Add Pandas.read_sql_redshift()

Author: igorborgest

awswrangler/pandas.py

@@ -523,7 +523,7 @@ def read_sql_athena(self,
         :param workgroup: The name of the workgroup in which the query is being started. (By default uses de Session() workgroup)
         :param encryption: None|'SSE_S3'|'SSE_KMS'|'CSE_KMS'
         :param kms_key: For SSE-KMS and CSE-KMS , this is the KMS key ARN or ID.
-        :param ctas_approach: Wraps the query with a CTAS (Session's deafult is False)
+        :param ctas_approach: Wraps the query with a CTAS (Session's default is False)
         :param procs_cpu_bound: Number of cores used for CPU bound tasks
         :param max_result_size: Max number of bytes on each request to S3 (VALID ONLY FOR ctas_approach=False)
         :return: Pandas Dataframe or Iterator of Pandas Dataframes if max_result_size was passed
@@ -1376,3 +1376,45 @@ def read_table(self,
         """
         path: str = self._session.glue.get_table_location(database=database, table=table)
         return self.read_parquet(path=path, columns=columns, filters=filters, procs_cpu_bound=procs_cpu_bound)
+
+    def read_sql_redshift(self,
+                          sql: str,
+                          iam_role: str,
+                          connection: Any,
+                          temp_s3_path: Optional[str] = None,
+                          procs_cpu_bound: Optional[int] = None) -> pd.DataFrame:
+        """
+        Convert a query result in a Pandas Dataframe.
+
+        :param sql: SQL Query
+        :param iam_role: AWS IAM role with the related permissions
+        :param connection: A PEP 249 compatible connection (Can be generated with Redshift.generate_connection())
+        :param temp_s3_path: AWS S3 path to write temporary data (e.g. s3://...) (Default uses the Athena's results bucket)
+        :param procs_cpu_bound: Number of cores used for CPU bound tasks
+        """
+        guid: str = pa.compat.guid()
+        name: str = f"temp_redshift_{guid}"
+        if temp_s3_path is None:
+            if self._session.athena_s3_output is not None:
+                temp_s3_path = self._session.redshift_temp_s3_path
+            else:
+                temp_s3_path = self._session.athena.create_athena_bucket()
+        temp_s3_path = temp_s3_path[:-1] if temp_s3_path[-1] == "/" else temp_s3_path
+        temp_s3_path = f"{temp_s3_path}/{name}"
+        logger.debug(f"temp_s3_path: {temp_s3_path}")
+        paths: Optional[List[str]] = None
+        try:
+            paths = self._session.redshift.to_parquet(sql=sql,
+                                                      path=temp_s3_path,
+                                                      iam_role=iam_role,
+                                                      connection=connection)
+            logger.debug(f"paths: {paths}")
+            df: pd.DataFrame = self.read_parquet(path=paths, procs_cpu_bound=procs_cpu_bound)  # type: ignore
+            self._session.s3.delete_listed_objects(objects_paths=paths)
+            return df
+        except Exception as e:
+            if paths is not None:
+                self._session.s3.delete_listed_objects(objects_paths=paths)
+            else:
+                self._session.s3.delete_objects(path=temp_s3_path)
+            raise e

awswrangler/redshift.py

@@ -351,20 +351,20 @@ def _get_redshift_schema(dataframe, dataframe_type, preserve_index=False, cast_c
     def to_parquet(sql: str,
                    path: str,
                    iam_role: str,
-                   redshift_conn: Any,
+                   connection: Any,
                    partition_cols: Optional[List] = None) -> List[str]:
         """
         Write a query result as parquet files on S3
 
         :param sql: SQL Query
         :param path: AWS S3 path to write the data (e.g. s3://...)
         :param iam_role: AWS IAM role with the related permissions
-        :param redshift_conn: A PEP 249 compatible connection (Can be generated with Redshift.generate_connection())
+        :param connection: A PEP 249 compatible connection (Can be generated with Redshift.generate_connection())
         :param partition_cols: Specifies the partition keys for the unload operation.
         """
         sql = sql.replace("'", "\'").replace(";", "")  # escaping single quote
         path = path if path[-1] == "/" else path + "/"
-        cursor: Any = redshift_conn.cursor()
+        cursor: Any = connection.cursor()
         partition_str: str = ""
         if partition_cols is not None:
             partition_str = f"PARTITION BY ({','.join([x for x in partition_cols])})\n"
@@ -389,6 +389,6 @@ def to_parquet(sql: str,
         cursor.execute(query)
         paths: List[str] = [row[0].replace(" ", "") for row in cursor.fetchall()]
         logger.debug(f"paths: {paths}")
-        redshift_conn.commit()
+        connection.commit()
         cursor.close()
         return paths

awswrangler/session.py

@@ -49,7 +49,8 @@ def __init__(self,
                  athena_encryption: Optional[str] = "SSE_S3",
                  athena_kms_key: Optional[str] = None,
                  athena_database: str = "default",
-                 athena_ctas_approach: bool = False):
+                 athena_ctas_approach: bool = False,
+                 redshift_temp_s3_path: Optional[str] = None):
         """
         Most parameters inherit from Boto3 or Pyspark.
         https://boto3.amazonaws.com/v1/documentation/api/latest/guide/configuration.html
@@ -73,6 +74,7 @@ def __init__(self,
         :param athena_s3_output: AWS S3 path
         :param athena_encryption: None|'SSE_S3'|'SSE_KMS'|'CSE_KMS'
         :param athena_kms_key: For SSE-KMS and CSE-KMS , this is the KMS key ARN or ID.
+        :param redshift_temp_s3_path: redshift_temp_s3_path: AWS S3 path to write temporary data (e.g. s3://...)
         """
         self._profile_name: Optional[str] = (boto3_session.profile_name if boto3_session else profile_name)
         self._aws_access_key_id: Optional[str] = (boto3_session.get_credentials().access_key
@@ -95,6 +97,7 @@ def __init__(self,
         self._athena_kms_key: Optional[str] = athena_kms_key
         self._athena_database: str = athena_database
         self._athena_ctas_approach: bool = athena_ctas_approach
+        self._redshift_temp_s3_path: Optional[str] = redshift_temp_s3_path
         self._primitives = None
         self._load_new_primitives()
         if boto3_session:
@@ -149,7 +152,8 @@ def _load_new_primitives(self):
                                              athena_encryption=self._athena_encryption,
                                              athena_kms_key=self._athena_kms_key,
                                              athena_database=self._athena_database,
-                                             athena_ctas_approach=self._athena_ctas_approach)
+                                             athena_ctas_approach=self._athena_ctas_approach,
+                                             redshift_temp_s3_path=self._redshift_temp_s3_path)
 
     @property
     def profile_name(self):
@@ -223,6 +227,10 @@ def athena_database(self) -> str:
     def athena_ctas_approach(self) -> bool:
         return self._athena_ctas_approach
 
+    @property
+    def redshift_temp_s3_path(self) -> Optional[str]:
+        return self._redshift_temp_s3_path
+
     @property
     def boto3_session(self):
         return self._boto3_session
@@ -304,7 +312,8 @@ def __init__(self,
                  athena_encryption: Optional[str] = None,
                  athena_kms_key: Optional[str] = None,
                  athena_database: Optional[str] = None,
-                 athena_ctas_approach: bool = False):
+                 athena_ctas_approach: bool = False,
+                 redshift_temp_s3_path: Optional[str] = None):
         """
         Most parameters inherit from Boto3.
         https://boto3.amazonaws.com/v1/documentation/api/latest/guide/configuration.html
@@ -325,6 +334,7 @@ def __init__(self,
         :param athena_s3_output: AWS S3 path
         :param athena_encryption: None|'SSE_S3'|'SSE_KMS'|'CSE_KMS'
         :param athena_kms_key: For SSE-KMS and CSE-KMS , this is the KMS key ARN or ID.
+        :param redshift_temp_s3_path: AWS S3 path to write temporary data (e.g. s3://...)
         """
         self._profile_name: Optional[str] = profile_name
         self._aws_access_key_id: Optional[str] = aws_access_key_id
@@ -342,6 +352,7 @@ def __init__(self,
         self._athena_kms_key: Optional[str] = athena_kms_key
         self._athena_database: Optional[str] = athena_database
         self._athena_ctas_approach: bool = athena_ctas_approach
+        self._redshift_temp_s3_path: Optional[str] = redshift_temp_s3_path
 
     @property
     def profile_name(self):
@@ -407,6 +418,10 @@ def athena_database(self) -> Optional[str]:
     def athena_ctas_approach(self) -> bool:
         return self._athena_ctas_approach
 
+    @property
+    def redshift_temp_s3_path(self) -> Optional[str]:
+        return self._redshift_temp_s3_path
+
     @property
     def session(self):
         """
@@ -427,4 +442,5 @@ def session(self):
                        athena_encryption=self._athena_encryption,
                        athena_kms_key=self._athena_kms_key,
                        athena_database=self._athena_database,
-                       athena_ctas_approach=self._athena_ctas_approach)
+                       athena_ctas_approach=self._athena_ctas_approach,
+                       redshift_temp_s3_path=self._redshift_temp_s3_path)

requirements.txt

@@ -1,8 +1,8 @@
 numpy~=1.17.4
 pandas~=0.25.3
 pyarrow~=0.15.1
-botocore~=1.13.36
-boto3~=1.10.36
+botocore~=1.13.37
+boto3~=1.10.37
 s3fs~=0.4.0
 tenacity~=6.0.0
 pg8000~=1.13.2

testing/test_awswrangler/test_redshift.py

@@ -522,6 +522,73 @@ def test_to_parquet(bucket, redshift_parameters):
     paths = Redshift.to_parquet(sql="SELECT * FROM public.test",
                                 path=path,
                                 iam_role=redshift_parameters.get("RedshiftRole"),
-                                redshift_conn=con,
+                                connection=con,
                                 partition_cols=["name"])
     assert len(paths) == 20
+
+
+@pytest.mark.parametrize("sample_name", ["micro", "small", "nano"])
+def test_read_sql_redshift_pandas(session, bucket, redshift_parameters, sample_name):
+    if sample_name == "micro":
+        dates = ["date"]
+    elif sample_name == "small":
+        dates = ["date"]
+    else:
+        dates = ["date", "time"]
+    df = pd.read_csv(f"data_samples/{sample_name}.csv", parse_dates=dates, infer_datetime_format=True)
+    df["date"] = df["date"].dt.date
+    con = Redshift.generate_connection(
+        database="test",
+        host=redshift_parameters.get("RedshiftAddress"),
+        port=redshift_parameters.get("RedshiftPort"),
+        user="test",
+        password=redshift_parameters.get("RedshiftPassword"),
+    )
+    path = f"s3://{bucket}/test_read_sql_redshift_pandas/"
+    session.pandas.to_redshift(
+        dataframe=df,
+        path=path,
+        schema="public",
+        table="test",
+        connection=con,
+        iam_role=redshift_parameters.get("RedshiftRole"),
+        mode="overwrite",
+        preserve_index=True,
+    )
+    path2 = f"s3://{bucket}/test_read_sql_redshift_pandas2/"
+    df2 = session.pandas.read_sql_redshift(sql="select * from public.test",
+                                           iam_role=redshift_parameters.get("RedshiftRole"),
+                                           connection=con,
+                                           temp_s3_path=path2)
+    assert len(df.index) == len(df2.index)
+    assert len(df.columns) + 1 == len(df2.columns)
+
+
+def test_read_sql_redshift_pandas2(session, bucket, redshift_parameters):
+    n: int = 1_000_000
+    df = pd.DataFrame({"id": list((range(n))), "val": list(["foo" if i % 2 == 0 else "boo" for i in range(n)])})
+    con = Redshift.generate_connection(
+        database="test",
+        host=redshift_parameters.get("RedshiftAddress"),
+        port=redshift_parameters.get("RedshiftPort"),
+        user="test",
+        password=redshift_parameters.get("RedshiftPassword"),
+    )
+    path = f"s3://{bucket}/test_read_sql_redshift_pandas2/"
+    session.pandas.to_redshift(
+        dataframe=df,
+        path=path,
+        schema="public",
+        table="test",
+        connection=con,
+        iam_role=redshift_parameters.get("RedshiftRole"),
+        mode="overwrite",
+        preserve_index=True,
+    )
+    path2 = f"s3://{bucket}/test_read_sql_redshift_pandas22/"
+    df2 = session.pandas.read_sql_redshift(sql="select * from public.test",
+                                           iam_role=redshift_parameters.get("RedshiftRole"),
+                                           connection=con,
+                                           temp_s3_path=path2)
+    assert len(df.index) == len(df2.index)
+    assert len(df.columns) + 1 == len(df2.columns)