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zwoop pushed a commit to branch 9.2.x
in repository https://gitbox.apache.org/repos/asf/trafficserver.git
The following commit(s) were added to refs/heads/9.2.x by this push:
new b1eed52a4 Serve stale content when DNS lookup fails (#8484)
b1eed52a4 is described below
commit b1eed52a4afa4fb191f92a665f3fb866729299a6
Author: Serris Lew <[email protected]>
AuthorDate: Tue Jan 11 10:36:19 2022 -0800
Serve stale content when DNS lookup fails (#8484)
* serve stale when dns lookups fails
* updated max-age in autest to run shorter
Co-authored-by: Serris Lew <[email protected]>
(cherry picked from commit 85be28242f02dd39b86766f4e61c7cb55a8d5e11)
---
proxy/http/HttpTransact.cc | 18 +++--
.../proxy_protocol/gold/serve_stale_dns_fail.gold | 57 ++++++++++++++++
.../proxy_serve_stale_dns_fail.test.py | 79 ++++++++++++++++++++++
3 files changed, 144 insertions(+), 10 deletions(-)
diff --git a/proxy/http/HttpTransact.cc b/proxy/http/HttpTransact.cc
index 2c8d260f0..0787e03c9 100644
--- a/proxy/http/HttpTransact.cc
+++ b/proxy/http/HttpTransact.cc
@@ -1970,6 +1970,13 @@ HttpTransact::OSDNSLookup(State *s)
} else {
TxnDebug("http_seq", "[HttpTransact::OSDNSLookup] DNS Lookup
unsuccessful");
+ // Even with unsuccessful DNS lookup, return stale object from cache if
applicable
+ if (is_cache_hit(s->cache_lookup_result) &&
is_stale_cache_response_returnable(s)) {
+ s->source = SOURCE_CACHE;
+ TxnDebug("http_trans", "[hscno] serving stale doc to client");
+ build_response_from_cache(s, HTTP_WARNING_CODE_REVALIDATION_FAILED);
+ return;
+ }
// output the DNS failure error message
SET_VIA_STRING(VIA_DETAIL_TUNNEL, VIA_DETAIL_TUNNEL_NO_FORWARD);
// Set to internal server error so later logging will pick up
SQUID_LOG_ERR_DNS_FAIL
@@ -2670,16 +2677,7 @@ HttpTransact::HandleCacheOpenReadHitFreshness(State *s)
SET_VIA_STRING(VIA_CACHE_RESULT, VIA_IN_CACHE_STALE);
}
- if (!s->force_dns) { // If DNS is not performed before
- if (need_to_revalidate(s)) {
- TRANSACT_RETURN(SM_ACTION_API_CACHE_LOOKUP_COMPLETE,
- CallOSDNSLookup); // content needs to be revalidated and
we did not perform a dns ....calling DNS lookup
- } else { // document can be served can cache
- TRANSACT_RETURN(SM_ACTION_API_CACHE_LOOKUP_COMPLETE,
HttpTransact::HandleCacheOpenReadHit);
- }
- } else { // we have done dns . Its up to HandleCacheOpenReadHit to decide to
go OS or serve from cache
- TRANSACT_RETURN(SM_ACTION_API_CACHE_LOOKUP_COMPLETE,
HttpTransact::HandleCacheOpenReadHit);
- }
+ TRANSACT_RETURN(SM_ACTION_API_CACHE_LOOKUP_COMPLETE,
HttpTransact::HandleCacheOpenReadHit);
}
///////////////////////////////////////////////////////////////////////////////
diff --git a/tests/gold_tests/proxy_protocol/gold/serve_stale_dns_fail.gold
b/tests/gold_tests/proxy_protocol/gold/serve_stale_dns_fail.gold
new file mode 100644
index 000000000..77271e28e
--- /dev/null
+++ b/tests/gold_tests/proxy_protocol/gold/serve_stale_dns_fail.gold
@@ -0,0 +1,57 @@
+``
+> GET / HTTP/1.1
+> Host: ``
+> User-Agent: curl/``
+> Accept: */*
+``
+< HTTP/1.1 200 OK
+< Server: ATS``
+< Accept-Ranges: bytes
+< Content-Length: 6
+< Cache-Control: public, max-age=5
+< Expires: ``
+< Age: ``
+< Date: ``
+< Connection: keep-alive
+``
+> GET / HTTP/1.1
+> Host: ``
+> User-Agent: curl/``
+> Accept: */*
+``
+< HTTP/1.1 500 Cannot find server.
+< Date: ``
+< Server: ATS``
+< Cache-Control: no-store
+< Content-Type: ``
+< Content-Language: ``
+< Content-Length: ``
+< Connection: keep-alive
+``
+> GET / HTTP/1.1
+> Host: ``
+> User-Agent: curl/``
+> Accept: */*
+``
+< HTTP/1.1 200 OK
+< Server: ATS``
+< Accept-Ranges: bytes
+< Content-Length: 6
+< Cache-Control: public, max-age=5
+< Age: ``
+< Date: ``
+< Connection: keep-alive
+``
+> GET / HTTP/1.1
+> Host: ``
+> User-Agent: curl/``
+> Accept: */*
+``
+< HTTP/1.1 500 Cannot find server.
+< Date: ``
+< Server: ATS``
+< Cache-Control: no-store
+< Content-Type: ``
+< Content-Language: ``
+< Content-Length: ``
+``
\ No newline at end of file
diff --git a/tests/gold_tests/proxy_protocol/proxy_serve_stale_dns_fail.test.py
b/tests/gold_tests/proxy_protocol/proxy_serve_stale_dns_fail.test.py
new file mode 100644
index 000000000..4334dd5c7
--- /dev/null
+++ b/tests/gold_tests/proxy_protocol/proxy_serve_stale_dns_fail.test.py
@@ -0,0 +1,79 @@
+'''
+Test proxy serving stale content when DNS lookup fails
+'''
+# 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.ContinueOnFail = True
+# Set up hierarchical caching processes
+ts_child = Test.MakeATSProcess("ts_child")
+ts_parent = Test.MakeATSProcess("ts_parent")
+server_name = "http://unknown.domain.com/";
+
+Test.testName = "STALE"
+
+# Config child proxy to route to parent proxy
+ts_child.Disk.records_config.update({
+ 'proxy.config.url_remap.pristine_host_hdr': 1,
+ 'proxy.config.http.cache.max_stale_age': 10,
+ 'proxy.config.http.parent_proxy.self_detect': 0,
+})
+ts_child.Disk.parent_config.AddLine(
+ f'dest_domain=. parent=localhost:{ts_parent.Variables.port}
round_robin=consistent_hash go_direct=false'
+)
+ts_child.Disk.remap_config.AddLine(
+ f'map http://localhost:{ts_child.Variables.port} {server_name}'
+)
+
+# Configure parent proxy
+ts_parent.Disk.records_config.update({
+ 'proxy.config.url_remap.pristine_host_hdr': 1,
+ 'proxy.config.http.cache.max_stale_age': 10,
+})
+ts_parent.Disk.remap_config.AddLine(
+ f'map http://localhost:{ts_parent.Variables.port} {server_name}'
+)
+ts_parent.Disk.remap_config.AddLine(
+ f'map {server_name} {server_name}'
+)
+
+# Object to push to proxies
+stale_5 = "HTTP/1.1 200 OK\nServer: ATS/10.0.0\nAccept-Ranges:
bytes\nContent-Length: 6\nCache-Control: public, max-age=5\n\nCACHED"
+stale_10 = "HTTP/1.1 200 OK\nServer: ATS/10.0.0\nAccept-Ranges:
bytes\nContent-Length: 6\nCache-Control: public, max-age=10\n\nCACHED"
+
+
+# Testing scenarios
+child_curl_request = (
+ # Test child serving stale with failed DNS OS lookup
+ f'curl -X PUSH -d "{stale_5}"
"http://localhost:{ts_child.Variables.port}";;'
+ f'curl -X PUSH -d "{stale_10}"
"http://localhost:{ts_parent.Variables.port}";;'
+ f'sleep 7; curl -s -v http://localhost:{ts_child.Variables.port};'
+ f'sleep 15; curl -s -v http://localhost:{ts_child.Variables.port};'
+ # Test parent serving stale with failed DNS OS lookup
+ f'curl -X PUSH -d "{stale_5}"
"http://localhost:{ts_parent.Variables.port}";;'
+ f'sleep 7; curl -s -v http://localhost:{ts_parent.Variables.port};'
+ f'sleep 15; curl -s -v http://localhost:{ts_parent.Variables.port};'
+)
+
+# Test case for when parent server is down but child proxy can serve cache
object
+tr = Test.AddTestRun()
+tr.Processes.Default.Command = child_curl_request
+tr.Processes.Default.ReturnCode = 0
+tr.Processes.Default.StartBefore(ts_child)
+tr.Processes.Default.StartBefore(ts_parent)
+tr.Processes.Default.Streams.stderr = "gold/serve_stale_dns_fail.gold"
+tr.StillRunningAfter = ts_child
+tr.StillRunningAfter = ts_parent
