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Cleanup serving stale while origin server down
1 parent da39efa commit bfc2ef4

3 files changed

Lines changed: 172 additions & 16 deletions

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‎src/proxy/http/HttpTransact.cc‎

Lines changed: 3 additions & 16 deletions
Original file line numberDiff line numberDiff line change
@@ -2902,23 +2902,10 @@ HttpTransact::HandleCacheOpenReadHit(State *s)
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find_server_and_update_current_info(s);
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// We do not want to try to revalidate documents if we think
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// the server is down due to the something report problem
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//
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// Note: we only want to skip origin servers because 1)
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// parent proxies have their own negative caching
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// scheme & 2) If we skip down parents, every page
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// we serve is potentially stale
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//
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if (s->current.request_to == ResolveInfo::ORIGIN_SERVER && is_server_negative_cached(s) && response_returnable == true &&
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is_stale_cache_response_returnable(s) == true) {
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server_up = false;
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update_current_info(&s->current, nullptr, ResolveInfo::UNDEFINED_LOOKUP, true);
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TxnDbg(dbg_ctl_http_trans, "CacheOpenReadHit - server_down, returning stale document");
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}
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// a parent lookup could come back as ParentResultType::FAIL if in parent.config, go_direct == false and
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// For origin servers (ResolveInfo::ORIGIN_SERVER): OSDNSLookup handles serving stale when all origin servers are down.
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// For parent proxies: a parent lookup could come back as ParentResultType::FAIL if in parent.config, go_direct == false and
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// there are no available parents (all down).
2921-
else if (s->current.request_to == ResolveInfo::HOST_NONE && s->parent_result.result == ParentResultType::FAIL) {
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if (s->current.request_to == ResolveInfo::HOST_NONE && s->parent_result.result == ParentResultType::FAIL) {
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if (response_returnable == true && is_stale_cache_response_returnable(s) == true) {
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server_up = false;
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update_current_info(&s->current, nullptr, ResolveInfo::UNDEFINED_LOOKUP, true);

‎tests/gold_tests/cache/proxy_serve_stale.test.py‎

Lines changed: 3 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -22,3 +22,6 @@
2222

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# Verify that stale content is served when the parent is down.
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Test.ATSReplayTest(replay_file="replay/proxy_serve_stale.replay.yaml")
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# Verify that stale content is served when the origin server is down.
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Test.ATSReplayTest(replay_file="replay/proxy_serve_stale_origin_down.replay.yaml")

‎tests/gold_tests/cache/replay/proxy_serve_stale_origin_down.replay.yaml‎

Lines changed: 166 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,166 @@
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# Licensed to the Apache Software Foundation (ASF) under one
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# or more contributor license agreements. See the NOTICE file
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# distributed with this work for additional information
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# regarding copyright ownership. The ASF licenses this file
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# to you under the Apache License, Version 2.0 (the
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# "License"); you may not use this file except in compliance
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# with the License. You may obtain a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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#
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# This replay file assumes that caching is enabled and
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# proxy.config.http.cache.ignore_client_cc_max_age is set to 0 so that we can
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# test max-age in the client requests.
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#
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meta:
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version: "1.0"
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autest:
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description: 'Verify that stale content is served when the origin server is down'
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dns:
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name: 'dns-serve-stale-origin-down'
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records:
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backend.example.com: ["127.0.0.1"]
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server:
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name: 'server-serve-stale-origin-down'
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client:
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name: 'client-serve-stale-origin-down'
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ats:
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name: 'ts-serve-stale-origin-down'
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process_config:
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enable_cache: true
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records_config:
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proxy.config.diags.debug.enabled: 1
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proxy.config.diags.debug.tags: 'cache|http|dns|hostdb'
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proxy.config.http.cache.max_stale_age: 10
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proxy.config.http.connect.down.policy: 4
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proxy.config.http.connect_attempts_timeout: 1
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proxy.config.http.connect_attempts_rr_retries: 0
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proxy.config.http.connect_attempts_max_retries: 1
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proxy.config.http.connect_attempts_max_retries_down_server: 0
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proxy.config.http.down_server.cache_time: 5
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remap_config:
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- from: "http://example.com/"
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to: "http://backend.example.com:{SERVER_HTTP_PORT}/"
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plugin_config:
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- 'xdebug.so --enable=x-cache,x-cache-key,via'
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sessions:
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- transactions:
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# 1. Cache object
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# cache-key: /path/a/
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# cache: miss
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# origin server: up
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- client-request:
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method: "GET"
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version: "1.1"
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url: /path/a/
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headers:
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fields:
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- [ Host, example.com ]
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- [ x-debug, "x-cache,x-cache-key,via" ]
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- [ uuid, a-1 ]
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server-response:
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status: 200
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headers:
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fields:
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- [ Content-Length, 16]
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- [ Cache-Control, "public, max-age=1"]
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proxy-response:
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status: 200
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headers:
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fields:
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- [ X-Cache, { value: miss, as: equal } ]
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# 2. Make the origin server down
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# cache-key: /path/b/
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# cache: miss
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# origin server: down
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- client-request:
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method: "GET"
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version: "1.1"
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url: /path/b/
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headers:
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fields:
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- [ Host, example.com ]
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- [ x-debug, "x-cache,x-cache-key,via" ]
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- [ uuid, b-1 ]
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server-response:
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on_connect: reset
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proxy-response:
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status: 502
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headers:
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fields:
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- [ X-Cache, { value: miss, as: equal } ]
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# 3. Serve stale while down_serve.cache_time
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# cache-key: /path/a/
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# cache: stale
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# origin server: down (cached)
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- client-request:
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delay: 2s
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method: "GET"
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version: "1.1"
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url: /path/a/
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headers:
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fields:
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- [ Host, example.com ]
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- [ x-debug, "x-cache,x-cache-key,via" ]
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- [ uuid, a-2 ]
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proxy-request:
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expect: absent
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server-response:
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on_connect: reset
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proxy-response:
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status: 200
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headers:
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fields:
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- [ X-Cache, { value: hit-stale, as: equal } ]
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# 4. Revalidate stale contents
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# cache-key: /path/a/
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# cache: stale
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# origin server: up
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- client-request:
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delay: 5s
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method: "GET"
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version: "1.1"
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url: /path/a/
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headers:
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fields:
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- [ Host, example.com ]
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- [ x-debug, "x-cache,x-cache-key,via" ]
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- [ uuid, a-99 ]
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server-response:
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status: 304
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proxy-response:
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status: 200
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headers:
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fields:
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- [ X-Cache, { value: hit-stale, as: equal } ]
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