clearml/trains/backend_api/session/session.py

import json as json_lib
import sys
import types
from socket import gethostname

import requests
import six
import jwt
from pyhocon import ConfigTree
from requests.auth import HTTPBasicAuth

from .callresult import CallResult
from .defs import ENV_VERBOSE, ENV_HOST, ENV_ACCESS_KEY, ENV_SECRET_KEY
from .request import Request, BatchRequest
from .token_manager import TokenManager
from ..config import load
from ..utils import get_http_session_with_retry
from ..version import __version__


class LoginError(Exception):
    pass


class Session(TokenManager):
    """ TRAINS API Session class. """

    _AUTHORIZATION_HEADER = "Authorization"
    _WORKER_HEADER = "X-Trains-Worker"
    _ASYNC_HEADER = "X-Trains-Async"
    _CLIENT_HEADER = "X-Trains-Client"

    _async_status_code = 202
    _session_requests = 0
    _session_initial_timeout = (1.0, 10)
    _session_timeout = (5.0, None)

    api_version = '2.1'

    # TODO: add requests.codes.gateway_timeout once we support async commits
    _retry_codes = [
        requests.codes.bad_gateway,
        requests.codes.service_unavailable,
        requests.codes.bandwidth_limit_exceeded,
        requests.codes.too_many_requests,
    ]

    @property
    def access_key(self):
        return self.__access_key

    @property
    def secret_key(self):
        return self.__secret_key

    @property
    def host(self):
        return self.__host

    @property
    def worker(self):
        return self.__worker

    def __init__(
        self,
        worker=None,
        api_key=None,
        secret_key=None,
        host=None,
        logger=None,
        verbose=None,
        initialize_logging=True,
        client=None,
        config=None,
        **kwargs
    ):

        if config is not None:
            self.config = config
        else:
            self.config = load()
            if initialize_logging:
                self.config.initialize_logging()

        token_expiration_threshold_sec = self.config.get(
            "auth.token_expiration_threshold_sec", 60
        )

        super(Session, self).__init__(
            token_expiration_threshold_sec=token_expiration_threshold_sec, **kwargs
        )

        self._verbose = verbose if verbose is not None else ENV_VERBOSE.get()
        self._logger = logger

        self.__access_key = api_key or ENV_ACCESS_KEY.get(
            default=self.config.get("api.credentials.access_key", None)
        )
        if not self.access_key:
            raise ValueError(
                "Missing access_key. Please set in configuration file or pass in session init."
            )

        self.__secret_key = secret_key or ENV_SECRET_KEY.get(
            default=self.config.get("api.credentials.secret_key", None)
        )
        if not self.secret_key:
            raise ValueError(
                "Missing secret_key. Please set in configuration file or pass in session init."
            )

        host = host or ENV_HOST.get(default=self.config.get("api.host"))
        if not host:
            raise ValueError("host is required in init or config")

        self.__host = host.strip("/")
        http_retries_config = self.config.get(
            "api.http.retries", ConfigTree()
        ).as_plain_ordered_dict()
        http_retries_config["status_forcelist"] = self._retry_codes
        self.__http_session = get_http_session_with_retry(**http_retries_config)

        self.__worker = worker or gethostname()

        self.__max_req_size = self.config.get("api.http.max_req_size")
        if not self.__max_req_size:
            raise ValueError("missing max request size")

        self.client = client or "api-{}".format(__version__)

        self.refresh_token()

        # update api version from server response
        try:
            api_version = jwt.decode(self.token, verify=False).get('api_version', Session.api_version)
            Session.api_version = str(api_version)
        except (jwt.DecodeError, ValueError):
            pass

    def _send_request(
        self,
        service,
        action,
        version=None,
        method="get",
        headers=None,
        auth=None,
        data=None,
        json=None,
        refresh_token_if_unauthorized=True,
    ):
        """ Internal implementation for making a raw API request.
            - Constructs the api endpoint name
            - Injects the worker id into the headers
            - Allows custom authorization using a requests auth object
            - Intercepts `Unauthorized` responses and automatically attempts to refresh the session token once in this
              case (only once). This is done since permissions are embedded in the token, and addresses a case where
              server-side permissions have changed but are not reflected in the current token. Refreshing the token will
              generate a token with the updated permissions.
        """
        host = self.host
        headers = headers.copy() if headers else {}
        headers[self._WORKER_HEADER] = self.worker
        headers[self._CLIENT_HEADER] = self.client

        token_refreshed_on_error = False
        url = (
            "{host}/v{version}/{service}.{action}"
            if version
            else "{host}/{service}.{action}"
        ).format(**locals())
        while True:
            res = self.__http_session.request(
                method, url, headers=headers, auth=auth, data=data, json=json,
                timeout=self._session_initial_timeout if self._session_requests < 1 else self._session_timeout,
            )
            if (
                refresh_token_if_unauthorized
                and res.status_code == requests.codes.unauthorized
                and not token_refreshed_on_error
            ):
                # it seems we're unauthorized, so we'll try to refresh our token once in case permissions changed since
                # the last time we got the token, and try again
                self.refresh_token()
                token_refreshed_on_error = True
                # try again
                continue
            if (
                res.status_code == requests.codes.service_unavailable
                and self.config.get("api.http.wait_on_maintenance_forever", True)
            ):
                self._logger.warn(
                    "Service unavailable: {} is undergoing maintenance, retrying...".format(
                        host
                    )
                )
                continue
            break
        self._session_requests += 1
        return res

    def send_request(
        self,
        service,
        action,
        version=None,
        method="get",
        headers=None,
        data=None,
        json=None,
        async_enable=False,
    ):
        """
        Send a raw API request.
        :param service: service name
        :param action: action name
        :param version: version number (default is the preconfigured api version)
        :param method: method type (default is 'get')
        :param headers: request headers (authorization and content type headers will be automatically added)
        :param json: json to send in the request body (jsonable object or builtin types construct. if used,
                     content type will be application/json)
        :param data: Dictionary, bytes, or file-like object to send in the request body
        :param async_enable: whether request is asynchronous
        :return: requests Response instance
        """
        headers = headers.copy() if headers else {}
        headers[self._AUTHORIZATION_HEADER] = "Bearer {}".format(self.token)
        if async_enable:
            headers[self._ASYNC_HEADER] = "1"
        return self._send_request(
            service=service,
            action=action,
            version=version,
            method=method,
            headers=headers,
            data=data,
            json=json,
        )

    def send_request_batch(
        self,
        service,
        action,
        version=None,
        headers=None,
        data=None,
        json=None,
        method="get",
    ):
        """
        Send a raw batch API request. Batch requests always use application/json-lines content type.
        :param service: service name
        :param action: action name
        :param version: version number (default is the preconfigured api version)
        :param headers: request headers (authorization and content type headers will be automatically added)
        :param json: iterable of json items (batched items, jsonable objects or builtin types constructs). These will
                     be sent as a multi-line payload in the request body.
        :param data: iterable of bytes objects (batched items). These will be sent as a multi-line payload in the
                     request body.
        :param method: HTTP method
        :return: requests Response instance
        """
        if not all(
            isinstance(x, (list, tuple, type(None), types.GeneratorType))
            for x in (data, json)
        ):
            raise ValueError("Expecting list, tuple or generator in 'data' or 'json'")

        if not data and not json:
            raise ValueError(
                "Missing data (data or json), batch requests are meaningless without it."
            )

        headers = headers.copy() if headers else {}
        headers["Content-Type"] = "application/json-lines"

        if data:
            req_data = "\n".join(data)
        else:
            req_data = "\n".join(json_lib.dumps(x) for x in json)

        cur = 0
        results = []
        while True:
            size = self.__max_req_size
            slice = req_data[cur : cur + size]
            if not slice:
                break
            if len(slice) < size:
                # this is the remainder, no need to search for newline
                pass
            elif slice[-1] != "\n":
                # search for the last newline in order to send a coherent request
                size = slice.rfind("\n") + 1
                # readjust the slice
                slice = req_data[cur : cur + size]
            res = self.send_request(
                method=method,
                service=service,
                action=action,
                data=slice,
                headers=headers,
                version=version,
            )
            results.append(res)
            if res.status_code != requests.codes.ok:
                break
            cur += size
        return results

    def validate_request(self, req_obj):
        """ Validate an API request against the current version and the request's schema """

        try:
            # make sure we're using a compatible version for this request
            # validate the request (checks required fields and specific field version restrictions)
            validate = req_obj.validate
        except AttributeError:
            raise TypeError(
                '"req_obj" parameter must be an backend_api.session.Request object'
            )

        validate()

    def send_async(self, req_obj):
        """
        Asynchronously sends an API request using a request object.
        :param req_obj: The request object
        :type req_obj: Request
        :return: CallResult object containing the raw response, response metadata and parsed response object.
        """
        return self.send(req_obj=req_obj, async_enable=True)

    def send(self, req_obj, async_enable=False, headers=None):
        """
        Sends an API request using a request object.
        :param req_obj: The request object
        :type req_obj: Request
        :param async_enable: Request this method be executed in an asynchronous manner
        :param headers: Additional headers to send with request
        :return: CallResult object containing the raw response, response metadata and parsed response object.
        """
        self.validate_request(req_obj)

        if isinstance(req_obj, BatchRequest):
            # TODO: support async for batch requests as well
            if async_enable:
                raise NotImplementedError(
                    "Async behavior is currently not implemented for batch requests"
                )

            json_data = req_obj.get_json()
            res = self.send_request_batch(
                service=req_obj._service,
                action=req_obj._action,
                version=req_obj._version,
                json=json_data,
                method=req_obj._method,
                headers=headers,
            )
            # TODO: handle multiple results in this case
            try:
                res = next(r for r in res if r.status_code != 200)
            except StopIteration:
                # all are 200
                res = res[0]
        else:
            res = self.send_request(
                service=req_obj._service,
                action=req_obj._action,
                version=req_obj._version,
                json=req_obj.to_dict(),
                method=req_obj._method,
                async_enable=async_enable,
                headers=headers,
            )

        call_result = CallResult.from_result(
            res=res,
            request_cls=req_obj.__class__,
            logger=self._logger,
            service=req_obj._service,
            action=req_obj._action,
            session=self,
        )

        return call_result

    def _do_refresh_token(self, old_token, exp=None):
        """ TokenManager abstract method implementation.
            Here we ignore the old token and simply obtain a new token.
        """
        verbose = self._verbose and self._logger
        if verbose:
            self._logger.info(
                "Refreshing token from {} (access_key={}, exp={})".format(
                    self.host, self.access_key, exp
                )
            )

        auth = HTTPBasicAuth(self.access_key, self.secret_key)
        try:
            data = {"expiration_sec": exp} if exp else {}
            res = self._send_request(
                service="auth",
                action="login",
                auth=auth,
                json=data,
                refresh_token_if_unauthorized=False,
            )
            try:
                resp = res.json()
            except ValueError:
                resp = {}
            if res.status_code != 200:
                msg = resp.get("meta", {}).get("result_msg", res.reason)
                raise LoginError(
                    "Failed getting token (error {} from {}): {}".format(
                        res.status_code, self.host, msg
                    )
                )
            if verbose:
                self._logger.info("Received new token")
            return resp["data"]["token"]
        except LoginError:
            six.reraise(*sys.exc_info())
        except Exception as ex:
            raise LoginError(str(ex))

    def __str__(self):
        return "{self.__class__.__name__}[{self.host}, {self.access_key}/{secret_key}]".format(
            self=self, secret_key=self.secret_key[:5] + "*" * (len(self.secret_key) - 5)
        )