hostname validation in InstanceSerializer (#12979)

* initial commit of hostname validation to InstanceSerializer

Co-authored-by: Cesar Francisco San Nicolas Martinez <cesarfsannicolasmartinez@gmail.com>

awx/main/tests/functional/api/test_instance.py

@@ -4,6 +4,8 @@ from awx.api.versioning import reverse
 from awx.main.models.activity_stream import ActivityStream
 from awx.main.models.ha import Instance
 
+from django.test.utils import override_settings
+
 
 INSTANCE_KWARGS = dict(hostname='example-host', cpu=6, memory=36000000000, cpu_capacity=6, mem_capacity=42)
 
@@ -54,3 +56,33 @@ def test_health_check_usage(get, post, admin_user):
     get(url=url, user=admin_user, expect=200)
     r = post(url=url, user=admin_user, expect=200)
     assert r.data['msg'] == f"Health check is running for {instance.hostname}."
+
+
+def test_custom_hostname_regex(post, admin_user):
+    url = reverse('api:instance_list')
+    with override_settings(IS_K8S=True):
+        for value in [
+            ("foo.bar.baz", 201),
+            ("f.bar.bz", 201),
+            ("foo.bar.b", 400),
+            ("a.b.c", 400),
+            ("localhost", 400),
+            ("127.0.0.1", 400),
+            ("192.168.56.101", 201),
+            ("2001:0db8:85a3:0000:0000:8a2e:0370:7334", 201),
+            ("foobar", 201),
+            ("--yoooo", 400),
+            ("$3$@foobar@#($!@#*$", 400),
+            ("999.999.999.999", 201),
+            ("0000:0000:0000:0000:0000:0000:0000:0001", 400),
+            ("whitespaces are bad for hostnames", 400),
+            ("0:0:0:0:0:0:0:1", 400),
+            ("192.localhost.domain.101", 201),
+            ("F@$%(@#$H%^(I@#^HCTQEWRFG", 400),
+        ]:
+            data = {
+                "hostname": value[0],
+                "node_type": "execution",
+                "node_state": "installed",
+            }
+            post(url=url, user=admin_user, data=data, expect=value[1])