feat: add connector for CrateDB

setup.py

@@ -121,6 +121,7 @@ def get_git_sha():
         "clickhouse": ["clickhouse-sqlalchemy>= 0.1.4, <0.2"],
         "cockroachdb": ["cockroachdb>=0.3.5, <0.4"],
         "cors": ["flask-cors>=2.0.0"],
+        "crate": ["crate[sqlalchemy]>=0.26.0, <0.27"],
         "db2": ["ibm-db-sa>=0.3.5, <0.4"],
         "dremio": ["sqlalchemy-dremio>=1.1.5, <1.2"],
         "drill": ["sqlalchemy-drill==0.1.dev"],

superset/db_engine_specs/crate.py

@@ -0,0 +1,64 @@
+# 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 datetime import datetime
+from typing import Optional, TYPE_CHECKING
+
+from superset.db_engine_specs.base import BaseEngineSpec
+from superset.utils import core as utils
+
+if TYPE_CHECKING:
+    from superset.connectors.sqla.models import TableColumn
+
+
+class CrateEngineSpec(BaseEngineSpec):
+
+    engine = "crate"
+    engine_name = "CrateDB"
+
+    _time_grain_expressions = {
+        None: "{col}",
+        "PT1S": "DATE_TRUNC('second', {col})",
+        "PT1M": "DATE_TRUNC('minute', {col})",
+        "PT1H": "DATE_TRUNC('hour', {col})",
+        "P1D": "DATE_TRUNC('day', {col})",
+        "P1W": "DATE_TRUNC('week', {col})",
+        "P1M": "DATE_TRUNC('month', {col})",
+        "P0.25Y": "DATE_TRUNC('quarter', {col})",
+        "P1Y": "DATE_TRUNC('year', {col})",
+    }
+
+    @classmethod
+    def epoch_to_dttm(cls) -> str:
+        return "{col} * 1000"
+
+    @classmethod
+    def epoch_ms_to_dttm(cls) -> str:
+        return "{col}"
+
+    @classmethod
+    def convert_dttm(cls, target_type: str, dttm: datetime) -> Optional[str]:
+        tt = target_type.upper()
+        if tt == utils.TemporalType.TIMESTAMP:
+            return f"{dttm.timestamp() * 1000}"
+        return None
+
+    @classmethod
+    def alter_new_orm_column(cls, orm_col: "TableColumn") -> None:
+        if orm_col.type == "TIMESTAMP":
+            orm_col.type = "INT"
+            orm_col.is_dttm = True
+            orm_col.python_date_format = "epoch_ms"