computer-playbook/cli/administration/deploy/development/inventory/legacy_resolver.py

"""Default (non-variant) include resolution for the matrix planner.

When NO primary app ships a `meta/variants.yml`, the planner falls back
to this path — the `CombinedResolver` walks `dependencies` and
`shared:`-edges in the variant-merged services map and Jinja flags are
evaluated at deploy time against `group_names`. `run_after` is NOT
followed for inclusion (it is a pure ordering hint), so a variant that
disables a service does not get the provider re-added through the
ordering edge. This module owns the two helpers that path needs and
nothing else; the variant-only path lives in `.variants`.
"""

from __future__ import annotations

from collections.abc import Iterable, Mapping, Sequence
from pathlib import Path

from utils.cache.applications import get_variants
from utils.cache.base import _deep_merge
from utils.cache.yaml import load_yaml_any
from utils.roles.mapping import ROLE_FILE_META_SERVICES

from .nested_overrides import apply_topic, collect_provider_overrides


def _build_services_overrides_for_round(
    *,
    roles_dir: str,
    round_index: int,
    primary_app_variants: Mapping[str, int],
) -> dict[str, dict]:
    """For every role with `meta/variants.yml`, return the services map
    that results from merging the round's variant payload onto the
    role's on-disk `meta/services.yml`.

    Apps in `primary_app_variants` use the supplied (already clamped)
    index. Other roles with their own variants clamp `round_index` to
    their own variant count. Roles without variants are absent from the
    result so the resolver falls through to its disk-read path.

    The merged map is what the inventory ALSO bakes into host_vars, so
    feeding the same dict into `CombinedResolver(services_overrides=...)`
    eliminates the topology-vs-host_vars drift that variant-blind
    resolution produced.
    """
    variants_per_app = get_variants(roles_dir=roles_dir)
    overrides: dict[str, dict] = {}
    roles_path = Path(roles_dir)
    for role_name, variant_list in variants_per_app.items():
        if not variant_list:
            continue
        variant_count = max(1, len(variant_list))
        if role_name in primary_app_variants:
            idx = primary_app_variants[role_name]
        else:
            idx = round_index if round_index < variant_count else 0
        if not 0 <= idx < len(variant_list):
            idx = 0
        variant_payload = variant_list[idx] if variant_list else {}
        if not isinstance(variant_payload, Mapping):
            variant_payload = {}
        variant_services = variant_payload.get("services", {})
        if not isinstance(variant_services, Mapping):
            continue
        services_path = roles_path / role_name / ROLE_FILE_META_SERVICES
        if not services_path.exists():
            continue
        try:
            base_services = load_yaml_any(services_path) or {}
        except Exception:  # noqa: S112  best-effort iteration over role files; skip malformed input
            continue
        if not isinstance(base_services, Mapping):
            continue
        merged = _deep_merge(dict(base_services), dict(variant_services))
        if isinstance(merged, dict):
            overrides[role_name] = merged
    _apply_nested_service_maps(overrides, roles_dir=roles_dir)
    return overrides


def _apply_nested_service_maps(overrides: dict[str, dict], *, roles_dir: str) -> None:
    """Replace a pulled-in provider's services map with what the round demands.

    Only the ``services`` topic reaches this path: the closure walks service
    edges, so the other config topics a variant may override are the inventory
    bake's business.

    Args:
        overrides: ``{role: services map}``, mutated in place.
        roles_dir: roles directory the service registry is built from.
    """
    payloads = {role: {"services": services} for role, services in overrides.items()}
    for provider, topics in collect_provider_overrides(
        payloads, roles_dir=roles_dir
    ).items():
        if "services" not in topics:
            continue
        overrides[provider] = apply_topic(overrides.get(provider), topics["services"])


def _resolve_round_include(
    *,
    primary_apps: Sequence[str],
    services_overrides: dict[str, dict],
) -> tuple[str, ...]:
    """Resolve transitive prerequisites for each primary app under a
    round's variant-merged services map. Returns the full include set
    in stable order (deps first per primary, primary last; primaries
    iterated in the user-provided order).

    The resolver import is deferred so the host-side import surface
    stays lean for callers that never need the variant-aware planner
    (e.g. lint/validation).
    """
    from cli.meta.roles.applications.resolution.combined.resolver import (
        CombinedResolver,
    )

    resolver = CombinedResolver(
        services_overrides=services_overrides, follow_run_after=False
    )
    out: list[str] = []
    seen: set[str] = set()
    for app_id in primary_apps:
        deps = resolver.resolve(app_id)
        for dep in deps:
            if dep != app_id and dep not in seen:
                out.append(dep)
                seen.add(dep)
        if app_id not in seen:
            out.append(app_id)
            seen.add(app_id)
    return tuple(out)


def prune_orphans_after_disable(
    *,
    include: Sequence[str],
    primary_apps: Sequence[str],
    disabled_app_ids: Iterable[str],
    services_overrides: dict[str, dict],
) -> tuple[tuple[str, ...], tuple[str, ...]]:
    """Split a round's ``include`` into ``(kept, pruned)`` after `disable`.

    `kept` are the members still reachable from a surviving primary app
    once every role in `disabled_app_ids` is cut from the graph; `pruned`
    are the orphaned remainder (the disabled roots themselves excluded).
    Reachability walks the same `dependencies` + `services` edges the
    round's closure was built from — `run_after` is NOT followed, matching
    ``CombinedResolver(follow_run_after=False)`` — using `services_overrides`
    so the variant-merged topology matches what the inventory bakes.

    Returned order follows `include` for both tuples.

    Args:
        include: the round's full closure (deps-first, primary last).
        primary_apps: the operator-selected roots (already `disable`-filtered).
        disabled_app_ids: provider roles cut by `disable`.
        services_overrides: round variant-merged services maps per role.
    """
    from cli.meta.roles.applications.resolution.combined.resolver import (
        CombinedResolver,
    )

    disabled = set(disabled_app_ids)
    resolver = CombinedResolver(
        services_overrides=services_overrides, follow_run_after=False
    )
    reachable: set[str] = set()
    stack = [a for a in primary_apps if a not in disabled]
    while stack:
        node = stack.pop()
        if node in reachable or node in disabled:
            continue
        reachable.add(node)
        edges = resolver.edges_for(node)
        stack.extend(
            dep
            for dep in (*edges.dependencies, *edges.services)
            if dep not in reachable and dep not in disabled
        )
    kept = tuple(role for role in include if role in reachable)
    pruned = tuple(
        role for role in include if role not in reachable and role not in disabled
    )
    return kept, pruned