From af08d71310862727669cb1a5041df64472857191 Mon Sep 17 00:00:00 2001
From: Guilherme Martins Crocetti <gmcrocetti@gmail.com>
Date: Wed, 1 Apr 2020 21:57:46 -0300
Subject: [PATCH] add support for RetentionInDays for LogGroup

---
 moto/cloudwatch/models.py                     |  2 +-
 moto/logs/models.py                           | 28 +++++++++----------
 .../test_cloudformation_stack_integration.py  |  1 +
 tests/test_logs/test_logs.py                  | 13 ++++-----
 4 files changed, 20 insertions(+), 24 deletions(-)

diff --git a/moto/cloudwatch/models.py b/moto/cloudwatch/models.py
index a8a1b1d1..4cd4df15 100644
--- a/moto/cloudwatch/models.py
+++ b/moto/cloudwatch/models.py
@@ -431,7 +431,7 @@ class LogGroup(BaseModel):
         properties = cloudformation_json["Properties"]
         log_group_name = properties["LogGroupName"]
         tags = properties.get("Tags", {})
-        return logs_backends[region_name].create_log_group(log_group_name, tags)
+        return logs_backends[region_name].create_log_group(log_group_name, tags, **properties)
 
 
 cloudwatch_backends = {}
diff --git a/moto/logs/models.py b/moto/logs/models.py
index 5e21d879..75560573 100644
--- a/moto/logs/models.py
+++ b/moto/logs/models.py
@@ -134,7 +134,7 @@ class LogStream:
             return None, 0
 
         events = sorted(
-            filter(filter_func, self.events), key=lambda event: event.timestamp,
+            filter(filter_func, self.events), key=lambda event: event.timestamp
         )
 
         direction, index = get_index_and_direction_from_token(next_token)
@@ -169,11 +169,7 @@ class LogStream:
         if end_index > final_index:
             end_index = final_index
         elif end_index < 0:
-            return (
-                [],
-                "b/{:056d}".format(0),
-                "f/{:056d}".format(0),
-            )
+            return ([], "b/{:056d}".format(0), "f/{:056d}".format(0))
 
         events_page = [
             event.to_response_dict() for event in events[start_index : end_index + 1]
@@ -219,7 +215,7 @@ class LogStream:
 
 
 class LogGroup:
-    def __init__(self, region, name, tags):
+    def __init__(self, region, name, tags, **kwargs):
         self.name = name
         self.region = region
         self.arn = "arn:aws:logs:{region}:1:log-group:{log_group}".format(
@@ -228,9 +224,9 @@ class LogGroup:
         self.creationTime = int(unix_time_millis())
         self.tags = tags
         self.streams = dict()  # {name: LogStream}
-        self.retentionInDays = (
-            None  # AWS defaults to Never Expire for log group retention
-        )
+        self.retention_in_days = kwargs.get(
+            "RetentionInDays"
+        )  # AWS defaults to Never Expire for log group retention
 
     def create_log_stream(self, log_stream_name):
         if log_stream_name in self.streams:
@@ -368,12 +364,12 @@ class LogGroup:
             "storedBytes": sum(s.storedBytes for s in self.streams.values()),
         }
         # AWS only returns retentionInDays if a value is set for the log group (ie. not Never Expire)
-        if self.retentionInDays:
-            log_group["retentionInDays"] = self.retentionInDays
+        if self.retention_in_days:
+            log_group["retentionInDays"] = self.retention_in_days
         return log_group
 
     def set_retention_policy(self, retention_in_days):
-        self.retentionInDays = retention_in_days
+        self.retention_in_days = retention_in_days
 
     def list_tags(self):
         return self.tags if self.tags else {}
@@ -401,10 +397,12 @@ class LogsBackend(BaseBackend):
         self.__dict__ = {}
         self.__init__(region_name)
 
-    def create_log_group(self, log_group_name, tags):
+    def create_log_group(self, log_group_name, tags, **kwargs):
         if log_group_name in self.groups:
             raise ResourceAlreadyExistsException()
-        self.groups[log_group_name] = LogGroup(self.region_name, log_group_name, tags)
+        self.groups[log_group_name] = LogGroup(
+            self.region_name, log_group_name, tags, **kwargs
+        )
         return self.groups[log_group_name]
 
     def ensure_log_group(self, log_group_name, tags):
diff --git a/tests/test_cloudformation/test_cloudformation_stack_integration.py b/tests/test_cloudformation/test_cloudformation_stack_integration.py
index e5017966..b7fe580d 100644
--- a/tests/test_cloudformation/test_cloudformation_stack_integration.py
+++ b/tests/test_cloudformation/test_cloudformation_stack_integration.py
@@ -2380,6 +2380,7 @@ def test_create_log_group_using_fntransform():
     logs_conn = boto3.client("logs", region_name="us-west-2")
     log_group = logs_conn.describe_log_groups()["logGroups"][0]
     log_group["logGroupName"].should.equal("some-log-group")
+    log_group["retentionInDays"].should.be.equal(90)
 
 
 @mock_cloudformation
diff --git a/tests/test_logs/test_logs.py b/tests/test_logs/test_logs.py
index e8f60ff0..2429d7e9 100644
--- a/tests/test_logs/test_logs.py
+++ b/tests/test_logs/test_logs.py
@@ -12,17 +12,14 @@ _logs_region = "us-east-1" if settings.TEST_SERVER_MODE else "us-west-2"
 
 
 @mock_logs
-def test_log_group_create():
+def test_create_log_group():
     conn = boto3.client("logs", "us-west-2")
-    log_group_name = "dummy"
-    response = conn.create_log_group(logGroupName=log_group_name)
 
-    response = conn.describe_log_groups(logGroupNamePrefix=log_group_name)
-    assert len(response["logGroups"]) == 1
-    # AWS defaults to Never Expire for log group retention
-    assert response["logGroups"][0].get("retentionInDays") == None
+    response = conn.create_log_group(logGroupName="dummy")
+    response = conn.describe_log_groups()
 
-    response = conn.delete_log_group(logGroupName=log_group_name)
+    response["logGroups"].should.have.length_of(1)
+    response["logGroups"][0].should_not.have.key("retentionInDays")
 
 
 @mock_logs