Attempt at reducing the possibility of having import cycles when user configs import rez

src/rez/package_order.py

@@ -6,7 +6,6 @@
 from hashlib import sha1
 from typing import Dict, Iterable, List, Optional, Union
 
-from rez.config import config
 from rez.utils.data_utils import cached_class_property
 from rez.version import Version, VersionRange
 from rez.version._version import _Comparable, _ReversedComparable, _LowerBound, _UpperBound, _Bound
@@ -637,6 +636,7 @@ def from_pod(cls, data):
     @cached_class_property
     def singleton(cls):
         """Filter list as configured by rezconfig.package_filter."""
+        from rez.config import config
         return cls.from_pod(config.package_orderers)
 
     @staticmethod

src/rez/package_repository.py

@@ -5,7 +5,6 @@
 from rez.utils.resources import ResourcePool, ResourceHandle
 from rez.utils.data_utils import cached_property
 from rez.plugin_managers import plugin_manager
-from rez.config import config
 from rez.exceptions import ResourceError
 from contextlib import contextmanager
 import threading
@@ -525,6 +524,7 @@ def __init__(self, resource_pool=None):
                 None, a default pool is created based on config settings.
         """
         if resource_pool is None:
+            from rez.config import config
             cache_size = config.resource_caching_maxsize
             if cache_size < 0:  # -1 == disable caching
                 cache_size = None

src/rez/packages.py

@@ -2,7 +2,6 @@
 # Copyright Contributors to the Rez Project
 
 
-from rez.package_repository import package_repository_manager
 from rez.package_resources import PackageFamilyResource, PackageResource, \
     VariantResource, package_family_schema, package_schema, variant_schema, \
     package_release_keys, late_requires_schema
@@ -17,7 +16,6 @@
 from rez.version import Version, VersionRange
 from rez.version import VersionedObject
 from rez.serialise import FileFormat
-from rez.config import config
 
 import os
 import sys
@@ -99,11 +97,13 @@ def config(self):
         Defaults to global config if this package did not provide a 'config'
         section.
         """
+        from rez.config import config
         return self.resource.config or config
 
     @cached_property
     def is_local(self):
         """Returns True if the package is in the local package repository"""
+        from rez.package_repository import package_repository_manager
         local_repo = package_repository_manager.get_repository(
             self.config.local_packages_path)
         return (self.resource._repository.uid == local_repo.uid)
@@ -262,6 +262,7 @@ def is_relocatable(self):
         if self.relocatable is not None:
             return self.relocatable
 
+        from rez.config import config
         if config.default_relocatable_per_repository:
             value = config.default_relocatable_per_repository.get(
                 self.repository.location)
@@ -282,6 +283,7 @@ def is_cachable(self):
         if self.cachable is not None:
             return self.cachable
 
+        from rez.config import config
         if config.default_cachable_per_repository:
             # TODO: The location of filesystem repository is canonical path,
             #   so if the path in `default_cachable_per_repository` isn't
@@ -451,6 +453,7 @@ def install(self, path, dry_run=False, overrides=None):
             `Variant` object - the (existing or newly created) variant in the
             specified repository. If `dry_run` is True, None may be returned.
         """
+        from rez.package_repository import package_repository_manager
         repo = package_repository_manager.get_repository(path)
         resource = repo.install_variant(self.resource,
                                         dry_run=dry_run,
@@ -507,6 +510,7 @@ def __contains__(self, package):
 
     @cached_property
     def _repository_uids(self):
+        from rez.package_repository import package_repository_manager
         uids = set()
         for path in self.paths:
             repo = package_repository_manager.get_repository(path)
@@ -532,6 +536,8 @@ def iter_package_families(paths=None):
     Returns:
         `PackageFamily` iterator.
     """
+    from rez.config import config
+    from rez.package_repository import package_repository_manager
     for path in (paths or config.packages_path):
         repo = package_repository_manager.get_repository(path)
         for resource in repo.iter_package_families():
@@ -607,6 +613,7 @@ def get_package_family_from_repository(name, path):
     Returns:
         `PackageFamily` object, or None if the family was not found.
     """
+    from rez.package_repository import package_repository_manager
     repo = package_repository_manager.get_repository(path)
 
     family_resource = repo.get_package_family(name)
@@ -626,6 +633,7 @@ def get_package_from_repository(name, version, path):
     Returns:
         `Package` object, or None if the package was not found.
     """
+    from rez.package_repository import package_repository_manager
     repo = package_repository_manager.get_repository(path)
 
     if isinstance(version, str):
@@ -649,6 +657,7 @@ def get_package_from_handle(package_handle):
     Returns:
         `Package`.
     """
+    from rez.package_repository import package_repository_manager
     if isinstance(package_handle, dict):
         package_handle = ResourceHandle.from_dict(package_handle)
     package_resource = package_repository_manager.get_resource_from_handle(package_handle)
@@ -713,6 +722,7 @@ def get_variant(variant_handle, context=None):
     Returns:
         `Variant`.
     """
+    from rez.package_repository import package_repository_manager
     if isinstance(variant_handle, dict):
         variant_handle = ResourceHandle.from_dict(variant_handle)
 
@@ -733,6 +743,7 @@ def get_package_from_uri(uri, paths=None):
     Returns:
         `Package`, or None if the package could not be found.
     """
+    from rez.package_repository import package_repository_manager
     def _find_in_path(path):
         repo = package_repository_manager.get_repository(path)
         pkg_resource = repo.get_package_from_uri(uri)
@@ -741,6 +752,7 @@ def _find_in_path(path):
         else:
             return None
 
+    from rez.config import config
     for path in (paths or config.packages_path):
         pkg = _find_in_path(path)
         if pkg is not None:
@@ -780,6 +792,7 @@ def get_variant_from_uri(uri, paths=None):
     Returns:
         `Variant`, or None if the variant could not be found.
     """
+    from rez.package_repository import package_repository_manager
     def _find_in_path(path):
         repo = package_repository_manager.get_repository(path)
         variant_resource = repo.get_variant_from_uri(uri)
@@ -788,6 +801,7 @@ def _find_in_path(path):
         else:
             return None
 
+    from rez.config import config
     for path in (paths or config.packages_path):
         variant = _find_in_path(path)
         if variant is not None:
@@ -951,6 +965,8 @@ def get_latest_package_from_string(txt, paths=None, error=False):
 
 def _get_families(name, paths=None):
     entries = []
+    from rez.config import config
+    from rez.package_repository import package_repository_manager
     for path in (paths or config.packages_path):
         repo = package_repository_manager.get_repository(path)
         family_resource = repo.get_package_family(name)

src/rez/plugin_managers.py

@@ -5,7 +5,6 @@
 """
 Manages loading of all types of Rez plugins.
 """
-from rez.config import config, expand_system_vars, _load_config_from_filepaths
 from rez.utils.formatting import columnise
 from rez.utils.schema import dict_to_schema
 from rez.utils.data_utils import LazySingleton, cached_property, deep_update
@@ -54,6 +53,7 @@ def extend_path(path, name):
     init_py = "__init__" + os.extsep + "py"
     path = path[:]
 
+    from rez.config import config
     def append_if_valid(dir_):
         if os.path.isdir(dir_):
             subdir = os.path.normcase(os.path.join(dir_, pname))
@@ -126,6 +126,7 @@ def load_plugins(self):
         # be found before the builtin plugins (from /rezplugins).
         paths = reversed(paths)
 
+        from rez.config import config, _load_config_from_filepaths
         for path in paths:
             if config.debug("plugins"):
                 print_debug("searching plugin path %s...", path)
@@ -226,6 +227,7 @@ def config_schema(self):
         """Returns the merged configuration data schema for this plugin
         type."""
         from rez.config import _plugin_config_dict
+        from rez.config import expand_system_vars
         d = _plugin_config_dict.get(self.type_name, {})
 
         for name, plugin_class in self.plugin_classes.items():

src/rez/serialise.py

@@ -24,13 +24,10 @@
 from rez.utils.memcached import memcached
 from rez.utils.execution import add_sys_paths
 from rez.util import get_function_arg_names
-from rez.config import config
 from rez.vendor.atomicwrites import atomic_write
 from rez.vendor import yaml
 
 
-tmpdir_manager = TempDirs(config.tmpdir, prefix="rez_write_")
-debug_print = config.debug_printer("file_loads")
 file_cache = {}
 
 
@@ -60,14 +57,19 @@ def open_file_for_write(filepath, mode=None):
     Yields:
         File-like object.
     """
+    from rez.config import config
+
     stream = StringIO()
     yield stream
     content = stream.getvalue()
 
     filepath = os.path.realpath(filepath)
+    tmpdir_manager = TempDirs(config.tmpdir, prefix="rez_write_")
+
     tmpdir = tmpdir_manager.mkdtemp()
     cache_filepath = os.path.join(tmpdir, os.path.basename(filepath))
 
+    debug_print = config.debug_printer("file_loads")
     debug_print("Writing to %s (local cache of %s)", cache_filepath, filepath)
 
     # Attempt to make file writable if it isn't already. Just fallthrough
@@ -136,9 +138,11 @@ def load_from_file(filepath, format_=FileFormat.py, update_data_callback=None,
                           format_=format_,
                           update_data_callback=update_data_callback)
     else:
-        return _load_from_file(filepath=filepath,
-                               format_=format_,
-                               update_data_callback=update_data_callback)
+        return _load_from_file()(
+            filepath=filepath,
+            format_=format_,
+            update_data_callback=update_data_callback
+        )
 
 
 def _load_from_file__key(filepath, format_, update_data_callback):
@@ -152,17 +156,28 @@ def _load_from_file__key(filepath, format_, update_data_callback):
                 int(st.st_ino), st.st_mtime))
 
 
-@memcached(servers=config.memcached_uri if config.cache_package_files else None,
-           min_compress_len=config.memcached_package_file_min_compress_len,
-           key=_load_from_file__key,
-           debug=config.debug_memcache)
-def _load_from_file(filepath, format_, update_data_callback):
-    return _load_file(filepath, format_, update_data_callback)
+def _load_from_file():
+    from rez.config import config
+
+    # A lot of gymnastics to avoid habing to import rez.config at the top level.
+    @memcached(
+        servers=config.memcached_uri if config.cache_package_files else None,
+        min_compress_len=config.memcached_package_file_min_compress_len,
+        key=_load_from_file__key,
+        debug=config.debug_memcache
+    )
+    def _load_from_file_inner(filepath, format_, update_data_callback):
+        return _load_file(filepath, format_, update_data_callback)
+
+    return _load_from_file_inner
 
 
 def _load_file(filepath, format_, update_data_callback, original_filepath=None):
+    from rez.config import config
+
     load_func = load_functions[format_]
 
+    debug_print = config.debug_printer("file_loads")
     if debug_print:
         if original_filepath:
             debug_print("Loading file: %s (local cache of %s)",
@@ -228,6 +243,7 @@ def load_py(stream, filepath=None):
     Returns:
         dict:
     """
+    from rez.config import config
     with add_sys_paths(config.package_definition_build_python_paths):
         return _load_py(stream, filepath=filepath)
 
@@ -441,7 +457,7 @@ def load_txt(stream, **kwargs):
 
 def clear_file_caches():
     """Clear any cached files."""
-    _load_from_file.forget()
+    _load_from_file().forget()
 
 
 load_functions = {FileFormat.py:      load_py,

src/rez/utils/memcached.py

@@ -2,7 +2,6 @@
 # Copyright Contributors to the Rez Project
 
 
-from rez.config import config
 from rez.vendor.memcache.memcache import Client as Client_, \
     SERVER_MAX_KEY_LENGTH, __version__ as memcache_client_version
 from rez.util import get_function_arg_names
@@ -32,7 +31,6 @@ def __bool__(self):
 
     miss = _Miss()
 
-    logger = config.debug_printer("memcache")
 
     def __init__(self, servers, debug=False):
         """Create a memcached client.
@@ -48,6 +46,8 @@ def __init__(self, servers, debug=False):
         self._client = None
         self.debug = debug
         self.current = ''
+        from rez.config import config
+        self.logger = config.debug_printer("memcache")
 
     def __bool__(self):
         return bool(self.servers)
@@ -223,7 +223,7 @@ def release(self, key):
 
 
 @contextmanager
-def memcached_client(servers=config.memcached_uri, debug=config.debug_memcache):
+def memcached_client(servers=None, debug=None):
     """Get a shared memcached instance.
 
     This function shares the same memcached instance across nested invocations.
@@ -236,6 +236,12 @@ def memcached_client(servers=config.memcached_uri, debug=config.debug_memcache):
     Returns:
         `Client`: Memcached instance.
     """
+    from rez.config import config
+    if servers is None:
+        servers = config.memcached_uri
+    if debug is None:
+        debug = config.debug_memcache
+
     key = None
     try:
         client, key = scoped_instance_manager.acquire(servers, debug=debug)