Set parameters for running flow instead of any imported

metaflow/flowspec.py

@@ -7,7 +7,7 @@
 from types import FunctionType, MethodType
 from typing import Any, Callable, List, Optional, Tuple
 
-from . import cmd_with_io
+from . import cmd_with_io, parameters
 from .parameters import DelayedEvaluationParameter, Parameter
 from .exception import (
     MetaflowException,
@@ -100,6 +100,9 @@ def __init__(self, use_cli=True):
         self._graph = FlowGraph(self.__class__)
         self._steps = [getattr(self, node.name) for node in self._graph]
 
+        # This must be set before calling cli.main() below (or specifically, add_custom_parameters)
+        parameters.parameters = [p for _, p in self._get_parameters()]
+
         if use_cli:
             # we import cli here to make sure custom parameters in
             # args.py get fully evaluated before cli.py is imported.

metaflow/parameters.py

@@ -31,11 +31,7 @@
     ],
 )
 
-# currently we execute only one flow per process, so we can treat
-# Parameters globally. If this was to change, it should/might be
-# possible to move these globals in a FlowSpec (instance) specific
-# closure.
-parameters = []
+parameters = []  # Set by FlowSpec.__init__()
 context_proto = None
 
 
@@ -335,7 +331,6 @@ def __init__(
                 "Parameter *%s*: Separator is only allowed "
                 "for string parameters." % name
             )
-        parameters.append(self)
 
     def option_kwargs(self, deploy_mode):
         kwargs = self.kwargs

test_runner

@@ -5,7 +5,7 @@ set -o errexit -o nounset -o pipefail
 install_deps() {
   for version in 2 3;
   do
-    python$version -m pip install . 
+    python$version -m pip install .
   done
 }
 

tox.ini

@@ -3,4 +3,3 @@
 [testenv]
 allowlist_externals = ./test_runner
 commands = ./test_runner
-