Client: Allow client to initialize without a set config file rucio#6410

lib/rucio/client/baseclient.py

@@ -111,8 +111,10 @@ def __init__(self, rucio_host=None, auth_host=None, account=None, ca_cert=None,
                 self.host = config_get('client', 'rucio_host')
             if self.auth_host is None:
                 self.auth_host = config_get('client', 'auth_host')
-        except (NoOptionError, NoSectionError) as error:
-            raise MissingClientParameter('Section client and Option \'%s\' cannot be found in config file' % error.args[0])
+        except (NoOptionError, NoSectionError):
+            self.host = "https://rucio:443"
+            self.auth_host = "https://rucio:443"
+            self.logger.debug(f"Section client and Option rucio_host, auth_host cannot be found in config file, using {self.host} as host")
 
         try:
             self.trace_host = config_get('trace', 'trace_host')
@@ -145,8 +147,9 @@ def __init__(self, rucio_host=None, auth_host=None, account=None, ca_cert=None,
             else:
                 try:
                     self.auth_type = config_get('client', 'auth_type')
-                except (NoOptionError, NoSectionError) as error:
-                    raise MissingClientParameter('Option \'%s\' cannot be found in config file' % error.args[0])
+                except (NoOptionError, NoSectionError):
+                    self.auth_type = "userpass"
+                    self.logger.debug(f'Option client/auth_type cannot be found in config file, using {self.auth_type}.')
 
         if self.auth_type == 'oidc':
             if not self.creds:
@@ -282,9 +285,7 @@ def __init__(self, rucio_host=None, auth_host=None, account=None, ca_cert=None,
         self.__authenticate()
 
         try:
-            self.request_retries = config_get_int('client', 'request_retries')
-        except (NoOptionError, RuntimeError):
-            LOG.debug('request_retries not specified in config file. Taking default.')
+            self.request_retries = config_get_int('client', 'request_retries', raise_exception=False, default=self.request_retries)
         except ValueError:
             self.logger.debug('request_retries must be an integer. Taking default.')
 

lib/rucio/common/config.py

@@ -19,17 +19,22 @@
 import json
 import os
 from collections.abc import Callable
-from typing import TYPE_CHECKING, overload, Optional, TypeVar, Union
+from typing import TYPE_CHECKING, Any, overload, Optional, TypeVar, Union
 
 from rucio.common import exception
 from rucio.common.exception import ConfigNotFound, DatabaseException
 
+import logging
+import tempfile
+
 _T = TypeVar('_T')
 _U = TypeVar('_U')
 
 if TYPE_CHECKING:
     from sqlalchemy.orm import Session
 
+    LoggerFunction = Callable[..., Any]
+
 
 def convert_to_any_type(value) -> Union[bool, int, float, str]:
     if value.lower() in ['true', 'yes', 'on']:
@@ -777,7 +782,7 @@ class Config:
     The configuration class reading the config file on init, located by using
     get_config_dirs or the use of the RUCIO_CONFIG environment variable.
     """
-    def __init__(self):
+    def __init__(self, logger: "LoggerFunction" = logging.log):
         self.parser = configparser.ConfigParser()
 
         if 'RUCIO_CONFIG' in os.environ:
@@ -786,9 +791,26 @@ def __init__(self):
             configs = [os.path.join(confdir, 'rucio.cfg') for confdir in get_config_dirs()]
             self.configfile = next(iter(filter(os.path.exists, configs)), None)
             if self.configfile is None:
-                raise RuntimeError('Could not load Rucio configuration file. '
-                                   'Rucio looked in the following paths for a configuration file, in order:'
-                                   '\n\t' + '\n\t'.join(configs))
+                if ('RUCIO_CLIENT_MODE' not in os.environ) or (not os.environ['RUCIO_CLIENT_MODE']):
+                    raise RuntimeError(
+                        'Could not load configuration file. '
+                        'A configuration file is required to run in server mode. '
+                        'If trying to run in client mode, be sure to set RUCIO_CLIENT_MODE=True in your envoriment. '
+                        'Rucio looked in the following paths for a configuration file, in order: '
+                        '\n\t' + '\n\t'.join(configs))
+
+                logger(
+                    level=30,
+                    msg='Could not load Rucio configuration file. '
+                    'Rucio looked in the following paths for a configuration file, in order: '
+                    '\n\t' + '\n\t'.join(configs) + ''
+                    '\n\t Using empty configuration.')
+
+                # Make a temp cfg file
+                self.configfile = tempfile.NamedTemporaryFile(suffix=".cfg").name
+                with open(self.configfile, 'w') as f:
+                    f.write("")  # File must have some content
+                f.close()
 
         if not self.parser.read(self.configfile) == [self.configfile]:
             raise RuntimeError('Could not load Rucio configuration file. '