[GitHub] [airflow] eladkal commented on a diff in pull request #23979: Add `PrestoToSlackOperator`

[GitBox <gi...@apache.org>]

eladkal commented on code in PR #23979:
URL: https://github.com/apache/airflow/pull/23979#discussion_r888918469


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airflow/providers/presto/transfers/presto_to_slack.py:
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@@ -0,0 +1,143 @@
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# 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.
+
+from typing import TYPE_CHECKING, Iterable, Mapping, Optional, Sequence, Union
+
+from pandas import DataFrame
+from tabulate import tabulate
+
+from airflow.exceptions import AirflowException
+from airflow.models import BaseOperator
+from airflow.providers.presto.hooks.presto import PrestoHook
+from airflow.providers.slack.hooks.slack_webhook import SlackWebhookHook
+
+if TYPE_CHECKING:
+    from airflow.utils.context import Context
+
+
+class PrestoToSlackOperator(BaseOperator):
+    """
+    Executes a single SQL statement in Presto and sends the results to Slack. The results of the query are
+    rendered into the 'slack_message' parameter as a Pandas dataframe using a JINJA variable called '{{
+    results_df }}'. The 'results_df' variable name can be changed by specifying a different
+    'results_df_name' parameter. The Tabulate library is added to the JINJA environment as a filter to
+    allow the dataframe to be rendered nicely. For example, set 'slack_message' to {{ results_df |
+    tabulate(tablefmt="pretty", headers="keys") }} to send the results to Slack as an ascii rendered table.
+
+    .. seealso::
+        For more information on how to use this operator, take a look at the guide:
+        :ref:`howto/operator:PrestoToSlackOperator`
+
+    :param sql: The SQL statement to execute on Presto (templated)
+    :param slack_message: The templated Slack message to send with the data returned from Presto.
+        You can use the default JINJA variable {{ results_df }} to access the pandas dataframe containing the
+        SQL results
+    :param presto_conn_id: destination presto connection
+    :param slack_conn_id: The connection id for Slack
+    :param results_df_name: The name of the JINJA template's dataframe variable, default is 'results_df'
+    :param parameters: The parameters to pass to the SQL query
+    :param slack_token: The token to use to authenticate to Slack. If this is not provided, the
+        'webhook_token' attribute needs to be specified in the 'Extra' JSON field against the slack_conn_id
+    :param slack_channel: The channel to send message. Override default from Slack connection.
+    """
+
+    template_fields: Sequence[str] = ('sql', 'slack_message')
+    template_ext: Sequence[str] = ('.sql', '.jinja', '.j2')
+    template_fields_renderers = {"sql": "sql", "slack_message": "jinja"}
+    times_rendered = 0
+
+    def __init__(
+        self,
+        *,
+        sql: str,
+        slack_message: str,
+        presto_conn_id: str = 'presto_default',
+        slack_conn_id: str = 'slack_default',
+        results_df_name: str = 'results_df',
+        parameters: Optional[Union[Iterable, Mapping]] = None,
+        slack_token: Optional[str] = None,
+        slack_channel: Optional[str] = None,
+        **kwargs,
+    ) -> None:
+        super().__init__(**kwargs)
+
+        self.presto_conn_id = presto_conn_id
+        self.sql = sql
+        self.parameters = parameters
+        self.slack_conn_id = slack_conn_id
+        self.slack_token = slack_token
+        self.slack_message = slack_message
+        self.results_df_name = results_df_name
+        self.slack_channel = slack_channel
+
+    def _get_query_results(self) -> DataFrame:
+        presto_hook = self._get_presto_hook()
+
+        self.log.info('Running SQL query: %s', self.sql)
+        df = presto_hook.get_pandas_df(self.sql, parameters=self.parameters)
+        return df
+
+    def _render_and_send_slack_message(self, context, df) -> None:
+        # Put the dataframe into the context and render the JINJA template fields
+        context[self.results_df_name] = df
+        self.render_template_fields(context)
+
+        slack_hook = self._get_slack_hook()
+        self.log.info('Sending slack message: %s', self.slack_message)
+        slack_hook.execute()
+
+    def _get_presto_hook(self) -> PrestoHook:
+        return PrestoHook(presto_conn_id=self.presto_conn_id)
+
+    def _get_slack_hook(self) -> SlackWebhookHook:
+        return SlackWebhookHook(
+            http_conn_id=self.slack_conn_id,
+            message=self.slack_message,
+            webhook_token=self.slack_token,
+            slack_channel=self.slack_channel,
+        )
+
+    def render_template_fields(self, context, jinja_env=None) -> None:
+        # If this is the first render of the template fields, exclude slack_message from rendering since
+        # the presto results haven't been retrieved yet.
+        if self.times_rendered == 0:
+            fields_to_render: Iterable[str] = filter(lambda x: x != 'slack_message', self.template_fields)
+        else:
+            fields_to_render = self.template_fields
+
+        if not jinja_env:
+            jinja_env = self.get_template_env()
+
+        # Add the tabulate library into the JINJA environment
+        jinja_env.filters['tabulate'] = tabulate
+
+        self._do_render_template_fields(self, fields_to_render, context, jinja_env, set())
+        self.times_rendered += 1
+
+    def execute(self, context: 'Context') -> None:
+        if not isinstance(self.sql, str):
+            raise AirflowException("Expected 'sql' parameter should be a string.")
+        if self.sql is None or self.sql.strip() == "":
+            raise AirflowException("Expected 'sql' parameter is missing.")
+        if self.slack_message is None or self.slack_message.strip() == "":
+            raise AirflowException("Expected 'slack_message' parameter is missing.")

Review Comment:
   https://github.com/apache/airflow/pull/23979/commits/8e2f2917c1d2f43ad77accceeb12ab1afa8aebba



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