Merge pull request #1363 from roverdotcom/feature/alias-macro

Adding a generate_alias_name macro

core/dbt/include/global_project/macros/etc/get_custom_alias.sql

@@ -0,0 +1,26 @@
+
+{#
+    Renders a alias name given a custom alias name. If the custom
+    alias name is none, then the resulting alias is just the filename of the
+    model. If a alias override is specified, then that is used.
+
+    This macro can be overriden in projects to define different semantics
+    for rendering a alias name.
+
+    Arguments:
+    custom_alias_name: The custom alias name specified for a model, or none
+
+#}
+{% macro generate_alias_name(node, custom_alias_name=none) -%}
+
+    {%- if custom_alias_name is none -%}
+
+        {{ node.name }}
+
+    {%- else -%}
+
+        {{ custom_alias_name | trim }}
+
+    {%- endif -%}
+
+{%- endmacro %}

core/dbt/parser/base.py

@@ -58,6 +58,7 @@ def __init__(self, root_project_config, all_projects, macro_manifest):
         )
         self.macro_manifest = macro_manifest
         self._get_schema_func = None
+        self._get_alias_func = None
 
     def get_schema_func(self):
         """The get_schema function is set by a few different things:
@@ -94,6 +95,44 @@ def get_schema(_):
         self._get_schema_func = get_schema
         return self._get_schema_func
 
+    def get_alias_func(self):
+        """The get_alias function is set by a few different things:
+            - if there is a 'generate_alias_name' macro in the root project,
+                it will be used.
+            - if that does not exist but there is a 'generate_alias_name'
+                macro in the 'dbt' internal project, that will be used
+            - if neither of those exist (unit tests?), a function that returns
+                the 'default alias' as set in the model's filename or alias
+                configuration.
+        """
+        if self._get_alias_func is not None:
+            return self._get_alias_func
+
+        get_alias_macro = self.macro_manifest.find_macro_by_name(
+            'generate_alias_name',
+            self.root_project_config.project_name
+        )
+        if get_alias_macro is None:
+            get_alias_macro = self.macro_manifest.find_macro_by_name(
+                'generate_alias_name',
+                GLOBAL_PROJECT_NAME
+            )
+        if get_alias_macro is None:
+            def get_alias(node, custom_alias_name=None):
+                if custom_alias_name is None:
+                    return node.name
+                else:
+                    return custom_alias_name
+        else:
+            root_context = dbt.context.parser.generate_macro(
+                get_alias_macro, self.root_project_config,
+                self.macro_manifest
+            )
+            get_alias = get_alias_macro.generator(root_context)
+
+        self._get_alias_func = get_alias
+        return self._get_alias_func
+
     def _build_intermediate_node_dict(self, config, node_dict, node_path,
                                       package_project_config, tags, fqn,
                                       agate_table, archive_config,
@@ -168,7 +207,11 @@ def _update_parsed_node_info(self, parsed_node, config):
         schema_override = config.config.get('schema')
         get_schema = self.get_schema_func()
         parsed_node.schema = get_schema(schema_override).strip()
-        parsed_node.alias = config.config.get('alias', parsed_node.get('name'))
+
+        alias_override = config.config.get('alias')
+        get_alias = self.get_alias_func()
+        parsed_node.alias = get_alias(parsed_node, alias_override).strip()
+
         parsed_node.database = config.config.get(
             'database', self.default_database
         ).strip()

test/integration/043_custom_aliases_test/macros/macros.sql

@@ -0,0 +1,21 @@
+
+{% macro generate_alias_name(node, custom_alias_name=none) -%}
+    {%- if custom_alias_name is none -%}
+        {{ node.name }}
+    {%- else -%}
+        custom_{{ custom_alias_name | trim }}
+    {%- endif -%}
+{%- endmacro %}
+
+
+{% macro string_literal(s) -%}
+  {{ adapter_macro('test.string_literal', s) }}
+{%- endmacro %}
+
+{% macro default__string_literal(s) %}
+    '{{ s }}'::text
+{% endmacro %}
+
+{% macro bigquery__string_literal(s) %}
+    cast('{{ s }}' as string)
+{% endmacro %}

test/integration/043_custom_aliases_test/models/model1.sql

@@ -0,0 +1,3 @@
+{{ config(materialized='table', alias='alias') }}
+
+select {{ string_literal(this.name) }} as model_name

test/integration/043_custom_aliases_test/models/model2.sql

@@ -0,0 +1,3 @@
+{{ config(materialized='table') }}
+
+select {{ string_literal(this.name) }} as model_name

test/integration/043_custom_aliases_test/models/schema.yml

@@ -0,0 +1,15 @@
+version: 2
+
+models:
+  - name: model1
+    columns:
+      - name: model_name
+        tests:
+          - accepted_values:
+             values: ['custom_alias']
+  - name: model2
+    columns:
+      - name: model_name
+        tests:
+          - accepted_values:
+             values: ['model2']

test/integration/043_custom_aliases_test/test_custom_aliases.py

@@ -0,0 +1,22 @@
+from test.integration.base import DBTIntegrationTest
+
+
+class TestAliases(DBTIntegrationTest):
+    @property
+    def schema(self):
+        return "custom_aliases_043"
+
+    @property
+    def models(self):
+        return "test/integration/043_custom_aliases_test/models"
+
+    @property
+    def project_config(self):
+        return {
+            "macro-paths": ['test/integration/043_custom_aliases_test/macros'],
+        }
+
+    def test__customer_alias_name(self):
+        results = self.run_dbt(['run'])
+        self.assertEqual(len(results), 1)
+        self.run_dbt(['test'])