fix var precedence from cli, add tests (#739)

* fix var precedence from cli, add tests

* updated from PR

dbt/context/common.py

@@ -175,17 +175,23 @@ class Var(object):
     NoneVarError = "Supplied var '{}' is undefined in config:\nVars supplied "\
                    "to {} = {}"
 
-    def __init__(self, model, context):
+    def __init__(self, model, context, overrides):
         self.model = model
         self.context = context
 
+        # These are hard-overrides (eg. CLI vars) that should take
+        # precedence over context-based var definitions
+        self.overrides = overrides
+
         if isinstance(model, dict) and model.get('unique_id'):
-            self.local_vars = model.get('config', {}).get('vars')
+            local_vars = model.get('config', {}).get('vars')
             self.model_name = model.get('name')
         else:
             # still used for wrapping
             self.model_name = model.nice_name
-            self.local_vars = model.config.get('vars', {})
+            local_vars = model.config.get('vars', {})
+
+        self.local_vars = dbt.utils.merge(local_vars, overrides)
 
     def pretty_dict(self, data):
         return json.dumps(data, sort_keys=True, indent=4)
@@ -297,6 +303,7 @@ def generate(model, project, flat_graph, provider=None):
     post_hooks = model.get('config', {}).get('post-hook')
 
     db_wrapper = DatabaseWrapper(model, adapter, profile)
+    cli_var_overrides = project.get('cli_vars', {})
 
     context = dbt.utils.merge(context, {
         "adapter": db_wrapper,
@@ -337,7 +344,7 @@ def generate(model, project, flat_graph, provider=None):
 
     context["write"] = write(model, project.get('target-path'), 'run')
     context["render"] = render(context, model)
-    context["var"] = Var(model, context=context)
+    context["var"] = Var(model, context=context, overrides=cli_var_overrides)
     context['context'] = context
 
     return context

dbt/project.py

@@ -95,10 +95,7 @@ def __init__(self, cfg, profiles, profiles_dir, profile_to_load=None,
             self.cfg['models']['vars'] = {}
 
         global_vars = dbt.utils.parse_cli_vars(getattr(args, 'vars', '{}'))
-        if 'vars' not in self.cfg['models']:
-            self.cfg['models']['vars'] = {}
-
-        self.cfg['models']['vars'].update(global_vars)
+        self.cfg['cli_vars'] = global_vars
 
     def __str__(self):
         return pprint.pformat({'project': self.cfg, 'profiles': self.profiles})

test/integration/028_cli_vars/models_override/schema.yml

@@ -0,0 +1,6 @@
+
+test_vars:
+    constraints:
+        accepted_values:
+            - {field: 'field', values: ['override']}
+

test/integration/028_cli_vars/models_override/test_vars.sql

@@ -0,0 +1,3 @@
+
+
+select '{{ var("required") }}'::varchar as field

test/integration/028_cli_vars/test_cli_var_override.py

@@ -0,0 +1,63 @@
+from nose.plugins.attrib import attr
+from test.integration.base import DBTIntegrationTest
+import yaml
+
+
+class TestCLIVarOverride(DBTIntegrationTest):
+    @property
+    def schema(self):
+        return "cli_vars_028"
+
+    @property
+    def models(self):
+        return "test/integration/028_cli_vars/models_override"
+
+    @property
+    def project_config(self):
+        return {
+            "models": {
+                "vars": {
+                    "required": "present"
+                }
+            }
+        }
+
+    @attr(type='postgres')
+    def test__overriden_vars_global(self):
+        self.use_default_project()
+        self.use_profile('postgres')
+
+        # This should be "override"
+        self.run_dbt(["run", "--vars", "{required: override}"])
+        self.run_dbt(["test"])
+
+
+class TestCLIVarOverridePorject(DBTIntegrationTest):
+    @property
+    def schema(self):
+        return "cli_vars_028"
+
+    @property
+    def models(self):
+        return "test/integration/028_cli_vars/models_override"
+
+    @property
+    def project_config(self):
+        return {
+            "models": {
+                "test": {
+                    "vars": {
+                        "required": "present"
+                    }
+                }
+            }
+        }
+
+    @attr(type='postgres')
+    def test__overriden_vars_project_level(self):
+        self.use_default_project()
+        self.use_profile('postgres')
+
+        # This should be "override"
+        self.run_dbt(["run", "--vars", "{required: override}"])
+        self.run_dbt(["test"])

test/integration/028_cli_vars/test_cli_vars.py

@@ -25,7 +25,7 @@ def test__cli_vars_longform(self):
             }
         }
         self.run_dbt(["run", "--vars", yaml.dump(cli_vars)])
-        self.run_dbt(["test"])
+        self.run_dbt(["test", "--vars", yaml.dump(cli_vars)])
 
 
 class TestCLIVarsSimple(DBTIntegrationTest):
@@ -43,12 +43,12 @@ def test__cli_vars_shorthand(self):
         self.use_profile('postgres')
 
         self.run_dbt(["run", "--vars", "simple: abc"])
-        self.run_dbt(["test"])
+        self.run_dbt(["test", "--vars", "simple: abc"])
 
     @attr(type='postgres')
     def test__cli_vars_longer(self):
         self.use_default_project()
         self.use_profile('postgres')
 
         self.run_dbt(["run", "--vars", "{simple: abc, unused: def}"])
-        self.run_dbt(["test"])
+        self.run_dbt(["test", "--vars", "{simple: abc, unused: def}"])