| :mod:`airflow.hooks.hive_hooks` |
| =============================== |
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| .. py:module:: airflow.hooks.hive_hooks |
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| Module Contents |
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| .. data:: HIVE_QUEUE_PRIORITIES |
| :annotation: = ['VERY_HIGH', 'HIGH', 'NORMAL', 'LOW', 'VERY_LOW'] |
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| .. function:: get_context_from_env_var() |
| Extract context from env variable, e.g. dag_id, task_id and execution_date, |
| so that they can be used inside BashOperator and PythonOperator. |
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| :return: The context of interest. |
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| .. py:class:: HiveCliHook(hive_cli_conn_id='hive_cli_default', run_as=None, mapred_queue=None, mapred_queue_priority=None, mapred_job_name=None) |
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| Bases: :class:`airflow.hooks.base_hook.BaseHook` |
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| Simple wrapper around the hive CLI. |
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| It also supports the ``beeline`` |
| a lighter CLI that runs JDBC and is replacing the heavier |
| traditional CLI. To enable ``beeline``, set the use_beeline param in the |
| extra field of your connection as in ``{ "use_beeline": true }`` |
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| Note that you can also set default hive CLI parameters using the |
| ``hive_cli_params`` to be used in your connection as in |
| ``{"hive_cli_params": "-hiveconf mapred.job.tracker=some.jobtracker:444"}`` |
| Parameters passed here can be overridden by run_cli's hive_conf param |
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| The extra connection parameter ``auth`` gets passed as in the ``jdbc`` |
| connection string as is. |
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| :param mapred_queue: queue used by the Hadoop Scheduler (Capacity or Fair) |
| :type mapred_queue: str |
| :param mapred_queue_priority: priority within the job queue. |
| Possible settings include: VERY_HIGH, HIGH, NORMAL, LOW, VERY_LOW |
| :type mapred_queue_priority: str |
| :param mapred_job_name: This name will appear in the jobtracker. |
| This can make monitoring easier. |
| :type mapred_job_name: str |
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| .. method:: _get_proxy_user(self) |
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| This function set the proper proxy_user value in case the user overwtire the default. |
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| .. method:: _prepare_cli_cmd(self) |
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| This function creates the command list from available information |
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| .. staticmethod:: _prepare_hiveconf(d) |
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| This function prepares a list of hiveconf params |
| from a dictionary of key value pairs. |
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| :param d: |
| :type d: dict |
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| >>> hh = HiveCliHook() |
| >>> hive_conf = {"hive.exec.dynamic.partition": "true", |
| ... "hive.exec.dynamic.partition.mode": "nonstrict"} |
| >>> hh._prepare_hiveconf(hive_conf) |
| ["-hiveconf", "hive.exec.dynamic.partition=true", "-hiveconf", "hive.exec.dynamic.partition.mode=nonstrict"] |
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| .. method:: run_cli(self, hql, schema=None, verbose=True, hive_conf=None) |
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| Run an hql statement using the hive cli. If hive_conf is specified |
| it should be a dict and the entries will be set as key/value pairs |
| in HiveConf |
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| :param hive_conf: if specified these key value pairs will be passed |
| to hive as ``-hiveconf "key"="value"``. Note that they will be |
| passed after the ``hive_cli_params`` and thus will override |
| whatever values are specified in the database. |
| :type hive_conf: dict |
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| >>> hh = HiveCliHook() |
| >>> result = hh.run_cli("USE airflow;") |
| >>> ("OK" in result) |
| True |
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| .. method:: test_hql(self, hql) |
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| Test an hql statement using the hive cli and EXPLAIN |
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| .. method:: load_df(self, df, table, field_dict=None, delimiter=',', encoding='utf8', pandas_kwargs=None, **kwargs) |
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| Loads a pandas DataFrame into hive. |
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| Hive data types will be inferred if not passed but column names will |
| not be sanitized. |
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| :param df: DataFrame to load into a Hive table |
| :type df: pandas.DataFrame |
| :param table: target Hive table, use dot notation to target a |
| specific database |
| :type table: str |
| :param field_dict: mapping from column name to hive data type. |
| Note that it must be OrderedDict so as to keep columns' order. |
| :type field_dict: collections.OrderedDict |
| :param delimiter: field delimiter in the file |
| :type delimiter: str |
| :param encoding: str encoding to use when writing DataFrame to file |
| :type encoding: str |
| :param pandas_kwargs: passed to DataFrame.to_csv |
| :type pandas_kwargs: dict |
| :param kwargs: passed to self.load_file |
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| .. method:: load_file(self, filepath, table, delimiter=',', field_dict=None, create=True, overwrite=True, partition=None, recreate=False, tblproperties=None) |
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| Loads a local file into Hive |
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| Note that the table generated in Hive uses ``STORED AS textfile`` |
| which isn't the most efficient serialization format. If a |
| large amount of data is loaded and/or if the tables gets |
| queried considerably, you may want to use this operator only to |
| stage the data into a temporary table before loading it into its |
| final destination using a ``HiveOperator``. |
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| :param filepath: local filepath of the file to load |
| :type filepath: str |
| :param table: target Hive table, use dot notation to target a |
| specific database |
| :type table: str |
| :param delimiter: field delimiter in the file |
| :type delimiter: str |
| :param field_dict: A dictionary of the fields name in the file |
| as keys and their Hive types as values. |
| Note that it must be OrderedDict so as to keep columns' order. |
| :type field_dict: collections.OrderedDict |
| :param create: whether to create the table if it doesn't exist |
| :type create: bool |
| :param overwrite: whether to overwrite the data in table or partition |
| :type overwrite: bool |
| :param partition: target partition as a dict of partition columns |
| and values |
| :type partition: dict |
| :param recreate: whether to drop and recreate the table at every |
| execution |
| :type recreate: bool |
| :param tblproperties: TBLPROPERTIES of the hive table being created |
| :type tblproperties: dict |
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| .. method:: kill(self) |
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| .. py:class:: HiveMetastoreHook(metastore_conn_id='metastore_default') |
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| Bases: :class:`airflow.hooks.base_hook.BaseHook` |
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| Wrapper to interact with the Hive Metastore |
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| .. attribute:: MAX_PART_COUNT |
| :annotation: = 32767 |
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| .. method:: __getstate__(self) |
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| .. method:: __setstate__(self, d) |
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| .. method:: get_metastore_client(self) |
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| Returns a Hive thrift client. |
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| .. method:: _find_valid_server(self) |
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| .. method:: get_conn(self) |
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| .. method:: check_for_partition(self, schema, table, partition) |
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| Checks whether a partition exists |
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| :param schema: Name of hive schema (database) @table belongs to |
| :type schema: str |
| :param table: Name of hive table @partition belongs to |
| :type schema: str |
| :partition: Expression that matches the partitions to check for |
| (eg `a = 'b' AND c = 'd'`) |
| :type schema: str |
| :rtype: bool |
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| >>> hh = HiveMetastoreHook() |
| >>> t = 'static_babynames_partitioned' |
| >>> hh.check_for_partition('airflow', t, "ds='2015-01-01'") |
| True |
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| .. method:: check_for_named_partition(self, schema, table, partition_name) |
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| Checks whether a partition with a given name exists |
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| :param schema: Name of hive schema (database) @table belongs to |
| :type schema: str |
| :param table: Name of hive table @partition belongs to |
| :type schema: str |
| :partition: Name of the partitions to check for (eg `a=b/c=d`) |
| :type schema: str |
| :rtype: bool |
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| >>> hh = HiveMetastoreHook() |
| >>> t = 'static_babynames_partitioned' |
| >>> hh.check_for_named_partition('airflow', t, "ds=2015-01-01") |
| True |
| >>> hh.check_for_named_partition('airflow', t, "ds=xxx") |
| False |
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| .. method:: get_table(self, table_name, db='default') |
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| Get a metastore table object |
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| >>> hh = HiveMetastoreHook() |
| >>> t = hh.get_table(db='airflow', table_name='static_babynames') |
| >>> t.tableName |
| 'static_babynames' |
| >>> [col.name for col in t.sd.cols] |
| ['state', 'year', 'name', 'gender', 'num'] |
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| .. method:: get_tables(self, db, pattern='*') |
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| Get a metastore table object |
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| .. method:: get_databases(self, pattern='*') |
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| Get a metastore table object |
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| .. method:: get_partitions(self, schema, table_name, filter=None) |
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| Returns a list of all partitions in a table. Works only |
| for tables with less than 32767 (java short max val). |
| For subpartitioned table, the number might easily exceed this. |
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| >>> hh = HiveMetastoreHook() |
| >>> t = 'static_babynames_partitioned' |
| >>> parts = hh.get_partitions(schema='airflow', table_name=t) |
| >>> len(parts) |
| 1 |
| >>> parts |
| [{'ds': '2015-01-01'}] |
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| .. staticmethod:: _get_max_partition_from_part_specs(part_specs, partition_key, filter_map) |
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| Helper method to get max partition of partitions with partition_key |
| from part specs. key:value pair in filter_map will be used to |
| filter out partitions. |
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| :param part_specs: list of partition specs. |
| :type part_specs: list |
| :param partition_key: partition key name. |
| :type partition_key: str |
| :param filter_map: partition_key:partition_value map used for partition filtering, |
| e.g. {'key1': 'value1', 'key2': 'value2'}. |
| Only partitions matching all partition_key:partition_value |
| pairs will be considered as candidates of max partition. |
| :type filter_map: map |
| :return: Max partition or None if part_specs is empty. |
| :rtype: basestring |
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| .. method:: max_partition(self, schema, table_name, field=None, filter_map=None) |
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| Returns the maximum value for all partitions with given field in a table. |
| If only one partition key exist in the table, the key will be used as field. |
| filter_map should be a partition_key:partition_value map and will be used to |
| filter out partitions. |
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| :param schema: schema name. |
| :type schema: str |
| :param table_name: table name. |
| :type table_name: str |
| :param field: partition key to get max partition from. |
| :type field: str |
| :param filter_map: partition_key:partition_value map used for partition filtering. |
| :type filter_map: map |
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| >>> hh = HiveMetastoreHook() |
| >>> filter_map = {'ds': '2015-01-01', 'ds': '2014-01-01'} |
| >>> t = 'static_babynames_partitioned' |
| >>> hh.max_partition(schema='airflow', ... table_name=t, field='ds', filter_map=filter_map) |
| '2015-01-01' |
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| .. method:: table_exists(self, table_name, db='default') |
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| Check if table exists |
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| >>> hh = HiveMetastoreHook() |
| >>> hh.table_exists(db='airflow', table_name='static_babynames') |
| True |
| >>> hh.table_exists(db='airflow', table_name='does_not_exist') |
| False |
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| .. py:class:: HiveServer2Hook(hiveserver2_conn_id='hiveserver2_default') |
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| Bases: :class:`airflow.hooks.base_hook.BaseHook` |
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| Wrapper around the pyhive library |
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| Notes: |
| * the default authMechanism is PLAIN, to override it you |
| can specify it in the ``extra`` of your connection in the UI |
| * the default for run_set_variable_statements is true, if you |
| are using impala you may need to set it to false in the |
| ``extra`` of your connection in the UI |
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| .. method:: get_conn(self, schema=None) |
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| Returns a Hive connection object. |
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| .. method:: _get_results(self, hql, schema='default', fetch_size=None, hive_conf=None) |
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| .. method:: get_results(self, hql, schema='default', fetch_size=None, hive_conf=None) |
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| Get results of the provided hql in target schema. |
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| :param hql: hql to be executed. |
| :type hql: str or list |
| :param schema: target schema, default to 'default'. |
| :type schema: str |
| :param fetch_size: max size of result to fetch. |
| :type fetch_size: int |
| :param hive_conf: hive_conf to execute alone with the hql. |
| :type hive_conf: dict |
| :return: results of hql execution, dict with data (list of results) and header |
| :rtype: dict |
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| .. method:: to_csv(self, hql, csv_filepath, schema='default', delimiter=',', lineterminator='\r\n', output_header=True, fetch_size=1000, hive_conf=None) |
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| Execute hql in target schema and write results to a csv file. |
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| :param hql: hql to be executed. |
| :type hql: str or list |
| :param csv_filepath: filepath of csv to write results into. |
| :type csv_filepath: str |
| :param schema: target schema, default to 'default'. |
| :type schema: str |
| :param delimiter: delimiter of the csv file, default to ','. |
| :type delimiter: str |
| :param lineterminator: lineterminator of the csv file. |
| :type lineterminator: str |
| :param output_header: header of the csv file, default to True. |
| :type output_header: bool |
| :param fetch_size: number of result rows to write into the csv file, default to 1000. |
| :type fetch_size: int |
| :param hive_conf: hive_conf to execute alone with the hql. |
| :type hive_conf: dict |
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| .. method:: get_records(self, hql, schema='default') |
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| Get a set of records from a Hive query. |
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| :param hql: hql to be executed. |
| :type hql: str or list |
| :param schema: target schema, default to 'default'. |
| :type schema: str |
| :param hive_conf: hive_conf to execute alone with the hql. |
| :type hive_conf: dict |
| :return: result of hive execution |
| :rtype: list |
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| >>> hh = HiveServer2Hook() |
| >>> sql = "SELECT * FROM airflow.static_babynames LIMIT 100" |
| >>> len(hh.get_records(sql)) |
| 100 |
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| .. method:: get_pandas_df(self, hql, schema='default', **kwargs) |
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| Get a pandas dataframe from a Hive query |
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| :param hql: hql to be executed. |
| :type hql: str or list |
| :param schema: target schema, default to 'default'. |
| :type schema: str |
| :param kwargs: (optional) passed into pandas.DataFrame constructor |
| :type kwargs: dict |
| :return: result of hql execution |
| :rtype: DataFrame |
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| >>> hh = HiveServer2Hook() |
| >>> sql = "SELECT * FROM airflow.static_babynames LIMIT 100" |
| >>> df = hh.get_pandas_df(sql) |
| >>> len(df.index) |
| 100 |
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| :return: pandas.DateFrame |
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