From db0dd6af09f92005e0f0eb1dbc021f1f12824970 Mon Sep 17 00:00:00 2001
From: Otto Winter <otto@otto-winter.com>
Date: Mon, 13 May 2019 12:03:52 +0200
Subject: [PATCH] Add custom component mechanism

---
 esphome/config.py | 45 ++++++++++++++++++++++++++++++++++++++++++---
 1 file changed, 42 insertions(+), 3 deletions(-)

diff --git a/esphome/config.py b/esphome/config.py
index d6f5735066..7ad707ee0d 100644
--- a/esphome/config.py
+++ b/esphome/config.py
@@ -7,6 +7,7 @@ import re
 import os.path
 
 # pylint: disable=unused-import, wrong-import-order
+import sys
 from contextlib import contextmanager
 
 import voluptuous as vol
@@ -17,7 +18,7 @@ from esphome.components.substitutions import CONF_SUBSTITUTIONS
 from esphome.const import CONF_ESPHOME, CONF_PLATFORM, ESP_PLATFORMS
 from esphome.core import CORE, EsphomeError  # noqa
 from esphome.helpers import color, indent
-from esphome.py_compat import text_type
+from esphome.py_compat import text_type, IS_PY2
 from esphome.util import safe_print, OrderedDict
 
 from typing import List, Optional, Tuple, Union  # noqa
@@ -106,15 +107,53 @@ class ComponentManifest(object):
 
 
 CORE_COMPONENTS_PATH = os.path.abspath(os.path.join(os.path.dirname(__file__), 'components'))
+_UNDEF = object()
+CUSTOM_COMPONENTS_PATH = _UNDEF
+
+
+def _mount_config_dir():
+    global CUSTOM_COMPONENTS_PATH
+    if CUSTOM_COMPONENTS_PATH is not _UNDEF:
+        return
+    custom_path = os.path.abspath(os.path.join(CORE.config_dir, 'custom_components'))
+    if not os.path.isdir(custom_path):
+        CUSTOM_COMPONENTS_PATH = None
+        return
+    init_path = os.path.join(custom_path, '__init__.py')
+    if IS_PY2 and not os.path.isfile(init_path):
+        _LOGGER.warning("Found 'custom_components' folder, but file __init__.py was not found. "
+                        "ESPHome will automatically create it now....")
+        with open(init_path, 'w') as f:
+            f.write('\n')
+    if CORE.config_dir not in sys.path:
+        sys.path.insert(0, CORE.config_dir)
+    CUSTOM_COMPONENTS_PATH = custom_path
 
 
 def _lookup_module(domain, is_platform):
     if domain in _COMPONENT_CACHE:
         return _COMPONENT_CACHE[domain]
 
-    path = 'esphome.components.{}'.format(domain)
+    _mount_config_dir()
+    # First look for custom_components
     try:
-        module = importlib.import_module(path)
+        module = importlib.import_module('custom_components.{}'.format(domain))
+    except ImportError as e:
+        # ImportError when no such module
+        if 'No module named' not in str(e):
+            _LOGGER.warn("Unable to import custom component %s:", domain, exc_info=True)
+    except Exception:  # pylint: disable=broad-except
+        # Other error means component has an issue
+        _LOGGER.error("Unable to load custom component %s:", domain, exc_info=True)
+        return None
+    else:
+        # Found in custom components
+        manif = ComponentManifest(module, CUSTOM_COMPONENTS_PATH, is_platform=is_platform)
+        _COMPONENT_CACHE[domain] = manif
+        return manif
+
+    try:
+        module = importlib.import_module('esphome.components.{}'.format(domain))
     except ImportError as e:
         if 'No module named' in str(e):
             _LOGGER.error("Unable to import component %s:", domain)