tutor/tutor/utils.py

294 lines
8.6 KiB
Python

import base64
import json
import os
import random
import shlex
import shutil
import string
import struct
import subprocess
import sys
from functools import lru_cache
from typing import List, Tuple
import click
from Crypto.Protocol.KDF import bcrypt, bcrypt_check
from Crypto.PublicKey import RSA
from Crypto.PublicKey.RSA import RsaKey
from . import exceptions, fmt
def encrypt(text: str) -> str:
"""
Encrypt some textual content with bcrypt.
https://pycryptodome.readthedocs.io/en/latest/src/protocol/kdf.html#bcrypt
The encryption process is compatible with the password verification performed by
`htpasswd <https://httpd.apache.org/docs/2.4/programs/htpasswd.html>`__.
"""
return bcrypt(text.encode(), 12).decode()
def verify_encrypted(encrypted: str, text: str) -> bool:
"""
Return True/False if the encrypted content corresponds to the unencrypted text.
"""
try:
bcrypt_check(text.encode(), encrypted.encode())
return True
except ValueError:
return False
def ensure_file_directory_exists(path: str) -> None:
"""
Create file's base directory if it does not exist.
"""
directory = os.path.dirname(path)
if os.path.isfile(directory):
raise exceptions.TutorError(
f"Attempting to create a directory, but a file with the same name already exists: {directory}"
)
if os.path.isdir(path):
raise exceptions.TutorError(
f"Attempting to write to a file, but a directory with the same name already exists: {directory}"
)
if not os.path.exists(directory):
os.makedirs(directory)
def random_string(length: int) -> str:
return "".join(
[random.choice(string.ascii_letters + string.digits) for _ in range(length)]
)
def list_if(services: List[Tuple[str, bool]]) -> str:
return json.dumps([service[0] for service in services if service[1]])
def common_domain(d1: str, d2: str) -> str:
"""
Return the common domain between two domain names.
Ex: "sub1.domain.com" and "sub2.domain.com" -> "domain.com"
"""
components1 = d1.split(".")[::-1]
components2 = d2.split(".")[::-1]
common = []
for c in range(0, min(len(components1), len(components2))):
if components1[c] == components2[c]:
common.append(components1[c])
else:
break
return ".".join(common[::-1])
def reverse_host(domain: str) -> str:
"""
Return the reverse domain name, java-style.
Ex: "www.google.com" -> "com.google.www"
"""
return ".".join(domain.split(".")[::-1])
def rsa_private_key(bits: int = 2048) -> str:
"""
Export an RSA private key in PEM format.
"""
key = RSA.generate(bits)
return key.export_key().decode()
def rsa_import_key(key: str) -> RsaKey:
"""
Import PEM-formatted RSA key and return the corresponding object.
"""
return RSA.import_key(key.encode())
def long_to_base64(n: int) -> str:
"""
Borrowed from jwkest.__init__
"""
def long2intarr(long_int: int) -> List[int]:
_bytes: List[int] = []
while long_int:
long_int, r = divmod(long_int, 256)
_bytes.insert(0, r)
return _bytes
bys = long2intarr(n)
data = struct.pack(f"{len(bys)}B", *bys)
if not data:
data = b"\x00"
s = base64.urlsafe_b64encode(data).rstrip(b"=")
return s.decode("ascii")
def is_root() -> bool:
"""
Check whether tutor is being run as root/sudo.
"""
if sys.platform == "win32":
# Don't even try
return False
return get_user_id() == 0
def get_user_id() -> int:
"""
Portable way to get user ID. Note: I have no idea if it actually works on windows...
"""
if sys.platform != "win32":
return os.getuid()
# Don't even try for windows
return 0
def docker_run(*command: str) -> int:
args = ["run", "--rm"]
if is_a_tty():
args.append("-it")
return docker(*args, *command)
def docker(*command: str) -> int:
if shutil.which("docker") is None:
raise exceptions.TutorError(
"docker is not installed. Please follow instructions from https://docs.docker.com/install/"
)
return execute("docker", *command)
@lru_cache(maxsize=None)
def _docker_compose_command() -> Tuple[str, ...]:
"""
A helper function to determine which program to call when running docker compose
"""
if os.environ.get("TUTOR_USE_COMPOSE_SUBCOMMAND") is not None:
return ("docker", "compose")
if shutil.which("docker-compose") is not None:
return ("docker-compose",)
if shutil.which("docker") is not None:
if subprocess.run(["docker", "compose"], capture_output=True).returncode == 0:
return ("docker", "compose")
raise exceptions.TutorError(
"docker-compose is not installed. Please follow instructions from https://docs.docker.com/compose/install/"
)
def docker_compose(*command: str) -> int:
return execute(*_docker_compose_command(), *command)
def kubectl(*command: str) -> int:
if shutil.which("kubectl") is None:
raise exceptions.TutorError(
"kubectl is not installed. Please follow instructions from https://kubernetes.io/docs/tasks/tools/install-kubectl/"
)
return execute("kubectl", *command)
def is_a_tty() -> bool:
"""
Return True if stdin is able to allocate a tty. Tty allocation sometimes cannot be
enabled, for instance in cron jobs
"""
return sys.stdin.isatty()
def execute(*command: str) -> int:
click.echo(fmt.command(_shlex_join(*command)))
return execute_silent(*command)
def execute_silent(*command: str) -> int:
with subprocess.Popen(command) as p:
try:
result = p.wait(timeout=None)
except KeyboardInterrupt:
p.kill()
p.wait()
raise
except Exception as e:
p.kill()
p.wait()
raise exceptions.TutorError(f"Command failed: {' '.join(command)}") from e
if result > 0:
raise exceptions.TutorError(
f"Command failed with status {result}: {' '.join(command)}"
)
return result
def _shlex_join(*split_command: str) -> str:
"""
Return a shell-escaped string from *split_command.
TODO: REMOVE THIS FUNCTION AFTER 2023-06-27.
This function is a shim for the ``shlex.join`` standard library function,
which becomes available in Python 3.8 The end-of-life date for Python 3.7
is in Jan 2023 (https://endoflife.date/python). After that point, it
would be good to delete this function and just use Py3.8's ``shlex.join``.
"""
return " ".join(shlex.quote(arg) for arg in split_command)
def check_output(*command: str) -> bytes:
literal_command = _shlex_join(*command)
click.echo(fmt.command(literal_command))
try:
return subprocess.check_output(command)
except Exception as e:
raise exceptions.TutorError(f"Command failed: {literal_command}") from e
def check_macos_docker_memory() -> None:
"""
Try to check that the RAM allocated to the Docker VM on macOS is at least 4 GB.
Parse macOS Docker settings file from user directory and return the max
allocated memory. Will raise TutorError in case of parsing/loading error.
"""
if sys.platform != "darwin":
return
settings_path = os.path.expanduser(
"~/Library/Group Containers/group.com.docker/settings.json"
)
try:
with open(settings_path, encoding="utf-8") as fp:
data = json.load(fp)
memory_mib = int(data["memoryMiB"])
except OSError as e:
raise exceptions.TutorError(f"Error accessing Docker settings file: {e}") from e
except json.JSONDecodeError as e:
raise exceptions.TutorError(
f"Error reading {settings_path}, invalid JSON: {e}"
) from e
except ValueError as e:
raise exceptions.TutorError(
f"Unexpected JSON data in {settings_path}: {e}"
) from e
except KeyError as e:
# Value is absent (Docker creates the file with the default setting of 2048 explicitly
# written in, so we shouldn't need to assume a default value here.)
raise exceptions.TutorError(
f"key 'memoryMiB' not found in {settings_path}"
) from e
except (TypeError, OverflowError) as e:
# TypeError from open() indicates an encoding error
raise exceptions.TutorError(
f"Text encoding error in {settings_path}: {e}"
) from e
if memory_mib < 4096:
raise exceptions.TutorError(
f"Docker is configured to allocate {memory_mib} MiB RAM, less than the recommended {4096} MiB"
)