Reorganize hooks into dedicated submodule

Fixes #93

tox_poetry_installer/hooks/tox_on_install.py

@@ -0,0 +1,104 @@
+"""Install the dependencies for the current environment
+
+Loads the local Poetry environment and the corresponding lockfile then pulls the dependencies
+specified by the Tox environment. Finally these dependencies are installed into the Tox
+environment using the Poetry ``PipInstaller`` backend.
+"""
+from itertools import chain
+
+from tox.plugin import impl
+from tox.tox_env.api import ToxEnv as ToxVirtualEnv
+
+from tox_poetry_installer import exceptions
+from tox_poetry_installer import installer
+from tox_poetry_installer import logger
+from tox_poetry_installer import utilities
+
+
+@impl
+def tox_on_install(
+    tox_env: ToxVirtualEnv, section: str  # pylint: disable=unused-argument
+) -> None:
+    try:
+        poetry = utilities.check_preconditions(tox_env)
+    except exceptions.SkipEnvironment as err:
+        if (
+            isinstance(err, exceptions.PoetryNotInstalledError)
+            and tox_env.conf["require_poetry"]
+        ):
+            logger.error(str(err))
+            raise err
+        logger.info(str(err))
+        return
+
+    logger.info(f"Loaded project pyproject.toml from {poetry.file}")
+
+    virtualenv = utilities.convert_virtualenv(tox_env)
+
+    if not poetry.locker.is_fresh():
+        logger.warning(
+            f"The Poetry lock file is not up to date with the latest changes in {poetry.file}"
+        )
+
+    try:
+        if tox_env.conf["require_locked_deps"] and tox_env.conf["deps"].lines():
+            raise exceptions.LockedDepsRequiredError(
+                f"Unlocked dependencies '{tox_env.conf['deps']}' specified for environment '{tox_env.name}' which requires locked dependencies"
+            )
+
+        packages = utilities.build_package_map(poetry)
+
+        group_deps = utilities.dedupe_packages(
+            list(
+                chain(
+                    *[
+                        utilities.find_group_deps(group, packages, virtualenv, poetry)
+                        for group in tox_env.conf["poetry_dep_groups"]
+                    ]
+                )
+            )
+        )
+        logger.info(
+            f"Identified {len(group_deps)} group dependencies to install to env"
+        )
+
+        env_deps = utilities.find_additional_deps(
+            packages, virtualenv, poetry, tox_env.conf["locked_deps"]
+        )
+
+        logger.info(
+            f"Identified {len(env_deps)} environment dependencies to install to env"
+        )
+
+        # extras are not set in a testenv if skip_install=true
+        try:
+            extras = tox_env.conf["extras"]
+        except KeyError:
+            extras = []
+
+        if tox_env.conf["install_project_deps"]:
+            project_deps = utilities.find_project_deps(
+                packages, virtualenv, poetry, extras
+            )
+            logger.info(
+                f"Identified {len(project_deps)} project dependencies to install to env"
+            )
+        else:
+            project_deps = []
+            logger.info("Env does not install project package dependencies, skipping")
+    except exceptions.ToxPoetryInstallerException as err:
+        logger.error(str(err))
+        raise err
+    except Exception as err:
+        logger.error(f"Internal plugin error: {err}")
+        raise err
+
+    dependencies = utilities.dedupe_packages(group_deps + env_deps + project_deps)
+
+    logger.info(f"Installing {len(dependencies)} dependencies from Poetry lock file")
+    installer.install(
+        poetry,
+        tox_env,
+        dependencies,
+        tox_env.options.parallel_install_threads,
+    )