feat(config): Reference value in environment var

This makes it possible to reference env vars from any
config parameter using ${VARNAME}

Closes jaagr/lemonbuddy#36
This commit is contained in:
Michael Carlberg 2016-07-27 02:53:47 +02:00
parent 7a141175b4
commit e94bd6a271
2 changed files with 62 additions and 3 deletions

View File

@ -253,6 +253,9 @@ The configuration syntax is based on the `ini` file format.
; Other values can be referenced using:
key = ${section.key}
; Environment variables can be referenced using:
key = ${env:VAR_NAME}
~~~
~~~ ini
[section/name]

View File

@ -2,6 +2,7 @@
#include <mutex>
#include <boost/lexical_cast.hpp>
#include <boost/property_tree/ptree.hpp>
#include <boost/property_tree/ini_parser.hpp>
@ -20,30 +21,71 @@ namespace config
static std::recursive_mutex mtx;
/**
* Gets the path used to access the current bar section
*/
std::string get_bar_path();
/**
* Sets the path used to access the current bar section
*/
void set_bar_path(std::string path);
/**
* Loads a configuration file
*/
void load(std::string path);
/**
* Loads a configuration file
*/
void load(const char *dir, std::string path);
/**
* Reloads the configuration values
* TODO: Implement properly
*/
// void reload();
/**
* Gets the boost property tree handler
*/
boost::property_tree::ptree get_tree();
/**
* Builds the path used to find a parameter in the given section
*/
std::string build_path(std::string section, std::string key);
/**
* Gets the location of the configuration file
*/
std::string get_file_path();
/**
* Finds the value of a config parameter defined
* as a reference variable using ${section.param} or ${env:VAR}
*/
template<typename T>
T dereference_var(std::string ref_section, std::string ref_key, std::string var, const T ref_val)
{
std::lock_guard<std::recursive_mutex> lck(config::mtx);
std::string::size_type n, m;
auto n = var.find("${");
auto m = var.find("}");
if ((n = var.find("${")) != 0) return ref_val;
if ((m = var.find("}")) != var.length()-1) return ref_val;
if (n != 0 || m != var.length()-1)
return ref_val;
auto path = var.substr(2, m-2);
if (path.find("env:") == 0) {
auto *envvar_value = std::getenv(path.substr(4).c_str());
if (envvar_value != nullptr)
return boost::lexical_cast<T>(envvar_value);
return ref_val;
}
auto ref_path = build_path(ref_section, ref_key);
if ((n = path.find(".")) == std::string::npos)
@ -62,6 +104,9 @@ namespace config
return dereference_var<T>(section, key, str_val, val.get());
}
/**
* Gets the value of a variable by section and parameter name
*/
template<typename T>
T get(std::string section, std::string key)
{
@ -77,6 +122,10 @@ namespace config
return dereference_var<T>(section, key, str_val, val.get());
}
/**
* Gets the value of a variable by section and parameter name
* with a default value in case the parameter isn't defined
*/
template<typename T>
T get(std::string section, std::string key, T default_value)
{
@ -88,6 +137,9 @@ namespace config
return dereference_var<T>(section, key, str_val.get_value_or(""), val.get_value_or(default_value));
}
/**
* Gets a list of values by section and parameter name
*/
template<typename T>
std::vector<T> get_list(std::string section, std::string key)
{
@ -107,6 +159,10 @@ namespace config
return vec;
}
/**
* Gets a list of values by section and parameter name
* with a default list in case the list isn't defined
*/
template<typename T>
std::vector<T> get_list(std::string section, std::string key, std::vector<T> default_value)
{