Fixes up the async example to use the tracker

But only if the server is running

examples/async/README.md

@@ -29,6 +29,12 @@ You should get the following result:
 {"pipeline":{"computation1":false,"computation2":true}}
 ```
 
+## Tracking
+
+This uses the async tracker if the [ui](https://hamilton.dagworks.io/en/latest/concepts/ui/)
+is running on port 8241 -- see [fastapi_example.py](fastapi_example.py) for the code.
+If it is not running it will proceed anyway without tracking.
+
 
 ## How it works
 

examples/async/async_module.py

@@ -24,17 +24,17 @@ def bar(request_raw: dict) -> str:
     return request_raw.get("bar", "baz")
 
 
-async def computation1(foo: str, some_data: dict) -> bool:
-    await asyncio.sleep(1)
-    return False
-
-
 async def some_data() -> dict:
     async with aiohttp.ClientSession() as session:
         async with session.get("http://httpbin.org/get") as resp:
             return await resp.json()
 
 
+async def computation1(foo: str, some_data: dict) -> bool:
+    await asyncio.sleep(1)
+    return False
+
+
 async def computation2(bar: str) -> bool:
     await asyncio.sleep(1)
     return True

examples/async/fastapi_example.py

@@ -1,13 +1,61 @@
+import logging
+from contextlib import asynccontextmanager
+
+import aiohttp
 import async_module
 import fastapi
+from aiohttp import client_exceptions
+from hamilton_sdk import adapters
 
-from hamilton import base
 from hamilton.experimental import h_async
 
-app = fastapi.FastAPI()
+logger = logging.getLogger(__name__)
 
 # can instantiate a driver once for the life of the app:
-dr = h_async.AsyncDriver({}, async_module, result_builder=base.DictResult())
+dr = None
+
+
+async def _tracking_server_running():
+    """Quickly tells if the tracking server is up and running"""
+    async with aiohttp.ClientSession() as session:
+        try:
+            async with session.get("http://localhost:8241/api/v1/ping") as response:
+                if response.status == 200:
+                    return True
+                else:
+                    return False
+        except client_exceptions.ClientConnectionError:
+            return False
+
+
+@asynccontextmanager
+async def lifespan(app: fastapi.FastAPI):
+    """Fast API lifespan context manager for setting up the driver and tracking adapters
+    This has to be done async as there are initializers
+    """
+    global dr
+    is_server_running = await _tracking_server_running()
+    if not is_server_running:
+        logger.warning(
+            "Tracking server is not running, skipping telemetry. To run the telemetry server, run hamilton ui. "
+            "Note you must have a project with ID 1 if it is running -- if not, you can change the project "
+            "ID in this file or create a new one from the UI"
+        )
+    tracking_adapters = []
+    if is_server_running:
+        tracker_async = adapters.AsyncHamiltonTracker(
+            project_id=1,
+            username="elijah",
+            dag_name="async_tracker",
+        )
+        tracking_adapters = [tracker_async]
+    dr = (
+        await h_async.Builder().with_modules(async_module).with_adapters(*tracking_adapters).build()
+    )
+    yield
+
+
+app = fastapi.FastAPI(lifespan=lifespan)
 
 
 @app.post("/execute")