Merge pull request #456 from seeM/layered-config

layered `Config` with `extra_files`; `Config` `repr`

Author: seeM

fastcore/foundation.py

@@ -249,16 +249,19 @@ def read_config_file(file, **kwargs):
 # %% ../nbs/02_foundation.ipynb 131
 class Config:
     "Reading and writing `ConfigParser` ini files"
-    def __init__(self, cfg_path, cfg_name, create=None, save=True):
+    def __init__(self, cfg_path, cfg_name, create=None, save=True, extra_files=None):
         cfg_path = Path(cfg_path).expanduser().absolute()
         self.config_path,self.config_file = cfg_path,cfg_path/cfg_name
-        if self.config_file.exists(): self.d = read_config_file(self.config_file)
-        elif create is not None:
-            self.d = ConfigParser(create)['DEFAULT']
+        self._cfg = ConfigParser()
+        self.d = self._cfg['DEFAULT']
+        found = [Path(o) for o in self._cfg.read(L(extra_files)+[self.config_file])]
+        if self.config_file not in found and create is not None:
+            self._cfg.read_dict({'DEFAULT':create})
             if save:
                 cfg_path.mkdir(exist_ok=True, parents=True)
-                self.save()
+                save_config_file(self.config_file, create)
 
+    def __repr__(self): return repr(dict(self._cfg.items('DEFAULT', raw=True)))
     def __setitem__(self,k,v): self.d[k] = str(v)
     def __contains__(self,k):  return k in self.d
     def save(self):            save_config_file(self.config_file,self.d)

nbs/02_foundation.ipynb

@@ -2004,16 +2004,19 @@
     "#|export\n",
     "class Config:\n",
     "    \"Reading and writing `ConfigParser` ini files\"\n",
-    "    def __init__(self, cfg_path, cfg_name, create=None, save=True):\n",
+    "    def __init__(self, cfg_path, cfg_name, create=None, save=True, extra_files=None):\n",
     "        cfg_path = Path(cfg_path).expanduser().absolute()\n",
     "        self.config_path,self.config_file = cfg_path,cfg_path/cfg_name\n",
-    "        if self.config_file.exists(): self.d = read_config_file(self.config_file)\n",
-    "        elif create is not None:\n",
-    "            self.d = ConfigParser(create)['DEFAULT']\n",
+    "        self._cfg = ConfigParser()\n",
+    "        self.d = self._cfg['DEFAULT']\n",
+    "        found = [Path(o) for o in self._cfg.read(L(extra_files)+[self.config_file])]\n",
+    "        if self.config_file not in found and create is not None:\n",
+    "            self._cfg.read_dict({'DEFAULT':create})\n",
     "            if save:\n",
     "                cfg_path.mkdir(exist_ok=True, parents=True)\n",
-    "                self.save()\n",
+    "                save_config_file(self.config_file, create)\n",
     "\n",
+    "    def __repr__(self): return repr(dict(self._cfg.items('DEFAULT', raw=True)))\n",
     "    def __setitem__(self,k,v): self.d[k] = str(v)\n",
     "    def __contains__(self,k):  return k in self.d\n",
     "    def save(self):            save_config_file(self.config_file,self.d)\n",
@@ -2033,26 +2036,70 @@
     "`Config` is a convenient wrapper around `ConfigParser` ini files with a single section (`DEFAULT`)."
    ]
   },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "Instantiate a `Config` from an ini file at `cfg_path/cfg_name`:"
+   ]
+  },
   {
    "cell_type": "code",
    "execution_count": null,
    "metadata": {},
-   "outputs": [],
+   "outputs": [
+    {
+     "data": {
+      "text/plain": [
+       "{'user': 'fastai', 'lib_name': 'fastcore', 'some_path': 'test'}"
+      ]
+     },
+     "execution_count": null,
+     "metadata": {},
+     "output_type": "execute_result"
+    }
+   ],
+   "source": [
+    "save_config_file('../tmp.ini', _d)\n",
+    "try: cfg = Config('..', 'tmp.ini')\n",
+    "finally: os.unlink('../tmp.ini')\n",
+    "cfg"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "You can create a new file if one doesn't exist by providing a `create` dict:"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [
+    {
+     "data": {
+      "text/plain": [
+       "{'user': 'fastai', 'lib_name': 'fastcore', 'some_path': 'test'}"
+      ]
+     },
+     "execution_count": null,
+     "metadata": {},
+     "output_type": "execute_result"
+    }
+   ],
    "source": [
     "try: cfg = Config('..', 'tmp.ini', create=_d)\n",
     "finally: os.unlink('../tmp.ini')\n",
-    "\n",
-    "test_eq(cfg.user,'fastai')\n",
-    "test_eq(cfg['some_path'], 'test')\n",
-    "test_eq(cfg.path('some_path'), Path('../test').absolute())\n",
-    "test_eq(cfg.get('foo','bar'),'bar')"
+    "cfg"
    ]
   },
   {
    "cell_type": "markdown",
    "metadata": {},
    "source": [
-    "You can also create an in-memory `Config` by passing `save=False`:"
+    "If you additionally pass `save=False`, the `Config` will contain the items from `create` without writing a new file:"
    ]
   },
   {
@@ -2066,6 +2113,60 @@
     "assert not Path('../tmp.ini').exists()"
    ]
   },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "Keys can be accessed as attributes, items, or with `get` and an optional default:"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "test_eq(cfg.user,'fastai')\n",
+    "test_eq(cfg['some_path'], 'test')\n",
+    "test_eq(cfg.get('foo','bar'),'bar')"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "Use `path` to access keys as `pathlib.Path`s relative to `cfg_path`:"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "test_eq(cfg.path('some_path'), Path('../test').absolute())"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "Extra files can be read _before_ `cfg_path/cfg_name` using `extra_files`, in the order they appear:"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "with tempfile.TemporaryDirectory() as d:\n",
+    "    a = Config(d, 'a.ini', {'a':0,'b':0})\n",
+    "    b = Config(d, 'b.ini', {'a':1,'c':0})\n",
+    "    c = Config(d, 'c.ini', {'a':2,'d':0}, extra_files=[a.config_file,b.config_file])\n",
+    "    test_eq(c.d, {'a':'2','b':'0','c':'0','d':'0'})"
+   ]
+  },
   {
    "cell_type": "markdown",
    "metadata": {},