Configuration and environment variable improvements

nano/lib/env.cpp

@@ -14,7 +14,8 @@ std::optional<std::string> nano::env::get (std::string_view name)
 	return std::nullopt;
 }
 
-std::optional<bool> nano::env::get_bool (std::string_view name)
+template <>
+std::optional<bool> nano::env::get (std::string_view name)
 {
 	std::vector<std::string> const on_values{ "1", "true", "on" };
 	std::vector<std::string> const off_values{ "0", "false", "off" };
@@ -34,36 +35,4 @@ std::optional<bool> nano::env::get_bool (std::string_view name)
 		throw std::invalid_argument ("Invalid environment boolean value: " + *value);
 	}
 	return std::nullopt;
-}
-
-std::optional<int> nano::env::get_int (std::string_view name)
-{
-	if (auto value = get (name))
-	{
-		try
-		{
-			return std::stoi (*value);
-		}
-		catch (std::invalid_argument const &)
-		{
-			throw std::invalid_argument ("Invalid environment integer value: " + *value);
-		}
-	}
-	return std::nullopt;
-}
-
-std::optional<unsigned> nano::env::get_uint (std::string_view name)
-{
-	if (auto value = get (name))
-	{
-		try
-		{
-			return std::stoul (*value);
-		}
-		catch (std::invalid_argument const &)
-		{
-			throw std::invalid_argument ("Invalid environment unsigned integer value: " + *value);
-		}
-	}
-	return std::nullopt;
 }

nano/lib/env.hpp

@@ -1,21 +1,42 @@
 #pragma once
 
+#include <boost/lexical_cast.hpp>
+
 #include <optional>
 #include <string_view>
 
-/*
- * Get environment variable as a specific type or none if variable is not present.
- */
 namespace nano::env
 {
+/**
+ * Get environment variable as a specific type or none if variable is not present.
+ */
 std::optional<std::string> get (std::string_view name);
 
-// @throws std::invalid_argument if the value is not a valid boolean
-std::optional<bool> get_bool (std::string_view name);
-
-// @throws std::invalid_argument if the value is not a valid integer
-std::optional<int> get_int (std::string_view name);
+/**
+ * Get environment variable as a specific type or none if variable is not present.
+ * @throws std::invalid_argument if the value cannot be converted
+ */
+template <typename T>
+std::optional<T> get (std::string_view name)
+{
+	if (auto value = get (name))
+	{
+		try
+		{
+			return boost::lexical_cast<T> (*value);
+		}
+		catch (boost::bad_lexical_cast const &)
+		{
+			throw std::invalid_argument ("Invalid environment value: " + *value);
+		}
+	}
+	return std::nullopt;
+}
 
-// @throws std::invalid_argument if the value is not a valid integer
-std::optional<unsigned> get_uint (std::string_view name);
+/**
+ * Specialization for boolean values.
+ * @throws std::invalid_argument if the value is not a valid boolean
+ */
+template <>
+std::optional<bool> get (std::string_view name);
 }

nano/lib/stats.cpp

@@ -33,7 +33,7 @@ std::string nano::stat_log_sink::tm_to_string (tm & tm)
 nano::stats::stats (nano::logger & logger_a, nano::stats_config config_a) :
 	config{ std::move (config_a) },
 	logger{ logger_a },
-	enable_logging{ nano::env::get_bool ("NANO_LOG_STATS").value_or (false) }
+	enable_logging{ nano::env::get<bool> ("NANO_LOG_STATS").value_or (false) }
 {
 }
 

nano/lib/threading.cpp

@@ -19,7 +19,7 @@ boost::thread::attributes nano::thread_attributes::get_default ()
 unsigned nano::hardware_concurrency ()
 {
 	static auto const concurrency = [] () {
-		if (auto value = nano::env::get_uint ("NANO_HARDWARE_CONCURRENCY"))
+		if (auto value = nano::env::get<unsigned> ("NANO_HARDWARE_CONCURRENCY"))
 		{
 			std::cerr << "Hardware concurrency overridden by NANO_HARDWARE_CONCURRENCY environment variable: " << *value << std::endl;
 			return *value;