Source code for seamm_installer.configuration
# !/usr/bin/env python
# -*- coding: utf-8 -*-
"""A class for reading, updating and writing the configuration file.
This class handles the configuration (.ini) file as text, so that comments
in the file are preserved.
"""
from pathlib import Path
[docs]
class Configuration(object):
def __init__(self, path=None):
self._path = None
"A dictionary to save the text of the configuration file."
self._data = {}
# Set the path, which reads the file if it exsists
self.path = path
def __eq__(self, other):
"Test if this configuration is equal to another in the sense of text."
return str(self) == str(other)
def __str__(self):
"""Create the text of the configuration file."""
return self.to_string()
@property
def path(self):
"""The path to the configuration file."""
return self._path
@path.setter
def path(self, value):
if value is None:
self._path = None
self._data = {}
else:
new_path = Path(value).expanduser().resolve()
if new_path != self._path:
self._path = new_path
if new_path.exists():
self._read()
else:
self._data = {}
[docs]
def add_prolog(self, text="", force=False):
"""Add the prolog to the configuration.
Parameters
----------
text : str = ''
The body of the prolog, which should be just comments.
force : bool = True
Whether to overwrite an existing prolog.
"""
if "PROLOG" in self._data and not force:
raise KeyError("The prolog already exists.")
self._data["PROLOG"] = text.splitlines()
[docs]
def add_section(self, name, text="", force=False):
"""Add a new section to the configuration.
Parameters
----------
name : str
The name of the section.
text : str = ''
The body of the section, which must be properly formatted.
force : bool = True
Whether to overwrite an existing section of the same name.
"""
if self.section_exists(name) and not force:
raise KeyError(f"Section '{name}' already exists.")
section = name.lower()
self._data[section] = [f"[{name}]"]
lines = text.splitlines()
if len(lines) > 0:
tmp = lines[0].strip()
if tmp[0] == "[" and tmp[-1] == "]":
if tmp[1:-1] != name:
raise ValueError(
"Section name doesn't match: '{tmp[1:-1]}' vs '{name}'"
)
lines = lines[1:]
self._data[section].extend(lines)
[docs]
def file_exists(self):
"""Whether the configuration file exists."""
if self.path is None:
return False
else:
return self.path.exists()
[docs]
def from_string(self, text):
"""Replace the contents of the configuration with those from `text`.
Parameters
----------
text : str
The configuration data as text.
"""
self._data = {}
section = "PROLOG"
lines = []
for line in text.splitlines():
if len(line) > 0:
# Look for a section name, like [<name>]
tmp = line.strip()
if tmp[0] == "[" and tmp[-1] == "]":
self._data[section] = lines
section = tmp[1:-1].lower()
lines = []
lines.append(line)
# Put the last section into the data
self._data[section] = lines
[docs]
def get_prolog(self):
"""Return the prolog of the file, if any.
Returns
-------
str
The prolog of the configuration.
"""
if "PROLOG" in self._data:
result = "\n".join(self._data["PROLOG"]) + "\n"
else:
result = ""
return result
[docs]
def get_values(self, section):
"""Return the values in a section as a dictionary.
Returns an empty dictionary if the section does not exist, or if it
does not contain any keyword definitions. Use `section_exists` to
differentiate.
Parameters
----------
section : str
The name of the section to retrieve.
Returns
-------
dict
A dictionary of keyword-value pairs, as strings.
"""
result = {}
if self.section_exists(section):
for line in self._data[section.lower()]:
line = line.strip()
if len(line) > 0:
if line[0] == "#":
continue
if "=" in line:
key, value = line.split("=", maxsplit=1)
result[key.strip()] = value.strip()
return result
def _read(self):
"""Read the configuration file and split into sections."""
self.from_string(self.path.read_text())
[docs]
def save(self):
"""Save the current configuration to disk."""
self.path.write_text(str(self))
[docs]
def sections(self):
"""Return a list of sections in the configuration.
Returns
-------
[str]
The list of sections.
"""
result = sorted(self._data.keys())
if "PROLOG" in result:
result.remove("PROLOG")
if "seamm" in result:
result.remove("seamm")
result.insert(0, "seamm")
if "default" in result:
result.remove("default")
result.insert(0, "default")
return result
[docs]
def section_exists(self, section):
"""Return whether a section exits in the configuration.
Parameters
----------
section : str
The name of the section.
Returns
-------
bool
True if the section exists; False otherwise.
"""
return section is not None and section.lower() in self._data
[docs]
def set_value(self, section, key, value, strict=False):
"""Set the key in a section.
Parameters
----------
section : str
The section to work with.
key : str
The key to set in the section.
value : str
The value to set the key to.
strict : bool = False
Raise an error is the key does not already exist.
"""
lines = self._data[section.lower()]
found = False
i = 0
for line in lines:
if "=" in line:
if line.strip().split("=", maxsplit=1)[0].strip() == key:
found = True
if value is None:
lines[i] = f"# {line}"
else:
lines[i] = f"{key} = {value}"
break
i += 1
if not found:
if strict:
raise KeyError(f"'{key}' not in section {section}.")
else:
# Maybe it is there but commented...
found = False
i = 0
for line in lines:
line = line.lstrip("#").strip()
if "=" in line:
if line.split("=", maxsplit=1)[0].strip() == key:
found = True
if value is not None:
lines[i] = f"{key} = {value}"
break
i += 1
if not found:
if value is None:
lines.append(f"# {key} = ")
else:
lines.append(f"{key} = {value}")
[docs]
def to_string(self, section=None):
"""Create the text of a section.
Parameters
----------
section : str
The name of the section. Defaults to the entire file.
"""
if section is None:
result = []
if "PROLOG" in self._data:
result.extend(self._data["PROLOG"])
if result[-1] != "":
result.append("")
for section in self.sections():
result.extend(self._data[section])
if result[-1] != "":
result.append("")
else:
result = self._data[section.lower()]
return "\n".join(result) + "\n"