elasticapm/utils/__init__.py

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import base64
import os
import re
import socket
import urllib.parse
from functools import partial, partialmethod
from types import FunctionType
from typing import Pattern

from elasticapm.conf import constants
from elasticapm.utils import encoding

partial_types = (partial, partialmethod)


default_ports = {"https": 443, "http": 80, "postgresql": 5432, "mysql": 3306, "mssql": 1433}
fqdn = None


def varmap(func, var, context=None, name=None, **kwargs):
    """
    Executes ``func(key_name, value)`` on all values,
    recursively discovering dict and list scoped
    values.
    """
    if context is None:
        context = set()
    objid = id(var)
    if objid in context:
        return func(name, "<...>", **kwargs)
    context.add(objid)

    # Apply func() before recursion, so that `shorten()` doesn't have to iterate over all the trimmed values
    ret = func(name, var, **kwargs)
    if isinstance(ret, dict):
        # iterate over a copy of the dictionary to avoid "dictionary changed size during iteration" issues
        ret = dict((k, varmap(func, v, context, k, **kwargs)) for k, v in ret.copy().items())
    elif isinstance(ret, (list, tuple)):
        # Apply func() before recursion, so that `shorten()` doesn't have to iterate over all the trimmed values
        ret = [varmap(func, f, context, name, **kwargs) for f in ret]
    context.remove(objid)
    return ret


def get_name_from_func(func: FunctionType) -> str:
    # partials don't have `__module__` or `__name__`, so we use the values from the "inner" function
    if isinstance(func, partial_types):
        return "partial({})".format(get_name_from_func(func.func))
    elif hasattr(func, "_partialmethod") and hasattr(func._partialmethod, "func"):
        return "partial({})".format(get_name_from_func(func._partialmethod.func))
    elif hasattr(func, "__partialmethod__") and hasattr(func.__partialmethod__, "func"):
        return "partial({})".format(get_name_from_func(func.__partialmethod__.func))

    module = func.__module__

    if hasattr(func, "view_class"):
        view_name = func.view_class.__name__
    elif hasattr(func, "__name__"):
        view_name = func.__name__
    else:  # Fall back if there's no __name__
        view_name = func.__class__.__name__

    return "{0}.{1}".format(module, view_name)


def build_name_with_http_method_prefix(name, request):
    return " ".join((request.method, name)) if name else name


def is_master_process() -> bool:
    # currently only recognizes uwsgi master process
    try:
        import uwsgi

        return os.getpid() == uwsgi.masterpid()
    except ImportError:
        return False


def get_url_dict(url: str) -> dict:
    parse_result = urllib.parse.urlparse(url)

    url_dict = {
        "full": encoding.keyword_field(url),
        "protocol": parse_result.scheme + ":",
        "hostname": encoding.keyword_field(parse_result.hostname),
        "pathname": encoding.keyword_field(parse_result.path),
    }

    port = None if parse_result.port is None else str(parse_result.port)

    if port:
        url_dict["port"] = port
    if parse_result.query:
        url_dict["search"] = encoding.keyword_field("?" + parse_result.query)
    return url_dict


def sanitize_url(url: str) -> str:
    if "@" not in url:
        return url
    parts = urllib.parse.urlparse(url)
    return url.replace("%s:%s" % (parts.username, parts.password), "%s:%s" % (parts.username, constants.MASK_URL))


def get_host_from_url(url: str) -> str:
    parsed_url = urllib.parse.urlparse(url)
    host = parsed_url.hostname or " "

    if parsed_url.port and default_ports.get(parsed_url.scheme) != parsed_url.port:
        host += ":" + str(parsed_url.port)

    return host


def url_to_destination_resource(url: str) -> str:
    parts = urllib.parse.urlsplit(url)
    hostname = parts.hostname if parts.hostname else ""
    # preserve brackets for IPv6 URLs
    if "://[" in url:
        hostname = "[%s]" % hostname
    try:
        port = parts.port
    except ValueError:
        # Malformed port, just use None rather than raising an exception
        port = None
    default_port = default_ports.get(parts.scheme, None)
    name = "%s://%s" % (parts.scheme, hostname)
    resource = hostname
    if not port and parts.scheme in default_ports:
        port = default_ports[parts.scheme]
    if port:
        if port != default_port:
            name += ":%d" % port
        resource += ":%d" % port
    return resource


def read_pem_file(file_obj) -> bytes:
    cert = b""
    for line in file_obj:
        if line.startswith(b"-----BEGIN CERTIFICATE-----"):
            break
    # scan until we find the first END CERTIFICATE marker
    for line in file_obj:
        if line.startswith(b"-----END CERTIFICATE-----"):
            break
        cert += line.strip()
    return base64.b64decode(cert)


def starmatch_to_regex(pattern: str) -> Pattern:
    options = re.DOTALL
    # check if we are case-sensitive
    if pattern.startswith("(?-i)"):
        pattern = pattern[5:]
    else:
        options |= re.IGNORECASE
    i, n = 0, len(pattern)
    res = []
    while i < n:
        c = pattern[i]
        i = i + 1
        if c == "*":
            res.append(".*")
        else:
            res.append(re.escape(c))
    return re.compile(r"(?:%s)\Z" % "".join(res), options)


def nested_key(d: dict, *args):
    """
    Traverses a dictionary for nested keys. Returns `None` if the at any point
    in the traversal a key cannot be found.

    Example:

        >>> from elasticapm.utils import nested_key
        >>> d = {"a": {"b": {"c": 0}}}
        >>> nested_key(d, "a", "b", "c")
        0
        >>> nested_key(d, "a", "b", "d")
        None
    """
    for arg in args:
        try:
            d = d[arg]
        except (TypeError, KeyError):
            d = None
            break
    return d


def getfqdn() -> str:
    """
    socket.getfqdn() has some issues. For one, it's slow (may do a DNS lookup).
    For another, it can return `localhost.localdomain`[1], which is less useful
    than socket.gethostname().

    This function handles the fallbacks and also ensures we don't try to lookup
    the fqdn more than once.

    [1]: https://stackoverflow.com/a/43330159
    """
    global fqdn
    if not fqdn:
        fqdn = socket.getfqdn()
        if fqdn == "localhost.localdomain":
            fqdn = socket.gethostname()
        if not fqdn:
            fqdn = os.environ.get("HOSTNAME")
        if not fqdn:
            fqdn = os.environ.get("HOST")
        if fqdn is None:
            fqdn = ""
        fqdn = fqdn.lower().strip()
    return fqdn