Add support for running (and installing) the main CLI

With this `python -m gel` or `uvx gel` will run automatically download,
cache and run the Gel CLI.  In virtualenvs the `gel` command is
automatically available once the `gel` package is installed without the
need to download and run the CLI separately.

Tested on Linux, native Windows and its various Posixish shells
(MINGW, MSYS, Cygwin) and macOS.

gel/__main__.py

@@ -0,0 +1,23 @@
+#
+# This source file is part of the EdgeDB open source project.
+#
+# Copyright 2022-present MagicStack Inc. and the EdgeDB authors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+
+
+from .cli import main
+
+if __name__ == "__main__":
+    main()

gel/cli.py

@@ -0,0 +1,271 @@
+#
+# This source file is part of the EdgeDB open source project.
+#
+# Copyright 2016-present MagicStack Inc. and the EdgeDB authors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+
+from typing import (
+    NoReturn,
+    Tuple,
+)
+
+import os
+import os.path
+import pathlib
+import platform
+import shutil
+import ssl
+import stat
+import subprocess
+import sys
+import tempfile
+import time
+import urllib.request
+
+
+PACKAGE_URL_PREFIX = "https://packages.edgedb.com/dist"
+STRONG_CIPHERSUITES = ":".join([
+    "TLS_AES_128_GCM_SHA256",
+    "TLS_CHACHA20_POLY1305_SHA256",
+    "TLS_AES_256_GCM_SHA384",
+    "ECDHE-ECDSA-AES128-GCM-SHA256",
+    "ECDHE-RSA-AES128-GCM-SHA256",
+    "ECDHE-ECDSA-CHACHA20-POLY1305",
+    "ECDHE-RSA-CHACHA20-POLY1305",
+    "ECDHE-ECDSA-AES256-GCM-SHA384",
+    "ECDHE-RSA-AES256-GCM-SHA384",
+])
+
+
+def _die(msg: str) -> NoReturn:
+    print(f"error: {msg}", file=sys.stderr)
+    sys.exit(1)
+
+
+def _warn(msg: str) -> NoReturn:
+    print(f"warning: {msg}", file=sys.stderr)
+
+
+def _run_cli(path: str) -> NoReturn:
+    cmd = [path] + sys.argv[1:]
+    if os.name == "nt":
+        result = subprocess.run(cmd)
+        sys.exit(result.returncode)
+    else:
+        os.execv(path, cmd)
+
+
+def _real_mac_machine(machine: str) -> str:
+    import ctypes
+    import ctypes.util
+
+    def _sysctl(libc: ctypes.CDLL, name: str) -> str:
+        size = ctypes.c_uint(0)
+        libc.sysctlbyname(name, None, ctypes.byref(size), None, 0)
+        buf = ctypes.create_string_buffer(size.value)
+        libc.sysctlbyname(name, buf, ctypes.byref(size), None, 0)
+        return buf.value
+
+    libc_path = ctypes.util.find_library("c")
+    if not libc_path:
+        _die("could not find the C library")
+    libc = ctypes.CDLL(libc_path)
+    if machine == "i386":
+        # check for 32-bit emulation on a 64-bit x86 machine
+        if _sysctl(libc, "hw.optional.x86_64") == "1":
+            machine = "x86_64"
+    elif machine == "x86_64":
+        # check for Rosetta
+        if _sysctl(libc, "sysctl.proc_translated") == "1":
+            machine = "aarch64"
+
+    return machine
+
+
+def _platform() -> Tuple[str, str]:
+    uname = platform.uname()
+    uname_sys = uname.system
+    machine = uname.machine.lower()
+    if (
+        uname_sys == "Windows"
+        or uname_sys.startswith("CYGWIN_NT")
+        or uname_sys.startswith("MINGW64_NT")
+        or uname_sys.startswith("MSYS_NT")
+    ):
+        os = "Windows"
+    elif uname_sys == "Darwin":
+        if machine == "i386" or machine == "x86_64":
+            machine = _real_mac_machine(machine)
+        os = "Darwin"
+    elif uname_sys == "Linux":
+        os = "Linux"
+    else:
+        _die(f"unsupported OS: {uname_sys}")
+
+    if machine in ("x86-64", "x64", "amd64"):
+        machine = "x86_64"
+    elif machine == "arm64":
+        machine = "aarch64"
+
+    if machine not in ("x86_64", "aarch64") or (
+        machine == "aarch64" and os not in ("Darwin", "Linux")
+    ):
+        _die(f"unsupported hardware architecture: {machine}")
+
+    return os, machine
+
+
+def _download(url: str, dest: pathlib.Path) -> None:
+    if not url.lower().startswith("https://"):
+        _die(f"unexpected insecure URL: {url}")
+
+    # Create an SSL context with certificate verification enabled
+    ssl_context = ssl.create_default_context()
+    ssl_context.minimum_version = ssl.TLSVersion.TLSv1_2
+    ssl_context.set_ciphers(STRONG_CIPHERSUITES)
+
+    try:
+        # Open the URL with the SSL context
+        with urllib.request.urlopen(url, context=ssl_context) as response:
+            final_url = response.geturl()
+            if not final_url.lower().startswith("https://"):
+                _die("redirected to a non-HTTPS URL, download aborted.")
+
+            if response.status != 200:
+                raise RuntimeError(f"{response.status}")
+
+            spinner_symbols = ['|', '/', '-', '\\']
+            msg = "downloading Gel CLI"
+            print(f"{msg}", end="\r")
+            start = time.monotonic()
+
+            with open(str(dest), mode="wb") as file:
+                i = 0
+                while True:
+                    chunk = response.read(524288)
+                    if not chunk:
+                        break
+                    file.write(chunk)
+                    now = time.monotonic()
+                    if now - start > 0.2:
+                        print(f"\r{msg} {spinner_symbols[i]}", end="\r")
+                        start = now
+                        i = (i + 1) % len(spinner_symbols)
+
+            # clear
+            print(f"{' ' * (len(msg) + 2)}", end="\r")
+
+    except Exception as e:
+        _die(f"could not download Gel CLI: {e}")
+
+
+def _get_binary_cache_dir(os_name) -> pathlib.Path:
+    home = pathlib.Path.home()
+    if os_name == 'Windows':
+        localappdata = os.environ.get('LOCALAPPDATA', '')
+        if localappdata:
+            base_cache_dir = pathlib.Path(localappdata)
+        else:
+            base_cache_dir = home / 'AppData' / 'Local'
+    elif os_name == 'Linux':
+        xdg_cache_home = os.environ.get('XDG_CACHE_HOME', '')
+        if xdg_cache_home:
+            base_cache_dir = pathlib.Path(xdg_cache_home)
+        else:
+            base_cache_dir = home / '.cache'
+    elif os_name == 'Darwin':
+        base_cache_dir = home / 'Library' / 'Caches'
+    else:
+        _die(f"unsupported OS: {os_name}")
+
+    cache_dir = base_cache_dir / "gel" / "bin"
+    try:
+        cache_dir.mkdir(parents=True, exist_ok=True)
+    except OSError as e:
+        _warn(f"could not create {cache_dir}: {e}")
+
+        try:
+            cache_dir = pathlib.Path(tempfile.mkdtemp(prefix="gel"))
+        except Exception as e:
+            _die(f"could not create temporary directory: {e}")
+
+    return cache_dir
+
+
+def _get_mountpoint(path: pathlib.Path) -> pathlib.Path:
+    path = path.resolve()
+    if os.path.ismount(str(path)):
+        return path
+    else:
+        for p in path.parents:
+            if os.path.ismount(str(p)):
+                return p
+
+        return p
+
+
+def _install_cli(os_name: str, arch: str, path: pathlib.Path) -> str:
+    triple = f"{arch}"
+    ext = ""
+    if os_name == "Windows":
+        triple += "-pc-windows-msvc"
+        ext = ".exe"
+    elif os_name == "Darwin":
+        triple += "-apple-darwin"
+    elif os_name == "Linux":
+        triple += "-unknown-linux-musl"
+    else:
+        _die(f"unexpected OS: {os}")
+
+    url = f"{PACKAGE_URL_PREFIX}/{triple}/edgedb-cli{ext}"
+
+    if path.exists() and not path.is_file():
+        _die(f"{path} exists but is not a regular file, "
+             f"please remove it and try again")
+
+    _download(url, path)
+
+    try:
+        path.chmod(
+            stat.S_IRWXU
+            | stat.S_IRGRP | stat.S_IXGRP
+            | stat.S_IROTH | stat.S_IXOTH,
+        )
+    except OSError as e:
+        _die(f"could not max {path!r} executable: {e}")
+
+    if not os.access(str(path), os.X_OK):
+        _die(
+            f"cannot execute {path!r} "
+            f"(likely because {_get_mountpoint(path)} is mounted as noexec)"
+        )
+
+
+def main() -> NoReturn:
+    dev_cli = shutil.which("gel-dev")
+    if dev_cli:
+        path = pathlib.Path(dev_cli)
+    else:
+        os, arch = _platform()
+        cache_dir = _get_binary_cache_dir(os)
+        path = cache_dir / "gel"
+        if not path.exists():
+            _install_cli(os, arch, path)
+
+    _run_cli(path)
+
+
+if __name__ == "__main__":
+    main()

setup.py

@@ -366,6 +366,7 @@ def finalize_options(self):
             "edgedb-py=gel.codegen.cli:main",
             "gel-py=gel.codegen.cli:main",
             "gel-orm=gel.orm.cli:main",
+            "gel=gel.cli:main",
         ]
     }
 )