Add lazy asyncio session creation for segment and mandrill

Signed-off-by: Lou Marvin Caraig <[email protected]>

Author: se7entyse7en

server/athenian/api/mandrill.py

@@ -35,24 +35,33 @@ class MandrillClient:
     def __init__(self, key: str, timeout: float = 10, retries: int = 5):
         """Initialize a new instance of Mandrill class."""
         self.key = key
-        self._session = aiohttp.ClientSession(
-            base_url="https://mandrillapp.com",
-            timeout=aiohttp.ClientTimeout(total=timeout),
-        )
+        self._session = None
+        self._timeout = timeout
         self.retries = retries
 
     async def close(self):
         """Free resources and close connections associated with the object."""
-        session = self._session
-        all_is_lost = create_aiohttp_closed_event(session)
-        await session.close()
-        await all_is_lost.wait()
+        if self._session and not self._session.closed:
+            session = self._session
+            all_is_lost = create_aiohttp_closed_event(session)
+            await session.close()
+            await all_is_lost.wait()
+
+    async def _get_session(self) -> aiohttp.ClientSession:
+        if self._session is None or self._session.closed:
+            self._session = aiohttp.ClientSession(
+                base_url="https://mandrillapp.com",
+                timeout=aiohttp.ClientTimeout(total=self._timeout),
+            )
+
+        return self._session
 
     async def _call(self, url: str, body: dict) -> dict:
         response = last_err = None
+        session = await self._get_session()
         for _ in range(self.retries):
             try:
-                response = await self._session.post(
+                response = await session.post(
                     "/api/1.0" + url,
                     json={
                         "key": self.key,

server/athenian/api/segment.py

@@ -31,7 +31,7 @@ class SegmentClient:
 
     def __init__(self, key: str):
         """Initialize a new isntance of SegmentClient."""
-        self._session = aiohttp.ClientSession()
+        self._session = None
         self._key = key
         self.log.info("enabled tracking API calls")
 
@@ -70,6 +70,12 @@ async def track_health_metrics(
         data["context"]["active"] = False
         await self._post(data, "group")
 
+    async def _get_session(self) -> aiohttp.ClientSession:
+        if self._session is None or self._session.closed:
+            self._session = aiohttp.ClientSession()
+
+        return self._session
+
     def _check_identify_full(result: bool, **_) -> bool:
         if not result:
             raise CancelCache()
@@ -155,7 +161,8 @@ def _common_data() -> Dict[str, Any]:
         }
 
     async def _post(self, data: Dict[str, Any], endpoint: str) -> None:
-        async with self._session.post(
+        session = await self._get_session()
+        async with session.post(
             f"{self.url}/{endpoint}", auth=aiohttp.BasicAuth(self._key, ""), json=data,
         ) as response:
             if response.status != 200:
@@ -170,4 +177,5 @@ async def _post(self, data: Dict[str, Any], endpoint: str) -> None:
 
     async def close(self) -> None:
         """Shut down the client."""
-        await self._session.close()
+        if self._session and not self._session.closed:
+            await self._session.close()