Implement Snowflake engine with supported time grains (apache#4882)

* Implement Snowflake engine with supported time grains * Fix typo in second grain
michellethomas · May 23, 2018 · 357b1d8 · 357b1d8
1 parent 6ef8b78
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diff --git a/docs/installation.rst b/docs/installation.rst
@@ -298,6 +298,8 @@ Here's a list of some of the recommended packages.
 +---------------+-------------------------------------+-------------------------------------------------+
 |  sqlite       |                                     | ``sqlite://``                                   |
 +---------------+-------------------------------------+-------------------------------------------------+
+|  Snowflake    | ``pip install snowflake-sqlalchemy``| ``snowflake://``                                |
++---------------+-------------------------------------+-------------------------------------------------+
 |  Redshift     | ``pip install sqlalchemy-redshift`` | ``redshift+psycopg2://``                        |
 +---------------+-------------------------------------+-------------------------------------------------+
 |  MSSQL        | ``pip install pymssql``             | ``mssql://``                                    |

diff --git a/superset/db_engine_specs.py b/superset/db_engine_specs.py
@@ -334,6 +334,22 @@ def get_table_names(cls, schema, inspector):
         return sorted(tables)
 
 
+class SnowflakeEngineSpec(PostgresBaseEngineSpec):
+    engine = 'snowflake'
+
+    time_grains = (
+        Grain('Time Column', _('Time Column'), '{col}', None),
+        Grain('second', _('second'), "DATE_TRUNC('SECOND', {col})", 'PT1S'),
+        Grain('minute', _('minute'), "DATE_TRUNC('MINUTE', {col})", 'PT1M'),
+        Grain('hour', _('hour'), "DATE_TRUNC('HOUR', {col})", 'PT1H'),
+        Grain('day', _('day'), "DATE_TRUNC('DAY', {col})", 'P1D'),
+        Grain('week', _('week'), "DATE_TRUNC('WEEK', {col})", 'P1W'),
+        Grain('month', _('month'), "DATE_TRUNC('MONTH', {col})", 'P1M'),
+        Grain('quarter', _('quarter'), "DATE_TRUNC('QUARTER', {col})", 'P0.25Y'),
+        Grain('year', _('year'), "DATE_TRUNC('YEAR', {col})", 'P1Y'),
+    )
+
+
 class VerticaEngineSpec(PostgresBaseEngineSpec):
     engine = 'vertica'