Parent Select Plugin

include/ts/apidefs.h.in

@@ -1303,6 +1303,26 @@ extern tsapi const char *const TS_PROTO_TAG_IPV6;
  */
 #define TS_NULL_MLOC ((TSMLoc)0)
 
+/* --------------------------------------------------------------------------
+   HostStatus types */
+
+typedef enum {
+  TS_HOST_STATUS_INIT,
+  TS_HOST_STATUS_DOWN,
+  TS_HOST_STATUS_UP,
+} TSHostStatus;
+
+/* MUST match proxy/HostStatus.h Reason.
+ * If a value is added here, it MUST be added there with the same value.
+ */
+typedef enum {
+  TS_HOST_STATUS_ACTIVE      = 0x1,
+  TS_HOST_STATUS_LOCAL       = 0x2,
+  TS_HOST_STATUS_MANUAL      = 0x4,
+  TS_HOST_STATUS_SELF_DETECT = 0x8,
+  TS_HOST_STATUS_ALL         = 0xf,
+} TSHostStatusReason;
+
 /* --------------------------------------------------------------------------
    Interface for the UUID APIs. https://www.ietf.org/rfc/rfc4122.txt. */
 typedef enum {

include/ts/parentselectdefs.h

@@ -0,0 +1,60 @@
+/** @file
+
+  Traffic Server SDK API header file
+
+  @section license License
+
+  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.
+
+  @section developers Developers
+
+  NextHop plugin interface.
+
+ */
+
+#pragma once
+
+#include <string.h>
+#include <netinet/in.h>
+
+// Plugins may set this to indicate how to retry.
+//
+// If handled is false, then no plugin set it, and Core will proceed to do its own thing.
+//
+// If handled is true, core will not do any parent processing, markdown, or anything else,
+// but will use the values in this for whether to use the existing response or make another request,
+// and what that request should look like.
+//
+// See the API functions which take this for ownership requirements of pointers, like hostname.
+//
+// hostname is the hostname to use for the next request. It must be null-terminated.
+// hostname_len is the length of hostname, not including the terminating null.
+//
+typedef struct {
+  // TODO this shouldn't be necessary - plugins should manipulate the response as they see fit,
+  // core shouldn't "know" if it was a "success" or "failure," only the response or retry data/action.
+  // But for now, core needs to know, for reasons.
+  const char *hostname;
+  size_t hostname_len;
+  in_port_t port;
+  bool fail;
+  bool is_retry;
+  bool nextHopExists;
+  bool responseIsRetryable;
+  bool goDirect;
+  bool parentIsProxy;
+} TSResponseAction;

include/ts/ts.h

@@ -30,6 +30,7 @@
 #pragma once
 
 #include <ts/apidefs.h>
+#include <ts/parentselectdefs.h>
 
 #ifdef __cplusplus
 extern "C" {
@@ -2601,6 +2602,12 @@ tsapi TSReturnCode TSRemapFromUrlGet(TSHttpTxn txnp, TSMLoc *urlLocp);
 //
 tsapi TSReturnCode TSRemapToUrlGet(TSHttpTxn txnp, TSMLoc *urlLocp);
 
+// Override response behavior, and hard-set the state machine for whether to succeed or fail, and how.
+tsapi void TSHttpTxnResponseActionSet(TSHttpTxn txnp, TSResponseAction *action);
+
+// Get the overridden response behavior set by previously called plugins.
+tsapi void TSHttpTxnResponseActionGet(TSHttpTxn txnp, TSResponseAction *action);
+
 /*
  * Get a TSIOBufferReader to read the buffered body. The return value needs to be freed.
  */
@@ -2641,6 +2648,27 @@ tsapi TSReturnCode TSHttpTxnClientStreamIdGet(TSHttpTxn txnp, uint64_t *stream_i
  */
 tsapi TSReturnCode TSHttpTxnClientStreamPriorityGet(TSHttpTxn txnp, TSHttpPriority *priority);
 
+/*
+ * Returns TS_SUCCESS if hostname is this machine, as used for parent and remap self-detection.
+ * Returns TS_ERROR if hostname is not this machine.
+ */
+tsapi TSReturnCode TSHostnameIsSelf(const char *hostname, size_t hostname_len);
+
+/*
+ * Gets the status of hostname in the outparam status, and the status reason in the outparam reason.
+ * The reason is a logical-or combination of the reasons in TSHostStatusReason.
+ * If either outparam is null, it will not be set and no error will be returned.
+ * Returns TS_SUCCESS if the hostname was a parent and existed in the HostStatus, else TS_ERROR.
+ */
+tsapi TSReturnCode TSHostStatusGet(const char *hostname, const size_t hostname_len, TSHostStatus *status, unsigned int *reason);
+
+/*
+ * Sets the status of hostname in status, down_time, and reason.
+ * The reason is a logical-or combination of the reasons in TSHostStatusReason.
+ */
+tsapi void TSHostStatusSet(const char *hostname, const size_t hostname_len, TSHostStatus status, const unsigned int down_time,
+                           const unsigned int reason);
+
 #ifdef __cplusplus
 }
 #endif /* __cplusplus */

iocore/cache/test/stub.cc

@@ -157,7 +157,7 @@ ts::svtoi(TextView src, TextView *out, int base)
 }
 
 void
-HostStatus::setHostStatus(const char *name, HostStatus_t status, const unsigned int down_time, const unsigned int reason)
+HostStatus::setHostStatus(const char *name, TSHostStatus status, const unsigned int down_time, const unsigned int reason)
 {
 }
 

iocore/utils/I_Machine.h

@@ -83,6 +83,7 @@ struct Machine {
   /// @return The global instance of this class.
   static self *instance();
   bool is_self(const char *name);
+  bool is_self(const char *name, int name_len);
   bool is_self(const IpAddr *ipaddr);
   bool is_self(struct sockaddr const *addr);
   void insert_id(char *id);

iocore/utils/Machine.cc

@@ -32,9 +32,8 @@
 #endif
 
 static void
-make_to_lower_case(const char *name, char *lower_case_name, int buf_len)
+make_to_lower_case(const char *name, int name_len, char *lower_case_name, int buf_len)
 {
-  int name_len = strlen(name);
   int i;
 
   if (name_len > (buf_len - 1)) {
@@ -238,14 +237,20 @@ Machine::~Machine()
 
 bool
 Machine::is_self(const char *name)
+{
+  return is_self(name, strlen(name));
+}
+
+bool
+Machine::is_self(const char *name, int name_len)
 {
   char lower_case_name[TS_MAX_HOST_NAME_LEN + 1] = {0};
 
-  if (name == nullptr) {
+  if (name_len == 0) {
     return false;
   }
 
-  make_to_lower_case(name, lower_case_name, sizeof(lower_case_name));
+  make_to_lower_case(name, name_len, lower_case_name, sizeof(lower_case_name));
 
   return machine_id_strings.find(lower_case_name) != machine_id_strings.end();
 }
@@ -279,7 +284,7 @@ Machine::insert_id(char *id)
 {
   char lower_case_name[TS_MAX_HOST_NAME_LEN + 1] = {0};
 
-  make_to_lower_case(id, lower_case_name, sizeof(lower_case_name));
+  make_to_lower_case(id, strlen(id), lower_case_name, sizeof(lower_case_name));
   machine_id_strings.emplace(lower_case_name);
 }
 

plugins/Makefile.am

@@ -66,6 +66,7 @@ include experimental/custom_redirect/Makefile.inc
 include experimental/fq_pacing/Makefile.inc
 include experimental/geoip_acl/Makefile.inc
 include experimental/header_freq/Makefile.inc
+include experimental/parent_select/Makefile.inc
 include experimental/hook-trace/Makefile.inc
 include experimental/icap/Makefile.inc
 include experimental/inliner/Makefile.inc

plugins/experimental/parent_select/Makefile.inc

@@ -0,0 +1,29 @@
+#  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.
+
+pkglib_LTLIBRARIES += experimental/parent_select/parent_select.la
+
+experimental_parent_select_parent_select_la_SOURCES = \
+  experimental/parent_select/strategy.cc \
+  experimental/parent_select/healthstatus.cc \
+  experimental/parent_select/consistenthash.cc \
+  experimental/parent_select/consistenthash_config.cc \
+  experimental/parent_select/parent_select.cc
+
+experimental_parent_select_parent_select_la_LDFLAGS = \
+  $(AM_LDFLAGS)
+
+AM_CPPFLAGS += @YAMLCPP_INCLUDES@ $(TS_INCLUDES)