__init__.py

# Copyright The OpenTelemetry 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 argparse import REMAINDER, ArgumentParser
from importlib.metadata import entry_points
from logging import getLogger
from os import environ, execl, getcwd
from os.path import abspath, dirname, pathsep
from re import sub
from shutil import which

from opentelemetry.instrumentation.version import __version__

_logger = getLogger(__name__)


def run() -> None:
    parser = ArgumentParser(
        description="""
        opentelemetry-instrument automatically instruments a Python
        program and its dependencies and then runs the program.
        """,
        epilog="""
        Optional arguments (except for --help and --version) for opentelemetry-instrument
        directly correspond with OpenTelemetry environment variables. The
        corresponding optional argument is formed by removing the OTEL_ or
        OTEL_PYTHON_ prefix from the environment variable and lower casing the
        rest. For example, the optional argument --attribute_value_length_limit
        corresponds with the environment variable
        OTEL_ATTRIBUTE_VALUE_LENGTH_LIMIT.

        These optional arguments will override the current value of the
        corresponding environment variable during the execution of the command.
        """,
    )

    argument_otel_environment_variable = {}

    for entry_point in entry_points(
        group="opentelemetry_environment_variables"
    ):
        environment_variable_module = entry_point.load()

        for attribute in dir(environment_variable_module):
            if attribute.startswith("OTEL_"):
                argument = sub(r"OTEL_(PYTHON_)?", "", attribute).lower()

                parser.add_argument(
                    f"--{argument}",
                    required=False,
                )
                argument_otel_environment_variable[argument] = attribute

    parser.add_argument(
        "--version",
        help="print version information",
        action="version",
        version="%(prog)s " + __version__,
    )
    parser.add_argument("command", help="Your Python application.")
    parser.add_argument(
        "command_args",
        help="Arguments for your application.",
        nargs=REMAINDER,
    )

    args = parser.parse_args()

    for argument, otel_environment_variable in (
        argument_otel_environment_variable
    ).items():
        value = getattr(args, argument)
        if value is not None:
            environ[otel_environment_variable] = value

    python_path = environ.get("PYTHONPATH")

    if not python_path:
        python_path = []

    else:
        python_path = python_path.split(pathsep)

    cwd_path = getcwd()

    # This is being added to support applications that are being run from their
    # own executable, like Django.
    # FIXME investigate if there is another way to achieve this
    if cwd_path not in python_path:
        python_path.insert(0, cwd_path)

    filedir_path = dirname(abspath(__file__))

    python_path = [path for path in python_path if path != filedir_path]

    python_path.insert(0, filedir_path)

    environ["PYTHONPATH"] = pathsep.join(python_path)

    executable = which(args.command)
    execl(executable, executable, *args.command_args)