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Posted to commits@airflow.apache.org by GitBox <gi...@apache.org> on 2018/12/18 04:20:44 UTC
[GitHub] stale[bot] closed pull request #2223: [AIRFLOW-1076] Add get method
for template variable accessor
stale[bot] closed pull request #2223: [AIRFLOW-1076] Add get method for template variable accessor
URL: https://github.com/apache/incubator-airflow/pull/2223
This is a PR merged from a forked repository.
As GitHub hides the original diff on merge, it is displayed below for
the sake of provenance:
As this is a foreign pull request (from a fork), the diff is supplied
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diff --git a/airflow/models.py b/airflow/models.py
index edb3b67a40..75e2238c67 100755
--- a/airflow/models.py
+++ b/airflow/models.py
@@ -1699,20 +1699,31 @@ def get_template_context(self, session=None):
class VariableAccessor:
"""
- Wrapper around Variable. This way you can get variables in templates by using
- {var.variable_name}.
+ Wrapper around Variable. This way you can get variables in
+ templates by using {{ var.value.variable_name }} or
+ {{ var.value.get('variable_name', 'backup') }}.
"""
def __init__(self):
self.var = None
- def __getattr__(self, item):
+ def __getattr__(self, item, default_var=None):
self.var = Variable.get(item)
return self.var
def __repr__(self):
return str(self.var)
+ @staticmethod
+ def get(item, default_var=None):
+ self.var = Variable.get(item, default_var=default_var)
+ return self.var
+
class VariableJsonAccessor:
+ """
+ Wrapper around Variable. This way you can get variables in
+ templates by using {{ var.json.variable_name }} or
+ {{ var.json.get('variable_name', 'backup') }}.
+ """
def __init__(self):
self.var = None
@@ -1723,6 +1734,12 @@ def __getattr__(self, item):
def __repr__(self):
return str(self.var)
+ @staticmethod
+ def get(item, default_var=None):
+ self.var = Variable.get(item, default_var=default_var,
+ deserialize_json=True)
+ return self.var
+
return {
'dag': task.dag,
'ds': ds,
diff --git a/docs/code.rst b/docs/code.rst
index d74d00ec56..ef5fa1ab2a 100644
--- a/docs/code.rst
+++ b/docs/code.rst
@@ -193,6 +193,11 @@ UI. You can access them as either plain-text or JSON. If you use JSON, you are
also able to walk nested structures, such as dictionaries like:
``{{ var.json.my_dict_var.key1 }}``
+It is also possible to fetch a variable by string if
+needed with ``{{ var.value.get('my_var', 'fallback') }}`` or
+``{{ var.json.get('my_dict_var', {'key1': 'val1'}).key1 }}``. Defaults can be
+supplied in case the variable does not exist.
+
Macros
''''''
Macros are a way to expose objects to your templates and live under the
diff --git a/tests/core.py b/tests/core.py
index f25d0e7ff2..6322a9fd05 100644
--- a/tests/core.py
+++ b/tests/core.py
@@ -520,7 +520,54 @@ def verify_templated_field(context):
some_templated_field='{{ var.value.a_variable }}',
on_success_callback=verify_templated_field,
dag=self.dag)
- t.run(start_date=DEFAULT_DATE, end_date=DEFAULT_DATE, ignore_ti_state=True)
+ t.run(start_date=DEFAULT_DATE, end_date=DEFAULT_DATE,
+ ignore_ti_state=True)
+ self.assertTrue(val['success'])
+
+ def test_template_with_variable_get(self):
+ """
+ Test the availability of variables in templates using get() method
+ """
+ val = {
+ 'success': False,
+ 'test_value': 'a test value'
+ }
+ Variable.set('a_variable', val['test_value'])
+
+ def verify_templated_field(context):
+ self.assertEqual(context['ti'].task.some_templated_field,
+ val['test_value'])
+ val['success'] = True
+
+ t = OperatorSubclass(
+ task_id='test_complex_template',
+ some_templated_field='{{ var.value.get("a_variable") }}',
+ on_success_callback=verify_templated_field,
+ dag=self.dag)
+ t.run(start_date=DEFAULT_DATE, end_date=DEFAULT_DATE,
+ ignore_ti_state=True)
+ self.assertTrue(val['success'])
+
+ def test_template_with_variable_get_with_default(self):
+ """
+ Test the availability of variables in templates using get() method with
+ a default value
+ """
+ val = {
+ 'success': False,
+ }
+
+ def verify_templated_field(context):
+ self.assertEqual(context['ti'].task.some_templated_field, 'N/A')
+ val['success'] = True
+
+ t = OperatorSubclass(
+ task_id='test_complex_template',
+ some_templated_field='{{ var.value.get("bad_variable", "N/A") }}',
+ on_success_callback=verify_templated_field,
+ dag=self.dag)
+ t.run(start_date=DEFAULT_DATE, end_date=DEFAULT_DATE,
+ ignore_ti_state=True)
self.assertTrue(val['success'])
def test_template_with_json_variable(self):
@@ -543,7 +590,58 @@ def verify_templated_field(context):
some_templated_field='{{ var.json.a_variable.obj.v2 }}',
on_success_callback=verify_templated_field,
dag=self.dag)
- t.run(start_date=DEFAULT_DATE, end_date=DEFAULT_DATE, ignore_ti_state=True)
+ t.run(start_date=DEFAULT_DATE, end_date=DEFAULT_DATE,
+ ignore_ti_state=True)
+ self.assertTrue(val['success'])
+
+ def test_template_with_json_variable_get(self):
+ """
+ Test the availability of variables (serialized as JSON) in templates
+ using get() method
+ """
+ val = {
+ 'success': False,
+ 'test_value': {'foo': 'bar', 'obj': {'v1': 'yes', 'v2': 'no'}}
+ }
+ Variable.set('a_variable', val['test_value'], serialize_json=True)
+
+ def verify_templated_field(context):
+ self.assertEqual(context['ti'].task.some_templated_field,
+ val['test_value']['obj']['v2'])
+ val['success'] = True
+
+ t = OperatorSubclass(
+ task_id='test_complex_template',
+ some_templated_field='{{ var.json.get("a_variable").obj.v2 }}',
+ on_success_callback=verify_templated_field,
+ dag=self.dag)
+ t.run(start_date=DEFAULT_DATE, end_date=DEFAULT_DATE,
+ ignore_ti_state=True)
+ self.assertTrue(val['success'])
+
+ def test_template_with_json_variable_get_with_default(self):
+ """
+ Test the availability of variables (serialized as JSON) in templates
+ using get() method with a default value
+ """
+ val = {
+ 'success': False,
+ }
+
+ def verify_templated_field(context):
+ self.assertEqual(context['ti'].task.some_templated_field,
+ 'unknown')
+ val['success'] = True
+
+ t = OperatorSubclass(
+ task_id='test_complex_template',
+ some_templated_field=(
+ '{{ var.json.get("bad_variable", {"obj": {"v2": "unknown"}})'
+ '.obj.v2 }}'),
+ on_success_callback=verify_templated_field,
+ dag=self.dag)
+ t.run(start_date=DEFAULT_DATE, end_date=DEFAULT_DATE,
+ ignore_ti_state=True)
self.assertTrue(val['success'])
def test_template_with_json_variable_as_value(self):
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