feat(settings): helper calculates runtime env from hosts

function rather than variable to enable dynamic runtime calculation
e.g. for unit tests

Author: thekaveman

benefits/settings.py

@@ -4,6 +4,8 @@
 
 import os
 
+from django.conf import settings
+
 from benefits import sentry
 
 
@@ -24,6 +26,20 @@ def _filter_empty(ls):
 
 ALLOWED_HOSTS = _filter_empty(os.environ.get("DJANGO_ALLOWED_HOSTS", "localhost,127.0.0.1").split(","))
 
+
+def RUNTIME_ENVIRONMENT():
+    """Helper calculates the current runtime environment from ALLOWED_HOSTS."""
+
+    # usage of django.conf.settings.ALLOWED_HOSTS here (rather than the module variable directly)
+    # is to ensure dynamic calculation, e.g. for unit tests and elsewhere this setting is needed
+    env = "dev"
+    if "test-benefits.calitp.org" in settings.ALLOWED_HOSTS:
+        env = "test"
+    elif "benefits.calitp.org" in settings.ALLOWED_HOSTS:
+        env = "prod"
+    return env
+
+
 # Application definition
 
 INSTALLED_APPS = [

tests/pytest/test_settings.py

@@ -0,0 +1,46 @@
+def test_runtime_environment__default(settings):
+    assert settings.RUNTIME_ENVIRONMENT() == "dev"
+
+
+def test_runtime_environment__dev(settings):
+    settings.ALLOWED_HOSTS = ["dev-benefits.calitp.org"]
+    assert settings.RUNTIME_ENVIRONMENT() == "dev"
+
+
+def test_runtime_environment__local(settings):
+    settings.ALLOWED_HOSTS = ["localhost", "127.0.0.1"]
+    assert settings.RUNTIME_ENVIRONMENT() == "dev"
+
+
+def test_runtime_environment__nonmatching(settings):
+    # with only nonmatching hosts, return dev
+    settings.ALLOWED_HOSTS = ["example.com", "example2.org"]
+    assert settings.RUNTIME_ENVIRONMENT() == "dev"
+
+
+def test_runtime_environment__test(settings):
+    settings.ALLOWED_HOSTS = ["test-benefits.calitp.org"]
+    assert settings.RUNTIME_ENVIRONMENT() == "test"
+
+
+def test_runtime_environment__test_and_nonmatching(settings):
+    # when test is specified with other nonmatching hosts, assume test
+    settings.ALLOWED_HOSTS = ["test-benefits.calitp.org", "example.com"]
+    assert settings.RUNTIME_ENVIRONMENT() == "test"
+
+
+def test_runtime_environment__test_and_prod(settings):
+    # if both test and prod are specified (edge case/error in configuration), assume test
+    settings.ALLOWED_HOSTS = ["benefits.calitp.org", "test-benefits.calitp.org"]
+    assert settings.RUNTIME_ENVIRONMENT() == "test"
+
+
+def test_runtime_environment__prod(settings):
+    settings.ALLOWED_HOSTS = ["benefits.calitp.org"]
+    assert settings.RUNTIME_ENVIRONMENT() == "prod"
+
+
+def test_runtime_environment__prod_and_nonmatching(settings):
+    # when prod is specified with other nonmatching hosts, assume prod
+    settings.ALLOWED_HOSTS = ["benefits.calitp.org", "https://example.com"]
+    assert settings.RUNTIME_ENVIRONMENT() == "prod"