Support the FastAPI app being mounted. (#1174)

Fixes #1170

integration_tests/fastapi_integration.py

@@ -0,0 +1,14 @@
+"""Integration tests where the FastAPI app is mounted."""
+import lilac.server
+from fastapi import FastAPI
+
+app = FastAPI()
+
+
+@app.get('/')
+def read_main():
+  """The main endpoint."""
+  return {'message': 'Hello World from main app'}
+
+
+app.mount('/lilac_sub', lilac.server.app)

integration_tests/fastapi_mount_test.sh

@@ -0,0 +1,29 @@
+# Tests the FastAPI server when it is mounted as a sub-path.
+
+MOUNT_PATH='lilac_sub'
+
+# Find a free port.
+PORT=$(python -c 'import socket; s=socket.socket(); s.bind(("", 0)); print(s.getsockname()[1]); s.close()');
+
+poetry run uvicorn integration_tests.fastapi_integration:app --port $PORT &
+pid="$!"
+
+
+URL="http://localhost:$PORT/"
+start_time="$(date -u +%s)"
+TIMEOUT_SEC=15
+until curl --fail --silent "$URL" > /dev/null; do
+  sleep 1
+  current_time="$(date -u +%s)"
+  elapsed_seconds=$(($current_time-$start_time))
+  if [ $elapsed_seconds -gt $TIMEOUT_SEC ]; then
+    echo "Timeout $TIMEOUT_SEC seconds to reach server."
+    kill $pid
+    exit 1
+  fi
+done
+
+
+curl --fail --silent "http://localhost:$PORT/lilac_sub/api/v1/tasks/"
+
+curl --fail --silent "http://localhost:$PORT/lilac_sub/"

integration_tests/run_integration_tests.sh

@@ -2,34 +2,8 @@
 
 set -e # Fail if any of the commands below fail.
 
-# Make sure the CLI succeeds for test_data.
-mkdir -p test_data
-touch test_data/lilac.yml
-
-# Find a free port.
-PORT=$(python -c 'import socket; s=socket.socket(); s.bind(("", 0)); print(s.getsockname()[1]); s.close()');
-
-
-poetry run lilac start ./test_data --port $PORT &
-pid="$!"
-
-URL="http://localhost:$PORT/docs"
-start_time="$(date -u +%s)"
-TIMEOUT_SEC=15
-until curl --fail --silent "$URL" > /dev/null; do
-  sleep 1
-  current_time="$(date -u +%s)"
-  elapsed_seconds=$(($current_time-$start_time))
-  if [ $elapsed_seconds -gt $TIMEOUT_SEC ]; then
-    echo "Timeout $TIMEOUT_SEC seconds to reach server."
-    kill $pid
-    exit 1
-  fi
-done
-
-echo "GET request to $URL succeeded."
-
-kill $pid
+./integration_tests/start_server_test.sh
+./integration_tests/fastapi_mount_test.sh
 
 echo
 echo "CLI integration tests passed."

integration_tests/start_server_test.sh

@@ -0,0 +1,32 @@
+# Tests that the lilac server starts from the CLI.
+
+set -e # Fail if any of the commands below fail.
+
+# Make sure the CLI succeeds for test_data.
+mkdir -p test_data
+touch test_data/lilac.yml
+
+# Find a free port.
+PORT=$(python -c 'import socket; s=socket.socket(); s.bind(("", 0)); print(s.getsockname()[1]); s.close()');
+
+
+poetry run lilac start ./test_data --port $PORT &
+pid="$!"
+
+URL="http://localhost:$PORT/docs"
+start_time="$(date -u +%s)"
+TIMEOUT_SEC=15
+until curl --fail --silent "$URL" > /dev/null; do
+  sleep 1
+  current_time="$(date -u +%s)"
+  elapsed_seconds=$(($current_time-$start_time))
+  if [ $elapsed_seconds -gt $TIMEOUT_SEC ]; then
+    echo "Timeout $TIMEOUT_SEC seconds to reach server."
+    kill $pid
+    exit 1
+  fi
+done
+
+echo "GET request to $URL succeeded."
+
+kill $pid

lilac/server.py

@@ -96,7 +96,10 @@ def __init__(self, app: ASGIApp) -> None:
   async def __call__(self, scope: Scope, receive: Receive, send: Send) -> None:
     """Redirect trailing slashes to non-trailing slashes."""
     url = URL(scope=scope).path
-    ends_with_slash = url.endswith('/') and url != '/' and not url.startswith('/api')
+    root_path = scope.get('root_path') or ''
+    ends_with_slash = (
+      url.endswith('/') and url != '/' and root_path and not url.startswith(root_path + '/api')
+    )
 
     if scope['type'] == 'http' and ends_with_slash:
       new_url = url.rstrip('/')