# -*- coding: utf-8 -*-
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import os
import subprocess
import re
import time

from airflow.hooks.base_hook import BaseHook
from airflow.exceptions import AirflowException
from airflow.utils.log.logging_mixin import LoggingMixin
from airflow.contrib.kubernetes import kube_client


class SparkSubmitHook(BaseHook, LoggingMixin):
    """
    This hook is a wrapper around the spark-submit binary to kick off a spark-submit job.
    It requires that the "spark-submit" binary is in the PATH or the spark_home to be
    supplied.

    :param conf: Arbitrary Spark configuration properties
    :type conf: dict
    :param conn_id: The connection id as configured in Airflow administration. When an
        invalid connection_id is supplied, it will default to yarn.
    :type conn_id: str
    :param files: Upload additional files to the executor running the job, separated by a
        comma. Files will be placed in the working directory of each executor.
        For example, serialized objects.
    :type files: str
    :param py_files: Additional python files used by the job, can be .zip, .egg or .py.
    :type py_files: str
    :param: archives: Archives that spark should unzip (and possibly tag with #ALIAS) into
        the application working directory.
    :param driver_class_path: Additional, driver-specific, classpath settings.
    :type driver_class_path: str
    :param jars: Submit additional jars to upload and place them in executor classpath.
    :type jars: str
    :param java_class: the main class of the Java application
    :type java_class: str
    :param packages: Comma-separated list of maven coordinates of jars to include on the
        driver and executor classpaths
    :type packages: str
    :param exclude_packages: Comma-separated list of maven coordinates of jars to exclude
        while resolving the dependencies provided in 'packages'
    :type exclude_packages: str
    :param repositories: Comma-separated list of additional remote repositories to search
        for the maven coordinates given with 'packages'
    :type repositories: str
    :param total_executor_cores: (Standalone & Mesos only) Total cores for all executors
        (Default: all the available cores on the worker)
    :type total_executor_cores: int
    :param executor_cores: (Standalone, YARN and Kubernetes only) Number of cores per
        executor (Default: 2)
    :type executor_cores: int
    :param executor_memory: Memory per executor (e.g. 1000M, 2G) (Default: 1G)
    :type executor_memory: str
    :param driver_memory: Memory allocated to the driver (e.g. 1000M, 2G) (Default: 1G)
    :type driver_memory: str
    :param keytab: Full path to the file that contains the keytab
    :type keytab: str
    :param principal: The name of the kerberos principal used for keytab
    :type principal: str
    :param proxy_user: User to impersonate when submitting the application
    :type proxy_user: str
    :param name: Name of the job (default airflow-spark)
    :type name: str
    :param num_executors: Number of executors to launch
    :type num_executors: int
    :param application_args: Arguments for the application being submitted
    :type application_args: list
    :param env_vars: Environment variables for spark-submit. It
        supports yarn and k8s mode too.
    :type env_vars: dict
    :param verbose: Whether to pass the verbose flag to spark-submit process for debugging
    :type verbose: bool
    :param spark_binary: The command to use for spark submit.
                         Some distros may use spark2-submit.
    :type spark_binary: str
    """
    def __init__(self,
                 conf=None,
                 conn_id='spark_default',
                 files=None,
                 py_files=None,
                 archives=None,
                 driver_class_path=None,
                 jars=None,
                 java_class=None,
                 packages=None,
                 exclude_packages=None,
                 repositories=None,
                 total_executor_cores=None,
                 executor_cores=None,
                 executor_memory=None,
                 driver_memory=None,
                 keytab=None,
                 principal=None,
                 proxy_user=None,
                 name='default-name',
                 num_executors=None,
                 application_args=None,
                 env_vars=None,
                 verbose=False,
                 spark_binary=None):
        self._conf = conf
        self._conn_id = conn_id
        self._files = files
        self._py_files = py_files
        self._archives = archives
        self._driver_class_path = driver_class_path
        self._jars = jars
        self._java_class = java_class
        self._packages = packages
        self._exclude_packages = exclude_packages
        self._repositories = repositories
        self._total_executor_cores = total_executor_cores
        self._executor_cores = executor_cores
        self._executor_memory = executor_memory
        self._driver_memory = driver_memory
        self._keytab = keytab
        self._principal = principal
        self._proxy_user = proxy_user
        self._name = name
        self._num_executors = num_executors
        self._application_args = application_args
        self._env_vars = env_vars
        self._verbose = verbose
        self._submit_sp = None
        self._yarn_application_id = None
        self._kubernetes_driver_pod = None
        self._spark_binary = spark_binary

        self._connection = self._resolve_connection()
        self._is_yarn = 'yarn' in self._connection['master']
        self._is_kubernetes = 'k8s' in self._connection['master']
        if self._is_kubernetes and kube_client is None:
            raise RuntimeError(
                "{} specified by kubernetes dependencies are not installed!".format(
                    self._connection['master']))

        self._should_track_driver_status = self._resolve_should_track_driver_status()
        self._driver_id = None
        self._driver_status = None
        self._spark_exit_code = None

    def _resolve_should_track_driver_status(self):
        """
        Determines whether or not this hook should poll the spark driver status through
        subsequent spark-submit status requests after the initial spark-submit request
        :return: if the driver status should be tracked
        """
        return ('spark://' in self._connection['master'] and
                self._connection['deploy_mode'] == 'cluster')

    def _resolve_connection(self):
        # Build from connection master or default to yarn if not available
        conn_data = {'master': 'yarn',
                     'queue': None,
                     'deploy_mode': None,
                     'spark_home': None,
                     'spark_binary': self._spark_binary or "spark-submit",
                     'namespace': None}

        try:
            # Master can be local, yarn, spark://HOST:PORT, mesos://HOST:PORT and
            # k8s://https://<HOST>:<PORT>
            conn = self.get_connection(self._conn_id)
            if conn.port:
                conn_data['master'] = "{}:{}".format(conn.host, conn.port)
            else:
                conn_data['master'] = conn.host

            # Determine optional yarn queue from the extra field
            extra = conn.extra_dejson
            conn_data['queue'] = extra.get('queue', None)
            conn_data['deploy_mode'] = extra.get('deploy-mode', None)
            conn_data['spark_home'] = extra.get('spark-home', None)
            conn_data['spark_binary'] = self._spark_binary or  \
                extra.get('spark-binary', "spark-submit")
            conn_data['namespace'] = extra.get('namespace')
        except AirflowException:
            self.log.info(
                "Could not load connection string %s, defaulting to %s",
                self._conn_id, conn_data['master']
            )

        return conn_data

    def get_conn(self):
        pass

    def _get_spark_binary_path(self):
        # If the spark_home is passed then build the spark-submit executable path using
        # the spark_home; otherwise assume that spark-submit is present in the path to
        # the executing user
        if self._connection['spark_home']:
            connection_cmd = [os.path.join(self._connection['spark_home'], 'bin',
                                           self._connection['spark_binary'])]
        else:
            connection_cmd = [self._connection['spark_binary']]

        return connection_cmd

    def _build_spark_submit_command(self, application):
        """
        Construct the spark-submit command to execute.

        :param application: command to append to the spark-submit command
        :type application: str
        :return: full command to be executed
        """
        connection_cmd = self._get_spark_binary_path()

        # The url of the spark master
        connection_cmd += ["--master", self._connection['master']]

        if self._conf:
            for key in self._conf:
                connection_cmd += ["--conf", "{}={}".format(key, str(self._conf[key]))]
        if self._env_vars and (self._is_kubernetes or self._is_yarn):
            if self._is_yarn:
                tmpl = "spark.yarn.appMasterEnv.{}={}"
                # Allow dynamic setting of hadoop/yarn configuration environments
                self._env = self._env_vars
            else:
                tmpl = "spark.kubernetes.driverEnv.{}={}"
            for key in self._env_vars:
                connection_cmd += [
                    "--conf",
                    tmpl.format(key, str(self._env_vars[key]))]
        elif self._env_vars and self._connection['deploy_mode'] != "cluster":
            self._env = self._env_vars  # Do it on Popen of the process
        elif self._env_vars and self._connection['deploy_mode'] == "cluster":
            raise AirflowException(
                "SparkSubmitHook env_vars is not supported in standalone-cluster mode.")
        if self._is_kubernetes and self._connection['namespace']:
            connection_cmd += ["--conf", "spark.kubernetes.namespace={}".format(
                self._connection['namespace'])]
        if self._files:
            connection_cmd += ["--files", self._files]
        if self._py_files:
            connection_cmd += ["--py-files", self._py_files]
        if self._archives:
            connection_cmd += ["--archives", self._archives]
        if self._driver_class_path:
            connection_cmd += ["--driver-class-path", self._driver_class_path]
        if self._jars:
            connection_cmd += ["--jars", self._jars]
        if self._packages:
            connection_cmd += ["--packages", self._packages]
        if self._exclude_packages:
            connection_cmd += ["--exclude-packages", self._exclude_packages]
        if self._repositories:
            connection_cmd += ["--repositories", self._repositories]
        if self._num_executors:
            connection_cmd += ["--num-executors", str(self._num_executors)]
        if self._total_executor_cores:
            connection_cmd += ["--total-executor-cores", str(self._total_executor_cores)]
        if self._executor_cores:
            connection_cmd += ["--executor-cores", str(self._executor_cores)]
        if self._executor_memory:
            connection_cmd += ["--executor-memory", self._executor_memory]
        if self._driver_memory:
            connection_cmd += ["--driver-memory", self._driver_memory]
        if self._keytab:
            connection_cmd += ["--keytab", self._keytab]
        if self._principal:
            connection_cmd += ["--principal", self._principal]
        if self._proxy_user:
            connection_cmd += ["--proxy-user", self._proxy_user]
        if self._name:
            connection_cmd += ["--name", self._name]
        if self._java_class:
            connection_cmd += ["--class", self._java_class]
        if self._verbose:
            connection_cmd += ["--verbose"]
        if self._connection['queue']:
            connection_cmd += ["--queue", self._connection['queue']]
        if self._connection['deploy_mode']:
            connection_cmd += ["--deploy-mode", self._connection['deploy_mode']]

        # The actual script to execute
        connection_cmd += [application]

        # Append any application arguments
        if self._application_args:
            connection_cmd += self._application_args

        self.log.info("Spark-Submit cmd: %s", connection_cmd)

        return connection_cmd

    def _build_track_driver_status_command(self):
        """
        Construct the command to poll the driver status.

        :return: full command to be executed
        """
        connection_cmd = self._get_spark_binary_path()

        # The url ot the spark master
        connection_cmd += ["--master", self._connection['master']]

        # The driver id so we can poll for its status
        if self._driver_id:
            connection_cmd += ["--status", self._driver_id]
        else:
            raise AirflowException(
                "Invalid status: attempted to poll driver " +
                "status but no driver id is known. Giving up.")

        self.log.debug("Poll driver status cmd: %s", connection_cmd)

        return connection_cmd

    def submit(self, application="", **kwargs):
        """
        Remote Popen to execute the spark-submit job

        :param application: Submitted application, jar or py file
        :type application: str
        :param kwargs: extra arguments to Popen (see subprocess.Popen)
        """
        spark_submit_cmd = self._build_spark_submit_command(application)

        if hasattr(self, '_env'):
            env = os.environ.copy()
            env.update(self._env)
            kwargs["env"] = env

        self._submit_sp = subprocess.Popen(spark_submit_cmd,
                                           stdout=subprocess.PIPE,
                                           stderr=subprocess.STDOUT,
                                           bufsize=-1,
                                           universal_newlines=True,
                                           **kwargs)

        self._process_spark_submit_log(iter(self._submit_sp.stdout.readline, ''))
        returncode = self._submit_sp.wait()

        # Check spark-submit return code. In Kubernetes mode, also check the value
        # of exit code in the log, as it may differ.
        if returncode or (self._is_kubernetes and self._spark_exit_code != 0):
            raise AirflowException(
                "Cannot execute: {}. Error code is: {}.".format(
                    spark_submit_cmd, returncode
                )
            )

        self.log.debug("Should track driver: {}".format(self._should_track_driver_status))

        # We want the Airflow job to wait until the Spark driver is finished
        if self._should_track_driver_status:
            if self._driver_id is None:
                raise AirflowException(
                    "No driver id is known: something went wrong when executing " +
                    "the spark submit command"
                )

            # We start with the SUBMITTED status as initial status
            self._driver_status = "SUBMITTED"

            # Start tracking the driver status (blocking function)
            self._start_driver_status_tracking()

            if self._driver_status != "FINISHED":
                raise AirflowException(
                    "ERROR : Driver {} badly exited with status {}"
                    .format(self._driver_id, self._driver_status)
                )

    def _process_spark_submit_log(self, itr):
        """
        Processes the log files and extracts useful information out of it.

        If the deploy-mode is 'client', log the output of the submit command as those
        are the output logs of the Spark worker directly.

        Remark: If the driver needs to be tracked for its status, the log-level of the
        spark deploy needs to be at least INFO (log4j.logger.org.apache.spark.deploy=INFO)

        :param itr: An iterator which iterates over the input of the subprocess
        """
        # Consume the iterator
        for line in itr:
            line = line.strip()
            # If we run yarn cluster mode, we want to extract the application id from
            # the logs so we can kill the application when we stop it unexpectedly
            if self._is_yarn and self._connection['deploy_mode'] == 'cluster':
                match = re.search('(application[0-9_]+)', line)
                if match:
                    self._yarn_application_id = match.groups()[0]
                    self.log.info("Identified spark driver id: %s",
                                  self._yarn_application_id)

            # If we run Kubernetes cluster mode, we want to extract the driver pod id
            # from the logs so we can kill the application when we stop it unexpectedly
            elif self._is_kubernetes:
                match = re.search(r'\s*pod name: ((.+?)-([a-z0-9]+)-driver)', line)
                if match:
                    self._kubernetes_driver_pod = match.groups()[0]
                    self.log.info("Identified spark driver pod: %s",
                                  self._kubernetes_driver_pod)

                # Store the Spark Exit code
                match_exit_code = re.search(r'\s*Exit code: (\d+)', line)
                if match_exit_code:
                    self._spark_exit_code = int(match_exit_code.groups()[0])

            # if we run in standalone cluster mode and we want to track the driver status
            # we need to extract the driver id from the logs. This allows us to poll for
            # the status using the driver id. Also, we can kill the driver when needed.
            elif self._should_track_driver_status and not self._driver_id:
                match_driver_id = re.search(r'(driver-[0-9\-]+)', line)
                if match_driver_id:
                    self._driver_id = match_driver_id.groups()[0]
                    self.log.info("identified spark driver id: {}"
                                  .format(self._driver_id))

            self.log.info(line)

    def _process_spark_status_log(self, itr):
        """
        parses the logs of the spark driver status query process

        :param itr: An iterator which iterates over the input of the subprocess
        """
        # Consume the iterator
        for line in itr:
            line = line.strip()

            # Check if the log line is about the driver status and extract the status.
            if "driverState" in line:
                self._driver_status = line.split(' : ')[1] \
                    .replace(',', '').replace('\"', '').strip()

            self.log.debug("spark driver status log: {}".format(line))

    def _start_driver_status_tracking(self):
        """
        Polls the driver based on self._driver_id to get the status.
        Finish successfully when the status is FINISHED.
        Finish failed when the status is ERROR/UNKNOWN/KILLED/FAILED.

        Possible status:

        SUBMITTED
            Submitted but not yet scheduled on a worker
        RUNNING
            Has been allocated to a worker to run
        FINISHED
            Previously ran and exited cleanly
        RELAUNCHING
            Exited non-zero or due to worker failure, but has not yet
            started running again
        UNKNOWN
            The status of the driver is temporarily not known due to
            master failure recovery
        KILLED
            A user manually killed this driver
        FAILED
            The driver exited non-zero and was not supervised
        ERROR
            Unable to run or restart due to an unrecoverable error
            (e.g. missing jar file)
        """

        # When your Spark Standalone cluster is not performing well
        # due to misconfiguration or heavy loads.
        # it is possible that the polling request will timeout.
        # Therefore we use a simple retry mechanism.
        missed_job_status_reports = 0
        max_missed_job_status_reports = 10

        # Keep polling as long as the driver is processing
        while self._driver_status not in ["FINISHED", "UNKNOWN",
                                          "KILLED", "FAILED", "ERROR"]:

            # Sleep for 1 second as we do not want to spam the cluster
            time.sleep(1)

            self.log.debug("polling status of spark driver with id {}"
                           .format(self._driver_id))

            poll_drive_status_cmd = self._build_track_driver_status_command()
            status_process = subprocess.Popen(poll_drive_status_cmd,
                                              stdout=subprocess.PIPE,
                                              stderr=subprocess.STDOUT,
                                              bufsize=-1,
                                              universal_newlines=True)

            self._process_spark_status_log(iter(status_process.stdout.readline, ''))
            returncode = status_process.wait()

            if returncode:
                if missed_job_status_reports < max_missed_job_status_reports:
                    missed_job_status_reports = missed_job_status_reports + 1
                else:
                    raise AirflowException(
                        "Failed to poll for the driver status {} times: returncode = {}"
                        .format(max_missed_job_status_reports, returncode)
                    )

    def _build_spark_driver_kill_command(self):
        """
        Construct the spark-submit command to kill a driver.
        :return: full command to kill a driver
        """

        # If the spark_home is passed then build the spark-submit executable path using
        # the spark_home; otherwise assume that spark-submit is present in the path to
        # the executing user
        if self._connection['spark_home']:
            connection_cmd = [os.path.join(self._connection['spark_home'],
                                           'bin',
                                           self._connection['spark_binary'])]
        else:
            connection_cmd = [self._connection['spark_binary']]

        # The url ot the spark master
        connection_cmd += ["--master", self._connection['master']]

        # The actual kill command
        connection_cmd += ["--kill", self._driver_id]

        self.log.debug("Spark-Kill cmd: %s", connection_cmd)

        return connection_cmd

    def on_kill(self):

        self.log.debug("Kill Command is being called")

        if self._should_track_driver_status:
            if self._driver_id:
                self.log.info('Killing driver {} on cluster'
                              .format(self._driver_id))

                kill_cmd = self._build_spark_driver_kill_command()
                driver_kill = subprocess.Popen(kill_cmd,
                                               stdout=subprocess.PIPE,
                                               stderr=subprocess.PIPE)

                self.log.info("Spark driver {} killed with return code: {}"
                              .format(self._driver_id, driver_kill.wait()))

        if self._submit_sp and self._submit_sp.poll() is None:
            self.log.info('Sending kill signal to %s', self._connection['spark_binary'])
            self._submit_sp.kill()

            if self._yarn_application_id:
                self.log.info('Killing application {} on YARN'
                              .format(self._yarn_application_id))

                kill_cmd = "yarn application -kill {}" \
                    .format(self._yarn_application_id).split()
                yarn_kill = subprocess.Popen(kill_cmd,
                                             stdout=subprocess.PIPE,
                                             stderr=subprocess.PIPE)

                self.log.info("YARN killed with return code: %s", yarn_kill.wait())

            if self._kubernetes_driver_pod:
                self.log.info('Killing pod %s on Kubernetes', self._kubernetes_driver_pod)

                # Currently only instantiate Kubernetes client for killing a spark pod.
                try:
                    import kubernetes
                    client = kube_client.get_kube_client()
                    api_response = client.delete_namespaced_pod(
                        self._kubernetes_driver_pod,
                        self._connection['namespace'],
                        body=kubernetes.client.V1DeleteOptions(),
                        pretty=True)

                    self.log.info("Spark on K8s killed with response: %s", api_response)

                except kube_client.ApiException as e:
                    self.log.info("Exception when attempting to kill Spark on K8s:")
                    self.log.exception(e)
