feat: add rest config and rest config checker

[joaoandre-avaiga]

What type of PR is this? (check all applicable)

• Refactor
• Feature
• Bug Fix
• Optimization
• Documentation Update

Description

Add option to inform rest server Host, Port and other attributes that could be used for a deploy in a production environment.

Related Tickets & Documents

• Related Issue Support production environment for taipy-rest #421
• Closes Support production environment for taipy-rest #421

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• The documentation has been updated, or a dedicated issue created. (If applicable)
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[jrobinAV]

Some refactoring is needed. You can have a look at the taipy/core/config/__init__.py and taipy/core/config/core_section.py files

[jrobinAV]

It should be a unique section, no? Only one RestConfig should be created in the Config. No?

[jrobinAV]

I would use the same design pattern as the existing section implementations for legacy and consistency, even if your proposal seems smoother. Changing the design pattern could be a good idea (the factory pattern can be cumbersome), but it requires some deep discussions before, as it is an important breaking change.

For the other sections, we reserve the __init__ constructors for Taipy's internal usage. It is indirectly used by serializers (TOML and JSON) that need to instantiate sections from files (eventually with some missing attributes). So they expose all the parameters as optional. On the contrary, the _configure method is a static method acting as a factory, so the developer doesn't need to use the constructor directly (__init__ method). It instantiates the Section, registers it in the Config, and returns it.

Something like:

    @staticmethod
    def _configure(
        port: int = 5000,
        host: str = "127.0.0.1",
        use_https: bool = False,
        ssl_cert: Optional[str] = None,
        ssl_key: Optional[str] = None,
    ):
        section = RestConfig(port, host, use_https, ssl_cert, ssl_key) 
        Config._register(section)
        return Config.unique_sections[RestConfig.name]

[jrobinAV]

We usually do it in the __init__.py file as the checker must also be added.

[jrobinAV]

Suggested change

	# specific language governing permissions and limitations under the License.
	# specific language governing permissions and limitations under the License.
	_inject_section(
	RestConfig,
	"rest",
	RestConfig.default_config(),
	[("configure_rest", RestConfig._configure)],
	add_to_unconflicted_sections=True,
	)
	_Checker.add_checker(_RestConfigChecker)

[jrobinAV]

Suggested change

	name: str = "REST"
	"""Configuration parameters for running the `Rest^` service."""
	name: str = "REST"

[jrobinAV]

If some values are None, they must not be added to the dict.

[jrobinAV]

We cannot set the default values here when an attribute is not in the dictionary. We must use None instead. Otherwise, the compilation mechanism won't work when the user overrides only one attribute from a TOML file (or from an env variable)

[jrobinAV]

All the getters should use the templating system to allow users to overwrite values from env variables. Use _tpl._replace_templates that should do the job.

[jrobinAV]

If the RestConfig is a unique section, this line should be simpler.

[jrobinAV]

We should not need to do anything to retrieve the default values.
Then when the configure method is called, it should overwrite the values.
Then when loading a TOML file, this should again overwrite the values.
And the same with the env variables:

Config.rest.port = RestConfig._DEFAULT_PORT
Config.rest.host = RestConfig._DEFAULT_HOST
... # etc for all the attributes

# Now we use the configure method
Config.configure_rest(port=1)
Config.rest.port = 1
Config.rest.host = RestConfig._DEFAULT_HOST

# now we load a toml file
toml_cfg = NamedTemporaryFile(
content="""
[TAIPY]

[REST]
port = 2
host = "192.168.0.87"
        """
)
Config.load(toml_cfg.filename)
Config.rest.port = 2
Config.rest.host = "192.168.0.87"

# And finally we use env variables
assert Config.rest.port == RestConfig._DEFAULT_PORT
assert Config.rest.host== RestConfig._DEFAULT_HOST
Config.configure_rest(port="ENV[PORT]", host="ENV[HOST]")

with pytest.raises(MissingEnvVariableError):
    _ = Config.rest.port
with pytest.raises(MissingEnvVariableError):
    _ = Config.rest.host
... # etc for all the attributes

with patch.dict(os.environ, {"PORT": "3:int", "HOST": "1.2.3.4"}):
    assert Config.rest.port == 3
    assert Config.rest.bar == "1.2.3.4"