point.py

"""Point data structure to represent LineProtocol."""

import math
from builtins import int
from datetime import datetime, timedelta
from decimal import Decimal
from numbers import Integral

from pytz import UTC

from influxdb_client.client.util.date_utils import get_date_helper
from influxdb_client.domain.write_precision import WritePrecision

EPOCH = UTC.localize(datetime.utcfromtimestamp(0))

DEFAULT_WRITE_PRECISION = WritePrecision.NS

_ESCAPE_MEASUREMENT = str.maketrans({
    ',': r'\,',
    ' ': r'\ ',
    '\n': r'\n',
    '\t': r'\t',
    '\r': r'\r',
})

_ESCAPE_KEY = str.maketrans({
    ',': r'\,',
    '=': r'\=',
    ' ': r'\ ',
    '\n': r'\n',
    '\t': r'\t',
    '\r': r'\r',
})

_ESCAPE_STRING = str.maketrans({
    '"': r'\"',
    '\\': r'\\',
})

try:
    import numpy as np

    _HAS_NUMPY = True
except ModuleNotFoundError:
    _HAS_NUMPY = False


class Point(object):
    """
    Point defines the values that will be written to the database.

    Ref: https://docs.influxdata.com/influxdb/latest/reference/key-concepts/data-elements/#point
    """

    @staticmethod
    def measurement(measurement):
        """Create a new Point with specified measurement name."""
        p = Point(measurement)
        return p

    @staticmethod
    def from_dict(dictionary: dict, write_precision: WritePrecision = DEFAULT_WRITE_PRECISION, **kwargs):
        """
        Initialize point from 'dict' structure.

        The expected dict structure is:
            - measurement
            - tags
            - fields
            - time

        Example:
            .. code-block:: python

                # Use default dictionary structure
                dict_structure = {
                    "measurement": "h2o_feet",
                    "tags": {"location": "coyote_creek"},
                    "fields": {"water_level": 1.0},
                    "time": 1
                }
                point = Point.from_dict(dict_structure, WritePrecision.NS)

        Example:
            .. code-block:: python

                # Use custom dictionary structure
                dictionary = {
                    "name": "sensor_pt859",
                    "location": "warehouse_125",
                    "version": "2021.06.05.5874",
                    "pressure": 125,
                    "temperature": 10,
                    "created": 1632208639,
                }
                point = Point.from_dict(dictionary,
                                        write_precision=WritePrecision.S,
                                        record_measurement_key="name",
                                        record_time_key="created",
                                        record_tag_keys=["location", "version"],
                                        record_field_keys=["pressure", "temperature"])

        :param dictionary: dictionary for serialize into data Point
        :param write_precision: sets the precision for the supplied time values
        :key record_measurement_key: key of dictionary with specified measurement
        :key record_measurement_name: static measurement name for data Point
        :key record_time_key: key of dictionary with specified timestamp
        :key record_tag_keys: list of dictionary keys to use as a tag
        :key record_field_keys: list of dictionary keys to use as a field
        :return: new data point
        """
        measurement_ = kwargs.get('record_measurement_name', None)
        if measurement_ is None:
            measurement_ = dictionary[kwargs.get('record_measurement_key', 'measurement')]
        point = Point(measurement_)

        record_tag_keys = kwargs.get('record_tag_keys', None)
        if record_tag_keys is not None:
            for tag_key in record_tag_keys:
                if tag_key in dictionary:
                    point.tag(tag_key, dictionary[tag_key])
        elif 'tags' in dictionary:
            for tag_key, tag_value in dictionary['tags'].items():
                point.tag(tag_key, tag_value)

        record_field_keys = kwargs.get('record_field_keys', None)
        if record_field_keys is not None:
            for field_key in record_field_keys:
                if field_key in dictionary:
                    point.field(field_key, dictionary[field_key])
        else:
            for field_key, field_value in dictionary['fields'].items():
                point.field(field_key, field_value)

        record_time_key = kwargs.get('record_time_key', 'time')
        if record_time_key in dictionary:
            point.time(dictionary[record_time_key], write_precision=write_precision)
        return point

    def __init__(self, measurement_name):
        """Initialize defaults."""
        self._tags = {}
        self._fields = {}
        self._name = measurement_name
        self._time = None
        self._write_precision = DEFAULT_WRITE_PRECISION

    def time(self, time, write_precision=DEFAULT_WRITE_PRECISION):
        """
        Specify timestamp for DataPoint with declared precision.

        If time doesn't have specified timezone we assume that timezone is UTC.

        Examples::
            Point.measurement("h2o").field("val", 1).time("2009-11-10T23:00:00.123456Z")
            Point.measurement("h2o").field("val", 1).time(1257894000123456000)
            Point.measurement("h2o").field("val", 1).time(datetime(2009, 11, 10, 23, 0, 0, 123456))
            Point.measurement("h2o").field("val", 1).time(1257894000123456000, write_precision=WritePrecision.NS)


        :param time: the timestamp for your data
        :param write_precision: sets the precision for the supplied time values
        :return: this point
        """
        self._write_precision = write_precision
        self._time = time
        return self

    def tag(self, key, value):
        """Add tag with key and value."""
        self._tags[key] = value
        return self

    def field(self, field, value):
        """Add field with key and value."""
        self._fields[field] = value
        return self

    def to_line_protocol(self, precision=None):
        """
        Create LineProtocol.

         :param precision: required precision of LineProtocol. If it's not set then use the precision from ``Point``.
        """
        _measurement = _escape_key(self._name, _ESCAPE_MEASUREMENT)
        _tags = _append_tags(self._tags)
        _fields = _append_fields(self._fields)
        if not _fields:
            return ""
        _time = _append_time(self._time, self._write_precision if precision is None else precision)

        return f"{_measurement}{_tags}{_fields}{_time}"

    @property
    def write_precision(self):
        """Get precision."""
        return self._write_precision

    @classmethod
    def set_str_rep(cls, rep_function):
        """Set the string representation for all Points."""
        cls.__str___rep = rep_function

    def __str__(self):
        """Create string representation of this Point."""
        return self.to_line_protocol()


def _append_tags(tags):
    _return = []
    for tag_key, tag_value in sorted(tags.items()):

        if tag_value is None:
            continue

        tag = _escape_key(tag_key)
        value = _escape_tag_value(tag_value)
        if tag != '' and value != '':
            _return.append(f'{tag}={value}')

    return f"{',' if _return else ''}{','.join(_return)} "


def _append_fields(fields):
    _return = []

    for field, value in sorted(fields.items()):
        if value is None:
            continue

        if isinstance(value, float) or isinstance(value, Decimal) or _np_is_subtype(value, 'float'):
            if not math.isfinite(value):
                continue
            s = str(value)
            # It's common to represent whole numbers as floats
            # and the trailing ".0" that Python produces is unnecessary
            # in line-protocol, inconsistent with other line-protocol encoders,
            # and takes more space than needed, so trim it off.
            if s.endswith('.0'):
                s = s[:-2]
            _return.append(f'{_escape_key(field)}={s}')
        elif (isinstance(value, int) or _np_is_subtype(value, 'int')) and not isinstance(value, bool):
            _return.append(f'{_escape_key(field)}={str(value)}i')
        elif isinstance(value, bool):
            _return.append(f'{_escape_key(field)}={str(value).lower()}')
        elif isinstance(value, str):
            _return.append(f'{_escape_key(field)}="{_escape_string(value)}"')
        else:
            raise ValueError(f'Type: "{type(value)}" of field: "{field}" is not supported.')

    return f"{','.join(_return)}"


def _append_time(time, write_precision):
    if time is None:
        return ''
    return f" {int(_convert_timestamp(time, write_precision))}"


def _escape_key(tag, escape_list=None):
    if escape_list is None:
        escape_list = _ESCAPE_KEY
    return str(tag).translate(escape_list)


def _escape_tag_value(value):
    ret = _escape_key(value)
    if ret.endswith('\\'):
        ret += ' '
    return ret


def _escape_string(value):
    return str(value).translate(_ESCAPE_STRING)


def _convert_timestamp(timestamp, precision=DEFAULT_WRITE_PRECISION):
    date_helper = get_date_helper()
    if isinstance(timestamp, Integral):
        return timestamp  # assume precision is correct if timestamp is int

    if isinstance(timestamp, str):
        timestamp = date_helper.parse_date(timestamp)

    if isinstance(timestamp, timedelta) or isinstance(timestamp, datetime):

        if isinstance(timestamp, datetime):
            timestamp = date_helper.to_utc(timestamp) - EPOCH

        ns = date_helper.to_nanoseconds(timestamp)

        if precision is None or precision == WritePrecision.NS:
            return ns
        elif precision == WritePrecision.US:
            return ns / 1e3
        elif precision == WritePrecision.MS:
            return ns / 1e6
        elif precision == WritePrecision.S:
            return ns / 1e9

    raise ValueError(timestamp)


def _np_is_subtype(value, np_type):
    if not _HAS_NUMPY or not hasattr(value, 'dtype'):
        return False

    if np_type == 'float':
        return np.issubdtype(value, np.floating)
    elif np_type == 'int':
        return np.issubdtype(value, np.integer)
    return False