add utils to get hostname from request and process from hostname

catfish/router/__init__.py

@@ -1,9 +1,11 @@
 import click
 from aiohttp import web
 
+from .utils import get_hostname_from_request
+
 
 async def handle_request(request):
-    return web.json_response({})
+    return web.json_response({"host": get_hostname_from_request(request)})
 
 
 def get_server():

catfish/router/utils.py

@@ -0,0 +1,24 @@
+from typing import Optional
+
+import psutil
+
+from catfish.utils.processes import get_root_process
+
+ROOT_PROCESS = get_root_process()
+HOSTNAME_ENV_VAR = "VIRTUAL_HOST"
+
+
+def get_process_for_hostname(hostname: str) -> Optional[psutil.Process]:
+    for process in ROOT_PROCESS.children(recursive=True):
+        try:
+            if hostname in process.environ().get(HOSTNAME_ENV_VAR, "").split(","):
+                return process
+        except psutil.AccessDenied:
+            continue
+    return None
+
+
+def get_hostname_from_request(request) -> str:
+    if getattr(request, "url", None) is not None:
+        return request.url.host
+    return request.host.split(":")[0]

tests/test_router/test_utils.py

@@ -0,0 +1,40 @@
+import os
+import subprocess
+
+from aiohttp.test_utils import make_mocked_request
+
+from catfish.router import utils
+from tests import BaseTestCase
+
+
+class ProcessForHostnameTestCase(BaseTestCase):
+    def test_no_matching_processes(self):
+        self.assertIsNone(utils.get_process_for_hostname("localhost"))
+
+    def test_finds_process(self):
+        proc = subprocess.Popen(
+            "yes",
+            stdout=subprocess.PIPE,
+            env={**os.environ, utils.HOSTNAME_ENV_VAR: "localhost"},
+        )
+        self.assertIsNone(proc.poll())
+        self.assertEqual(utils.get_process_for_hostname("localhost").pid, proc.pid)
+
+
+class HostnameFromRequestTestCase(BaseTestCase):
+    def get_request_for_hostname(self, hostname):
+        return make_mocked_request("GET", "/", headers={"HOST": hostname})
+
+    def test_hostname(self):
+        self.assertEqual(
+            utils.get_hostname_from_request(self.get_request_for_hostname("localhost")),
+            "localhost",
+        )
+
+    def test_hostname_with_port(self):
+        self.assertEqual(
+            utils.get_hostname_from_request(
+                self.get_request_for_hostname("localhost:8080")
+            ),
+            "localhost",
+        )