query_api.py

"""
Querying InfluxDB bu FluxLang.

Flux is InfluxData’s functional data scripting language designed for querying, analyzing, and acting on data.
"""

import codecs
import csv
from datetime import datetime, timedelta
from typing import List, Generator, Any, Union, Iterable

from influxdb_client import Dialect, IntegerLiteral, BooleanLiteral, FloatLiteral, DateTimeLiteral, StringLiteral, \
    VariableAssignment, Identifier, OptionStatement, File, DurationLiteral, Duration, UnaryExpression, Expression, \
    ImportDeclaration, MemberAssignment, MemberExpression, ArrayExpression
from influxdb_client import Query, QueryService
from influxdb_client.client.flux_csv_parser import FluxCsvParser, FluxSerializationMode
from influxdb_client.client.flux_table import FluxTable, FluxRecord
from influxdb_client.client.util.date_utils import get_date_helper
from influxdb_client.client.util.helpers import get_org_query_param


class QueryOptions(object):
    """Query options."""

    def __init__(self, profilers: List[str] = None) -> None:
        """
        Initialize query options.

        :param profilers: list of enabled flux profilers
        """
        self.profilers = profilers


class QueryApi(object):
    """Implementation for '/api/v2/query' endpoint."""

    default_dialect = Dialect(header=True, delimiter=",", comment_prefix="#",
                              annotations=["datatype", "group", "default"], date_time_format="RFC3339")

    def __init__(self, influxdb_client, query_options=QueryOptions()):
        """
        Initialize query client.

        :param influxdb_client: influxdb client
        """
        self._influxdb_client = influxdb_client
        self._query_options = query_options
        self._query_api = QueryService(influxdb_client.api_client)

    def query_csv(self, query: str, org=None, dialect: Dialect = default_dialect, params: dict = None):
        """
        Execute the Flux query and return results as a CSV iterator. Each iteration returns a row of the CSV file.

        :param query: a Flux query
        :param str, Organization org: specifies the organization for executing the query;
                                      take the ID, Name or Organization;
                                      if it's not specified then is used default from client.org.
        :param dialect: csv dialect format
        :param params: bind parameters
        :return: The returned object is an iterator.  Each iteration returns a row of the CSV file
                 (which can span multiple input lines).
        """
        org = self._org_param(org)
        response = self._query_api.post_query(org=org, query=self._create_query(query, dialect, params),
                                              async_req=False, _preload_content=False)

        return csv.reader(codecs.iterdecode(response, 'utf-8'))

    def query_raw(self, query: str, org=None, dialect=default_dialect, params: dict = None):
        """
        Execute synchronous Flux query and return result as raw unprocessed result as a str.

        :param query: a Flux query
        :param str, Organization org: specifies the organization for executing the query;
                                      take the ID, Name or Organization;
                                      if it's not specified then is used default from client.org.
        :param dialect: csv dialect format
        :param params: bind parameters
        :return: str
        """
        org = self._org_param(org)
        result = self._query_api.post_query(org=org, query=self._create_query(query, dialect, params), async_req=False,
                                            _preload_content=False)

        return result

    def query(self, query: str, org=None, params: dict = None) -> List['FluxTable']:
        """
        Execute synchronous Flux query and return result as a List['FluxTable'].

        :param query: the Flux query
        :param str, Organization org: specifies the organization for executing the query;
                                      take the ID, Name or Organization;
                                      if it's not specified then is used default from client.org.
        :param params: bind parameters
        :return:
        """
        org = self._org_param(org)

        response = self._query_api.post_query(org=org, query=self._create_query(query, self.default_dialect, params),
                                              async_req=False, _preload_content=False, _return_http_data_only=False)

        _parser = FluxCsvParser(response=response, serialization_mode=FluxSerializationMode.tables,
                                profilers=self._profilers())

        list(_parser.generator())

        return _parser.table_list()

    def query_stream(self, query: str, org=None, params: dict = None) -> Generator['FluxRecord', Any, None]:
        """
        Execute synchronous Flux query and return stream of FluxRecord as a Generator['FluxRecord'].

        :param query: the Flux query
        :param str, Organization org: specifies the organization for executing the query;
                                      take the ID, Name or Organization;
                                      if it's not specified then is used default from client.org.
        :param params: bind parameters
        :return:
        """
        org = self._org_param(org)

        response = self._query_api.post_query(org=org, query=self._create_query(query, self.default_dialect, params),
                                              async_req=False, _preload_content=False, _return_http_data_only=False)
        _parser = FluxCsvParser(response=response, serialization_mode=FluxSerializationMode.stream,
                                profilers=self._profilers())

        return _parser.generator()

    def query_data_frame(self, query: str, org=None, data_frame_index: List[str] = None, params: dict = None):
        """
        Execute synchronous Flux query and return Pandas DataFrame.

        Note that if a query returns more then one table than the client generates a DataFrame for each of them.

        :param query: the Flux query
        :param str, Organization org: specifies the organization for executing the query;
                                      take the ID, Name or Organization;
                                      if it's not specified then is used default from client.org.
        :param data_frame_index: the list of columns that are used as DataFrame index
        :param params: bind parameters
        :return:
        """
        from ..extras import pd

        _generator = self.query_data_frame_stream(query, org=org, data_frame_index=data_frame_index, params=params)
        _dataFrames = list(_generator)

        if len(_dataFrames) == 0:
            return pd.DataFrame(columns=[], index=None)
        elif len(_dataFrames) == 1:
            return _dataFrames[0]
        else:
            return _dataFrames

    def query_data_frame_stream(self, query: str, org=None, data_frame_index: List[str] = None, params: dict = None):
        """
        Execute synchronous Flux query and return stream of Pandas DataFrame as a Generator['pd.DataFrame'].

        Note that if a query returns more then one table than the client generates a DataFrame for each of them.

        :param query: the Flux query
        :param str, Organization org: specifies the organization for executing the query;
                                      take the ID, Name or Organization;
                                      if it's not specified then is used default from client.org.
        :param data_frame_index: the list of columns that are used as DataFrame index
        :param params: bind parameters
        :return:
        """
        org = self._org_param(org)

        response = self._query_api.post_query(org=org, query=self._create_query(query, self.default_dialect, params),
                                              async_req=False, _preload_content=False, _return_http_data_only=False)

        _parser = FluxCsvParser(response=response, serialization_mode=FluxSerializationMode.dataFrame,
                                data_frame_index=data_frame_index,
                                profilers=self._profilers())
        return _parser.generator()

    def _profilers(self):
        if self._query_options and self._query_options.profilers:
            return self._query_options.profilers
        else:
            return self._influxdb_client.profilers

    def _create_query(self, query, dialect=default_dialect, params: dict = None):
        profilers = self._profilers()
        q = Query(query=query, dialect=dialect, extern=QueryApi._build_flux_ast(params, profilers))

        if profilers:
            print("\n===============")
            print("Profiler: query")
            print("===============")
            print(query)

        return q

    def _org_param(self, org):
        return get_org_query_param(org=org, client=self._influxdb_client)

    @staticmethod
    def _params_to_extern_ast(params: dict) -> List['OptionStatement']:

        statements = []
        for key, value in params.items():
            expression = QueryApi._parm_to_extern_ast(value)
            if expression is None:
                continue

            statements.append(OptionStatement("OptionStatement",
                                              VariableAssignment("VariableAssignment", Identifier("Identifier", key),
                                                                 expression)))
        return statements

    @staticmethod
    def _parm_to_extern_ast(value) -> Union[Expression, None]:
        if value is None:
            return None
        if isinstance(value, bool):
            return BooleanLiteral("BooleanLiteral", value)
        elif isinstance(value, int):
            return IntegerLiteral("IntegerLiteral", str(value))
        elif isinstance(value, float):
            return FloatLiteral("FloatLiteral", value)
        elif isinstance(value, datetime):
            value = get_date_helper().to_utc(value)
            return DateTimeLiteral("DateTimeLiteral", value.strftime('%Y-%m-%dT%H:%M:%S.%fZ'))
        elif isinstance(value, timedelta):
            _micro_delta = int(value / timedelta(microseconds=1))
            if _micro_delta < 0:
                return UnaryExpression("UnaryExpression", argument=DurationLiteral("DurationLiteral", [
                    Duration(magnitude=-_micro_delta, unit="us")]), operator="-")
            else:
                return DurationLiteral("DurationLiteral", [Duration(magnitude=_micro_delta, unit="us")])
        elif isinstance(value, str):
            return StringLiteral("StringLiteral", str(value))
        elif isinstance(value, Iterable):
            return ArrayExpression("ArrayExpression",
                                   elements=list(map(lambda it: QueryApi._parm_to_extern_ast(it), value)))
        else:
            return value

    @staticmethod
    def _build_flux_ast(params: dict = None, profilers: List[str] = None):

        imports = []
        body = []

        if profilers is not None and len(profilers) > 0:
            imports.append(ImportDeclaration(
                "ImportDeclaration",
                path=StringLiteral("StringLiteral", "profiler")))

            elements = []
            for profiler in profilers:
                elements.append(StringLiteral("StringLiteral", value=profiler))

            member = MemberExpression(
                "MemberExpression",
                object=Identifier("Identifier", "profiler"),
                _property=Identifier("Identifier", "enabledProfilers"))

            prof = OptionStatement(
                "OptionStatement",
                assignment=MemberAssignment(
                    "MemberAssignment",
                    member=member,
                    init=ArrayExpression(
                        "ArrayExpression",
                        elements=elements)))

            body.append(prof)

        if params is not None:
            body.extend(QueryApi._params_to_extern_ast(params))

        return File(package=None, name=None, type=None, imports=imports, body=body)

    def __del__(self):
        """Close QueryAPI."""
        pass