HttpSM: fix no_dns_forward_to_parent for cache stale

proxy/http/HttpSM.cc

@@ -4221,7 +4221,12 @@ HttpSM::do_hostdb_lookup()
 
   milestones[TS_MILESTONE_DNS_LOOKUP_BEGIN] = Thread::get_hrtime();
 
-  if (t_state.txn_conf->srv_enabled) {
+  // If directed to not look up fqdns then mark as resolved
+  if (t_state.http_config_param->no_dns_forward_to_parent && t_state.parent_result.result == PARENT_UNDEFINED) {
+    t_state.dns_info.resolved_p = true;
+    call_transact_and_set_next_state(nullptr);
+    return;
+  } else if (t_state.txn_conf->srv_enabled) {
     char d[MAXDNAME];
 
     // Look at the next_hop_scheme to determine what scheme to put in the SRV lookup

tests/gold_tests/next_hop/strategies_stale/body.gold

@@ -0,0 +1 @@
+This is the body.

tests/gold_tests/next_hop/strategies_stale/strategies_stale.test.py

@@ -0,0 +1,145 @@
+'''
+'''
+#  Licensed to the Apache Software Foundation (ASF) under one
+#  or more contributor license agreements.  See the NOTICE file
+#  distributed with this work for additional information
+#  regarding copyright ownership.  The ASF licenses this file
+#  to you under the Apache License, Version 2.0 (the
+#  "License"); you may not use this file except in compliance
+#  with the License.  You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+#  Unless required by applicable law or agreed to in writing, software
+#  distributed under the License is distributed on an "AS IS" BASIS,
+#  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+#  See the License for the specific language governing permissions and
+#  limitations under the License.
+
+Test.Summary = '''
+Test next hop selection using strategies.yaml with consistent hashing.
+'''
+
+# Define and populate MicroServer.
+#
+server = Test.MakeOriginServer("server")
+response_header = {
+    "headers":
+        "HTTP/1.1 200 OK\r\n"
+        "Connection: close\r\n"
+        "Cache-control: max-age=2\r\n"
+        "\r\n",
+    "timestamp": "1469733493.993",
+    "body": "This is the body.\n"
+}
+
+request_header = {
+    "headers":
+        f"GET /obj0 HTTP/1.1\r\n"
+        "Host: does.not.matter\r\n"  # But cannot be omitted.
+        "\r\n",
+    "timestamp": "1469733493.993",
+    "body": ""
+}
+server.addResponse("sessionlog.json", request_header, response_header)
+
+dns = Test.MakeDNServer("dns")
+
+# Define next hop trafficserver instances.
+#
+ts_nh = Test.MakeATSProcess(f"ts_nh0", use_traffic_out=False, command=f"traffic_server 2>nh_trace.log")
+ts_nh.Disk.records_config.update({
+    'proxy.config.diags.debug.enabled': 1,
+    'proxy.config.diags.debug.tags': 'http|dns',
+    'proxy.config.dns.nameservers': f"127.0.0.1:{dns.Variables.Port}",
+    'proxy.config.dns.resolv_conf': "NULL",
+})
+ts_nh.Disk.remap_config.AddLine(
+    f"map / http://127.0.0.1:{server.Variables.Port}"
+)
+
+ts = Test.MakeATSProcess("ts")
+
+ts.Disk.records_config.update({
+    'proxy.config.diags.debug.enabled': 1,
+    'proxy.config.diags.debug.tags': 'http|dns|parent|next_hop|host_statuses|hostdb',
+    'proxy.config.dns.nameservers': f"127.0.0.1:{dns.Variables.Port}",  # Only nameservers if resolv_conf NULL.
+    'proxy.config.dns.resolv_conf': "NULL",  # This defaults to /etc/resvolv.conf (OS namesevers) if not NULL.
+    'proxy.config.http.cache.http': 1,
+    'proxy.config.http.uncacheable_requests_bypass_parent': 0,
+    'proxy.config.http.no_dns_just_forward_to_parent': 1,
+    'proxy.config.http.parent_proxy.mark_down_hostdb': 0,
+    'proxy.config.http.parent_proxy.self_detect': 0,
+})
+
+ts.Disk.File(ts.Variables.CONFIGDIR + "/strategies.yaml", id="strategies", typename="ats:config")
+s = ts.Disk.strategies
+s.AddLine("groups:")
+s.AddLine("  - &g1")
+dns.addRecords(records={"next_hop0": ["127.0.0.1"]})
+s.AddLine(f"    - host: next_hop0")
+s.AddLine(f"      protocol:")
+s.AddLine(f"        - scheme: http")
+s.AddLine(f"          port: {ts_nh.Variables.port}")
+# The health check URL does not seem to be used currently.
+# s.AddLine(f"          health_check_url: http://next_hop0:{ts_nh.Variables.port}")
+s.AddLine(f"      weight: 1.0")
+s.AddLines([
+    "strategies:",
+    "  - strategy: the-strategy",
+    "    policy: consistent_hash",
+    "    hash_key: path",
+    "    go_direct: false",
+    "    parent_is_proxy: true",
+    "    ignore_self_detect: true",
+    "    groups:",
+    "      - *g1",
+    "    scheme: http"])
+
+# Fallover not currently tested.
+#
+# s.AddLines([
+# "    fallover:",
+# "      max_simple_retries: 2",
+# "      ring_mode: exhaust_ring",
+# "      response_codes:",
+# "        - 404",
+# "      health_check:",
+# "        - passive"])
+
+ts.Disk.remap_config.AddLine(
+    "map http://dummy.com http://not_used @strategy=the-strategy"
+)
+
+tr = Test.AddTestRun()
+tr.Processes.Default.StartBefore(server)
+tr.Processes.Default.StartBefore(dns)
+tr.Processes.Default.StartBefore(ts_nh)
+tr.Processes.Default.StartBefore(Test.Processes.ts)
+tr.Processes.Default.Command = 'echo start TS, HTTP server, DNS server and next hop TSes'
+tr.Processes.Default.ReturnCode = 0
+
+tr = Test.AddTestRun()
+tr.Processes.Default.Command = (
+    f'curl --verbose --proxy 127.0.0.1:{ts.Variables.port} http://dummy.com/obj0'
+)
+tr.Processes.Default.Streams.stdout = "body.gold"
+tr.Processes.Default.ReturnCode = 0
+
+# Wait enough time that the item should be aged out of the cache.
+tr = Test.AddTestRun("Wait for cached object to be stale.")
+tr.Processes.Default.Command = "sleep 4"
+tr.StillRunningAfter = ts
+
+# Request should come back as 200
+tr = Test.AddTestRun()
+tr.Processes.Default.Command = (
+    f'curl --verbose --proxy 127.0.0.1:{ts.Variables.port} http://dummy.com/obj0'
+)
+tr.Processes.Default.Streams.stdout = "body.gold"
+tr.Processes.Default.ReturnCode = 0
+
+tr = Test.AddTestRun()
+tr.Processes.Default.Command = "grep 'Stale in cache' nh_trace*.log | cat"
+tr.Processes.Default.Streams.stdout.Content = Testers.ContainsExpression("Stale in cache", "Expected stale content to be evaluated")
+tr.Processes.Default.ReturnCode = 0