Settings

The settings of a yuno, defining the tree of gobj’s to be created and their configuration, can be done with the function:

    PUBLIC json_t *json_config(
        BOOL print_verbose_config,
        BOOL print_final_config,
        const char *fixed_config,
        const char *variable_config,
        const char *config_json_file,
        const char *parameter_config,
        pe_flag_t quit
    );

Source code in:

json_config.c

The json_config() function is a utility in Yuneta designed to generate a final JSON configuration by merging multiple JSON inputs. It supports advanced features like comment handling, variable substitution, and range-based expansion. The function can output the resulting configuration, validate it, and handle errors robustly.

The json_config() function merges multiple JSON configurations into a single final configuration string, following a specific order of precedence. It also includes features like comment handling, variable substitution, and range-based expansion for flexibility and advanced use cases.

The return of json_config() is a json_t * object (owned by the caller, must be freed with json_decref()).

Global Settings¶

If the final JSON has a key global, his value will be used as the argument jn_global_settings in gobj_start_up, and will be merge to kw when creating a gobj.

Features¶

1. Global Variable Substitution¶

The function replaces strings enclosed in (^^ ^^) with corresponding values from the __json_config_variables__ dictionary. This dictionary includes global variables returned by gobj_global_variables().

Predefined Variables in `__json_config_variables__`¶

Variable	Description
`__node_owner__`	Node owner of the Yuno.
`__realm_id__`	Realm ID of the Yuno.
`__realm_owner__`	Realm owner of the Yuno.
`__realm_role__`	Realm role of the Yuno.
`__realm_name__`	Name of the realm.
`__realm_env__`	Environment of the realm.
`__yuno_id__`	Unique ID of the Yuno.
`__yuno_role__`	Role of the Yuno.
`__yuno_name__`	Name of the Yuno.
`__yuno_tag__`	Tag of the Yuno.
`__yuno_role_plus_name__`	Role and name of the Yuno.
`__hostname__`	Hostname of the system.
`__sys_system_name__`	System name (Linux only).
`__sys_node_name__`	Node name (Linux only).
`__sys_version__`	System version (Linux only).
`__sys_release__`	System release (Linux only).
`__sys_machine__`	Machine type (Linux only).
`__tls_library__`	Active TLS backend: `"openssl"` or `"mbedtls"` (compile-time).
`__bind_ip__`	Bind IP address of the Yuno.
`__multiple__`	Whether the Yuno allows multiple instances (boolean).

2. Comment Handling¶

Supports single-line comments using the syntax ##^ in JSON strings.

3. Range-Based Expansion¶

Expands JSON objects based on ranges defined within the input JSON. For example:

{
"__range__": [12000, 12002],
"__content__": {
"item(^^__range__^^)": { "id": "(^^__range__^^)" }
}
}

Will expand into:

{
"item12000": { "id": "12000" },
"item12001": { "id": "12001" },
"item12002": { "id": "12002" }
}

4. Order of Precedence¶

The function processes inputs in the following order:

fixed_config: Non-writable configuration.
variable_config: Writable configuration.
config_json_file: Overwrites variable_config if specified.
parameter_config: Final overwrites.

Behavior¶

Error Handling: The function exits or continues based on the quit parameter if a JSON parsing error occurs.
Verbose Outputs: If print_verbose_config or print_final_config is TRUE, the function prints the configurations and exits.

Return Value¶

Returns a dynamically allocated string containing the final JSON configuration.
Important: The returned string must be freed using jsonp_free() to avoid memory leaks.