From 1440709e4c5a4fa33953f63921e358eb5189057c Mon Sep 17 00:00:00 2001
From: Tom Noble <53005340+TSNoble@users.noreply.github.com>
Date: Thu, 1 Apr 2021 10:31:10 +0100
Subject: [PATCH] Enhancement/3821 (#3822)

* Add _does_event_match_pattern() to EventsBackend and use when determining whether to archive an event

* Add comment to _does_event_item_match_pattern_item()

* Expand test case for Archive EventFilter

* Apply black formatting

Co-authored-by: Tom Noble <tom.noble@bjss.com>
---
 moto/events/models.py            | 25 +++++++++++++--
 tests/test_events/test_events.py | 53 ++++++++++++++++++++++++++++++++
 2 files changed, 76 insertions(+), 2 deletions(-)

diff --git a/moto/events/models.py b/moto/events/models.py
index 6818aa3ec..eb8d41422 100644
--- a/moto/events/models.py
+++ b/moto/events/models.py
@@ -92,6 +92,24 @@ class Rule(CloudFormationModel):
             if index is not None:
                 self.targets.pop(index)
 
+    def _does_event_match_pattern(self, event, pattern):
+        if not pattern:
+            return True
+        event_pattern_pairs = [(event.get(k), v) for k, v in pattern.items()]
+        for event_item, pattern_item in event_pattern_pairs:
+            if not self._does_event_item_match_pattern_item(event_item, pattern_item):
+                return False
+        return True
+
+    def _does_event_item_match_pattern_item(self, event_item, pattern_item):
+        #  Only supports "key: [value]" filters currently
+        if not event_item:
+            return False
+        if isinstance(pattern_item, list):
+            return event_item in pattern_item
+        if isinstance(pattern_item, dict):
+            return self._does_event_match_pattern(event_item, pattern_item)
+
     def send_to_targets(self, event_bus_name, event):
         event_bus_name = event_bus_name.split("/")[-1]
         if event_bus_name != self.event_bus_name:
@@ -186,9 +204,12 @@ class Rule(CloudFormationModel):
     def _send_to_events_archive(self, resource_id, event):
         archive_name, archive_uuid = resource_id.split(":")
         archive = events_backends[self.region_name].archives.get(archive_name)
-
+        pattern = archive.event_pattern
         if archive.uuid == archive_uuid:
-            archive.events.append(event)
+            event = json.loads(json.dumps(event))
+            pattern = json.loads(pattern) if pattern else None
+            if self._does_event_match_pattern(event, pattern):
+                archive.events.append(event)
 
     def _send_to_sqs_queue(self, resource_id, event):
         from moto.sqs import sqs_backends
diff --git a/tests/test_events/test_events.py b/tests/test_events/test_events.py
index 073ba56cd..ee92e8707 100644
--- a/tests/test_events/test_events.py
+++ b/tests/test_events/test_events.py
@@ -1488,6 +1488,59 @@ def test_archive_event_with_bus_arn():
     response["SizeBytes"].should.be.greater_than(0)
 
 
+@mock_events
+def test_event_not_routed_to_archive_when_detail_does_not_match_pattern():
+    # given
+    client = boto3.client("events", "eu-central-1")
+    event_bus_arn = "arn:aws:events:eu-central-1:{}:event-bus/default".format(
+        ACCOUNT_ID
+    )
+    client.create_archive(
+        ArchiveName="archive-with-dict-filter",
+        EventSourceArn=event_bus_arn,
+        EventPattern=json.dumps({"detail": {"foo": ["bar"]}}),
+    )
+    client.create_archive(
+        ArchiveName="archive-with-list-filter",
+        EventSourceArn=event_bus_arn,
+        EventPattern=json.dumps({"source": ["foo", "bar"]}),
+    )
+
+    # when
+    event_matching_detail = {
+        "Source": "source",
+        "DetailType": "type",
+        "Detail": '{"foo": "bar"}',
+    }
+    event_not_matching_detail = {
+        "Source": "source",
+        "DetailType": "type",
+        "Detail": '{"foo": "baz"}',
+    }
+    event_matching_source_foo = {"Source": "foo", "DetailType": "type", "Detail": "{}"}
+    event_matching_source_bar = {"Source": "bar", "DetailType": "type", "Detail": "{}"}
+    event_not_matching_source = {"Source": "baz", "DetailType": "type", "Detail": "{}"}
+
+    client.put_events(
+        Entries=[
+            event_matching_detail,
+            event_not_matching_detail,
+            event_matching_source_foo,
+            event_matching_source_bar,
+            event_not_matching_source,
+        ]
+    )
+
+    # then
+    response = client.describe_archive(ArchiveName="archive-with-dict-filter")
+    response["EventCount"].should.equal(1)
+    response["SizeBytes"].should.be.greater_than(0)
+
+    response = client.describe_archive(ArchiveName="archive-with-list-filter")
+    response["EventCount"].should.equal(2)
+    response["SizeBytes"].should.be.greater_than(0)
+
+
 @mock_events
 def test_start_replay():
     # given