Attempt to fix detection of locust-plugins version

setup.py

@@ -10,37 +10,37 @@
 from setuptools.command.develop import develop
 
 
+def install_check(self, command):
+    try:
+        import locust_plugins  # noqa
+
+        major, minor, _patch = locust_plugins.__version__.split(".")
+        if int(major) < 2 or int(major) == 2 and int(minor) < 7:
+            sys.exit(
+                "Please update (or uninstall) locust-plugins, your version is not compatible with this version of locust-swarm"
+            )
+    except ImportError:
+        pass  # plugins wasnt installed, no worries
+    if os.name == "nt":
+        sys.exit("Looks like you are on windows. Only MacOS and Linux are supported :(")
+    command.run(self)
+
+
 class PostDevelopCommand(develop):
     def run(self):
-        if os.name == "nt":
-            sys.exit("Looks like you are on windows. Only MacOS and Linux are supported :(")
-        develop.run(self)
+        install_check(self, develop)
 
 
 class PostInstallCommand(install):
     def run(self):
-        if os.name == "nt":
-            sys.exit("Looks like you are on windows. Only MacOS and Linux are supported :(")
-        install.run(self)
+        install_check(self, install)
 
 
 class PostEggInfoCommand(egg_info):
     def run(self):
-        if os.name == "nt":
-            sys.exit("Looks like you are on windows. Only MacOS and Linux are supported :(")
-        egg_info.run(self)
+        install_check(self, egg_info)
 
 
-requirements_list = [
-    "keyring==21.4.0",
-    "psutil",
-    "ConfigArgParse>=1.0",
-]
-# if locust-plugins IS installed, then require a version known to work with this version of swarm.
-spec = importlib.util.find_spec("locust_plugins")
-if spec is not None:
-    requirements_list.append("locust-plugins>=2.7.0")
-
 setup(
     name="locust-swarm",
     description="Load test + test data distribution & launching tool for Locust",
@@ -68,7 +68,11 @@ def run(self):
     packages=find_packages(),
     include_package_data=True,
     zip_safe=False,
-    install_requires=requirements_list,
+    install_requires=[
+        "keyring==21.4.0",
+        "psutil",
+        "ConfigArgParse>=1.0",
+    ],
     entry_points={
         "console_scripts": ["swarm = locust_swarm.swarm:main"],
     },