Add column comments to Snowflake views (#53)

* Add column comments to Snowflake views
* Update create_view_as macro to include column comments
* Add test for column-level view comments
* Add testing for column comments with non-lowercase column names

* Organizing adapter macros for column persistence

CHANGELOG.md

@@ -2,13 +2,15 @@
 
 ### Fixes
 - Apply query tags for Seed and Snapshot materialisations ([#20](https://github.com/dbt-labs/dbt-snowflake/issues/20), [#48](https://github.com/dbt-labs/dbt-snowflake/issues/48))
+- Adds column-level comments to Snowflake views ([#17](https://github.com/dbt-labs/dbt-snowflake/issues/17))
 
 ### Under the hood
 - Resolves an issue caused when the Snowflake OCSP server is not accessible, by exposing the `insecure_mode` boolean avalable in the Snowflake python connector ([#31](https://github.com/dbt-labs/dbt-snowflake/issues/31), [#49](https://github.com/dbt-labs/dbt-snowflake/pull/49))
 
 ### Contributors
 - [@anthu](https://github.com/anthu) ([#48](https://github.com/dbt-labs/dbt-snowflake/pull/48))
 - [@JoshuaHuntley](https://github.com/JoshuaHuntley) ([#49](https://github.com/dbt-labs/dbt-snowflake/pull/49))
+- [@spencer-taylor-workrise](https://github.com/spencer-taylor-workrise) ([#17](https://github.com/dbt-labs/dbt-snowflake/issues/17))
 
 ## dbt-snowflake 1.0.0rc1 (November 10, 2021)
 

dbt/include/snowflake/macros/adapters.sql

@@ -38,6 +38,23 @@
     {%- endif -%}
 {% endmacro %}
 
+{% macro get_column_comment_sql(column_name, column_dict) %}
+  {{ adapter.quote(column_name) if column_dict[column_name]['quote'] else column_name }} COMMENT $${{ column_dict[column_name]['description'] | replace('$', '[$]') }}$$
+{% endmacro %}
+
+{% macro get_persist_docs_column_list(model_columns, query_columns) %}
+(
+  {% for column_name in query_columns %}
+    {% if (column_name|upper in model_columns) or (column_name in model_columns) %}
+      {{ get_column_comment_sql(column_name, model_columns) }}
+    {% else %}
+      {{column_name}}
+    {% endif %}
+    {{ ", " if not loop.last else "" }}
+  {% endfor %}
+)
+{% endmacro %}
+
 {% macro snowflake__create_view_as(relation, sql) -%}
   {%- set secure = config.get('secure', default=false) -%}
   {%- set copy_grants = config.get('copy_grants', default=false) -%}
@@ -46,7 +63,14 @@
   {{ sql_header if sql_header is not none }}
   create or replace {% if secure -%}
     secure
-  {%- endif %} view {{ relation }} {% if copy_grants -%} copy grants {%- endif %} as (
+  {%- endif %} view {{ relation }} 
+  {% if config.persist_column_docs() -%}
+    {% set model_columns = model.columns %}
+    {% set query_columns = get_columns_in_query(sql) %}
+    {{ get_persist_docs_column_list(model_columns, query_columns) }}
+
+  {%- endif %}
+  {% if copy_grants -%} copy grants {%- endif %} as (
     {{ sql }}
   );
 {% endmacro %}
@@ -158,7 +182,7 @@
     {% set existing_columns = adapter.get_columns_in_relation(relation) | map(attribute="name") | list %}
     alter {{ relation.type }} {{ relation }} alter
     {% for column_name in column_dict if (column_name in existing_columns) or (column_name|upper in existing_columns) %}
-        {{ adapter.quote(column_name) if column_dict[column_name]['quote'] else column_name }} COMMENT $${{ column_dict[column_name]['description'] | replace('$', '[$]') }}$$ {{ ',' if not loop.last else ';' }}
+        {{ get_column_comment_sql(column_name, column_dict) }} {{ ',' if not loop.last else ';' }}
     {% endfor %}
 {% endmacro %}
 

tests/integration/column_comments_tests/models/quote_model.sql

@@ -1 +1 @@
-select 1 as {{ adapter.quote("2id") }}
+select 1 as {{ adapter.quote("2id") }}, 2 as {{ adapter.quote("3iD") }}

tests/integration/column_comments_tests/models/schema.yml

@@ -6,4 +6,6 @@ models:
       - name: 2id
         description: "XXX My description"
         quote: true
-
+      - name: 3iD
+        description: "XXX Testing for non-lowercase column name"
+        quote: true

tests/integration/column_comments_tests/test_column_comments.py

@@ -2,8 +2,7 @@
 
 from tests.integration.base import DBTIntegrationTest, use_profile
 
-
-class TestColumnComment(DBTIntegrationTest):
+class BaseTestColumnComment(DBTIntegrationTest):
     @property
     def schema(self):
         return "column_comment"
@@ -12,6 +11,19 @@ def schema(self):
     def models(self):
         return "models"
 
+    def run_has_comments(self):
+        self.run_dbt()
+        self.run_dbt(['docs', 'generate'])
+        with open('target/catalog.json') as fp:
+            catalog_data = json.load(fp)
+        assert 'nodes' in catalog_data
+        assert len(catalog_data['nodes']) == 1
+        column_node = catalog_data['nodes']['model.test.quote_model']
+        for column in column_node['columns'].keys():
+            column_comment = column_node['columns'][column]['comment']
+            assert column_comment.startswith('XXX')
+
+class TestColumnCommentInTable(BaseTestColumnComment):
     @property
     def project_config(self):
         return {
@@ -26,18 +38,25 @@ def project_config(self):
                 }
             }
         }
+    @use_profile('snowflake')
+    def test_snowflake_comments(self):
+        self.run_has_comments()
 
-    def run_has_comments(self):
-        self.run_dbt()
-        self.run_dbt(['docs', 'generate'])
-        with open('target/catalog.json') as fp:
-            catalog_data = json.load(fp)
-        assert 'nodes' in catalog_data
-        assert len(catalog_data['nodes']) == 1
-        column_node = catalog_data['nodes']['model.test.quote_model']
-        column_comment = column_node['columns']['2id']['comment']
-        assert column_comment.startswith('XXX')
-
+class TestColumnCommentInView(BaseTestColumnComment):
+    @property
+    def project_config(self):
+        return {
+            'config-version': 2,
+            'models': {
+                'test': {
+                    'materialized': 'view',
+                    '+persist_docs': {
+                        "relation": True,
+                        "columns": True,
+                    },
+                }
+            }
+        }
     @use_profile('snowflake')
     def test_snowflake_comments(self):
         self.run_has_comments()