allow to read environment variables as config parameters

Environment variables must be prefixed with winix_ to be loaded by winix.
The winix_ prefix is then removed and the key value converted to lowercase.

Sample:
evn WINIX_MY_OPTION=TEST123test winix -c config_file

This will add my_option to the config with value TEST123test.
Environment variables are read last so they will overwrite the values
from the configuration files.

winixd/core/config.cpp

@@ -95,8 +95,6 @@ bool Config::ReadConfig(const std::wstring & config_file)
 
 	if( status == pt::SpaceParser::ok )
 	{
-		AssignValues();
-		SetAdditionalVariables();
 		return true;
 	}
 	else
@@ -107,6 +105,12 @@ bool Config::ReadConfig(const std::wstring & config_file)
 }
 
 
+void Config::AssignValuesFromSpace()
+{
+	AssignValues();
+	SetAdditionalVariables();
+}
+
 
 
 void Config::AssignValues()

winixd/core/config.h

@@ -854,6 +854,8 @@ public:
 
 	Config();
 	bool ReadConfig(const std::wstring & config_file);
+	void AssignValuesFromSpace();
+
 
 	/*
 	 *

winixd/main/main.cpp

@@ -47,6 +47,7 @@
 
 
 
+
 namespace Winix
 {
 
@@ -67,11 +68,22 @@ void print_syntax()
 	std::cout << "Usage: winix [options]" << std::endl;
 	std::cout << "  -c             : a path to the config file" << std::endl;
 	std::cout << "  --config       : a path to the config file" << std::endl;
+	std::cout << "  --use-env      : allow to use environment variables" << std::endl;
+	std::cout << "  --dump-config  : dump all read config options to stdout and exit" << std::endl;
 	std::cout << "  -h             : print usage information" << std::endl;
 	std::cout << "  --help         : print usage information" << std::endl;
 	std::cout << "  -?             : print usage information" << std::endl;
+	std::cout << std::endl;
 	std::cout << "At least one -c or --config parameter is required, use -c or --config option" << std::endl;
 	std::cout << "multiple times to load more than one config." << std::endl;
+	std::cout << std::endl;
+	std::cout << "Environment variables must be prefixed with winix_ to be loaded by winix." << std::endl;
+	std::cout << "The winix_ prefix is then removed and the key value converted to lowercase." << std::endl;
+	std::cout << "Sample:" << std::endl;
+	std::cout << "evn WINIX_MY_OPTION=TEST123test winix -c config_file" << std::endl;
+	std::cout << "This will add my_option to the config with value TEST123test." << std::endl;
+	std::cout << "Environment variables are read last so they will overwrite the values" << std::endl;
+	std::cout << "from the configuration files." << std::endl;
 }
 
 
@@ -179,7 +191,42 @@ bool ReadConfigs(const pt::Space::TableType & table, size_t & config_read)
 }
 
 
-bool ReadConfigs(const pt::Space & options)
+void ReadEnvOption(const char * option)
+{
+	const char winix_prefix[] = "winix_";
+	size_t prefix_len = sizeof(winix_prefix) - 1; // null terminating table
+	std::wstring opt, val;
+
+	if( pt::is_substr_nc(winix_prefix, option) )
+	{
+		pt::utf8_to_wide(option + prefix_len, opt);
+
+		std::wstring::size_type sep = opt.find('=');
+
+		if( sep != std::wstring::npos )
+		{
+			val = opt.substr(sep + 1);
+			opt.erase(sep);
+		}
+
+		TemplatesFunctions::locale.ToSmall(opt);
+		app.config.space.add(opt, val);
+	}
+}
+
+
+void ReadConfigFromEnv(const char ** env)
+{
+	for(size_t i = 0 ; env[i] ; ++i)
+	{
+		ReadEnvOption(env[i]);
+	}
+}
+
+
+
+
+bool ReadConfigs(const pt::Space & options, const char ** env)
 {
 	size_t config_read = 0;
 	bool status = true;
@@ -205,6 +252,13 @@ bool ReadConfigs(const pt::Space & options)
 		return false;
 	}
 
+	if( options.has_key(L"use-env") )
+	{
+		ReadConfigFromEnv(env);
+	}
+
+	app.config.AssignValuesFromSpace();
+
 	return status;
 }
 
@@ -212,7 +266,7 @@ bool ReadConfigs(const pt::Space & options)
 
 
 
-int main(int argc, const char ** argv)
+int main(int argc, const char ** argv, const char ** env)
 {
 using Winix::app;
 
@@ -241,22 +295,35 @@ using Winix::app;
 	}
 
 	Winix::Log & log = app.GetMainLog();
+	pt::WTextStream * log_buffer = log.get_log_buffer();
 	Winix::LogInfo(log, Winix::log3, "UTC booting Winix", true, ""); // date will be printed as UTC because the time zones are not loaded yet
 
-	if( !Winix::ReadConfigs(options) )
+	if( !Winix::ReadConfigs(options, env) )
 	{
 		// we need to print the buffer by hand because the logger
 		// is not fully initialized yet
-		pt::WTextStream * buffer = log.get_log_buffer();
-
-		if( buffer && !buffer->empty() )
+		if( log_buffer && !log_buffer->empty() )
 		{
-			pt::wide_stream_to_utf8(*buffer, std::cout);
+			pt::wide_stream_to_utf8(*log_buffer, std::cout);
 		}
 
 		return 2;
 	}
 
+	if( options.has_key(L"dump-config") )
+	{
+		if( log_buffer )
+		{
+			log << "all read config options (some of the values could have been modified by winix"
+				<< " but the modified values are not printed here):" << Winix::logend;
+			app.config.space.serialize_to_space_stream(*log_buffer, true);
+			log << Winix::logend;
+			pt::wide_stream_to_utf8(*log_buffer, std::cout);
+		}
+
+		return 0;
+	}
+
 	app.InitLoggers();
 
 	if( app.stdout_is_closed || app.config.demonize )