Datatype that represents YAML with substituted variables.
If YAML has value that starts with an $, then such value is treated as a variable from config_vars. For example if config_vars contains variable: 42 and the YAML is following:
Then the result of yaml["some_element"]["some"].As<int>() is 42.
If YAML key ends on '#env' and the mode is YamlConfig::Mode::kEnvAllowed, then the value of the key is searched in environment variables of the process and returned as a value. For example:
If YAML key ends on '#fallback', then the value of the key is used as a fallback for environment and $ variables. For example for the following YAML with YamlConfig::Mode::kEnvAllowed:
The result of yaml["some_element"]["some"].As<int>() is the value of variable from config_vars if it exists; otherwise the value is the contents of the environment variable SOME_ENV_VARIABLE if it exists; otherwise the value if 100500, from the fallback.
Another example:
With YamlConfig::Mode::kEnvAllowed the result of yaml["some_element"]["value"].As<int>() is the value of ENV_NAME environment variable if it exists; otherwise it is 5.
- Warning
- YamlConfig::Mode::kEnvAllowed should be used only on configs that come from trusted environments. Otherwise, an attacker could create a config with
#env and read any of your environment variables, including variables that contain passwords and other sensitive data.
Definition at line 60 of file yaml_config.hpp.
Inheritance diagram for yaml_config::YamlConfig: