Add Command Execution backend which uses Command Execution API on a c…

…luster (#95)

src/databricks/labs/lsql/backends.py

@@ -7,6 +7,7 @@
 from types import UnionType
 from typing import Any, ClassVar, Protocol, TypeVar
 
+from databricks.labs.blueprint.commands import CommandExecutor
 from databricks.sdk import WorkspaceClient
 from databricks.sdk.errors import (
     BadRequest,
@@ -16,6 +17,7 @@
     PermissionDenied,
     Unknown,
 )
+from databricks.sdk.service.compute import Language
 
 from databricks.labs.lsql.core import Row, StatementExecutionExt
 
@@ -129,21 +131,20 @@ def _api_error_from_message(error_message: str) -> DatabricksError:
         return Unknown(error_message)
 
 
-class StatementExecutionBackend(SqlBackend):
-    def __init__(self, ws: WorkspaceClient, warehouse_id, *, max_records_per_batch: int = 1000, **kwargs):
-        self._sql = StatementExecutionExt(ws, warehouse_id=warehouse_id, **kwargs)
+class ExecutionBackend(SqlBackend):
+    """Abstract base class for Statement & Command Execution backends.
+    This class defines the save_table method that is used to save data to tables."""
+
+    def __init__(self, max_records_per_batch: int = 1000):
         self._max_records_per_batch = max_records_per_batch
-        debug_truncate_bytes = ws.config.debug_truncate_bytes
-        # while unit-testing, this value will contain a mock
-        self._debug_truncate_bytes = debug_truncate_bytes if isinstance(debug_truncate_bytes, int) else 96
 
+    @abstractmethod
     def execute(self, sql: str, *, catalog: str | None = None, schema: str | None = None) -> None:
-        logger.debug(f"[api][execute] {self._only_n_bytes(sql, self._debug_truncate_bytes)}")
-        self._sql.execute(sql, catalog=catalog, schema=schema)
+        raise NotImplementedError
 
-    def fetch(self, sql: str, *, catalog: str | None = None, schema: str | None = None) -> Iterator[Row]:
-        logger.debug(f"[api][fetch] {self._only_n_bytes(sql, self._debug_truncate_bytes)}")
-        return self._sql.fetch_all(sql, catalog=catalog, schema=schema)
+    @abstractmethod
+    def fetch(self, sql: str, *, catalog: str | None = None, schema: str | None = None) -> Iterator[Any]:
+        raise NotImplementedError
 
     def save_table(self, full_name: str, rows: Sequence[DataclassInstance], klass: Dataclass, mode="append"):
         rows = self._filter_none_rows(rows, klass)
@@ -183,6 +184,47 @@ def _row_to_sql(row: DataclassInstance, fields: tuple[dataclasses.Field[Any], ..
         return ", ".join(data)
 
 
+class StatementExecutionBackend(ExecutionBackend):
+    def __init__(self, ws: WorkspaceClient, warehouse_id, *, max_records_per_batch: int = 1000, **kwargs):
+        self._sql = StatementExecutionExt(ws, warehouse_id=warehouse_id, **kwargs)
+        debug_truncate_bytes = ws.config.debug_truncate_bytes
+        # while unit-testing, this value will contain a mock
+        self._debug_truncate_bytes = debug_truncate_bytes if isinstance(debug_truncate_bytes, int) else 96
+        super().__init__(max_records_per_batch)
+
+    def execute(self, sql: str, *, catalog: str | None = None, schema: str | None = None) -> None:
+        logger.debug(f"[api][execute] {self._only_n_bytes(sql, self._debug_truncate_bytes)}")
+        self._sql.execute(sql, catalog=catalog, schema=schema)
+
+    def fetch(self, sql: str, *, catalog: str | None = None, schema: str | None = None) -> Iterator[Row]:
+        logger.debug(f"[api][fetch] {self._only_n_bytes(sql, self._debug_truncate_bytes)}")
+        return self._sql.fetch_all(sql, catalog=catalog, schema=schema)
+
+
+class CommandExecutionBackend(ExecutionBackend):
+    def __init__(self, ws: WorkspaceClient, cluster_id, *, max_records_per_batch: int = 1000):
+        self._sql = CommandExecutor(ws.clusters, ws.command_execution, lambda: cluster_id, language=Language.SQL)
+        debug_truncate_bytes = ws.config.debug_truncate_bytes
+        self._debug_truncate_bytes = debug_truncate_bytes if isinstance(debug_truncate_bytes, int) else 96
+        super().__init__(max_records_per_batch)
+
+    def execute(self, sql: str, *, catalog: str | None = None, schema: str | None = None) -> None:
+        logger.debug(f"[api][execute] {self._only_n_bytes(sql, self._debug_truncate_bytes)}")
+        if catalog:
+            self._sql.run(f"USE CATALOG {catalog}")
+        if schema:
+            self._sql.run(f"USE SCHEMA {schema}")
+        self._sql.run(sql)
+
+    def fetch(self, sql: str, *, catalog: str | None = None, schema: str | None = None) -> Iterator[Row]:
+        logger.debug(f"[api][fetch] {self._only_n_bytes(sql, self._debug_truncate_bytes)}")
+        if catalog:
+            self._sql.run(f"USE CATALOG {catalog}")
+        if schema:
+            self._sql.run(f"USE SCHEMA{schema}")
+        return self._sql.run(sql, result_as_json=True)
+
+
 class _SparkBackend(SqlBackend):
     def __init__(self, spark, debug_truncate_bytes):
         self._spark = spark

tests/unit/test_command_execution_backend.py

@@ -0,0 +1,236 @@
+from dataclasses import dataclass
+from unittest import mock
+from unittest.mock import call, create_autospec
+
+from databricks.sdk import WorkspaceClient
+from databricks.sdk.service._internal import Wait
+from databricks.sdk.service.compute import (
+    CommandStatus,
+    CommandStatusResponse,
+    ContextStatusResponse,
+    Language,
+    Results,
+    ResultType,
+)
+
+from databricks.labs.lsql.backends import CommandExecutionBackend
+
+
+@dataclass
+class Foo:
+    first: str
+    second: bool
+
+
+@dataclass
+class Baz:
+    first: str
+    second: str | None = None
+
+
+@dataclass
+class Bar:
+    first: str
+    second: bool
+    third: float
+
+
+def test_command_context_backend_execute_happy():
+    ws = create_autospec(WorkspaceClient)
+    ws.command_execution.create.return_value = Wait[ContextStatusResponse](
+        waiter=lambda callback, timeout: ContextStatusResponse(id="abc")
+    )
+    ws.command_execution.execute.return_value = Wait[CommandStatusResponse](
+        waiter=lambda callback, timeout: CommandStatusResponse(
+            results=Results(data="success"), status=CommandStatus.FINISHED
+        )
+    )
+
+    ceb = CommandExecutionBackend(ws, "abc")
+
+    ceb.execute("CREATE TABLE foo")
+
+    ws.command_execution.execute.assert_called_with(
+        cluster_id="abc", language=Language.SQL, context_id="abc", command="CREATE TABLE foo"
+    )
+
+
+def test_command_context_backend_with_overrides():
+    ws = create_autospec(WorkspaceClient)
+    ws.command_execution.create.return_value = Wait[ContextStatusResponse](
+        waiter=lambda callback, timeout: ContextStatusResponse(id="abc")
+    )
+    ws.command_execution.execute.return_value = Wait[CommandStatusResponse](
+        waiter=lambda callback, timeout: CommandStatusResponse(
+            results=Results(data="success"), status=CommandStatus.FINISHED
+        )
+    )
+
+    ceb = CommandExecutionBackend(ws, "abc")
+
+    ceb.execute("CREATE TABLE foo", catalog="foo", schema="bar")
+
+    ws.command_execution.execute.assert_has_calls(
+        [
+            call(cluster_id="abc", language=Language.SQL, context_id="abc", command="USE CATALOG foo"),
+            call(cluster_id="abc", language=Language.SQL, context_id="abc", command="USE SCHEMA bar"),
+            call(cluster_id="abc", language=Language.SQL, context_id="abc", command="CREATE TABLE foo"),
+        ]
+    )
+
+
+def test_command_context_backend_fetch_happy():
+    ws = create_autospec(WorkspaceClient)
+    ws.command_execution.create.return_value = Wait[ContextStatusResponse](
+        waiter=lambda callback, timeout: ContextStatusResponse(id="abc")
+    )
+    ws.command_execution.execute.return_value = Wait[CommandStatusResponse](
+        waiter=lambda callback, timeout: CommandStatusResponse(
+            results=Results(
+                data=[["1"], ["2"], ["3"]],
+                result_type=ResultType.TABLE,
+                schema=[{"name": "id", "type": '"int"', "metadata": "{}"}],
+            ),
+            status=CommandStatus.FINISHED,
+        )
+    )
+
+    ceb = CommandExecutionBackend(ws, "abc")
+
+    result = list(ceb.fetch("SELECT id FROM range(3)"))
+
+    assert [["1"], ["2"], ["3"]] == result
+
+
+def test_command_context_backend_save_table_overwrite_empty_table():
+    ws = create_autospec(WorkspaceClient)
+    ws.command_execution.create.return_value = Wait[ContextStatusResponse](
+        waiter=lambda callback, timeout: ContextStatusResponse(id="abc")
+    )
+    ws.command_execution.execute.return_value = Wait[CommandStatusResponse](
+        waiter=lambda callback, timeout: CommandStatusResponse(
+            results=Results(data="success"), status=CommandStatus.FINISHED
+        )
+    )
+
+    ceb = CommandExecutionBackend(ws, "abc")
+    ceb.save_table("a.b.c", [Baz("1")], Baz, mode="overwrite")
+
+    ws.command_execution.execute.assert_has_calls(
+        [
+            mock.call(
+                cluster_id="abc",
+                language=Language.SQL,
+                context_id="abc",
+                command="CREATE TABLE IF NOT EXISTS a.b.c (first STRING NOT NULL, second STRING) USING DELTA",
+            ),
+            mock.call(
+                cluster_id="abc",
+                language=Language.SQL,
+                context_id="abc",
+                command="TRUNCATE TABLE a.b.c",
+            ),
+            mock.call(
+                cluster_id="abc",
+                language=Language.SQL,
+                context_id="abc",
+                command="INSERT INTO a.b.c (first, second) VALUES ('1', NULL)",
+            ),
+        ]
+    )
+
+
+def test_command_context_backend_save_table_empty_records():
+    ws = create_autospec(WorkspaceClient)
+    ws.command_execution.create.return_value = Wait[ContextStatusResponse](
+        waiter=lambda callback, timeout: ContextStatusResponse(id="abc")
+    )
+    ws.command_execution.execute.return_value = Wait[CommandStatusResponse](
+        waiter=lambda callback, timeout: CommandStatusResponse(
+            results=Results(data="success"), status=CommandStatus.FINISHED
+        )
+    )
+
+    ceb = CommandExecutionBackend(ws, "abc")
+
+    ceb.save_table("a.b.c", [], Bar)
+
+    ws.command_execution.execute.assert_called_with(
+        cluster_id="abc",
+        language=Language.SQL,
+        context_id="abc",
+        command="CREATE TABLE IF NOT EXISTS a.b.c "
+        "(first STRING NOT NULL, second BOOLEAN NOT NULL, third FLOAT NOT NULL) USING DELTA",
+    )
+
+
+def test_command_context_backend_save_table_two_records():
+    ws = create_autospec(WorkspaceClient)
+    ws.command_execution.create.return_value = Wait[ContextStatusResponse](
+        waiter=lambda callback, timeout: ContextStatusResponse(id="abc")
+    )
+    ws.command_execution.execute.return_value = Wait[CommandStatusResponse](
+        waiter=lambda callback, timeout: CommandStatusResponse(
+            results=Results(data="success"), status=CommandStatus.FINISHED
+        )
+    )
+
+    ceb = CommandExecutionBackend(ws, "abc")
+
+    ceb.save_table("a.b.c", [Foo("aaa", True), Foo("bbb", False)], Foo)
+
+    ws.command_execution.execute.assert_has_calls(
+        [
+            mock.call(
+                cluster_id="abc",
+                language=Language.SQL,
+                context_id="abc",
+                command="CREATE TABLE IF NOT EXISTS a.b.c (first STRING NOT NULL, second BOOLEAN NOT NULL) USING DELTA",
+            ),
+            mock.call(
+                cluster_id="abc",
+                language=Language.SQL,
+                context_id="abc",
+                command="INSERT INTO a.b.c (first, second) VALUES ('aaa', TRUE), ('bbb', FALSE)",
+            ),
+        ]
+    )
+
+
+def test_command_context_backend_save_table_in_batches_of_two(mocker):
+    ws = create_autospec(WorkspaceClient)
+    ws.command_execution.create.return_value = Wait[ContextStatusResponse](
+        waiter=lambda callback, timeout: ContextStatusResponse(id="abc")
+    )
+    ws.command_execution.execute.return_value = Wait[CommandStatusResponse](
+        waiter=lambda callback, timeout: CommandStatusResponse(
+            results=Results(data="success"), status=CommandStatus.FINISHED
+        )
+    )
+
+    ceb = CommandExecutionBackend(ws, "abc", max_records_per_batch=2)
+
+    ceb.save_table("a.b.c", [Foo("aaa", True), Foo("bbb", False), Foo("ccc", True)], Foo)
+
+    ws.command_execution.execute.assert_has_calls(
+        [
+            mock.call(
+                cluster_id="abc",
+                language=Language.SQL,
+                context_id="abc",
+                command="CREATE TABLE IF NOT EXISTS a.b.c (first STRING NOT NULL, second BOOLEAN NOT NULL) USING DELTA",
+            ),
+            mock.call(
+                cluster_id="abc",
+                language=Language.SQL,
+                context_id="abc",
+                command="INSERT INTO a.b.c (first, second) VALUES ('aaa', TRUE), ('bbb', FALSE)",
+            ),
+            mock.call(
+                cluster_id="abc",
+                language=Language.SQL,
+                context_id="abc",
+                command="INSERT INTO a.b.c (first, second) VALUES ('ccc', TRUE)",
+            ),
+        ]
+    )