Resolve which container tool to use

When tool is specified explicitly, validates that it is installed and responsive. When tool = NULL, tries each candidate in preference order (Podman first, then Docker), selecting the first one that is both installed and responsive. Errors informatively if no tool is available.

Usage

.resolve_tool(tool = NULL)

Arguments

tool

A character string ("podman" or "docker") or NULL.

Value

A character string, either "podman" or "docker".