default-env-file, default-env, and env-file now in place alongside env. default-env-file and default-env both use os.environ.setdefault so as not to overwrite existing variables (system environment) while env-file and env will overwrite existing variables. All four allow for multiple values (***How might this affect multiple default-env and default-env-file values, I expect that unlike env-file and env the first passed variables would win).

bonobo/commands/run.py

@@ -1,8 +1,10 @@
 import codecs
 import os
+from pathlib import Path
 
 import bonobo
 from bonobo.constants import DEFAULT_SERVICES_ATTR, DEFAULT_SERVICES_FILENAME
+from dotenv import load_dotenv
 
 DEFAULT_GRAPH_FILENAMES = ('__main__.py', 'main.py', )
 DEFAULT_GRAPH_ATTR = 'get_graph'
@@ -41,7 +43,7 @@ def _install_requirements(requirements):
     importlib.reload(site)
 
 
-def read(filename, module, install=False, quiet=False, verbose=False, env=None):
+def read(filename, module, install=False, quiet=False, verbose=False, default_env_file=None, default_env=None, env_file=None, env=None):
 
     import runpy
     from bonobo import Graph, settings
@@ -52,21 +54,6 @@ def read(filename, module, install=False, quiet=False, verbose=False, env=None):
     if verbose:
         settings.DEBUG.set(True)
 
-    if env:
-        __escape_decoder = codecs.getdecoder('unicode_escape')
-
-        def decode_escaped(escaped):
-            return __escape_decoder(escaped)[0]
-
-        for e in env:
-            ename, evalue = e.split('=', 1)
-
-            if len(evalue) > 0:
-                if evalue[0] == evalue[len(evalue) - 1] in ['"', "'"]:
-                    evalue = decode_escaped(evalue[1:-1])
-
-            os.environ[ename] = evalue
-
     if filename:
         if os.path.isdir(filename):
             if install:
@@ -84,12 +71,38 @@ def read(filename, module, install=False, quiet=False, verbose=False, env=None):
             requirements = os.path.join(os.path.dirname(filename), 'requirements.txt')
             _install_requirements(requirements)
         context = runpy.run_path(filename, run_name='__bonobo__')
+        env_dir = Path(filename).parent
     elif module:
         context = runpy.run_module(module, run_name='__bonobo__')
         filename = context['__file__']
+        env_dir = Path(module)
     else:
         raise RuntimeError('UNEXPECTED: argparse should not allow this.')
 
+    if default_env_file:
+        for f in default_env_file:
+            env_file_path = env_dir.joinpath(f)
+            load_dotenv(env_file_path)
+    else:
+        try:
+            env_file_path = env_dir.joinpath('.env')
+            load_dotenv(env_file_path)
+        except FileNotFoundError:
+            pass
+
+    if default_env:
+        for e in default_env:
+            set_env_var(e)
+
+    if env_file:
+        for f in env_file:
+            env_file_path = env_dir.joinpath(f)
+            load_dotenv(env_file_path, override=True)
+
+    if env:
+        for e in env:
+            set_env_var(e, override=True)
+
     graphs = dict((k, v) for k, v in context.items() if isinstance(v, Graph))
 
     assert len(graphs) == 1, (
@@ -106,8 +119,25 @@ def read(filename, module, install=False, quiet=False, verbose=False, env=None):
     return graph, plugins, services
 
 
-def execute(filename, module, install=False, quiet=False, verbose=False, env=None):
-    graph, plugins, services = read(filename, module, install, quiet, verbose, env)
+def set_env_var(e, override=False):
+    __escape_decoder = codecs.getdecoder('unicode_escape')
+    ename, evalue = e.split('=', 1)
+
+    def decode_escaped(escaped):
+        return __escape_decoder(escaped)[0]
+
+    if len(evalue) > 0:
+        if evalue[0] == evalue[len(evalue) - 1] in ['"', "'"]:
+            evalue = decode_escaped(evalue[1:-1])
+
+    if override:
+        os.environ[ename] = evalue
+    else:
+        os.environ.setdefault(ename, evalue)
+
+
+def execute(filename, module, install=False, quiet=False, verbose=False, default_env_file=None, default_env=None, env_file=None, env=None):
+    graph, plugins, services = read(filename, module, install, quiet, verbose, default_env_file, default_env, env_file, env)
 
     return bonobo.run(graph, plugins=plugins, services=services)
 
@@ -116,6 +146,9 @@ def register_generic_run_arguments(parser, required=True):
     source_group = parser.add_mutually_exclusive_group(required=required)
     source_group.add_argument('filename', nargs='?', type=str)
     source_group.add_argument('--module', '-m', type=str)
+    parser.add_argument('--default-env-file', action='append')
+    parser.add_argument('--default-env', action='append')
+    parser.add_argument('--env-file', action='append')
     parser.add_argument('--env', '-e', action='append')
     return parser
 

bonobo/examples/env_vars/get_passed_env_file.py

@@ -0,0 +1,22 @@
+import os
+
+import bonobo
+
+
+def extract():
+    my_secret = os.getenv('MY_SECRET')
+    test_user_password = os.getenv('TEST_USER_PASSWORD')
+    user = os.getenv('USERNAME')
+    path = os.getenv('PATH')
+
+    return my_secret, test_user_password, user, path
+
+
+def load(s: str):
+    print(s)
+
+
+graph = bonobo.Graph(extract, load)
+
+if __name__ == '__main__':
+    bonobo.run(graph)

tests/test_commands.py

@@ -98,6 +98,33 @@ def test_version(runner, capsys):
     assert __version__ in out
 
 
+@all_runners
+def test_run_module_with_default_env_file(runner, capsys):
+    runner(
+        'run', '--quiet', get_examples_path('env_vars/get_passed_env_file.py')
+    )
+    out, err = capsys.readouterr()
+    out = out.split('\n')
+    assert out[0] == '321'
+    assert out[1] == 'sweetpassword'
+    assert out[2] != 'not_cwandrews_123'
+    assert out[3] != 'marzo'
+
+
+# @all_runners
+# def test_run_with_env_file(runner, capsys):
+#     runner(
+#         'run', '--quiet',
+#         get_examples_path('env_vars/get_passed_env.py'), '--env', 'ENV_TEST_NUMBER=123', '--env',
+#         'ENV_TEST_USER=cwandrews', '--env', "ENV_TEST_STRING='my_test_string'"
+#     )
+#     out, err = capsys.readouterr()
+#     out = out.split('\n')
+#     assert out[0] == 'cwandrews'
+#     assert out[1] == '123'
+#     assert out[2] == 'my_test_string'
+
+
 @all_runners
 def test_run_with_env(runner, capsys):
     runner(