Fix docs server for Windows.

A bit hacky, but this seems to work well. Hack tracked in pex-tool#2699.

More work towards pex-tool#2658.

pex/commands/command.py

@@ -19,7 +19,7 @@
 from pex.cache import access as cache_access
 from pex.common import environment_as, safe_mkdtemp, safe_open
 from pex.compatibility import shlex_quote
-from pex.os import LINUX
+from pex.os import MAC, WINDOWS
 from pex.result import Error, Ok, Result
 from pex.subprocess import subprocess_daemon_kwargs
 from pex.typing import TYPE_CHECKING, Generic, cast
@@ -33,6 +33,7 @@
         Dict,
         Iterable,
         Iterator,
+        List,
         NoReturn,
         Optional,
         Sequence,
@@ -91,19 +92,24 @@ def try_open_file(
 ):
     # type: (...) -> Result
 
+    args = []  # type: List[str]
     url = None  # type: Optional[str]
     if open_program:
         opener = open_program
-    elif LINUX:
+    elif WINDOWS:
+        opener = os.environ.get("COMSPEC", "cmd.exe")
+        args.append("/C")
+    elif MAC:
+        opener = "open"
+    else:
         opener = "xdg-open"
         url = "https://www.freedesktop.org/wiki/Software/xdg-utils/"
-    else:
-        opener = "open"
+    args.append(path)
 
     with open(os.devnull, "wb") as devnull:
         return try_run_program(
             opener,
-            [path],
+            args,
             url=url,
             error=error,
             disown=True,
@@ -112,6 +118,18 @@ def try_open_file(
         )
 
 
+def try_open_url(
+    url,  # type: str
+    open_program=None,  # type: Optional[str]
+    error=None,  # type: Optional[str]
+    suppress_stderr=False,  # type: bool
+):
+    # type: (...) -> Result
+    return try_open_file(
+        url, open_program=open_program or "explorer", error=error, suppress_stderr=suppress_stderr
+    )
+
+
 @attr.s(frozen=True)
 class Command(object):
     @staticmethod

pex/docs/command.py

@@ -8,7 +8,7 @@
 from textwrap import dedent
 
 from pex import docs
-from pex.commands.command import try_open_file
+from pex.commands.command import try_open_url
 from pex.docs.server import SERVER_NAME, LaunchError, LaunchResult
 from pex.docs.server import launch as launch_docs_server
 from pex.result import Error, try_
@@ -92,7 +92,7 @@ def serve_html_docs(
 
     if open_browser:
         try_(
-            try_open_file(result.server_info.url, open_program=config.browser, suppress_stderr=True)
+            try_open_url(result.server_info.url, open_program=config.browser, suppress_stderr=True)
         )
 
     return result

pex/docs/server.py

@@ -1,7 +1,6 @@
 # Copyright 2024 Pex project contributors.
 # Licensed under the Apache License, Version 2.0 (see LICENSE).
 
-import errno
 import json
 import logging
 import os
@@ -13,7 +12,7 @@
 
 from pex.cache.dirs import CacheDir
 from pex.common import safe_open
-from pex.os import kill
+from pex.os import is_alive, kill
 from pex.subprocess import launch_python_daemon
 from pex.typing import TYPE_CHECKING
 from pex.version import __version__
@@ -79,7 +78,7 @@ def _read_url(
             with open(server_log) as fp:
                 for line in fp:
                     if line.endswith(("\r", "\n")):
-                        match = re.search(r"Serving HTTP on 0\.0\.0\.0 port (?P<port>\d+)", line)
+                        match = re.search(r"Serving HTTP on \S+ port (?P<port>\d+)", line)
                         if match:
                             port = match.group("port")
                             return "http://localhost:{port}".format(port=port)
@@ -106,13 +105,7 @@ def record(
     def alive(self):
         # type: () -> bool
         # TODO(John Sirois): Handle pid rollover
-        try:
-            os.kill(self.server_info.pid, 0)
-            return True
-        except OSError as e:
-            if e.errno == errno.ESRCH:  # No such process.
-                return False
-            raise
+        return is_alive(self.server_info.pid)
 
     def kill(self):
         # type: () -> None

pex/os.py

@@ -120,6 +120,49 @@ def is_exe(path):
 
 if WINDOWS:
 
+    def is_alive(pid):
+        # type: (int) -> bool
+
+        # TODO(John Sirois): This is extremely hacky, consider adding a psutil dependency for
+        #  Windows. See: https://github.com/pex-tool/pex/issues/2699
+
+        import csv
+        import subprocess
+
+        args = ["tasklist", "/FI", "PID eq {pid}".format(pid=pid), "/FO", "CSV"]
+        process = subprocess.Popen(args=args, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
+        stdout, stderr = process.communicate()
+        if process.returncode != 0:
+            raise RuntimeError(
+                "Failed to query status of process with pid {pid}.\n"
+                "Execution of `{args}` returned exit code {returncode}.\n"
+                "{stderr}".format(
+                    pid=pid,
+                    args=" ".join(args),
+                    returncode=process.returncode,
+                    stderr=stderr.decode("utf-8"),
+                )
+            )
+
+        output = stdout.decode("utf-8")
+        if "No tasks are running" in output:
+            return False
+
+        lines = output.splitlines()
+        if len(lines) != 2:
+            return False
+
+        csv_reader = csv.DictReader(lines)
+        for row in csv_reader:
+            pid_value = row.get("PID", -1)
+            if pid_value == -1:
+                return False
+            try:
+                return pid == int(pid_value)
+            except (ValueError, TypeError):
+                return False
+        return False
+
     # https://learn.microsoft.com/en-us/windows/win32/procthread/process-security-and-access-rights
     _PROCESS_TERMINATE = 0x1  # Required to terminate a process using TerminateProcess.
 
@@ -170,6 +213,19 @@ def kill(pid):
 
 else:
 
+    def is_alive(pid):
+        # type: (int) -> bool
+
+        import errno
+
+        try:
+            os.kill(pid, 0)
+            return True
+        except OSError as e:
+            if e.errno == errno.ESRCH:  # No such process.
+                return False
+            raise
+
     def kill(pid):
         # type: (int) -> None