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* Add method to get our global configs path * Add utilities for managing the list of active servers * Add basic start-server functionality * Start calling the new server functionality * ensure servers start and stop correctly --------- Co-authored-by: Oscar Levin <oscar.levin@unco.edu>
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,201 @@ | ||
| from __future__ import annotations | ||
| from dataclasses import dataclass | ||
| from http.server import SimpleHTTPRequestHandler | ||
| import logging | ||
| import os | ||
| from pathlib import Path | ||
| import socketserver | ||
| import typing as t | ||
| import psutil | ||
|
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||
| from pretext.utils import hash_path, home_path | ||
|
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| # Get access to logger | ||
| log = logging.getLogger("ptxlogger") | ||
|
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|
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| @dataclass | ||
| class RunningServerInfo: | ||
| """A simple dataclass to hold the information in the running servers file.""" | ||
|
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| pathHash: str | ||
| pid: int | ||
| port: int | ||
| binding: str | ||
|
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| @staticmethod | ||
| def fromFileLine(line: str) -> RunningServerInfo: | ||
| (pathHash, pid, port, binding) = line.split() | ||
| return RunningServerInfo( | ||
| pathHash=pathHash, pid=int(pid), port=int(port), binding=binding | ||
| ) | ||
|
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| def toFileLine(self) -> str: | ||
| return f"{self.pathHash} {self.pid} {self.port} {self.binding}\n" | ||
|
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| def isActiveServer(self) -> bool: | ||
| """Returns whether the server represented by this object is active on the provided port""" | ||
| p = psutil.Process(self.pid) | ||
| if not p.is_running(): | ||
| log.info(f"Found entry no longer running {p.pid}") | ||
| return False | ||
| if p.status == psutil.STATUS_ZOMBIE: | ||
| log.info(f"Found zombie process {p.pid}") | ||
| return False | ||
| for _, _, _, laddr, _, _ in p.net_connections("all"): | ||
| if laddr.port == self.port: | ||
| log.info(f"Found server at {self.url()}") | ||
| return True | ||
| log.info( | ||
| f"Found process {self.pid} no longer listening on specified port {self.port}" | ||
| ) | ||
| return False | ||
|
|
||
| def terminate(self) -> None: | ||
| """Attempt to terminate the process described by this info.""" | ||
| try: | ||
| log.info(f"Terminating {self.pid}") | ||
| psutil.Process(self.pid).terminate() | ||
| remove_server_entry(self.pathHash) | ||
| except Exception as e: | ||
| log.info(f"Terminate failed for {self.pid}.") | ||
| log.exception(e, exc_info=True) | ||
|
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| def url(self) -> str: | ||
| return f"{self.binding}:{self.port}" | ||
|
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| def get_running_servers() -> t.List[RunningServerInfo]: | ||
| """ | ||
| Processes the ~/.ptx/running_servers file to retrieve a list | ||
| of any possibly current running servers. | ||
| """ | ||
| if not home_path().exists(): | ||
| return [] | ||
| try: | ||
| runningServersFile = home_path() / "running_servers" | ||
| if not runningServersFile.is_file(): | ||
| return [] | ||
| with open(runningServersFile, "r") as f: | ||
| return [RunningServerInfo.fromFileLine(line) for line in f.readlines()] | ||
| except IOError as e: | ||
| log.info("Unable to open running servers file.") | ||
| log.exception(e, exc_info=True) | ||
| return [] | ||
|
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|
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| def save_running_servers(runningServers: t.List[RunningServerInfo]) -> None: | ||
| """ | ||
| Overwrites the ~/.ptx/running_servers file to store | ||
| the new list of running servers. | ||
| """ | ||
| # Ensure home path exists | ||
| os.makedirs(home_path(), exist_ok=True) | ||
| try: | ||
| runningServersFile = home_path() / "running_servers" | ||
| with open(runningServersFile, "w") as f: | ||
| # Write each server info to a new line | ||
| f.writelines([info.toFileLine() for info in runningServers]) | ||
| except IOError as e: | ||
| log.info("Unable to write running servers file.") | ||
| log.exception(e, exc_info=True) | ||
|
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| def add_server_entry(pathHash: str, pid: int, port: int, binding: str) -> None: | ||
| """Add a new server entry to ~/.ptx/running_servers. | ||
| This function does not attempt to ensure that an active server doesn't already exist. | ||
| """ | ||
| PURGE_LIMIT = 10 # If more servers active, try to clean up | ||
| runningServers = get_running_servers() | ||
| newEntry = RunningServerInfo(pathHash=pathHash, pid=pid, port=port, binding=binding) | ||
| runningServers.append(newEntry) | ||
| if len(runningServers) >= PURGE_LIMIT: | ||
| log.info(f"There are {PURGE_LIMIT} or more servers on file. Cleaning up ...") | ||
| runningServers = list(stop_inactive_servers(runningServers)) | ||
| save_running_servers(runningServers) | ||
| log.info(f"Added server entry {newEntry.toFileLine()}") | ||
|
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|
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| def remove_server_entry(pathHash: str) -> None: | ||
| remainingServers = [ | ||
| info for info in get_running_servers() if info.pathHash != pathHash | ||
| ] | ||
| save_running_servers(remainingServers) | ||
|
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|
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| def stop_inactive_servers( | ||
| servers: t.List[RunningServerInfo], | ||
| ) -> t.Iterator[RunningServerInfo]: | ||
| """Stops any inactive servers and yields the active ones.""" | ||
| for server in servers: | ||
| if server.isActiveServer(): | ||
| yield server | ||
| else: | ||
| server.terminate() | ||
|
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| def active_server_for_path_hash(pathHash: str) -> t.Optional[RunningServerInfo]: | ||
| return next( | ||
| (info for info in get_running_servers() if info.pathHash == pathHash), | ||
| None, | ||
| ) | ||
|
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| # boilerplate to prevent overzealous caching by preview server, and | ||
| # avoid port issues | ||
| def binding_for_access(access: t.Literal["public", "private"] = "private") -> str: | ||
| if access == "private": | ||
| return "localhost" | ||
| return "0.0.0.0" | ||
|
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|
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| def start_server( | ||
| base_dir: Path, | ||
| access: t.Literal["public", "private"] = "private", | ||
| port: int = 8128, | ||
| callback: t.Callable[[int], None] | None = None, | ||
| ) -> None: | ||
| log.info("setting up ...") | ||
| pathHash = hash_path(base_dir) | ||
| pid = os.getpid() | ||
| binding = binding_for_access(access) | ||
| log.info("values set...") | ||
|
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| # Previously we defined a custom handler to prevent caching, but we don't need to do that anymore. It was causing issues with the _static js/css files inside codespaces for an unknown reason. Might bring this back in the future. | ||
| # 2024-04-05: try using this again to let Firefox work | ||
| class RequestHandler(SimpleHTTPRequestHandler): | ||
| def __init__(self, *args: t.Any, **kwargs: t.Any): | ||
| super().__init__(*args, directory=base_dir.as_posix(), **kwargs) | ||
|
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| """HTTP request handler with no caching""" | ||
|
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| def end_headers(self) -> None: | ||
| self.send_my_headers() | ||
| SimpleHTTPRequestHandler.end_headers(self) | ||
|
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| def send_my_headers(self) -> None: | ||
| self.send_header("Cache-Control", "no-cache, no-store, must-revalidate") | ||
| self.send_header("Pragma", "no-cache") | ||
| self.send_header("Expires", "0") | ||
|
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| class TCPServer(socketserver.TCPServer): | ||
| allow_reuse_address = True | ||
|
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||
| while True: | ||
| try: | ||
| with TCPServer((binding, port), RequestHandler) as httpd: | ||
| log.info("adding server entry") | ||
| add_server_entry(pathHash, pid, port, binding) | ||
| log.info("Starting the server") | ||
| if callback is not None: | ||
| callback(port) | ||
| httpd.serve_forever() | ||
| except OSError: | ||
| log.warning(f"Port {port} could not be used.") | ||
| port += 1 | ||
| log.warning(f"Trying port {port} instead.\n") | ||
| except KeyboardInterrupt: | ||
| log.info("Stopping server.") | ||
| remove_server_entry(pathHash) | ||
| return |
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