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The following commit(s) were added to refs/heads/master by this push:
new e5090a8 TS-4701: Add a new latched parent selection strategy.
e5090a8 is described below
commit e5090a83125046b7af0ad8c802b7408a431d9968
Author: John J. Rushford <jrushf...@apache.org>
AuthorDate: Thu Oct 6 20:22:59 2016 +0000
TS-4701: Add a new latched parent selection strategy.
---
doc/admin-guide/files/parent.config.en.rst | 7 ++++
proxy/ParentRoundRobin.cc | 11 ++++-
proxy/ParentRoundRobin.h | 1 +
proxy/ParentSelection.cc | 66 ++++++++++++++++++++++++++++++
proxy/ParentSelection.h | 1 +
5 files changed, 84 insertions(+), 2 deletions(-)
diff --git a/doc/admin-guide/files/parent.config.en.rst
b/doc/admin-guide/files/parent.config.en.rst
index c3df065..93238d7 100644
--- a/doc/admin-guide/files/parent.config.en.rst
+++ b/doc/admin-guide/files/parent.config.en.rst
@@ -207,6 +207,13 @@ The following list shows the possible actions and their
allowed values.
The other traffic is unaffected. Once the downed parent becomes
available, the traffic distribution returns to the pre-down
state.
+ - ``latched`` - The first parent in the list is marked as primary and is
+ always chosen until connection errors cause it to be marked down. When
+ this occurs the next parent in the list then becomes primary. The
primary
+ will wrap back to the first parent in the list when it is the last parent
+ in the list and is marked down due to a connection error. Newly chosen
+ primary parents marked as unavailable will then be restored if the
failure
+ retry time has elapsed and the transaction using the primary succeeds.
.. _parent-config-format-go-direct:
diff --git a/proxy/ParentRoundRobin.cc b/proxy/ParentRoundRobin.cc
index 93a3e5a..f7a40b8 100644
--- a/proxy/ParentRoundRobin.cc
+++ b/proxy/ParentRoundRobin.cc
@@ -25,6 +25,7 @@
ParentRoundRobin::ParentRoundRobin(ParentRecord *parent_record, ParentRR_t
_round_robin_type)
{
round_robin_type = _round_robin_type;
+ latched_parent = 0;
if (is_debug_tag_set("parent_select")) {
switch (round_robin_type) {
@@ -37,6 +38,9 @@ ParentRoundRobin::ParentRoundRobin(ParentRecord
*parent_record, ParentRR_t _roun
case P_HASH_ROUND_ROBIN:
Debug("parent_select", "Using a round robin parent selection strategy of
type P_HASH_ROUND_ROBIN.");
break;
+ case P_LATCHED_ROUND_ROBIN:
+ Debug("parent_select", "Using a round robin parent selection strategy of
type P_LATCHED_ROUND_ROBIN.");
+ break;
default:
// should never see this, there is a problem if you do.
Debug("parent_select", "Using a round robin parent selection strategy of
type UNKNOWN TYPE.");
@@ -97,13 +101,16 @@ ParentRoundRobin::selectParent(const ParentSelectionPolicy
*policy, bool first_c
case P_NO_ROUND_ROBIN:
cur_index = result->start_parent = 0;
break;
+ case P_LATCHED_ROUND_ROBIN:
+ cur_index = result->start_parent = latched_parent;
+ break;
default:
ink_release_assert(0);
}
}
} else {
// Move to next parent due to failure
- cur_index = (result->last_parent + 1) % result->rec->num_parents;
+ latched_parent = cur_index = (result->last_parent + 1) %
result->rec->num_parents;
// Check to see if we have wrapped around
if ((unsigned int)cur_index == result->start_parent) {
@@ -158,7 +165,7 @@ ParentRoundRobin::selectParent(const ParentSelectionPolicy
*policy, bool first_c
Debug("parent_select", "Chosen parent = %s.%d", result->hostname,
result->port);
return;
}
- cur_index = (cur_index + 1) % result->rec->num_parents;
+ latched_parent = cur_index = (cur_index + 1) % result->rec->num_parents;
} while ((unsigned int)cur_index != result->start_parent);
if (result->rec->go_direct == true && result->rec->parent_is_proxy == true) {
diff --git a/proxy/ParentRoundRobin.h b/proxy/ParentRoundRobin.h
index 57b6832..818e26c 100644
--- a/proxy/ParentRoundRobin.h
+++ b/proxy/ParentRoundRobin.h
@@ -35,6 +35,7 @@
class ParentRoundRobin : public ParentSelectionStrategy
{
ParentRR_t round_robin_type;
+ int latched_parent;
public:
ParentRoundRobin(ParentRecord *_parent_record, ParentRR_t _round_robin_type);
diff --git a/proxy/ParentSelection.cc b/proxy/ParentSelection.cc
index 91ae19e..332cdae 100644
--- a/proxy/ParentSelection.cc
+++ b/proxy/ParentSelection.cc
@@ -543,6 +543,8 @@ ParentRecord::Init(matcher_line *line_info)
round_robin = P_NO_ROUND_ROBIN;
} else if (strcasecmp(val, "consistent_hash") == 0) {
round_robin = P_CONSISTENT_HASH;
+ } else if (strcasecmp(val, "latched") == 0) {
+ round_robin = P_LATCHED_ROUND_ROBIN;
} else {
round_robin = P_NO_ROUND_ROBIN;
errPtr = "invalid argument to round_robin directive";
@@ -681,6 +683,7 @@ ParentRecord::Init(matcher_line *line_info)
case P_NO_ROUND_ROBIN:
case P_STRICT_ROUND_ROBIN:
case P_HASH_ROUND_ROBIN:
+ case P_LATCHED_ROUND_ROBIN:
TSDebug("parent_select", "allocating ParentRoundRobin() lookup strategy.");
selection_strategy = new ParentRoundRobin(this, round_robin);
break;
@@ -1282,6 +1285,69 @@
EXCLUSIVE_REGRESSION_TEST(PARENTSELECTION)(RegressionTest * /* t ATS_UNUSED */,
sleep(1);
RE(verify(result, PARENT_FAIL, NULL, 80), 177);
+ // Test 178
+ tbl[0] = '\0';
+ ST(178);
+ T("dest_domain=rabbit.net
parent=fuzzy:80|1.0;fluffy:80|1.0;furry:80|1.0;frisky:80|1.0 "
+ "round_robin=latched go_direct=false\n");
+ REBUILD;
+ REINIT;
+ br(request, "i.am.rabbit.net");
+ FP;
+ sleep(1);
+ RE(verify(result, PARENT_SPECIFIED, "fuzzy", 80), 178);
+
+ params->markParentDown(result); // fuzzy is down
+
+ // Test 179
+ ST(179);
+ REINIT;
+ br(request, "i.am.rabbit.net");
+ FP;
+ sleep(1);
+ RE(verify(result, PARENT_SPECIFIED, "fluffy", 80), 179);
+
+ params->markParentDown(result); // fluffy is down
+
+ // Test 180
+ ST(180);
+ REINIT;
+ br(request, "i.am.rabbit.net");
+ FP;
+ sleep(1);
+ RE(verify(result, PARENT_SPECIFIED, "furry", 80), 180);
+
+ params->markParentDown(result); // furry is down
+
+ // Test 181
+ ST(181);
+ REINIT;
+ br(request, "i.am.rabbit.net");
+ FP;
+ sleep(1);
+ RE(verify(result, PARENT_SPECIFIED, "frisky", 80), 181);
+
+ params->markParentDown(result); // frisky is down and we should be back on
fuzzy.
+
+ // Test 182
+ ST(182);
+ REINIT;
+ br(request, "i.am.rabbit.net");
+ FP;
+ sleep(1);
+ RE(verify(result, PARENT_FAIL, NULL, 80), 182);
+
+ // wait long enough so that fuzzy is retryable.
+ sleep(params->policy.ParentRetryTime - 1);
+
+ // Test 183
+ ST(183);
+ REINIT;
+ br(request, "i.am.rabbit.net");
+ FP;
+ sleep(1);
+ RE(verify(result, PARENT_SPECIFIED, "fuzzy", 80), 183);
+
delete request;
delete result;
delete params;
diff --git a/proxy/ParentSelection.h b/proxy/ParentSelection.h
index 3fd2826..78c0942 100644
--- a/proxy/ParentSelection.h
+++ b/proxy/ParentSelection.h
@@ -64,6 +64,7 @@ enum ParentRR_t {
P_STRICT_ROUND_ROBIN,
P_HASH_ROUND_ROBIN,
P_CONSISTENT_HASH,
+ P_LATCHED_ROUND_ROBIN,
};
enum ParentRetry_t {
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