add notebook functions for starting dashboard and cloud functions (#35)

Co-authored-by: Ankit Saini <[email protected]>

singlestoredb/apps/__init__.py

@@ -0,0 +1,2 @@
+from ._cloud_functions import run_function_app  # noqa: F401
+from ._dashboards import run_dashboard_app  # noqa: F401

singlestoredb/apps/_cloud_functions.py

@@ -0,0 +1,70 @@
+import asyncio
+import typing
+import urllib.parse
+
+from ._config import AppConfig
+from ._process import kill_process_by_port
+
+if typing.TYPE_CHECKING:
+    from fastapi import FastAPI
+    from ._uvicorn_util import AwaitableUvicornServer
+
+# Keep track of currently running server
+_running_server: 'typing.Optional[AwaitableUvicornServer]' = None
+
+
+async def run_function_app(
+    app: 'FastAPI',
+    log_level: str = 'error',
+    kill_existing_app_server: bool = True,
+) -> None:
+
+    global _running_server
+    from ._uvicorn_util import AwaitableUvicornServer
+
+    try:
+        import uvicorn
+    except ImportError:
+        raise ImportError('package uvicorn is required to run cloud functions')
+    try:
+        import fastapi
+    except ImportError:
+        raise ImportError('package fastapi is required to run cloud functions')
+
+    if not isinstance(app, fastapi.FastAPI):
+        raise TypeError('app is not an instance of FastAPI')
+
+    app_config = AppConfig.from_env()
+
+    if kill_existing_app_server:
+        # Shutdown the server gracefully if it was started by us.
+        # Since the uvicorn server doesn't start a new subprocess
+        # killing the process would result in kernel dying.
+        if _running_server is not None:
+            await _running_server.shutdown()
+            _running_server = None
+
+        # Kill if any other process is occupying the port
+        kill_process_by_port(app_config.listen_port)
+
+    # Add `GET /` route, used for liveness check
+    @app.get('/')
+    def ping() -> str:
+        return 'Success!'
+
+    base_path = urllib.parse.urlparse(app_config.url).path
+    app.root_path = base_path
+
+    config = uvicorn.Config(
+        app,
+        host='0.0.0.0',
+        port=app_config.listen_port,
+        log_level=log_level,
+    )
+    _running_server = AwaitableUvicornServer(config)
+
+    asyncio.create_task(_running_server.serve())
+    await _running_server.wait_for_startup()
+
+    if app_config.running_interactively:
+        print(f'Cloud function available at {app_config.url}')

singlestoredb/apps/_config.py

@@ -0,0 +1,33 @@
+import os
+from dataclasses import dataclass
+
+
+@dataclass
+class AppConfig:
+    listen_port: int
+    url: str
+    running_interactively: bool
+
+    @classmethod
+    def from_env(cls) -> 'AppConfig':
+        port = os.environ.get('SINGLESTOREDB_APP_LISTEN_PORT')
+        if port is None:
+            raise RuntimeError(
+                'Missing SINGLESTOREDB_APP_LISTEN_PORT environment variable. '
+                'Is the code running outside SingleStoreDB notebook environment?',
+            )
+        url = os.environ.get('SINGLESTOREDB_APP_URL')
+        if url is None:
+            raise RuntimeError(
+                'Missing SINGLESTOREDB_APP_URL environment variable. '
+                'Is the code running outside SingleStoreDB notebook environment?',
+            )
+
+        workload_type = os.environ.get('SINGLESTOREDB_WORKLOAD_TYPE')
+        running_interactively = workload_type == 'InteractiveNotebook'
+
+        return cls(
+            listen_port=int(port),
+            url=url,
+            running_interactively=running_interactively,
+        )

singlestoredb/apps/_dashboards.py

@@ -0,0 +1,51 @@
+import typing
+import urllib.parse
+
+from ._config import AppConfig
+from ._process import kill_process_by_port
+
+if typing.TYPE_CHECKING:
+    from plotly.graph_objs import Figure
+
+
+def run_dashboard_app(
+    figure: 'Figure',
+    debug: bool = False,
+    kill_existing_app_server: bool = True,
+) -> None:
+    try:
+        import dash
+    except ImportError:
+        raise ImportError('package dash is required to run dashboards')
+
+    try:
+        from plotly.graph_objs import Figure
+    except ImportError:
+        raise ImportError('package dash is required to run dashboards')
+
+    if not isinstance(figure, Figure):
+        raise TypeError('figure is not an instance of plotly Figure')
+
+    app_config = AppConfig.from_env()
+
+    if kill_existing_app_server:
+        kill_process_by_port(app_config.listen_port)
+
+    base_path = urllib.parse.urlparse(app_config.url).path
+
+    app = dash.Dash(requests_pathname_prefix=base_path)
+    app.layout = dash.html.Div(
+        [
+            dash.dcc.Graph(figure=figure),
+        ],
+    )
+
+    app.run(
+        host='0.0.0.0',
+        debug=debug,
+        port=str(app_config.listen_port),
+        jupyter_mode='external',
+    )
+
+    if app_config.running_interactively:
+        print(f'Dash app available at {app_config.url}')

singlestoredb/apps/_process.py

@@ -0,0 +1,32 @@
+import os
+import signal
+import typing
+if typing.TYPE_CHECKING:
+    from psutil import Process
+
+
+def kill_process_by_port(port: int) -> None:
+    existing_process = _find_process_by_port(port)
+    kernel_pid = os.getpid()
+    # Make sure we are not killing current kernel
+    if existing_process is not None and kernel_pid != existing_process.pid:
+        print(f'Killing process {existing_process.pid} which is using port {port}')
+        os.kill(existing_process.pid, signal.SIGKILL)
+
+
+def _find_process_by_port(port: int) -> 'Process | None':
+    try:
+        import psutil
+    except ImportError:
+        raise ImportError('package psutil is required')
+
+    for proc in psutil.process_iter(['pid']):
+        try:
+            connections = proc.connections()
+            for conn in connections:
+                if conn.laddr.port == port:
+                    return proc
+        except psutil.AccessDenied:
+            pass
+
+    return None

singlestoredb/apps/_uvicorn_util.py

@@ -0,0 +1,32 @@
+import asyncio
+import socket
+from typing import List
+from typing import Optional
+try:
+    import uvicorn
+except ImportError:
+    raise ImportError('package uvicorn is required')
+
+
+class AwaitableUvicornServer(uvicorn.Server):
+    """
+    Adds `wait_for_startup` method.
+    The function (asynchronously) blocks until the server
+    starts listening or throws an error.
+    """
+
+    def __init__(self, config: 'uvicorn.Config') -> None:
+        super().__init__(config)
+        self._startup_future = asyncio.get_event_loop().create_future()
+
+    async def startup(self, sockets: Optional[List[socket.socket]] = None) -> None:
+        try:
+            result = await super().startup(sockets)
+            self._startup_future.set_result(True)
+            return result
+        except Exception as error:
+            self._startup_future.set_exception(error)
+            raise error
+
+    async def wait_for_startup(self) -> None:
+        await self._startup_future

test-requirements.txt

@@ -1,4 +1,6 @@
 coverage
+dash
+fastapi
 pandas
 parameterized
 polars