Add dotenv read support

py/circuitpy_defns.mk

@@ -158,6 +158,9 @@ endif
 ifeq ($(CIRCUITPY_DISPLAYIO),1)
 SRC_PATTERNS += displayio/%
 endif
+ifeq ($(CIRCUITPY_DOTENV),1)
+SRC_PATTERNS += dotenv/%
+endif
 ifeq ($(CIRCUITPY_PARALLELDISPLAY),1)
 SRC_PATTERNS += paralleldisplay/%
 endif
@@ -548,6 +551,7 @@ SRC_SHARED_MODULE_ALL = \
 	displayio/TileGrid.c \
 	displayio/area.c \
 	displayio/__init__.c \
+	dotenv/__init__.c \
 	floppyio/__init__.c \
 	fontio/BuiltinFont.c \
 	fontio/__init__.c \

py/circuitpy_mpconfig.mk

@@ -199,6 +199,9 @@ CFLAGS += -DCIRCUITPY_BITMAPTOOLS=$(CIRCUITPY_BITMAPTOOLS)
 CFLAGS += -DCIRCUITPY_FRAMEBUFFERIO=$(CIRCUITPY_FRAMEBUFFERIO)
 CFLAGS += -DCIRCUITPY_VECTORIO=$(CIRCUITPY_VECTORIO)
 
+CIRCUITPY_DOTENV ?= $(CIRCUITPY_FULL_BUILD)
+CFLAGS += -DCIRCUITPY_DOTENV=$(CIRCUITPY_DOTENV)
+
 CIRCUITPY_DUALBANK ?= 0
 CFLAGS += -DCIRCUITPY_DUALBANK=$(CIRCUITPY_DUALBANK)
 

shared-bindings/dotenv/__init__.c

@@ -0,0 +1,105 @@
+/*
+ * This file is part of the Micro Python project, http://micropython.org/
+ *
+ * The MIT License (MIT)
+ *
+ * SPDX-FileCopyrightText: Copyright (c) 2022 Scott Shawcroft for Adafruit Industries
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#include <string.h>
+
+#include "extmod/vfs.h"
+#include "lib/oofatfs/ff.h"
+#include "lib/oofatfs/diskio.h"
+#include "py/mpstate.h"
+#include "py/obj.h"
+#include "py/objstr.h"
+#include "py/runtime.h"
+#include "shared-bindings/dotenv/__init__.h"
+
+//| """Functions to manage environment variables from a .env file.
+//|
+//|    A subset of the CPython `dotenv library <https://saurabh-kumar.com/python-dotenv/>`_. It does
+//|    not support variables or double quotes.
+//|
+//|    The simplest way to define keys and values is to put them in single quotes. \ and ' are
+//|    escaped by \ in single quotes. Newlines can occur in quotes for multiline values. Comments
+//|    start with # and apply for the rest of the line.
+//|
+//|    File format example:
+//|
+//|    .. code-block::
+//|
+//|        key=value
+//|          key2 = value2
+//|        'key3' = 'value with spaces'
+//|        # comment
+//|        key4 = value3 # comment 2
+//|        'key5'=value4
+//|        key=value5 # overrides the first one
+//|        multiline = 'hello
+//|        world
+//|        how are you?'
+//|
+//| """
+//|
+//| import typing
+
+//| def get_key(dotenv_path: str, key_to_get: str) -> Optional[str]:
+//|     """Get the value for the given key from the given .env file. If the key occurs multiple
+//|        times in the file, then the last value will be returned.
+//|
+//|        Returns None if the key isn't found or doesn't have a value."""
+//|     ...
+//|
+STATIC mp_obj_t _dotenv_get_key(mp_obj_t path_in, mp_obj_t key_to_get_in) {
+    return common_hal_dotenv_get_key(mp_obj_str_get_str(path_in),
+        mp_obj_str_get_str(key_to_get_in));
+}
+MP_DEFINE_CONST_FUN_OBJ_2(dotenv_get_key_obj, _dotenv_get_key);
+
+//| def load_dotenv() -> None:
+//|     """Does nothing in CircuitPython because os.getenv will automatically read .env when
+//|        available.
+//|
+//|        Present in CircuitPython so CPython-compatible code can use it without error."""
+//|     ...
+//|
+STATIC mp_obj_t dotenv_load_dotenv(void) {
+    return mp_const_none;
+}
+MP_DEFINE_CONST_FUN_OBJ_0(dotenv_load_dotenv_obj, dotenv_load_dotenv);
+
+STATIC const mp_rom_map_elem_t dotenv_module_globals_table[] = {
+    { MP_ROM_QSTR(MP_QSTR___name__), MP_ROM_QSTR(MP_QSTR_dotenv) },
+
+    { MP_ROM_QSTR(MP_QSTR_get_key), MP_ROM_PTR(&dotenv_get_key_obj) },
+    { MP_ROM_QSTR(MP_QSTR_load_dotenv), MP_ROM_PTR(&dotenv_load_dotenv_obj) },
+};
+
+STATIC MP_DEFINE_CONST_DICT(dotenv_module_globals, dotenv_module_globals_table);
+
+const mp_obj_module_t dotenv_module = {
+    .base = { &mp_type_module },
+    .globals = (mp_obj_dict_t *)&dotenv_module_globals,
+};
+
+MP_REGISTER_MODULE(MP_QSTR_dotenv, dotenv_module, CIRCUITPY_DOTENV);

shared-bindings/dotenv/__init__.h

@@ -0,0 +1,39 @@
+/*
+ * This file is part of the MicroPython project, http://micropython.org/
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2022 Scott Shawcroft for Adafruit Industries
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#ifndef MICROPY_INCLUDED_SHARED_BINDINGS_DOTENV___INIT___H
+#define MICROPY_INCLUDED_SHARED_BINDINGS_DOTENV___INIT___H
+
+#include <stdint.h>
+#include <stdbool.h>
+
+#include "py/objtuple.h"
+
+#include "shared-module/dotenv/__init__.h"
+
+mp_obj_t common_hal_dotenv_get_key(const char *path, const char *key);
+
+#endif  // MICROPY_INCLUDED_SHARED_BINDINGS_DOTENV___INIT___H

shared-bindings/os/__init__.c

@@ -83,6 +83,25 @@ STATIC mp_obj_t os_getcwd(void) {
 }
 MP_DEFINE_CONST_FUN_OBJ_0(os_getcwd_obj, os_getcwd);
 
+//| def getenv(key: str, default: Optional[str] = None) -> Optional[str]:
+//|     """Get the environment variable value for the given key or return ``default``.
+//|
+//|        This may load values from disk so cache the result instead of calling this often."""
+//|     ...
+//|
+STATIC mp_obj_t os_getenv(size_t n_args, const mp_obj_t *pos_args, mp_map_t *kw_args) {
+    enum { ARG_key, ARG_default };
+    static const mp_arg_t allowed_args[] = {
+        { MP_QSTR_key, MP_ARG_REQUIRED | MP_ARG_OBJ },
+        { MP_QSTR_default,  MP_ARG_OBJ, {.u_obj = mp_const_none} },
+    };
+    mp_arg_val_t args[MP_ARRAY_SIZE(allowed_args)];
+    mp_arg_parse_all(n_args, pos_args, kw_args, MP_ARRAY_SIZE(allowed_args), allowed_args, args);
+
+    return common_hal_os_getenv(mp_obj_str_get_str(args[ARG_key].u_obj), args[ARG_default].u_obj);
+}
+STATIC MP_DEFINE_CONST_FUN_OBJ_KW(os_getenv_obj, 1, os_getenv);
+
 //| def listdir(dir: str) -> str:
 //|     """With no argument, list the current directory.  Otherwise list the given directory."""
 //|     ...
@@ -220,6 +239,7 @@ STATIC const mp_rom_map_elem_t os_module_globals_table[] = {
 
     { MP_ROM_QSTR(MP_QSTR_chdir), MP_ROM_PTR(&os_chdir_obj) },
     { MP_ROM_QSTR(MP_QSTR_getcwd), MP_ROM_PTR(&os_getcwd_obj) },
+    { MP_ROM_QSTR(MP_QSTR_getenv), MP_ROM_PTR(&os_getenv_obj) },
     { MP_ROM_QSTR(MP_QSTR_listdir), MP_ROM_PTR(&os_listdir_obj) },
     { MP_ROM_QSTR(MP_QSTR_mkdir), MP_ROM_PTR(&os_mkdir_obj) },
     { MP_ROM_QSTR(MP_QSTR_remove), MP_ROM_PTR(&os_remove_obj) },

shared-bindings/os/__init__.h

@@ -37,6 +37,7 @@ extern const mp_rom_obj_tuple_t common_hal_os_uname_info_obj;
 mp_obj_t common_hal_os_uname(void);
 void common_hal_os_chdir(const char *path);
 mp_obj_t common_hal_os_getcwd(void);
+mp_obj_t common_hal_os_getenv(const char *key, mp_obj_t default_);
 mp_obj_t common_hal_os_listdir(const char *path);
 void common_hal_os_mkdir(const char *path);
 void common_hal_os_remove(const char *path);