From 22c984cd8a9a56769a6941541221495a7734127d Mon Sep 17 00:00:00 2001
From: bolkedebruin <bolkedebruin@users.noreply.github.com>
Date: Tue, 7 May 2019 22:42:28 +0200
Subject: [PATCH] [AIRFLOW-4472] Use json.dumps/loads for templating lineage
 data (#5253)

jinja2 cannot use dict/lists as templates hence converting
it to json solves this while keeping complexity down.

(cherry picked from commit a6daeb544e815fe350a96d24ae3bb14aee4079a7)
---
 airflow/lineage/datasets.py    | 11 +++++++++--
 airflow/models/baseoperator.py |  4 ++--
 2 files changed, 11 insertions(+), 4 deletions(-)

diff --git a/airflow/lineage/datasets.py b/airflow/lineage/datasets.py
index 260277065b6f0b..3d61e5d3f48436 100644
--- a/airflow/lineage/datasets.py
+++ b/airflow/lineage/datasets.py
@@ -16,6 +16,7 @@
 # KIND, either express or implied.  See the License for the
 # specific language governing permissions and limitations
 # under the License.
+import json
 import six
 
 from typing import List
@@ -62,7 +63,11 @@ def __getattr__(self, attr):
         if attr in self.attributes:
             if self.context:
                 env = Environment()
-                return env.from_string(self._data.get(attr)).render(**self.context)
+                # dump to json here in order to be able to manage dicts and lists
+                rendered = env.from_string(
+                    json.dumps(self._data.get(attr))
+                ).render(**self.context)
+                return json.loads(rendered)
 
             return self._data.get(attr)
 
@@ -82,7 +87,9 @@ def as_dict(self):
         env = Environment()
         if self.context:
             for key, value in six.iteritems(attributes):
-                attributes[key] = env.from_string(value).render(**self.context)
+                attributes[key] = json.loads(
+                    env.from_string(json.dumps(value)).render(**self.context)
+                )
 
         d = {
             "typeName": self.type_name,
diff --git a/airflow/models/baseoperator.py b/airflow/models/baseoperator.py
index b61c9808d442a3..52037c56a756c3 100644
--- a/airflow/models/baseoperator.py
+++ b/airflow/models/baseoperator.py
@@ -428,8 +428,8 @@ def __init__(
         self._log = logging.getLogger("airflow.task.operators")
 
         # lineage
-        self.inlets = []  # type: Iterable[DataSet]
-        self.outlets = []  # type: Iterable[DataSet]
+        self.inlets = []   # type: List[DataSet]
+        self.outlets = []  # type: List[DataSet]
         self.lineage_data = None
 
         self._inlets = {