tox: bump the pylint version to 2.6.0 in the default run (#544)

Changes:

tox: bump the pylint version to 2.6.0 in the default run
Fix pylint 2.6.0 W0707 warnings (raise-missing-from)

10 files changed, 65 insertions, 42 deletions

diff --git a/cloudinit/sources/DataSourceAzure.py b/cloudinit/sources/DataSourceAzure.py
index 86cc7c28..f3c6452b 100755
--- a/cloudinit/sources/DataSourceAzure.py
+++ b/cloudinit/sources/DataSourceAzure.py
@@ -1147,7 +1147,7 @@ def read_azure_ovf(contents):
     except Exception as e:
         error_str = "Invalid ovf-env.xml: %s" % e
         report_diagnostic_event(error_str)
-        raise BrokenAzureDataSource(error_str)
+        raise BrokenAzureDataSource(error_str) from e
 
     results = find_child(dom.documentElement,
                          lambda n: n.localName == "ProvisioningSection")
diff --git a/cloudinit/sources/DataSourceEc2.py b/cloudinit/sources/DataSourceEc2.py
index 355b4e2f..1d09c12a 100644
--- a/cloudinit/sources/DataSourceEc2.py
+++ b/cloudinit/sources/DataSourceEc2.py
@@ -617,9 +617,11 @@ def parse_strict_mode(cfgval):
     if sleep:
         try:
             sleep = int(sleep)
-        except ValueError:
-            raise ValueError("Invalid sleep '%s' in strict_id setting '%s': "
-                             "not an integer" % (sleep, cfgval))
+        except ValueError as e:
+            raise ValueError(
+                "Invalid sleep '%s' in strict_id setting '%s': not an integer"
+                % (sleep, cfgval)
+            ) from e
     else:
         sleep = None
 
diff --git a/cloudinit/sources/DataSourceIBMCloud.py b/cloudinit/sources/DataSourceIBMCloud.py
index d2aa9a58..8d196185 100644
--- a/cloudinit/sources/DataSourceIBMCloud.py
+++ b/cloudinit/sources/DataSourceIBMCloud.py
@@ -303,7 +303,8 @@ def read_md():
     except sources.BrokenMetadata as e:
         raise RuntimeError(
             "Failed reading IBM config disk (platform=%s path=%s): %s" %
-            (platform, path, e))
+            (platform, path, e)
+        ) from e
 
     ret.update(results)
     return ret
diff --git a/cloudinit/sources/DataSourceMAAS.py b/cloudinit/sources/DataSourceMAAS.py
index c80f70c2..9156925f 100644
--- a/cloudinit/sources/DataSourceMAAS.py
+++ b/cloudinit/sources/DataSourceMAAS.py
@@ -226,7 +226,8 @@ def read_maas_seed_url(seed_url, read_file_or_url=None, timeout=None,
         except url_helper.UrlError as e:
             if e.code == 404 and not optional:
                 raise MAASSeedDirMalformed(
-                    "Missing required %s: %s" % (path, e))
+                    "Missing required %s: %s" % (path, e)
+                ) from e
             elif e.code != 404:
                 raise e
 
diff --git a/cloudinit/sources/DataSourceOpenNebula.py b/cloudinit/sources/DataSourceOpenNebula.py
index 12b1f94f..45481938 100644
--- a/cloudinit/sources/DataSourceOpenNebula.py
+++ b/cloudinit/sources/DataSourceOpenNebula.py
@@ -399,18 +399,23 @@ def read_context_disk_dir(source_dir, distro, asuser=None):
         if asuser is not None:
             try:
                 pwd.getpwnam(asuser)
-            except KeyError:
+            except KeyError as e:
                 raise BrokenContextDiskDir(
                     "configured user '{user}' does not exist".format(
-                        user=asuser))
+                        user=asuser)
+                ) from e
         try:
             path = os.path.join(source_dir, 'context.sh')
             content = util.load_file(path)
             context = parse_shell_config(content, asuser=asuser)
         except subp.ProcessExecutionError as e:
-            raise BrokenContextDiskDir("Error processing context.sh: %s" % (e))
+            raise BrokenContextDiskDir(
+                "Error processing context.sh: %s" % (e)
+            ) from e
         except IOError as e:
-            raise NonContextDiskDir("Error reading context.sh: %s" % (e))
+            raise NonContextDiskDir(
+                "Error reading context.sh: %s" % (e)
+            ) from e
     else:
         raise NonContextDiskDir("Missing context.sh")
 
diff --git a/cloudinit/sources/DataSourceOpenStack.py b/cloudinit/sources/DataSourceOpenStack.py
index bf539091..d4b43f44 100644
--- a/cloudinit/sources/DataSourceOpenStack.py
+++ b/cloudinit/sources/DataSourceOpenStack.py
@@ -194,10 +194,10 @@ class DataSourceOpenStack(openstack.SourceMixin, sources.DataSource):
                         'timeout': url_params.timeout_seconds})
         except openstack.NonReadable as e:
             raise sources.InvalidMetaDataException(str(e))
-        except (openstack.BrokenMetadata, IOError):
+        except (openstack.BrokenMetadata, IOError) as e:
             msg = 'Broken metadata address {addr}'.format(
                 addr=self.metadata_address)
-            raise sources.InvalidMetaDataException(msg)
+            raise sources.InvalidMetaDataException(msg) from e
         return result
 
 
diff --git a/cloudinit/sources/DataSourceSmartOS.py b/cloudinit/sources/DataSourceSmartOS.py
index 843b3a2a..f1f903bc 100644
--- a/cloudinit/sources/DataSourceSmartOS.py
+++ b/cloudinit/sources/DataSourceSmartOS.py
@@ -413,7 +413,9 @@ class JoyentMetadataClient(object):
                 response.append(byte)
             except OSError as exc:
                 if exc.errno == errno.EAGAIN:
-                    raise JoyentMetadataTimeoutException(msg % as_ascii())
+                    raise JoyentMetadataTimeoutException(
+                        msg % as_ascii()
+                    ) from exc
                 raise
 
     def _write(self, msg):
diff --git a/cloudinit/sources/helpers/azure.py b/cloudinit/sources/helpers/azure.py
index 6156c75b..b968a96f 100755
--- a/cloudinit/sources/helpers/azure.py
+++ b/cloudinit/sources/helpers/azure.py
@@ -98,8 +98,10 @@ def get_boot_telemetry():
     LOG.debug("Collecting boot telemetry")
     try:
         kernel_start = float(time.time()) - float(util.uptime())
-    except ValueError:
-        raise RuntimeError("Failed to determine kernel start timestamp")
+    except ValueError as e:
+        raise RuntimeError(
+            "Failed to determine kernel start timestamp"
+        ) from e
 
     try:
         out, _ = subp.subp(['/bin/systemctl',
@@ -116,12 +118,13 @@ def get_boot_telemetry():
 
         user_start = kernel_start + (float(tsm) / 1000000)
     except subp.ProcessExecutionError as e:
-        raise RuntimeError("Failed to get UserspaceTimestampMonotonic: %s"
-                           % e)
+        raise RuntimeError(
+            "Failed to get UserspaceTimestampMonotonic: %s" % e
+        ) from e
     except ValueError as e:
-        raise RuntimeError("Failed to parse "
-                           "UserspaceTimestampMonotonic from systemd: %s"
-                           % e)
+        raise RuntimeError(
+            "Failed to parse UserspaceTimestampMonotonic from systemd: %s" % e
+        ) from e
 
     try:
         out, _ = subp.subp(['/bin/systemctl', 'show',
@@ -137,12 +140,14 @@ def get_boot_telemetry():
 
         cloudinit_activation = kernel_start + (float(tsm) / 1000000)
     except subp.ProcessExecutionError as e:
-        raise RuntimeError("Failed to get InactiveExitTimestampMonotonic: %s"
-                           % e)
+        raise RuntimeError(
+            "Failed to get InactiveExitTimestampMonotonic: %s" % e
+        ) from e
     except ValueError as e:
-        raise RuntimeError("Failed to parse "
-                           "InactiveExitTimestampMonotonic from systemd: %s"
-                           % e)
+        raise RuntimeError(
+            "Failed to parse InactiveExitTimestampMonotonic from systemd: %s"
+            % e
+        ) from e
 
     evt = events.ReportingEvent(
         BOOT_EVENT_TYPE, 'boot-telemetry',
@@ -642,9 +647,10 @@ class WALinuxAgentShim:
             try:
                 name = os.path.basename(hook_file).replace('.json', '')
                 dhcp_options[name] = json.loads(util.load_file((hook_file)))
-            except ValueError:
+            except ValueError as e:
                 raise ValueError(
-                    '{_file} is not valid JSON data'.format(_file=hook_file))
+                    '{_file} is not valid JSON data'.format(_file=hook_file)
+                ) from e
         return dhcp_options
 
     @staticmethod
diff --git a/cloudinit/sources/helpers/netlink.py b/cloudinit/sources/helpers/netlink.py
index a74a3588..c2ad587b 100644
--- a/cloudinit/sources/helpers/netlink.py
+++ b/cloudinit/sources/helpers/netlink.py
@@ -74,7 +74,7 @@ def create_bound_netlink_socket():
         netlink_socket.setblocking(0)
     except socket.error as e:
         msg = "Exception during netlink socket create: %s" % e
-        raise NetlinkCreateSocketError(msg)
+        raise NetlinkCreateSocketError(msg) from e
     LOG.debug("Created netlink socket")
     return netlink_socket
 
diff --git a/cloudinit/sources/helpers/openstack.py b/cloudinit/sources/helpers/openstack.py
index 1050efb0..65e020c5 100644
--- a/cloudinit/sources/helpers/openstack.py
+++ b/cloudinit/sources/helpers/openstack.py
@@ -280,8 +280,9 @@ class BaseReader(metaclass=abc.ABCMeta):
                 try:
                     data = translator(data)
                 except Exception as e:
-                    raise BrokenMetadata("Failed to process "
-                                         "path %s: %s" % (path, e))
+                    raise BrokenMetadata(
+                        "Failed to process path %s: %s" % (path, e)
+                    ) from e
             if found:
                 results[name] = data
 
@@ -291,8 +292,9 @@ class BaseReader(metaclass=abc.ABCMeta):
             try:
                 metadata['random_seed'] = base64.b64decode(random_seed)
             except (ValueError, TypeError) as e:
-                raise BrokenMetadata("Badly formatted metadata"
-                                     " random_seed entry: %s" % e)
+                raise BrokenMetadata(
+                    "Badly formatted metadata random_seed entry: %s" % e
+                ) from e
 
         # load any files that were provided
         files = {}
@@ -304,8 +306,9 @@ class BaseReader(metaclass=abc.ABCMeta):
             try:
                 files[path] = self._read_content_path(item)
             except Exception as e:
-                raise BrokenMetadata("Failed to read provided "
-                                     "file %s: %s" % (path, e))
+                raise BrokenMetadata(
+                    "Failed to read provided file %s: %s" % (path, e)
+                ) from e
         results['files'] = files
 
         # The 'network_config' item in metadata is a content pointer
@@ -317,8 +320,9 @@ class BaseReader(metaclass=abc.ABCMeta):
                 content = self._read_content_path(net_item, decode=True)
                 results['network_config'] = content
             except IOError as e:
-                raise BrokenMetadata("Failed to read network"
-                                     " configuration: %s" % (e))
+                raise BrokenMetadata(
+                    "Failed to read network configuration: %s" % (e)
+                ) from e
 
         # To openstack, user can specify meta ('nova boot --meta=key=value')
         # and those will appear under metadata['meta'].
@@ -370,8 +374,9 @@ class ConfigDriveReader(BaseReader):
             try:
                 return util.load_json(self._path_read(path))
             except Exception as e:
-                raise BrokenMetadata("Failed to process "
-                                     "path %s: %s" % (path, e))
+                raise BrokenMetadata(
+                    "Failed to process path %s: %s" % (path, e)
+                ) from e
 
     def read_v1(self):
         """Reads a version 1 formatted location.
@@ -395,16 +400,17 @@ class ConfigDriveReader(BaseReader):
                 path = found[name]
                 try:
                     contents = self._path_read(path)
-                except IOError:
-                    raise BrokenMetadata("Failed to read: %s" % path)
+                except IOError as e:
+                    raise BrokenMetadata("Failed to read: %s" % path) from e
                 try:
                     # Disable not-callable pylint check; pylint isn't able to
                     # determine that every member of FILES_V1 has a callable in
                     # the appropriate position
                     md[key] = translator(contents)  # pylint: disable=E1102
                 except Exception as e:
-                    raise BrokenMetadata("Failed to process "
-                                         "path %s: %s" % (path, e))
+                    raise BrokenMetadata(
+                        "Failed to process path %s: %s" % (path, e)
+                    ) from e
             else:
                 md[key] = copy.deepcopy(default)