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from enum import Enum
from typing import Optional, Any, Tuple, Dict, AnyStr, IO, List, Iterator
import ijson
from ijson import IncompleteJSONError
from azure.kusto.data._models import WellKnownDataSet
from azure.kusto.data.exceptions import KustoServiceError, KustoTokenParsingError, KustoUnsupportedApiError, KustoApiError, KustoMultiApiError
class JsonTokenType(Enum):
NULL = 0
BOOLEAN = 1
NUMBER = 2
STRING = 3
MAP_KEY = 4
START_MAP = 5
END_MAP = 6
START_ARRAY = 7
END_ARRAY = 8
@staticmethod
def start_tokens() -> "List[JsonTokenType]":
return [JsonTokenType.START_MAP, JsonTokenType.START_ARRAY]
@staticmethod
def end_tokens() -> "List[JsonTokenType]":
return [JsonTokenType.END_MAP, JsonTokenType.END_ARRAY]
class FrameType(Enum):
DataSetHeader = 0
TableHeader = 1
TableFragment = 2
TableCompletion = 3
TableProgress = 4
DataTable = 5
DataSetCompletion = 6
class JsonToken:
def __init__(self, token_path: str, token_type: JsonTokenType, token_value: Optional[Any]):
self.token_path = token_path
self.token_type = token_type
self.token_value = token_value
class JsonTokenReader:
def __init__(self, stream: IO[AnyStr]):
self.json_iter = ijson.parse(stream, use_float=True)
def __iter__(self) -> "JsonTokenReader":
return self
def __next__(self) -> JsonToken:
return self.read_next_token_or_throw()
def read_next_token_or_throw(self) -> JsonToken:
try:
next_item = next(self.json_iter)
except IncompleteJSONError:
next_item = None
if next_item is None:
raise KustoTokenParsingError("Unexpected end of stream")
(token_path, token_type, token_value) = next_item
return JsonToken(token_path, JsonTokenType[token_type.upper()], token_value)
def read_token_of_type(self, *token_types: JsonTokenType) -> JsonToken:
token = self.read_next_token_or_throw()
if token.token_type not in token_types:
raise KustoTokenParsingError(f"Expected one the following types: '{','.join(t.name for t in token_types)}' , got type {token.token_type}")
return token
def read_start_object(self) -> JsonToken:
return self.read_token_of_type(JsonTokenType.START_MAP)
def read_start_array(self) -> JsonToken:
return self.read_token_of_type(JsonTokenType.START_ARRAY)
def read_string(self) -> str:
return self.read_token_of_type(JsonTokenType.STRING).token_value
def read_boolean(self) -> bool:
return self.read_token_of_type(JsonTokenType.BOOLEAN).token_value
def read_number(self) -> float:
return self.read_token_of_type(JsonTokenType.NUMBER).token_value
def skip_children(self, prev_token: JsonToken):
if prev_token.token_type == JsonTokenType.MAP_KEY:
prev_token = self.read_next_token_or_throw()
if prev_token.token_type in JsonTokenType.start_tokens():
for potential_end_token in self:
if potential_end_token.token_path == prev_token.token_path and potential_end_token.token_type in JsonTokenType.end_tokens():
break
def skip_until_property_name(self, name: str) -> JsonToken:
while True:
token = self.read_token_of_type(JsonTokenType.MAP_KEY)
if token.token_value == name:
return token
self.skip_children(token)
def skip_until_any_property_name(self, *names: str) -> JsonToken:
while True:
token = self.read_token_of_type(JsonTokenType.MAP_KEY)
if token.token_value in names:
return token
self.skip_children(token)
def skip_until_property_name_or_end_object(self, *names: str) -> JsonToken:
for token in self:
if token.token_type == JsonTokenType.END_MAP:
return token
if token.token_type == JsonTokenType.MAP_KEY:
if token.token_value in names:
return token
self.skip_children(token)
continue
raise Exception(f"Unexpected token {token}")
def skip_until_token_with_paths(self, *tokens: (JsonTokenType, str)) -> JsonToken:
for token in self:
if any((token.token_type == t_type and token.token_path == t_path) for (t_type, t_path) in tokens):
return token
self.skip_children(token)
class StreamingDataSetEnumerator:
def __init__(self, reader: JsonTokenReader):
self.reader = reader
self.done = False
self.started = False
self.started_primary_results = False
self.finished_primary_results = False
def __iter__(self) -> "StreamingDataSetEnumerator":
return self
def __next__(self) -> Dict[str, Any]:
if self.done:
raise StopIteration()
if not self.started:
self.reader.read_start_array()
self.started = True
token = self.reader.skip_until_token_with_paths((JsonTokenType.START_MAP, "item"), (JsonTokenType.END_ARRAY, ""))
if token == JsonTokenType.END_ARRAY:
self.done = True
raise StopIteration()
frame_type = self.read_frame_type()
parsed_frame = self.parse_frame(frame_type)
is_primary_result = parsed_frame["FrameType"] == FrameType.DataTable and parsed_frame["TableKind"] == WellKnownDataSet.PrimaryResult.value
if is_primary_result:
self.started_primary_results = True
elif self.started_primary_results:
self.finished_primary_results = True
return parsed_frame
def parse_frame(self, frame_type: FrameType) -> Dict[str, Any]:
if frame_type == FrameType.DataSetHeader:
frame = self.extract_props(frame_type, ("IsProgressive", JsonTokenType.BOOLEAN), ("Version", JsonTokenType.STRING))
if frame["IsProgressive"]:
raise KustoUnsupportedApiError.progressive_api_unsupported()
return frame
if frame_type in [FrameType.TableHeader, FrameType.TableFragment, FrameType.TableCompletion, FrameType.TableProgress]:
raise KustoUnsupportedApiError.progressive_api_unsupported()
if frame_type == FrameType.DataTable:
props = self.extract_props(
frame_type,
("TableId", JsonTokenType.NUMBER),
("TableKind", JsonTokenType.STRING),
("TableName", JsonTokenType.STRING),
("Columns", JsonTokenType.START_ARRAY),
)
self.reader.skip_until_property_name("Rows")
props["Rows"] = self.row_iterator()
if props["TableKind"] != WellKnownDataSet.PrimaryResult.value:
props["Rows"] = list(props["Rows"])
return props
if frame_type == FrameType.DataSetCompletion:
res = self.extract_props(frame_type, ("HasErrors", JsonTokenType.BOOLEAN), ("Cancelled", JsonTokenType.BOOLEAN))
token = self.reader.skip_until_property_name_or_end_object("OneApiErrors")
if token.token_type != JsonTokenType.END_MAP:
res["OneApiErrors"] = self.parse_array(skip_start=False)
return res
def row_iterator(self) -> Iterator[list]:
self.reader.read_token_of_type(JsonTokenType.START_ARRAY)
while True:
token = self.reader.read_token_of_type(JsonTokenType.START_ARRAY, JsonTokenType.END_ARRAY, JsonTokenType.START_MAP)
if token.token_type == JsonTokenType.START_MAP:
# Todo - this method of error handling may be problematic, since after raising an error the iteration stops.
# This means that if there are more data or even more errors, we can't read them
raise KustoMultiApiError([self.parse_object(skip_start=True)])
if token.token_type == JsonTokenType.END_ARRAY:
return
yield self.parse_array(skip_start=True)
def parse_array(self, skip_start: bool) -> list:
if not skip_start:
self.reader.read_start_array()
arr = []
while True:
token = self.reader.read_token_of_type(
JsonTokenType.NULL,
JsonTokenType.BOOLEAN,
JsonTokenType.NUMBER,
JsonTokenType.STRING,
JsonTokenType.START_MAP,
JsonTokenType.START_ARRAY,
JsonTokenType.END_ARRAY,
)
if token.token_type == JsonTokenType.END_ARRAY:
return arr
if token.token_type == JsonTokenType.START_MAP:
arr.append(self.parse_object(skip_start=True))
elif token.token_type == JsonTokenType.START_ARRAY:
arr.append(self.parse_array(skip_start=True))
else:
arr.append(token.token_value)
def parse_object(self, skip_start: bool) -> Dict[str, Any]:
if not skip_start:
self.reader.read_start_object()
obj = {}
while True:
token_prop_name = self.reader.read_token_of_type(JsonTokenType.MAP_KEY, JsonTokenType.END_MAP)
if token_prop_name.token_type == JsonTokenType.END_MAP:
return obj
prop_name = token_prop_name.token_value
token = self.reader.read_token_of_type(
JsonTokenType.NULL, JsonTokenType.BOOLEAN, JsonTokenType.NUMBER, JsonTokenType.STRING, JsonTokenType.START_MAP, JsonTokenType.START_ARRAY
)
if token.token_type == JsonTokenType.START_MAP:
obj[prop_name] = self.parse_object(skip_start=True)
elif token.token_type == JsonTokenType.START_ARRAY:
obj[prop_name] = self.parse_array(skip_start=True)
else:
obj[prop_name] = token.token_value
def extract_props(self, frame_type: FrameType, *props: Tuple[str, JsonTokenType]) -> Dict[str, Any]:
result = {"FrameType": frame_type}
props_dict = dict(props)
while props_dict:
name = self.reader.skip_until_any_property_name(*props_dict.keys()).token_value
if props_dict[name] == JsonTokenType.START_ARRAY:
result[name] = self.parse_array(skip_start=False)
else:
result[name] = self.reader.read_token_of_type(props_dict[name]).token_value
props_dict.pop(name)
return result
def read_frame_type(self) -> FrameType:
self.reader.skip_until_property_name("FrameType")
return FrameType[self.reader.read_string()]
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