Remove labscript_suite from default config file

But add it as a default option so that config files may continue to use
it as an interpolation value.

Saving config files whenever a value is set breaks this, as it actually
saves the default value to disk. Without adding a guard against it, it
actually writes any provided default values to disk before loading the
existing config file, actually wiping out the user's config completely.

So this commit removes the overridden methods that save back to disk.

No labscript code actually sets config values except for some code in
the BLACS plugins `__init__.py`, which adds the list of available
plugins. Not writing this back to disk is fine. If we ever make GUI
interfaces for manipulating the config file, it is poor form to just
overwrite the user's config file anyway, which may re-order sections and
remove comments. For that we would want to use something like
https://pypi.org/project/ConfigUpdater/.

Also simplify the code that gets the config path. There is only one
place on disk for config paths now, and if it doesn't exist the user
will get a FileNotFoundError with the full path, so I don't think there
is a strong need to wrap that error in one written by us that basically
says the same thing!

This change removes the hostname and config_prefix variables. These
variables are imported (unused) by lyse and runviewer, so I will remove
them from those projects. They are also imported and used by BLACS to
construct its config filepath. I will modify BLACS to instead put its
config file in the standard config file locations for apps.

Fixes #22

Author: chrisjbillington

labscript_profile/default_profile/labconfig/example.ini

@@ -2,7 +2,6 @@
 experiment_name = default_experiment
 shared_drive = C:
 experiment_shot_storage = %(shared_drive)s\Experiments\%(experiment_name)s
-labscript_suite = C:\labscript_suite
 userlib=%(labscript_suite)s\userlib
 pythonlib = %(userlib)s\pythonlib
 labscriptlib = %(userlib)s\labscriptlib\%(experiment_name)s

labscript_utils/labconfig.py

@@ -12,48 +12,13 @@
 #####################################################################
 import sys
 import os
-import socket
-import subprocess
-import errno
 import configparser
 
-from labscript_profile import LABSCRIPT_SUITE_PROFILE
-# Look for a 'labconfig' folder in the labscript install directory:
-if LABSCRIPT_SUITE_PROFILE is not None:
-    config_prefix = os.path.join(LABSCRIPT_SUITE_PROFILE, 'labconfig')
-else:
-    # No labscript install directory found? Revert to system defaults
-    if os.name == 'nt':
-        config_prefix = os.path.abspath(r'C:\labconfig')
-    else:
-        config_prefix = os.path.join(os.getenv('HOME'),'labconfig')
-        if not os.path.exists(config_prefix):
-            config_prefix='/etc/labconfig/'
+from labscript_utils import dedent
+from labscript_profile import default_labconfig_path, LABSCRIPT_SUITE_PROFILE
 
-if not os.path.exists(config_prefix):
-    message = (r"Couldn't find labconfig folder. Please ensure it exists. " +
-               r"If the labscript suite is installed, labconfig must be <labscript_suite_profile>/labconfig/. " +
-               r"If the labscript suite is not installed, then C:\labconfig\ is checked on Windows, " +
-               r" and $HOME/labconfig/ then /etc/labconfig/ checked on unix.")
-    raise IOError(message)
+default_config_path = default_labconfig_path()
 
-config_prefix = os.path.abspath(config_prefix)
-
-if sys.platform == 'darwin':
-    hostname = subprocess.check_output(['scutil', '--get', 'LocalHostName']).decode('utf8').strip()
-else:
-    hostname = socket.gethostname()
-default_config_path = os.path.join(config_prefix,'%s.ini'%hostname)
-
-
-def mkdir_p(path):
-    try:
-        os.makedirs(path)
-    except OSError as exc:
-        if exc.errno == errno.EEXIST and os.path.isdir(path):
-            pass
-        else:
-            raise
 
 class EnvInterpolation(configparser.BasicInterpolation):
     """Interpolation which expands environment variables in values,
@@ -63,69 +28,44 @@ def before_get(self, *args):
         value = super(EnvInterpolation, self).before_get(*args)
         return os.path.expandvars(value)
 
+
 class LabConfig(configparser.ConfigParser):
     NoOptionError = configparser.NoOptionError
     NoSectionError = configparser.NoSectionError
 
-    def __init__(self,config_path=default_config_path,required_params={},defaults={}):
-        if isinstance(config_path,list):
+    def __init__(
+        self, config_path=default_config_path, required_params=None, defaults=None,
+    ):
+        if required_params is None:
+            required_params = {}
+        if defaults is None:
+            defaults = {}
+        defaults['labscript_suite'] = LABSCRIPT_SUITE_PROFILE
+        if isinstance(config_path, list):
             self.config_path = config_path[0]
         else:
             self.config_path = config_path
 
         self.file_format = ""
         for section, options in required_params.items():
-            self.file_format += "[%s]\n"%section
+            self.file_format += "[%s]\n" % section
             for option in options:
-                self.file_format += "%s = <value>\n"%option
-
-        # Ensure the folder exists:
-        mkdir_p(os.path.dirname(self.config_path))
-
-        # If the file doesn't exist, create it
-        if not os.path.exists(self.config_path):
-            with open(self.config_path,'a+') as f:
-                f.write(self.file_format)
+                self.file_format += "%s = <value>\n" % option
 
         # Load the config file
-        configparser.ConfigParser.__init__(self, defaults=defaults, interpolation=EnvInterpolation())
-        self.read(config_path) #read all files in the config path if it is a list (self.config_path only contains one string)
+        configparser.ConfigParser.__init__(
+            self, defaults=defaults, interpolation=EnvInterpolation()
+        )
+        # read all files in the config path if it is a list (self.config_path only
+        # contains one string):
+        self.read(config_path)
 
         try:
             for section, options in required_params.items():
                 for option in options:
-                    self.get(section,option)
-
-        except configparser.NoOptionError as e:
-            raise Exception('The experiment configuration file located at %s does not have the required keys. Make sure the config file containes the following structure:\n%s'%(config_path, self.file_format))
-
-
-    # Overwrite the add_section method to only attempt to add a section if it doesn't
-    # exist. We don't ever care whether a section exists or not, only that it does exist
-    # when we try and save an attribute into it.
-    def add_section(self,section):
-        # Create the group if it doesn't exist
-        if not section.lower() == 'default' and not self.has_section(section):
-            configparser.ConfigParser.add_section(self, section)
-
-    # Overwrite the set method so that it adds the section if it doesn't exist,
-    # and immediately saves the data to the file (to avoid data loss on program crash)
-    def set(self, section, option, value):
-        self.add_section(section)
-        configparser.ConfigParser.set(self,section,option,value)
-        self.save()
-
-    # Overwrite the remove section function so that it immediately saves the change to disk
-    def remove_section(self,section):
-        configparser.ConfigParser.remove_section(self,section)
-        self.save()
-
-    # Overwrite the remove option function so that it immediately saves the change to disk
-    def remove_option(self,section,option):
-        configparser.ConfigParser.remove_option(self,section,option)
-        self.save()
-
-    # Provide a convenience method to save the contents of the ConfigParser to disk
-    def save(self):
-        with open(self.config_path, 'w+') as f:
-            self.write(f)
+                    self.get(section, option)
+        except configparser.NoOptionError:
+            msg = f"""The experiment configuration file located at {config_path} does
+                not have the required keys. Make sure the config file containes the
+                following structure:\n{self.file_format}"""
+            raise Exception(dedent(msg))