From 8438f95e687a5563ad454b7364bb54bd07122083 Mon Sep 17 00:00:00 2001
From: Benjamin Renard <brenard@easter-eggs.com>
Date: Fri, 19 Nov 2021 16:16:46 +0100
Subject: [PATCH] Config: Add config_file_env_variable parameter

The new config_file_env_variable parameter allow to specify environment
variable name that will be used to determine configuration file path if
it's not explicitly provided using -c/--config parameter.
---
 mylib/config.py | 12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)

diff --git a/mylib/config.py b/mylib/config.py
index 54d4060..00eabda 100644
--- a/mylib/config.py
+++ b/mylib/config.py
@@ -412,7 +412,8 @@ class RawWrappedTextHelpFormatter(argparse.RawDescriptionHelpFormatter):
 class Config:
     """ Configuration helper """
 
-    def __init__(self, appname, shortname=None, version=None, encoding=None):
+    def __init__(self, appname, shortname=None, version=None, encoding=None,
+                 config_file_env_variable=None):
         self.appname = appname
         self.shortname = shortname
         self.version = version if version else '0.0'
@@ -424,6 +425,7 @@ class Config:
         self._loaded_callbacks = []
         self._loaded_callbacks_executed = []
         self._filepath = None
+        self.config_file_env_variable = config_file_env_variable
 
     def add_section(self, name, loaded_callback=None, **kwargs):
         """
@@ -567,12 +569,14 @@ class Config:
             formatter_class=RawWrappedTextHelpFormatter,
             **kwargs)
 
+        config_file_help = 'Configuration file to use (default: %s)' % self.config_filepath
+        if self.config_file_env_variable:
+            config_file_help += '\n\nYou also could set %s environment variable to specify your configuration file path.' % self.config_file_env_variable
         self.options_parser.add_argument(
             '-c',
             '--config',
             default=self.config_filepath,
-            help='Configuration file to use (default: %s)' %
-            self.config_filepath
+            help=config_file_help
         )
 
         self.options_parser.add_argument(
@@ -684,6 +688,8 @@ class Config:
         """ Retrieve configuration file path """
         if self._filepath:
             return self._filepath
+        if self.config_file_env_variable and os.environ.get(self.config_file_env_variable):
+            return os.environ.get(self.config_file_env_variable)
         return os.path.join(
             self.config_dir,
             ("%s.ini" % self.shortname) if self.shortname