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Collapsed forwarding support in ATS core #5377

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a7509ed
Collapsed forwarding support in ATS core
ezelkow1 May 24, 2018
5f60f48
Add increment on open write tries to ensure we skip at some point. Op…
ezelkow1 Oct 11, 2019
663bd98
Remove commented case
ezelkow1 Oct 16, 2019
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9 changes: 1 addition & 8 deletions doc/admin-guide/files/records.config.en.rst
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Original file line number Diff line number Diff line change
Expand Up @@ -2304,14 +2304,7 @@ Dynamic Content & Content Negotiation
===== ======================================================================
``0`` Default. Disable cache and go to origin server.
``1`` Return a ``502`` error on a cache miss.
``2`` Serve stale if object's age is under
:ts:cv:`proxy.config.http.cache.max_stale_age`. Otherwise, go to
origin server.
``3`` Return a ``502`` error on a cache miss or serve stale on a cache
revalidate if object's age is under
:ts:cv:`proxy.config.http.cache.max_stale_age`. Otherwise, go to
origin server.
``4`` Return a ``502`` error on either a cache miss or on a revalidation.
``2`` Retry a cache read. This will do another cache lookup for max_open_read_retries attempts, collapsing requests
===== ======================================================================

Customizable User Response Pages
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22 changes: 18 additions & 4 deletions proxy/http/HttpCacheSM.cc
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Expand Up @@ -171,6 +171,13 @@ HttpCacheSM::state_cache_open_write(int event, void *data)
break;

case CACHE_EVENT_OPEN_WRITE_FAILED:
if (master_sm->t_state.txn_conf->cache_open_write_fail_action == HttpTransact::CACHE_WL_FAIL_ACTION_READ_RETRY) {
// Use open read retry settings, if we dont fail here we will do write_retries*read_retries nested retries
Debug("http_cache",
"state cache openwrite, cachesm, got open_write_failed, wfail is read retry, set retries to max to schedule");
open_read_tries = 0;
open_write_tries = master_sm->t_state.txn_conf->max_cache_open_write_retries + 1;
}
if (open_write_tries <= master_sm->t_state.txn_conf->max_cache_open_write_retries) {
// Retry open write;
open_write_cb = false;
Expand All @@ -196,10 +203,17 @@ HttpCacheSM::state_cache_open_write(int event, void *data)
"retrying cache open write...",
master_sm->sm_id, open_write_tries);

open_write(&cache_key, lookup_url, read_request_hdr, master_sm->t_state.cache_info.object_read,
static_cast<time_t>(
(master_sm->t_state.cache_control.pin_in_cache_for < 0) ? 0 : master_sm->t_state.cache_control.pin_in_cache_for),
retry_write, false);
if (master_sm->t_state.txn_conf->cache_open_write_fail_action != HttpTransact::CACHE_WL_FAIL_ACTION_READ_RETRY) {
open_write(
&cache_key, lookup_url, read_request_hdr, master_sm->t_state.cache_info.object_read,
(time_t)((master_sm->t_state.cache_control.pin_in_cache_for < 0) ? 0 : master_sm->t_state.cache_control.pin_in_cache_for),
retry_write, false);
} else {
Debug("http_cache", "[%" PRId64 "] [state_cache_open_write] cache open write failure INTERVAL. Saw CF, not attempting write",
master_sm->sm_id);
open_write_cb = false;
master_sm->handleEvent(CACHE_EVENT_OPEN_READ, data);
}
break;

default:
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12 changes: 10 additions & 2 deletions proxy/http/HttpSM.cc
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Expand Up @@ -2439,8 +2439,7 @@ HttpSM::state_cache_open_write(int event, void *data)
break;
} else {
t_state.cache_open_write_fail_action = t_state.txn_conf->cache_open_write_fail_action;
if (!t_state.cache_info.object_read ||
(t_state.cache_open_write_fail_action == HttpTransact::CACHE_WL_FAIL_ACTION_ERROR_ON_MISS_OR_REVALIDATE)) {
if (!t_state.cache_info.object_read) {
// cache miss, set wl_state to fail
SMDebug("http", "[%" PRId64 "] cache object read %p, cache_wl_fail_action %d", sm_id, t_state.cache_info.object_read,
t_state.cache_open_write_fail_action);
Expand All @@ -2453,6 +2452,14 @@ HttpSM::state_cache_open_write(int event, void *data)
case CACHE_EVENT_OPEN_READ:
// The write vector was locked and the cache_sm retried
// and got the read vector again.
// We might not have an object here, if so we want to retry
if (!t_state.cache_info.object_read) {
ink_assert(t_state.cache_open_write_fail_action == HttpTransact::CACHE_WL_FAIL_ACTION_READ_RETRY);
t_state.cache_lookup_result = HttpTransact::CACHE_LOOKUP_NONE;
t_state.cache_info.write_lock_state = HttpTransact::CACHE_WL_READ_RETRY;
break;
}

cache_sm.cache_read_vc->get_http_info(&t_state.cache_info.object_read);
// ToDo: Should support other levels of cache hits here, but the cache does not support it (yet)
if (cache_sm.cache_read_vc->is_ram_cache_hit()) {
Expand All @@ -2463,6 +2470,7 @@ HttpSM::state_cache_open_write(int event, void *data)

ink_assert(t_state.cache_info.object_read != nullptr);
t_state.source = HttpTransact::SOURCE_CACHE;

// clear up CACHE_LOOKUP_MISS, let Freshness function decide
// hit status
t_state.cache_lookup_result = HttpTransact::CACHE_LOOKUP_NONE;
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21 changes: 11 additions & 10 deletions proxy/http/HttpTransact.cc
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Expand Up @@ -2874,8 +2874,6 @@ HttpTransact::handle_cache_write_lock(State *s)
s->cache_info.action = CACHE_DO_NO_ACTION;
switch (s->cache_open_write_fail_action) {
case CACHE_WL_FAIL_ACTION_ERROR_ON_MISS:
case CACHE_WL_FAIL_ACTION_ERROR_ON_MISS_STALE_ON_REVALIDATE:
case CACHE_WL_FAIL_ACTION_ERROR_ON_MISS_OR_REVALIDATE:
TxnDebug("http_error", "cache_open_write_fail_action %d, cache miss, return error", s->cache_open_write_fail_action);
s->cache_info.write_status = CACHE_WRITE_ERROR;
build_error_response(s, HTTP_STATUS_BAD_GATEWAY, "Connection Failed", "connect#failed_connect");
Expand Down Expand Up @@ -2911,7 +2909,17 @@ HttpTransact::handle_cache_write_lock(State *s)
s->request_sent_time = UNDEFINED_TIME;
s->response_received_time = UNDEFINED_TIME;
s->cache_info.action = CACHE_DO_LOOKUP;
remove_ims = true;
if (!s->cache_info.object_read) {
ink_assert(s->cache_open_write_fail_action == HttpTransact::CACHE_WL_FAIL_ACTION_READ_RETRY);
s->cache_info.write_status = CACHE_WRITE_LOCK_MISS;
StateMachineAction_t next;
next = SM_ACTION_CACHE_LOOKUP;
s->next_action = next;
s->hdr_info.server_request.destroy();
TRANSACT_RETURN(next, nullptr);
return;
}
remove_ims = true;
SET_VIA_STRING(VIA_DETAIL_CACHE_TYPE, VIA_DETAIL_CACHE);
break;
case CACHE_WL_INIT:
Expand Down Expand Up @@ -7079,13 +7087,6 @@ HttpTransact::what_is_document_freshness(State *s, HTTPHdr *client_request, HTTP
uint32_t cc_mask, cooked_cc_mask;
uint32_t os_specifies_revalidate;

if (s->cache_open_write_fail_action & CACHE_WL_FAIL_ACTION_STALE_ON_REVALIDATE) {
if (is_stale_cache_response_returnable(s)) {
TxnDebug("http_match", "[what_is_document_freshness] cache_serve_stale_on_write_lock_fail, return FRESH");
return (FRESHNESS_FRESH);
}
}

//////////////////////////////////////////////////////
// If config file has a ttl-in-cache field set, //
// it has priority over any other http headers and //
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8 changes: 3 additions & 5 deletions proxy/http/HttpTransact.h
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Expand Up @@ -246,11 +246,9 @@ class HttpTransact
};

enum CacheOpenWriteFailAction_t {
CACHE_WL_FAIL_ACTION_DEFAULT = 0x00,
CACHE_WL_FAIL_ACTION_ERROR_ON_MISS = 0x01,
CACHE_WL_FAIL_ACTION_STALE_ON_REVALIDATE = 0x02,
CACHE_WL_FAIL_ACTION_ERROR_ON_MISS_STALE_ON_REVALIDATE = 0x03,
CACHE_WL_FAIL_ACTION_ERROR_ON_MISS_OR_REVALIDATE = 0x04,
CACHE_WL_FAIL_ACTION_DEFAULT = 0x00,
CACHE_WL_FAIL_ACTION_ERROR_ON_MISS = 0x01,
CACHE_WL_FAIL_ACTION_READ_RETRY = 0x02,
TOTAL_CACHE_WL_FAIL_ACTION_TYPES
};

Expand Down