Add --env-manager option for mlflow models commands and deprecate --no-conda flag

[harupy]

Signed-off-by: harupy 17039389+harupy@users.noreply.github.com

What changes are proposed in this pull request?

As a stepping stone for pyenv + virtualenv support in MLflow Models & Projects, introduce --env-manager option and deprecate --no-conda.

How is this patch tested?

Unit tests

Does this PR change the documentation?

• No. You can skip the rest of this section.
• Yes. Make sure the changed pages / sections render correctly by following the steps below.

1. Check the status of the ci/circleci: build_doc check. If it's successful, proceed to the
   next step, otherwise fix it.
2. Click Details on the right to open the job page of CircleCI.
3. Click the Artifacts tab.
4. Click docs/build/html/index.html.
5. Find the changed pages / sections and make sure they render correctly.

Release Notes

Is this a user-facing change?

• No. You can skip the rest of this section.
• Yes. Give a description of this change to be included in the release notes for MLflow users.

(Details in 1-2 sentences. You can just refer to another PR with a description if this PR is part of a larger change.)

What component(s), interfaces, languages, and integrations does this PR affect?

Components

• area/artifacts: Artifact stores and artifact logging
• area/build: Build and test infrastructure for MLflow
• area/docs: MLflow documentation pages
• area/examples: Example code
• area/model-registry: Model Registry service, APIs, and the fluent client calls for Model Registry
• area/models: MLmodel format, model serialization/deserialization, flavors
• area/projects: MLproject format, project running backends
• area/scoring: MLflow Model server, model deployment tools, Spark UDFs
• area/server-infra: MLflow Tracking server backend
• area/tracking: Tracking Service, tracking client APIs, autologging

Interface

• area/uiux: Front-end, user experience, plotting, JavaScript, JavaScript dev server
• area/docker: Docker use across MLflow's components, such as MLflow Projects and MLflow Models
• area/sqlalchemy: Use of SQLAlchemy in the Tracking Service or Model Registry
• area/windows: Windows support

Language

• language/r: R APIs and clients
• language/java: Java APIs and clients
• language/new: Proposals for new client languages

Integrations

• integrations/azure: Azure and Azure ML integrations
• integrations/sagemaker: SageMaker integrations
• integrations/databricks: Databricks integrations

How should the PR be classified in the release notes? Choose one:

• rn/breaking-change - The PR will be mentioned in the "Breaking Changes" section
• rn/none - No description will be included. The PR will be mentioned only by the PR number in the "Small Bugfixes and Documentation Updates" section
• rn/feature - A new user-facing feature worth mentioning in the release notes
• rn/bug-fix - A user-facing bug fix worth mentioning in the release notes
• rn/documentation - A user-facing documentation change worth mentioning in the release notes

[harupy]

Suggested change

	CONDA = "conda"
	CONDA = "conda"
	VIRTUALENV = "virtualenv"

VIRTUALENV will be added in #5380

[WeichenXu123]

LGTM

[dbczumar]

Can we update the help message to tell the user to use --env-manager=local instead?

[harupy]

Sure!

[dbczumar]

Can we explain what each of this values means? I.e. local -> use the local environment. conda -> use conda.

[harupy]

Sure!

[dbczumar]

Can we default to conda instead of defaulting to None and resolving later?

[WeichenXu123]

If so, suppose old version users he might use command with argument --no-conda, then when upgrading to new version mlflow command will fail.

[WeichenXu123]

currently --no-conda argument is deprecated not removed, so we should keep --no-conda works.

[harupy]

@dbczumar I chose None to detect whether or not --env-manager is specified and distinguish the following cases:

mlflow models ... --no-conda
mlflow models ... --no-conda --env-manager=conda  # should fail

[harupy]

Or we could use sys.argv:

import sys


def _resolve_env_manager(ctx, param, value):
    no_conda = ctx.params["no_conda"]
    env_manager = EnvManager.from_string(value)
    if not no_conda:
        return env_manager

    is_env_manager_specified = param.opts[0] in sys.argv[1:]
    # only --no-conda is specified
    if not is_env_manager_specified:
        return EnvManager.LOCAL

    # Both --no-conda and --env-manager are specified. An exception should be thrown.
    raise Exception("...")


ENV_MANAGER = click.option(
    "--env-manager",
    default="conda",
    required=False,
    type=click.UNPROCESSED,
    callback=_resolve_env_manager,
    ...
)

[harupy]

Or can we ignore --env-manager (and raise a warning) if --no-conda is supplied?

[dbczumar]

Let's throw if both are supplied.

[dbczumar]

We can leave this as None by default; that's fine :). I didn't see the issue before. Makes sense now!

[dbczumar]

Nit: resolve_env_manager seems clearer. We're not just performing validation, we're figuring out which internal env manager to use based on the value of no_conda and env_manager. Can we add a docstring here too?

[harupy]

I was actually looking for a better name for this function. resolve_env_manager sounds much better, thanks!

[dbczumar]

LGTM once remaining comments are addressed. Thanks @harupy !

[WeichenXu123]

LGTM