#
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# distributed with this work for additional information
# regarding copyright ownership. The ASF licenses this file
# to you 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.
import logging
import sys
from collections import defaultdict
from datetime import datetime
from time import time
from typing import List, Optional, Tuple
from urllib.parse import quote
# Using `from elasticsearch import *` would break elasticsearch mocking used in unit test.
import elasticsearch
import pendulum
from elasticsearch_dsl import Search
from airflow.configuration import conf
from airflow.models import TaskInstance
from airflow.utils import timezone
from airflow.utils.helpers import parse_template_string
from airflow.utils.log.file_task_handler import FileTaskHandler
from airflow.utils.log.json_formatter import JSONFormatter
from airflow.utils.log.logging_mixin import LoggingMixin
# Elasticsearch hosted log type
[docs]EsLogMsgType = List[Tuple[str, str]]
[docs]class ElasticsearchTaskHandler(FileTaskHandler, LoggingMixin):
"""
ElasticsearchTaskHandler is a python log handler that
reads logs from Elasticsearch. Note logs are not directly
indexed into Elasticsearch. Instead, it flushes logs
into local files. Additional software setup is required
to index the log into Elasticsearch, such as using
Filebeat and Logstash.
To efficiently query and sort Elasticsearch results, we assume each
log message has a field `log_id` consists of ti primary keys:
`log_id = {dag_id}-{task_id}-{execution_date}-{try_number}`
Log messages with specific log_id are sorted based on `offset`,
which is a unique integer indicates log message's order.
Timestamp here are unreliable because multiple log messages
might have the same timestamp.
"""
[docs] MAX_LINE_PER_PAGE = 1000
[docs] LOG_NAME = 'Elasticsearch'
def __init__( # pylint: disable=too-many-arguments
self,
base_log_folder: str,
filename_template: str,
log_id_template: str,
end_of_log_mark: str,
write_stdout: bool,
json_format: bool,
json_fields: str,
host: str = "localhost:9200",
frontend: str = "localhost:5601",
es_kwargs: Optional[dict] = conf.getsection("elasticsearch_configs"),
):
"""
:param base_log_folder: base folder to store logs locally
:param log_id_template: log id template
:param host: Elasticsearch host name
"""
es_kwargs = es_kwargs or {}
super().__init__(base_log_folder, filename_template)
self.closed = False
self.log_id_template, self.log_id_jinja_template = parse_template_string(log_id_template)
self.client = elasticsearch.Elasticsearch([host], **es_kwargs)
self.frontend = frontend
self.mark_end_on_close = True
self.end_of_log_mark = end_of_log_mark
self.write_stdout = write_stdout
self.json_format = json_format
self.json_fields = [label.strip() for label in json_fields.split(",")]
self.handler = None
self.context_set = False
[docs] def _render_log_id(self, ti: TaskInstance, try_number: int) -> str:
if self.log_id_jinja_template:
jinja_context = ti.get_template_context()
jinja_context['try_number'] = try_number
return self.log_id_jinja_template.render(**jinja_context)
if self.json_format:
execution_date = self._clean_execution_date(ti.execution_date)
else:
execution_date = ti.execution_date.isoformat()
return self.log_id_template.format(
dag_id=ti.dag_id, task_id=ti.task_id, execution_date=execution_date, try_number=try_number
)
@staticmethod
[docs] def _clean_execution_date(execution_date: datetime) -> str:
"""
Clean up an execution date so that it is safe to query in elasticsearch
by removing reserved characters.
# https://www.elastic.co/guide/en/elasticsearch/reference/current/query-dsl-query-string-query.html#_reserved_characters
:param execution_date: execution date of the dag run.
"""
return execution_date.strftime("%Y_%m_%dT%H_%M_%S_%f")
@staticmethod
[docs] def _group_logs_by_host(logs):
grouped_logs = defaultdict(list)
for log in logs:
key = getattr(log, 'host', 'default_host')
grouped_logs[key].append(log)
# return items sorted by timestamp.
result = sorted(grouped_logs.items(), key=lambda kv: getattr(kv[1][0], 'message', '_'))
return result
[docs] def _read_grouped_logs(self):
return True
[docs] def _read(
self, ti: TaskInstance, try_number: int, metadata: Optional[dict] = None
) -> Tuple[EsLogMsgType, dict]:
"""
Endpoint for streaming log.
:param ti: task instance object
:param try_number: try_number of the task instance
:param metadata: log metadata,
can be used for steaming log reading and auto-tailing.
:return: a list of tuple with host and log documents, metadata.
"""
if not metadata:
metadata = {'offset': 0}
if 'offset' not in metadata:
metadata['offset'] = 0
offset = metadata['offset']
log_id = self._render_log_id(ti, try_number)
logs = self.es_read(log_id, offset, metadata)
logs_by_host = self._group_logs_by_host(logs)
next_offset = offset if not logs else logs[-1].offset
# Ensure a string here. Large offset numbers will get JSON.parsed incorrectly
# on the client. Sending as a string prevents this issue.
# https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Number/MAX_SAFE_INTEGER
metadata['offset'] = str(next_offset)
# end_of_log_mark may contain characters like '\n' which is needed to
# have the log uploaded but will not be stored in elasticsearch.
loading_hosts = [
item[0] for item in logs_by_host if item[-1][-1].message != self.end_of_log_mark.strip()
]
metadata['end_of_log'] = False if not logs else len(loading_hosts) == 0
cur_ts = pendulum.now()
# Assume end of log after not receiving new log for 5 min,
# as executor heartbeat is 1 min and there might be some
# delay before Elasticsearch makes the log available.
if 'last_log_timestamp' in metadata:
last_log_ts = timezone.parse(metadata['last_log_timestamp'])
if (
cur_ts.diff(last_log_ts).in_minutes() >= 5
or 'max_offset' in metadata
and int(offset) >= int(metadata['max_offset'])
):
metadata['end_of_log'] = True
if int(offset) != int(next_offset) or 'last_log_timestamp' not in metadata:
metadata['last_log_timestamp'] = str(cur_ts)
# If we hit the end of the log, remove the actual end_of_log message
# to prevent it from showing in the UI.
def concat_logs(lines):
log_range = (len(lines) - 1) if lines[-1].message == self.end_of_log_mark.strip() else len(lines)
return '\n'.join([self._format_msg(lines[i]) for i in range(log_range)])
message = [(host, concat_logs(hosted_log)) for host, hosted_log in logs_by_host]
return message, metadata
[docs] def es_read(self, log_id: str, offset: str, metadata: dict) -> list:
"""
Returns the logs matching log_id in Elasticsearch and next offset.
Returns '' if no log is found or there was an error.
:param log_id: the log_id of the log to read.
:type log_id: str
:param offset: the offset start to read log from.
:type offset: str
:param metadata: log metadata, used for steaming log download.
:type metadata: dict
"""
# Offset is the unique key for sorting logs given log_id.
search = Search(using=self.client).query('match_phrase', log_id=log_id).sort('offset')
search = search.filter('range', offset={'gt': int(offset)})
max_log_line = search.count()
if 'download_logs' in metadata and metadata['download_logs'] and 'max_offset' not in metadata:
try:
if max_log_line > 0:
metadata['max_offset'] = search[max_log_line - 1].execute()[-1].offset
else:
metadata['max_offset'] = 0
except Exception: # pylint: disable=broad-except
self.log.exception('Could not get current log size with log_id: %s', log_id)
logs = []
if max_log_line != 0:
try:
logs = search[self.MAX_LINE_PER_PAGE * self.PAGE : self.MAX_LINE_PER_PAGE].execute()
except Exception as e: # pylint: disable=broad-except
self.log.exception('Could not read log with log_id: %s, error: %s', log_id, str(e))
return logs
[docs] def set_context(self, ti: TaskInstance) -> None:
"""
Provide task_instance context to airflow task handler.
:param ti: task instance object
"""
self.mark_end_on_close = not ti.raw
if self.json_format:
self.formatter = JSONFormatter(
fmt=self.formatter._fmt, # pylint: disable=protected-access
json_fields=self.json_fields,
extras={
'dag_id': str(ti.dag_id),
'task_id': str(ti.task_id),
'execution_date': self._clean_execution_date(ti.execution_date),
'try_number': str(ti.try_number),
'log_id': self._render_log_id(ti, ti.try_number),
'offset': int(time() * (10 ** 9)),
},
)
if self.write_stdout:
if self.context_set:
# We don't want to re-set up the handler if this logger has
# already been initialized
return
self.handler = logging.StreamHandler(stream=sys.__stdout__) # type: ignore
self.handler.setLevel(self.level) # type: ignore
self.handler.setFormatter(self.formatter) # type: ignore
else:
super().set_context(ti)
self.context_set = True
[docs] def close(self) -> None:
# When application exit, system shuts down all handlers by
# calling close method. Here we check if logger is already
# closed to prevent uploading the log to remote storage multiple
# times when `logging.shutdown` is called.
if self.closed:
return
if not self.mark_end_on_close:
self.closed = True
return
# Case which context of the handler was not set.
if self.handler is None:
self.closed = True
return
# Reopen the file stream, because FileHandler.close() would be called
# first in logging.shutdown() and the stream in it would be set to None.
if self.handler.stream is None or self.handler.stream.closed:
self.handler.stream = self.handler._open() # pylint: disable=protected-access
# Mark the end of file using end of log mark,
# so we know where to stop while auto-tailing.
self.handler.stream.write(self.end_of_log_mark)
if self.write_stdout:
self.handler.close()
sys.stdout = sys.__stdout__
super().close()
self.closed = True
@property
[docs] def log_name(self) -> str:
"""The log name"""
return self.LOG_NAME
[docs] def get_external_log_url(self, task_instance: TaskInstance, try_number: int) -> str:
"""
Creates an address for an external log collecting service.
:param task_instance: task instance object
:type: task_instance: TaskInstance
:param try_number: task instance try_number to read logs from.
:type try_number: Optional[int]
:return: URL to the external log collection service
:rtype: str
"""
log_id = self.log_id_template.format(
dag_id=task_instance.dag_id,
task_id=task_instance.task_id,
execution_date=task_instance.execution_date,
try_number=try_number,
)
url = 'https://' + self.frontend.format(log_id=quote(log_id))
return url
[docs]class _ESJsonLogFmt:
"""Helper class to read ES Logs and re-format it to match settings.LOG_FORMAT"""
# A separate class is needed because 'self.formatter._style.format' uses '.__dict__'
def __init__(self, **kwargs):
self.__dict__.update(kwargs)