chore: initial support for dot env loading

src/appier/config.py

@@ -172,6 +172,7 @@ def load(names=(FILE_NAME,), path=None, encoding="utf-8", ctx=None):
     for path in paths:
         for name in names:
             load_file(name=name, path=path, encoding=encoding, ctx=ctx)
+    load_dot_env(ctx=ctx)
     load_env(ctx=ctx)
 
 
@@ -218,6 +219,54 @@ def load_file(name=FILE_NAME, path=None, encoding="utf-8", ctx=None):
         configs[key] = value
 
 
+def load_dot_env(name=".env", encoding="utf-8", ctx=None):
+    configs = ctx["configs"] if ctx else CONFIGS
+    config_f = ctx["config_f"] if ctx else CONFIG_F
+
+    file_path = os.path.abspath(name)
+    file_path = os.path.normpath(file_path)
+
+    exists = os.path.exists(file_path)
+    if not exists:
+        return
+
+    exists = file_path in config_f
+    if exists:
+        config_f.remove(file_path)
+    config_f.append(file_path)
+
+    file = open(file_path, "rb")
+    try:
+        data = file.read()
+    finally:
+        file.close()
+    if not data:
+        return
+
+    data = data.decode(encoding)
+    data = data.strip()
+    lines = data.splitlines()
+    lines = [line.strip() for line in lines]
+
+    for line in lines:
+        line = line.strip()
+        if not line:
+            continue
+        if line.startswith("#"):
+            continue
+        key, value = line.split("=", 1)
+        key = key.strip()
+        value = value.strip()
+        if (
+            value.startswith('"')
+            and value.endswith('"')
+            or value.startswith("'")
+            and value.endswith("'")
+        ):
+            value = value[1:-1].replace('\\"', '"')
+        configs[key] = value
+
+
 def load_env(ctx=None):
     configs = ctx["configs"] if ctx else CONFIGS
 

src/appier/test/config.py

@@ -32,6 +32,11 @@
 
 import appier
 
+try:
+    import unittest.mock as mock
+except ImportError:
+    mock = None
+
 
 class ConfigTest(unittest.TestCase):
     def test_basic(self):
@@ -79,3 +84,34 @@ def test_none(self):
         result = appier.conf("HEIGHT", cast=int)
 
         self.assertEqual(result, None)
+
+    def test_load_dot_env(self):
+        if mock == None:
+            self.skipTest("Skipping test: mock unavailable")
+
+        mock_data = mock.mock_open(
+            read_data=b"#This is a comment\nAGE=10\nNAME=colony\n"
+        )
+
+        with mock.patch("os.path.exists", return_value=True), mock.patch(
+            "builtins.open", mock_data, create=True
+        ) as mock_open:
+            ctx = dict(configs={}, config_f=[])
+
+            appier.config.load_dot_env(".env", "utf-8", ctx)
+
+            result = appier.conf("AGE", cast=int)
+            self.assertEqual(type(result), int)
+            self.assertEqual(result, 10)
+
+            result = appier.conf("AGE", cast=str)
+
+            self.assertEqual(result, "10")
+            self.assertEqual(type(result), str)
+
+            result = appier.conf("HEIGHT", cast=int)
+            self.assertEqual(result, None)
+
+            self.assertEqual(len(ctx["configs"]), 2)
+
+            self.assertEqual(mock_open.return_value.close.call_count, 1)