automatic generation of json schema for plugin config

[milyin]

The schema is generated on build stage by build.rs based on rust config structure. When structure is changed, schema is regenerated and should be committed into git together with changes in Rust code.

[gabrik]

LGTM, modulo the failing CI, I think there should be some feature-gate for no_std.

[p-avital]

The generated schema here is incomplete: a number would also be accepted. Not sure it that's an issue for our purpose though

[milyin]

This goes directly from definition of port field in zenoh-plugin-rest/config.rs. If we want to correct it, we should fix this type

pub struct Config {
    #[serde(deserialize_with = "deserialize_http_port")]
    pub http_port: String,
    __path__: Option<String>,
    __required__: Option<bool>,
}

[p-avital]

I would have expected {"type": "boolean", "required": false}. Is this equivalent, or is the _required_ key now mandatory, but nullable?

[milyin]

I need to check json schema standard, but at least example file without __required__ field passes the check.
I've added additional verification of sample config file against generated schema. Seems that serde is much less strict than formal schema validation. Sometimes it seems completely wrong: schema requires volumes and storages to be vectors, but our config sample shows them as objects:

pub struct PluginConfig {
    pub name: String,
    pub required: bool,
    pub backend_search_dirs: Option<Vec<String>>,
    pub volumes: Vec<VolumeConfig>,
    pub storages: Vec<StorageConfig>,
...