -1034,7 +1034,7 @@ def _find(
         matches = node.findall(
             "./%s:%s" % (namespace, name), OvfEnvXml.NAMESPACES
         )
-        if len(matches) == 0:
+        if not matches:
             msg = "missing configuration for %r" % name
             LOG.debug(msg)
             if required:
@@ -1058,13 +1058,14 @@ def _parse_property(
         default=None,
     ):
         matches = node.findall("./wa:" + name, OvfEnvXml.NAMESPACES)
-        if len(matches) == 0:
+        if not matches:
             msg = "missing configuration for %r" % name
             LOG.debug(msg)
             if required:
                 raise errors.ReportableErrorOvfInvalidMetadata(msg)
             return default
-        elif len(matches) > 1:
+
+        if len(matches) > 1:
             raise errors.ReportableErrorOvfInvalidMetadata(
                 "multiple configuration matches for %r (%d)"
                 % (name, len(matches))