Add Sentinel configuration reading

Added reading Sentinel configuration from environment variables.

Sentinel address is configured via 'DBAAS_SERVICE_HOST' and
'DBAAS_SERVICE_SENTINEL_PORT' environment variables.

Sentinel master name is configured via 'DBAAS_MASTER_NAME' environment
variable.

Sentinel support is now activated.

Using Sentinel is optional. If Sentinel related environment variables
are not set, then static address for Redis server is used as before
(i.e. this change is backward compatible).

Signed-off-by: Rolf Badorek <rolf.badorek@nokia.com>
Change-Id: I34031ac56268673996c6fecb00eeed6e5dda8b9a
diff --git a/include/private/configurationreader.hpp b/include/private/configurationreader.hpp
index 6c175e7..7cb6f1a 100644
--- a/include/private/configurationreader.hpp
+++ b/include/private/configurationreader.hpp
@@ -19,6 +19,8 @@
 
 #define DB_HOST_ENV_VAR_NAME "DBAAS_SERVICE_HOST"
 #define DB_PORT_ENV_VAR_NAME "DBAAS_SERVICE_PORT"
+#define SENTINEL_PORT_ENV_VAR_NAME "DBAAS_SERVICE_SENTINEL_PORT"
+#define SENTINEL_MASTER_NAME_ENV_VAR_NAME "DBAAS_MASTER_NAME"
 
 #include <iosfwd>
 #include <string>
@@ -61,6 +63,10 @@
         std::string dbHostEnvVariableValue;
         const std::string dbPortEnvVariableName;
         std::string dbPortEnvVariableValue;
+        const std::string sentinelPortEnvVariableName;
+        std::string sentinelPortEnvVariableValue;
+        const std::string sentinelMasterNameEnvVariableName;
+        std::string sentinelMasterNameEnvVariableValue;
         boost::optional<boost::property_tree::ptree> jsonDatabaseConfiguration;
         std::string sourceForDatabaseConfiguration;
         std::unordered_map<std::string, std::pair<boost::property_tree::ptree, std::string>> jsonNamespaceConfigurations;