Merge github.com:grpc/grpc into epex4

19 files changed, 241 insertions, 196 deletions

diff --git a/src/compiler/python_generator.cc b/src/compiler/python_generator.cc
index 2649c1688d..50ee54abff 100644
--- a/src/compiler/python_generator.cc
+++ b/src/compiler/python_generator.cc
@@ -101,6 +101,14 @@ PrivateGenerator::PrivateGenerator(const GeneratorConfiguration& config,
 void PrivateGenerator::PrintAllComments(StringVector comments,
                                         grpc_generator::Printer* out) {
   if (comments.empty()) {
+    // Python requires code structures like class and def to have
+    // a body, even if it is just "pass" or a docstring.  We need
+    // to ensure not to generate empty bodies. We could do something
+    // smarter and more sophisticated, but at the moment, if there is
+    // no docstring to print, we simply emit "pass" to ensure validity
+    // of the generated code.
+    out->Print("# missing associated documentation comment in .proto file\n");
+    out->Print("pass\n");
     return;
   }
   out->Print("\"\"\"");
diff --git a/src/core/ext/filters/client_channel/subchannel.c b/src/core/ext/filters/client_channel/subchannel.c
index 362b4a4a28..967e571221 100644
--- a/src/core/ext/filters/client_channel/subchannel.c
+++ b/src/core/ext/filters/client_channel/subchannel.c
@@ -59,9 +59,9 @@
 #define INTERNAL_REF_BITS 16
 #define STRONG_REF_MASK (~(gpr_atm)((1 << INTERNAL_REF_BITS) - 1))
 
-#define GRPC_SUBCHANNEL_MIN_CONNECT_TIMEOUT_SECONDS 20
 #define GRPC_SUBCHANNEL_INITIAL_CONNECT_BACKOFF_SECONDS 1
 #define GRPC_SUBCHANNEL_RECONNECT_BACKOFF_MULTIPLIER 1.6
+#define GRPC_SUBCHANNEL_RECONNECT_MIN_BACKOFF_SECONDS 20
 #define GRPC_SUBCHANNEL_RECONNECT_MAX_BACKOFF_SECONDS 120
 #define GRPC_SUBCHANNEL_RECONNECT_JITTER 0.2
 
@@ -353,8 +353,8 @@ grpc_subchannel *grpc_subchannel_create(grpc_exec_ctx *exec_ctx,
                                "subchannel");
   int initial_backoff_ms =
       GRPC_SUBCHANNEL_INITIAL_CONNECT_BACKOFF_SECONDS * 1000;
+  int min_backoff_ms = GRPC_SUBCHANNEL_RECONNECT_MIN_BACKOFF_SECONDS * 1000;
   int max_backoff_ms = GRPC_SUBCHANNEL_RECONNECT_MAX_BACKOFF_SECONDS * 1000;
-  int min_backoff_ms = GRPC_SUBCHANNEL_MIN_CONNECT_TIMEOUT_SECONDS * 1000;
   bool fixed_reconnect_backoff = false;
   if (c->args) {
     for (size_t i = 0; i < c->args->num_args; i++) {
@@ -366,6 +366,12 @@ grpc_subchannel *grpc_subchannel_create(grpc_exec_ctx *exec_ctx,
                 &c->args->args[i],
                 (grpc_integer_options){initial_backoff_ms, 100, INT_MAX});
       } else if (0 == strcmp(c->args->args[i].key,
+                             GRPC_ARG_MIN_RECONNECT_BACKOFF_MS)) {
+        fixed_reconnect_backoff = false;
+        min_backoff_ms = grpc_channel_arg_get_integer(
+            &c->args->args[i],
+            (grpc_integer_options){min_backoff_ms, 100, INT_MAX});
+      } else if (0 == strcmp(c->args->args[i].key,
                              GRPC_ARG_MAX_RECONNECT_BACKOFF_MS)) {
         fixed_reconnect_backoff = false;
         max_backoff_ms = grpc_channel_arg_get_integer(
diff --git a/src/core/ext/filters/load_reporting/load_reporting.c b/src/core/ext/filters/load_reporting/load_reporting.c
index 3b5d2103c1..4e9d0937ae 100644
--- a/src/core/ext/filters/load_reporting/load_reporting.c
+++ b/src/core/ext/filters/load_reporting/load_reporting.c
@@ -47,23 +47,6 @@
 #include "src/core/lib/surface/call.h"
 #include "src/core/lib/surface/channel_init.h"
 
-static void destroy_lr_cost_context(void *c) {
-  grpc_exec_ctx exec_ctx = GRPC_EXEC_CTX_INIT;
-  grpc_load_reporting_cost_context *cost_ctx = c;
-  for (size_t i = 0; i < cost_ctx->values_count; ++i) {
-    grpc_slice_unref_internal(&exec_ctx, cost_ctx->values[i]);
-  }
-  grpc_exec_ctx_finish(&exec_ctx);
-  gpr_free(cost_ctx->values);
-  gpr_free(cost_ctx);
-}
-
-void grpc_call_set_load_reporting_cost_context(
-    grpc_call *call, grpc_load_reporting_cost_context *ctx) {
-  grpc_call_context_set(call, GRPC_CONTEXT_LR_COST, ctx,
-                        destroy_lr_cost_context);
-}
-
 static bool is_load_reporting_enabled(const grpc_channel_args *a) {
   return grpc_channel_arg_get_bool(
       grpc_channel_args_find(a, GRPC_ARG_ENABLE_LOAD_REPORTING), false);
diff --git a/src/core/ext/filters/load_reporting/load_reporting_filter.c b/src/core/ext/filters/load_reporting/load_reporting_filter.c
index 57b25d0651..75a9a56687 100644
--- a/src/core/ext/filters/load_reporting/load_reporting_filter.c
+++ b/src/core/ext/filters/load_reporting/load_reporting_filter.c
@@ -48,6 +48,8 @@
 
 typedef struct call_data {
   intptr_t id; /**< an id unique to the call */
+  bool have_trailing_md_string;
+  grpc_slice trailing_md_string;
   bool have_initial_md_string;
   grpc_slice initial_md_string;
   bool have_service_method;
@@ -140,6 +142,9 @@ static void destroy_call_elem(grpc_exec_ctx *exec_ctx, grpc_call_element *elem,
   if (calld->have_initial_md_string) {
     grpc_slice_unref_internal(exec_ctx, calld->initial_md_string);
   }
+  if (calld->have_trailing_md_string) {
+    grpc_slice_unref_internal(exec_ctx, calld->trailing_md_string);
+  }
   if (calld->have_service_method) {
     grpc_slice_unref_internal(exec_ctx, calld->service_method);
   }
@@ -183,6 +188,18 @@ static void destroy_channel_elem(grpc_exec_ctx *exec_ctx,
   */
 }
 
+static grpc_filtered_mdelem lr_trailing_md_filter(grpc_exec_ctx *exec_ctx,
+                                                  void *user_data,
+                                                  grpc_mdelem md) {
+  grpc_call_element *elem = user_data;
+  call_data *calld = elem->call_data;
+  if (grpc_slice_eq(GRPC_MDKEY(md), GRPC_MDSTR_LB_COST_BIN)) {
+    calld->trailing_md_string = GRPC_MDVALUE(md);
+    return GRPC_FILTERED_REMOVE();
+  }
+  return GRPC_FILTERED_MDELEM(md);
+}
+
 static void lr_start_transport_stream_op_batch(
     grpc_exec_ctx *exec_ctx, grpc_call_element *elem,
     grpc_transport_stream_op_batch *op) {
@@ -190,13 +207,21 @@ static void lr_start_transport_stream_op_batch(
   call_data *calld = elem->call_data;
 
   if (op->recv_initial_metadata) {
+    /* substitute our callback for the higher callback */
     calld->recv_initial_metadata =
         op->payload->recv_initial_metadata.recv_initial_metadata;
-    /* substitute our callback for the higher callback */
     calld->ops_recv_initial_metadata_ready =
         op->payload->recv_initial_metadata.recv_initial_metadata_ready;
     op->payload->recv_initial_metadata.recv_initial_metadata_ready =
         &calld->on_initial_md_ready;
+  } else if (op->send_trailing_metadata) {
+    GRPC_LOG_IF_ERROR(
+        "grpc_metadata_batch_filter",
+        grpc_metadata_batch_filter(
+            exec_ctx,
+            op->payload->send_trailing_metadata.send_trailing_metadata,
+            lr_trailing_md_filter, elem,
+            "LR trailing metadata filtering error"));
   }
   grpc_call_next_op(exec_ctx, elem, op);
 
diff --git a/src/core/lib/channel/context.h b/src/core/lib/channel/context.h
index 2c1174ce7a..6c931ad28a 100644
--- a/src/core/lib/channel/context.h
+++ b/src/core/lib/channel/context.h
@@ -50,9 +50,6 @@ typedef enum {
   /// Reserved for traffic_class_context.
   GRPC_CONTEXT_TRAFFIC,
 
-  /// Costs for Load Reporting.
-  GRPC_CONTEXT_LR_COST,
-
   GRPC_CONTEXT_COUNT
 } grpc_context_index;
 
diff --git a/src/core/lib/transport/static_metadata.c b/src/core/lib/transport/static_metadata.c
index 599d4ad117..862cdaa8e0 100644
--- a/src/core/lib/transport/static_metadata.c
+++ b/src/core/lib/transport/static_metadata.c
@@ -97,23 +97,23 @@ static uint8_t g_bytes[] = {
     101, 105, 102, 45,  110, 111, 110, 101, 45,  109, 97,  116, 99,  104, 105,
     102, 45,  114, 97,  110, 103, 101, 105, 102, 45,  117, 110, 109, 111, 100,
     105, 102, 105, 101, 100, 45,  115, 105, 110, 99,  101, 108, 97,  115, 116,
-    45,  109, 111, 100, 105, 102, 105, 101, 100, 108, 105, 110, 107, 108, 111,
-    99,  97,  116, 105, 111, 110, 109, 97,  120, 45,  102, 111, 114, 119, 97,
-    114, 100, 115, 112, 114, 111, 120, 121, 45,  97,  117, 116, 104, 101, 110,
-    116, 105, 99,  97,  116, 101, 112, 114, 111, 120, 121, 45,  97,  117, 116,
-    104, 111, 114, 105, 122, 97,  116, 105, 111, 110, 114, 97,  110, 103, 101,
-    114, 101, 102, 101, 114, 101, 114, 114, 101, 102, 114, 101, 115, 104, 114,
-    101, 116, 114, 121, 45,  97,  102, 116, 101, 114, 115, 101, 114, 118, 101,
-    114, 115, 101, 116, 45,  99,  111, 111, 107, 105, 101, 115, 116, 114, 105,
-    99,  116, 45,  116, 114, 97,  110, 115, 112, 111, 114, 116, 45,  115, 101,
-    99,  117, 114, 105, 116, 121, 116, 114, 97,  110, 115, 102, 101, 114, 45,
-    101, 110, 99,  111, 100, 105, 110, 103, 118, 97,  114, 121, 118, 105, 97,
-    119, 119, 119, 45,  97,  117, 116, 104, 101, 110, 116, 105, 99,  97,  116,
-    101, 105, 100, 101, 110, 116, 105, 116, 121, 44,  100, 101, 102, 108, 97,
-    116, 101, 105, 100, 101, 110, 116, 105, 116, 121, 44,  103, 122, 105, 112,
-    100, 101, 102, 108, 97,  116, 101, 44,  103, 122, 105, 112, 105, 100, 101,
-    110, 116, 105, 116, 121, 44,  100, 101, 102, 108, 97,  116, 101, 44,  103,
-    122, 105, 112};
+    45,  109, 111, 100, 105, 102, 105, 101, 100, 108, 98,  45,  99,  111, 115,
+    116, 45,  98,  105, 110, 108, 105, 110, 107, 108, 111, 99,  97,  116, 105,
+    111, 110, 109, 97,  120, 45,  102, 111, 114, 119, 97,  114, 100, 115, 112,
+    114, 111, 120, 121, 45,  97,  117, 116, 104, 101, 110, 116, 105, 99,  97,
+    116, 101, 112, 114, 111, 120, 121, 45,  97,  117, 116, 104, 111, 114, 105,
+    122, 97,  116, 105, 111, 110, 114, 97,  110, 103, 101, 114, 101, 102, 101,
+    114, 101, 114, 114, 101, 102, 114, 101, 115, 104, 114, 101, 116, 114, 121,
+    45,  97,  102, 116, 101, 114, 115, 101, 114, 118, 101, 114, 115, 101, 116,
+    45,  99,  111, 111, 107, 105, 101, 115, 116, 114, 105, 99,  116, 45,  116,
+    114, 97,  110, 115, 112, 111, 114, 116, 45,  115, 101, 99,  117, 114, 105,
+    116, 121, 116, 114, 97,  110, 115, 102, 101, 114, 45,  101, 110, 99,  111,
+    100, 105, 110, 103, 118, 97,  114, 121, 118, 105, 97,  119, 119, 119, 45,
+    97,  117, 116, 104, 101, 110, 116, 105, 99,  97,  116, 101, 105, 100, 101,
+    110, 116, 105, 116, 121, 44,  100, 101, 102, 108, 97,  116, 101, 105, 100,
+    101, 110, 116, 105, 116, 121, 44,  103, 122, 105, 112, 100, 101, 102, 108,
+    97,  116, 101, 44,  103, 122, 105, 112, 105, 100, 101, 110, 116, 105, 116,
+    121, 44,  100, 101, 102, 108, 97,  116, 101, 44,  103, 122, 105, 112};
 
 static void static_ref(void *unused) {}
 static void static_unref(grpc_exec_ctx *exec_ctx, void *unused) {}
@@ -223,6 +223,7 @@ grpc_slice_refcount grpc_static_metadata_refcounts[GRPC_STATIC_MDSTR_COUNT] = {
     {&grpc_static_metadata_vtable, &static_sub_refcnt},
     {&grpc_static_metadata_vtable, &static_sub_refcnt},
     {&grpc_static_metadata_vtable, &static_sub_refcnt},
+    {&grpc_static_metadata_vtable, &static_sub_refcnt},
 };
 
 const grpc_slice grpc_static_slice_table[GRPC_STATIC_MDSTR_COUNT] = {
@@ -383,64 +384,67 @@ const grpc_slice grpc_static_slice_table[GRPC_STATIC_MDSTR_COUNT] = {
     {.refcount = &grpc_static_metadata_refcounts[77],
      .data.refcounted = {g_bytes + 791, 13}},
     {.refcount = &grpc_static_metadata_refcounts[78],
-     .data.refcounted = {g_bytes + 804, 4}},
+     .data.refcounted = {g_bytes + 804, 11}},
     {.refcount = &grpc_static_metadata_refcounts[79],
-     .data.refcounted = {g_bytes + 808, 8}},
+     .data.refcounted = {g_bytes + 815, 4}},
     {.refcount = &grpc_static_metadata_refcounts[80],
-     .data.refcounted = {g_bytes + 816, 12}},
+     .data.refcounted = {g_bytes + 819, 8}},
     {.refcount = &grpc_static_metadata_refcounts[81],
-     .data.refcounted = {g_bytes + 828, 18}},
+     .data.refcounted = {g_bytes + 827, 12}},
     {.refcount = &grpc_static_metadata_refcounts[82],
-     .data.refcounted = {g_bytes + 846, 19}},
+     .data.refcounted = {g_bytes + 839, 18}},
     {.refcount = &grpc_static_metadata_refcounts[83],
-     .data.refcounted = {g_bytes + 865, 5}},
+     .data.refcounted = {g_bytes + 857, 19}},
     {.refcount = &grpc_static_metadata_refcounts[84],
-     .data.refcounted = {g_bytes + 870, 7}},
+     .data.refcounted = {g_bytes + 876, 5}},
     {.refcount = &grpc_static_metadata_refcounts[85],
-     .data.refcounted = {g_bytes + 877, 7}},
+     .data.refcounted = {g_bytes + 881, 7}},
     {.refcount = &grpc_static_metadata_refcounts[86],
-     .data.refcounted = {g_bytes + 884, 11}},
+     .data.refcounted = {g_bytes + 888, 7}},
     {.refcount = &grpc_static_metadata_refcounts[87],
-     .data.refcounted = {g_bytes + 895, 6}},
+     .data.refcounted = {g_bytes + 895, 11}},
     {.refcount = &grpc_static_metadata_refcounts[88],
-     .data.refcounted = {g_bytes + 901, 10}},
+     .data.refcounted = {g_bytes + 906, 6}},
     {.refcount = &grpc_static_metadata_refcounts[89],
-     .data.refcounted = {g_bytes + 911, 25}},
+     .data.refcounted = {g_bytes + 912, 10}},
     {.refcount = &grpc_static_metadata_refcounts[90],
-     .data.refcounted = {g_bytes + 936, 17}},
+     .data.refcounted = {g_bytes + 922, 25}},
     {.refcount = &grpc_static_metadata_refcounts[91],
-     .data.refcounted = {g_bytes + 953, 4}},
+     .data.refcounted = {g_bytes + 947, 17}},
     {.refcount = &grpc_static_metadata_refcounts[92],
-     .data.refcounted = {g_bytes + 957, 3}},
+     .data.refcounted = {g_bytes + 964, 4}},
     {.refcount = &grpc_static_metadata_refcounts[93],
-     .data.refcounted = {g_bytes + 960, 16}},
+     .data.refcounted = {g_bytes + 968, 3}},
     {.refcount = &grpc_static_metadata_refcounts[94],
-     .data.refcounted = {g_bytes + 976, 16}},
+     .data.refcounted = {g_bytes + 971, 16}},
     {.refcount = &grpc_static_metadata_refcounts[95],
-     .data.refcounted = {g_bytes + 992, 13}},
+     .data.refcounted = {g_bytes + 987, 16}},
     {.refcount = &grpc_static_metadata_refcounts[96],
-     .data.refcounted = {g_bytes + 1005, 12}},
+     .data.refcounted = {g_bytes + 1003, 13}},
     {.refcount = &grpc_static_metadata_refcounts[97],
-     .data.refcounted = {g_bytes + 1017, 21}},
+     .data.refcounted = {g_bytes + 1016, 12}},
+    {.refcount = &grpc_static_metadata_refcounts[98],
+     .data.refcounted = {g_bytes + 1028, 21}},
 };
 
 uintptr_t grpc_static_mdelem_user_data[GRPC_STATIC_MDELEM_COUNT] = {
-    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
-    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
-    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
-    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 2, 4, 4, 6, 6, 8, 8};
+    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 2, 4, 4, 6, 6, 8, 8};
 
 static const int8_t elems_r[] = {
-    10, 8,   -3,  0,  9,   21,  -76, 22,  0,   10,  -7,  0,  0,  0,  14, 0,
-    13, 12,  11,  0,  0,   0,   0,   0,   0,   0,   0,   0,  0,  0,  0,  0,
-    0,  0,   0,   0,  0,   0,   0,   0,   0,   0,   0,   0,  0,  0,  0,  0,
-    0,  -50, -51, 15, -53, -54, -55, -56, -56, -57, -58, 0,  37, 36, 35, 34,
-    33, 32,  31,  30, 29,  28,  27,  26,  25,  24,  23,  22, 21, 20, 19, 18,
-    17, 16,  15,  14, 13,  12,  11,  10,  13,  12,  11,  10, 9,  8,  7,  0};
+    10,  8,   -3,  0,   9,  21, -77, 22,  0,   10, -7,  0,   0,   0,
+    14,  0,   13,  12,  11, 0,  0,   0,   0,   0,  0,   0,   0,   0,
+    0,   0,   0,   0,   0,  0,  0,   0,   0,   0,  0,   0,   0,   0,
+    0,   0,   0,   0,   0,  0,  0,   -50, -51, 16, -53, -54, -55, -56,
+    -56, -57, -58, -59, 0,  37, 36,  35,  34,  33, 32,  31,  30,  29,
+    28,  27,  26,  25,  24, 23, 22,  21,  20,  19, 18,  17,  16,  15,
+    14,  13,  12,  11,  10, 13, 12,  11,  10,  9,  8,   7,   0};
 static uint32_t elems_phash(uint32_t i) {
   i -= 42;
-  uint32_t x = i % 96;
-  uint32_t y = i / 96;
+  uint32_t x = i % 97;
+  uint32_t y = i / 97;
   uint32_t h = x;
   if (y < GPR_ARRAY_SIZE(elems_r)) {
     uint32_t delta = (uint32_t)elems_r[y];
@@ -450,29 +454,30 @@ static uint32_t elems_phash(uint32_t i) {
 }
 
 static const uint16_t elem_keys[] = {
-    1009, 1010, 1011, 240,  241,  242,  243,  244,  138,  139,  42,   43,
-    429,  430,  431,  911,  912,  913,  712,  713,  1392, 522,  714,  1588,
-    1686, 1784, 4822, 4920, 4951, 5116, 5214, 5312, 5410, 1405, 5508, 5606,
-    5704, 5802, 5900, 5998, 6096, 6194, 6292, 6390, 6488, 6586, 6684, 6782,
-    6880, 6978, 7076, 7174, 7272, 7370, 7468, 7566, 7664, 7762, 7860, 7958,
-    8056, 8154, 8252, 8350, 8448, 1074, 1075, 1076, 1077, 8546, 8644, 8742,
-    8840, 8938, 9036, 9134, 0,    314,  0,    0,    0,    0,    0,    0,
+    1019, 1020, 1021, 242,  243,  244,  245,  246,  139,  140,  42,   43,
+    433,  434,  435,  920,  921,  922,  719,  720,  1406, 527,  721,  1604,
+    1703, 1802, 4871, 4970, 5001, 5168, 5267, 5366, 5465, 1419, 5564, 5663,
+    5762, 5861, 5960, 6059, 6158, 6257, 6356, 6455, 6554, 6653, 6752, 6851,
+    6950, 7049, 7148, 7247, 7346, 7445, 7544, 7643, 7742, 7841, 7940, 8039,
+    8138, 8237, 8336, 8435, 8534, 8633, 1085, 1086, 1087, 1088, 8732, 8831,
+    8930, 9029, 9128, 9227, 9326, 0,    317,  0,    0,    0,    0,    0,
+    0,    0,    0,    0,    0,    0,    0,    0,    0,    0,    0,    0,
+    0,    0,    0,    0,    0,    133,  233,  234,  0,    0,    0,    0,
     0,    0,    0,    0,    0,    0,    0,    0,    0,    0,    0,    0,
-    0,    0,    0,    0,    132,  231,  232,  0,    0,    0,    0,    0,
     0,    0,    0,    0,    0,    0,    0,    0,    0,    0,    0,    0,
-    0,    0,    0,    0,    0,    0,    0,    0,    0,    0,    0,    0};
+    0};
 static const uint8_t elem_idxs[] = {
-    73,  76,  74,  19,  20,  21,  22,  23,  15,  16,  17,  18,  11,  12,  13,
-    3,   4,   5,   0,   1,   41,  6,   2,   69,  48,  55,  24,  25,  26,  27,
+    74,  77,  75,  19,  20,  21,  22,  23,  15,  16,  17,  18,  11,  12,  13,
+    3,   4,   5,   0,   1,   41,  6,   2,   70,  48,  55,  24,  25,  26,  27,
     28,  29,  30,  7,   31,  32,  33,  34,  35,  36,  37,  38,  39,  40,  42,
     43,  44,  45,  46,  47,  49,  50,  51,  52,  53,  54,  56,  57,  58,  59,
-    60,  61,  62,  63,  64,  75,  77,  78,  79,  65,  66,  67,  68,  70,  71,
-    72,  255, 14,  255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
-    255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 8,   9,   10};
+    60,  61,  62,  63,  64,  65,  76,  78,  79,  80,  66,  67,  68,  69,  71,
+    72,  73,  255, 14,  255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
+    255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 8,   9,   10};
 
 grpc_mdelem grpc_static_mdelem_for_static_strings(int a, int b) {
   if (a == -1 || b == -1) return GRPC_MDNULL;
-  uint32_t k = (uint32_t)(a * 98 + b);
+  uint32_t k = (uint32_t)(a * 99 + b);
   uint32_t h = elems_phash(k);
   return h < GPR_ARRAY_SIZE(elem_keys) && elem_keys[h] == k
              ? GRPC_MAKE_MDELEM(&grpc_static_mdelem_table[elem_idxs[h]],
@@ -706,71 +711,75 @@ grpc_mdelem_data grpc_static_mdelem_table[GRPC_STATIC_MDELEM_COUNT] = {
      {.refcount = &grpc_static_metadata_refcounts[20],
       .data.refcounted = {g_bytes + 234, 0}}},
     {{.refcount = &grpc_static_metadata_refcounts[78],
-      .data.refcounted = {g_bytes + 804, 4}},
+      .data.refcounted = {g_bytes + 804, 11}},
      {.refcount = &grpc_static_metadata_refcounts[20],
       .data.refcounted = {g_bytes + 234, 0}}},
     {{.refcount = &grpc_static_metadata_refcounts[79],
-      .data.refcounted = {g_bytes + 808, 8}},
+      .data.refcounted = {g_bytes + 815, 4}},
      {.refcount = &grpc_static_metadata_refcounts[20],
       .data.refcounted = {g_bytes + 234, 0}}},
     {{.refcount = &grpc_static_metadata_refcounts[80],
-      .data.refcounted = {g_bytes + 816, 12}},
+      .data.refcounted = {g_bytes + 819, 8}},
      {.refcount = &grpc_static_metadata_refcounts[20],
       .data.refcounted = {g_bytes + 234, 0}}},
     {{.refcount = &grpc_static_metadata_refcounts[81],
-      .data.refcounted = {g_bytes + 828, 18}},
+      .data.refcounted = {g_bytes + 827, 12}},
      {.refcount = &grpc_static_metadata_refcounts[20],
       .data.refcounted = {g_bytes + 234, 0}}},
     {{.refcount = &grpc_static_metadata_refcounts[82],
-      .data.refcounted = {g_bytes + 846, 19}},
+      .data.refcounted = {g_bytes + 839, 18}},
      {.refcount = &grpc_static_metadata_refcounts[20],
       .data.refcounted = {g_bytes + 234, 0}}},
     {{.refcount = &grpc_static_metadata_refcounts[83],
-      .data.refcounted = {g_bytes + 865, 5}},
+      .data.refcounted = {g_bytes + 857, 19}},
      {.refcount = &grpc_static_metadata_refcounts[20],
       .data.refcounted = {g_bytes + 234, 0}}},
     {{.refcount = &grpc_static_metadata_refcounts[84],
-      .data.refcounted = {g_bytes + 870, 7}},
+      .data.refcounted = {g_bytes + 876, 5}},
      {.refcount = &grpc_static_metadata_refcounts[20],
       .data.refcounted = {g_bytes + 234, 0}}},
     {{.refcount = &grpc_static_metadata_refcounts[85],
-      .data.refcounted = {g_bytes + 877, 7}},
+      .data.refcounted = {g_bytes + 881, 7}},
      {.refcount = &grpc_static_metadata_refcounts[20],
       .data.refcounted = {g_bytes + 234, 0}}},
     {{.refcount = &grpc_static_metadata_refcounts[86],
-      .data.refcounted = {g_bytes + 884, 11}},
+      .data.refcounted = {g_bytes + 888, 7}},
      {.refcount = &grpc_static_metadata_refcounts[20],
       .data.refcounted = {g_bytes + 234, 0}}},
     {{.refcount = &grpc_static_metadata_refcounts[87],
-      .data.refcounted = {g_bytes + 895, 6}},
+      .data.refcounted = {g_bytes + 895, 11}},
      {.refcount = &grpc_static_metadata_refcounts[20],
       .data.refcounted = {g_bytes + 234, 0}}},
     {{.refcount = &grpc_static_metadata_refcounts[88],
-      .data.refcounted = {g_bytes + 901, 10}},
+      .data.refcounted = {g_bytes + 906, 6}},
      {.refcount = &grpc_static_metadata_refcounts[20],
       .data.refcounted = {g_bytes + 234, 0}}},
     {{.refcount = &grpc_static_metadata_refcounts[89],
-      .data.refcounted = {g_bytes + 911, 25}},
+      .data.refcounted = {g_bytes + 912, 10}},
      {.refcount = &grpc_static_metadata_refcounts[20],
       .data.refcounted = {g_bytes + 234, 0}}},
     {{.refcount = &grpc_static_metadata_refcounts[90],
-      .data.refcounted = {g_bytes + 936, 17}},
+      .data.refcounted = {g_bytes + 922, 25}},
      {.refcount = &grpc_static_metadata_refcounts[20],
       .data.refcounted = {g_bytes + 234, 0}}},
-    {{.refcount = &grpc_static_metadata_refcounts[16],
-      .data.refcounted = {g_bytes + 200, 10}},
+    {{.refcount = &grpc_static_metadata_refcounts[91],
+      .data.refcounted = {g_bytes + 947, 17}},
      {.refcount = &grpc_static_metadata_refcounts[20],
       .data.refcounted = {g_bytes + 234, 0}}},
-    {{.refcount = &grpc_static_metadata_refcounts[91],
-      .data.refcounted = {g_bytes + 953, 4}},
+    {{.refcount = &grpc_static_metadata_refcounts[16],
+      .data.refcounted = {g_bytes + 200, 10}},
      {.refcount = &grpc_static_metadata_refcounts[20],
       .data.refcounted = {g_bytes + 234, 0}}},
     {{.refcount = &grpc_static_metadata_refcounts[92],
-      .data.refcounted = {g_bytes + 957, 3}},
+      .data.refcounted = {g_bytes + 964, 4}},
      {.refcount = &grpc_static_metadata_refcounts[20],
       .data.refcounted = {g_bytes + 234, 0}}},
     {{.refcount = &grpc_static_metadata_refcounts[93],
-      .data.refcounted = {g_bytes + 960, 16}},
+      .data.refcounted = {g_bytes + 968, 3}},
+     {.refcount = &grpc_static_metadata_refcounts[20],
+      .data.refcounted = {g_bytes + 234, 0}}},
+    {{.refcount = &grpc_static_metadata_refcounts[94],
+      .data.refcounted = {g_bytes + 971, 16}},
      {.refcount = &grpc_static_metadata_refcounts[20],
       .data.refcounted = {g_bytes + 234, 0}}},
     {{.refcount = &grpc_static_metadata_refcounts[10],
@@ -783,24 +792,24 @@ grpc_mdelem_data grpc_static_mdelem_table[GRPC_STATIC_MDELEM_COUNT] = {
       .data.refcounted = {g_bytes + 377, 7}}},
     {{.refcount = &grpc_static_metadata_refcounts[10],
       .data.refcounted = {g_bytes + 90, 20}},
-     {.refcount = &grpc_static_metadata_refcounts[94],
-      .data.refcounted = {g_bytes + 976, 16}}},
+     {.refcount = &grpc_static_metadata_refcounts[95],
+      .data.refcounted = {g_bytes + 987, 16}}},
     {{.refcount = &grpc_static_metadata_refcounts[10],
       .data.refcounted = {g_bytes + 90, 20}},
      {.refcount = &grpc_static_metadata_refcounts[30],
       .data.refcounted = {g_bytes + 373, 4}}},
     {{.refcount = &grpc_static_metadata_refcounts[10],
       .data.refcounted = {g_bytes + 90, 20}},
-     {.refcount = &grpc_static_metadata_refcounts[95],
-      .data.refcounted = {g_bytes + 992, 13}}},
-    {{.refcount = &grpc_static_metadata_refcounts[10],
-      .data.refcounted = {g_bytes + 90, 20}},
      {.refcount = &grpc_static_metadata_refcounts[96],
-      .data.refcounted = {g_bytes + 1005, 12}}},
+      .data.refcounted = {g_bytes + 1003, 13}}},
     {{.refcount = &grpc_static_metadata_refcounts[10],
       .data.refcounted = {g_bytes + 90, 20}},
      {.refcount = &grpc_static_metadata_refcounts[97],
-      .data.refcounted = {g_bytes + 1017, 21}}},
+      .data.refcounted = {g_bytes + 1016, 12}}},
+    {{.refcount = &grpc_static_metadata_refcounts[10],
+      .data.refcounted = {g_bytes + 90, 20}},
+     {.refcount = &grpc_static_metadata_refcounts[98],
+      .data.refcounted = {g_bytes + 1028, 21}}},
 };
-const uint8_t grpc_static_accept_encoding_metadata[8] = {0,  73, 74, 75,
-                                                         76, 77, 78, 79};
+const uint8_t grpc_static_accept_encoding_metadata[8] = {0,  74, 75, 76,
+                                                         77, 78, 79, 80};
diff --git a/src/core/lib/transport/static_metadata.h b/src/core/lib/transport/static_metadata.h
index dcbe418edc..84fb316fd6 100644
--- a/src/core/lib/transport/static_metadata.h
+++ b/src/core/lib/transport/static_metadata.h
@@ -44,7 +44,7 @@
 
 #include "src/core/lib/transport/metadata.h"
 
-#define GRPC_STATIC_MDSTR_COUNT 98
+#define GRPC_STATIC_MDSTR_COUNT 99
 extern const grpc_slice grpc_static_slice_table[GRPC_STATIC_MDSTR_COUNT];
 /* ":path" */
 #define GRPC_MDSTR_PATH (grpc_static_slice_table[0])
@@ -205,47 +205,49 @@ extern const grpc_slice grpc_static_slice_table[GRPC_STATIC_MDSTR_COUNT];
 #define GRPC_MDSTR_IF_UNMODIFIED_SINCE (grpc_static_slice_table[76])
 /* "last-modified" */
 #define GRPC_MDSTR_LAST_MODIFIED (grpc_static_slice_table[77])
+/* "lb-cost-bin" */
+#define GRPC_MDSTR_LB_COST_BIN (grpc_static_slice_table[78])
 /* "link" */
-#define GRPC_MDSTR_LINK (grpc_static_slice_table[78])
+#define GRPC_MDSTR_LINK (grpc_static_slice_table[79])
 /* "location" */
-#define GRPC_MDSTR_LOCATION (grpc_static_slice_table[79])
+#define GRPC_MDSTR_LOCATION (grpc_static_slice_table[80])
 /* "max-forwards" */
-#define GRPC_MDSTR_MAX_FORWARDS (grpc_static_slice_table[80])
+#define GRPC_MDSTR_MAX_FORWARDS (grpc_static_slice_table[81])
 /* "proxy-authenticate" */
-#define GRPC_MDSTR_PROXY_AUTHENTICATE (grpc_static_slice_table[81])
+#define GRPC_MDSTR_PROXY_AUTHENTICATE (grpc_static_slice_table[82])
 /* "proxy-authorization" */
-#define GRPC_MDSTR_PROXY_AUTHORIZATION (grpc_static_slice_table[82])
+#define GRPC_MDSTR_PROXY_AUTHORIZATION (grpc_static_slice_table[83])
 /* "range" */
-#define GRPC_MDSTR_RANGE (grpc_static_slice_table[83])
+#define GRPC_MDSTR_RANGE (grpc_static_slice_table[84])
 /* "referer" */
-#define GRPC_MDSTR_REFERER (grpc_static_slice_table[84])
+#define GRPC_MDSTR_REFERER (grpc_static_slice_table[85])
 /* "refresh" */
-#define GRPC_MDSTR_REFRESH (grpc_static_slice_table[85])
+#define GRPC_MDSTR_REFRESH (grpc_static_slice_table[86])
 /* "retry-after" */
-#define GRPC_MDSTR_RETRY_AFTER (grpc_static_slice_table[86])
+#define GRPC_MDSTR_RETRY_AFTER (grpc_static_slice_table[87])
 /* "server" */
-#define GRPC_MDSTR_SERVER (grpc_static_slice_table[87])
+#define GRPC_MDSTR_SERVER (grpc_static_slice_table[88])
 /* "set-cookie" */
-#define GRPC_MDSTR_SET_COOKIE (grpc_static_slice_table[88])
+#define GRPC_MDSTR_SET_COOKIE (grpc_static_slice_table[89])
 /* "strict-transport-security" */
-#define GRPC_MDSTR_STRICT_TRANSPORT_SECURITY (grpc_static_slice_table[89])
+#define GRPC_MDSTR_STRICT_TRANSPORT_SECURITY (grpc_static_slice_table[90])
 /* "transfer-encoding" */
-#define GRPC_MDSTR_TRANSFER_ENCODING (grpc_static_slice_table[90])
+#define GRPC_MDSTR_TRANSFER_ENCODING (grpc_static_slice_table[91])
 /* "vary" */
-#define GRPC_MDSTR_VARY (grpc_static_slice_table[91])
+#define GRPC_MDSTR_VARY (grpc_static_slice_table[92])
 /* "via" */
-#define GRPC_MDSTR_VIA (grpc_static_slice_table[92])
+#define GRPC_MDSTR_VIA (grpc_static_slice_table[93])
 /* "www-authenticate" */
-#define GRPC_MDSTR_WWW_AUTHENTICATE (grpc_static_slice_table[93])
+#define GRPC_MDSTR_WWW_AUTHENTICATE (grpc_static_slice_table[94])
 /* "identity,deflate" */
-#define GRPC_MDSTR_IDENTITY_COMMA_DEFLATE (grpc_static_slice_table[94])
+#define GRPC_MDSTR_IDENTITY_COMMA_DEFLATE (grpc_static_slice_table[95])
 /* "identity,gzip" */
-#define GRPC_MDSTR_IDENTITY_COMMA_GZIP (grpc_static_slice_table[95])
+#define GRPC_MDSTR_IDENTITY_COMMA_GZIP (grpc_static_slice_table[96])
 /* "deflate,gzip" */
-#define GRPC_MDSTR_DEFLATE_COMMA_GZIP (grpc_static_slice_table[96])
+#define GRPC_MDSTR_DEFLATE_COMMA_GZIP (grpc_static_slice_table[97])
 /* "identity,deflate,gzip" */
 #define GRPC_MDSTR_IDENTITY_COMMA_DEFLATE_COMMA_GZIP \
-  (grpc_static_slice_table[97])
+  (grpc_static_slice_table[98])
 
 extern const grpc_slice_refcount_vtable grpc_static_metadata_vtable;
 extern grpc_slice_refcount
@@ -257,7 +259,7 @@ extern grpc_slice_refcount
 #define GRPC_STATIC_METADATA_INDEX(static_slice) \
   ((int)((static_slice).refcount - grpc_static_metadata_refcounts))
 
-#define GRPC_STATIC_MDELEM_COUNT 80
+#define GRPC_STATIC_MDELEM_COUNT 81
 extern grpc_mdelem_data grpc_static_mdelem_table[GRPC_STATIC_MDELEM_COUNT];
 extern uintptr_t grpc_static_mdelem_user_data[GRPC_STATIC_MDELEM_COUNT];
 /* "grpc-status": "0" */
@@ -428,78 +430,81 @@ extern uintptr_t grpc_static_mdelem_user_data[GRPC_STATIC_MDELEM_COUNT];
 /* "lb-token": "" */
 #define GRPC_MDELEM_LB_TOKEN_EMPTY \
   (GRPC_MAKE_MDELEM(&grpc_static_mdelem_table[55], GRPC_MDELEM_STORAGE_STATIC))
+/* "lb-cost-bin": "" */
+#define GRPC_MDELEM_LB_COST_BIN_EMPTY \
+  (GRPC_MAKE_MDELEM(&grpc_static_mdelem_table[56], GRPC_MDELEM_STORAGE_STATIC))
 /* "link": "" */
 #define GRPC_MDELEM_LINK_EMPTY \
-  (GRPC_MAKE_MDELEM(&grpc_static_mdelem_table[56], GRPC_MDELEM_STORAGE_STATIC))
+  (GRPC_MAKE_MDELEM(&grpc_static_mdelem_table[57], GRPC_MDELEM_STORAGE_STATIC))
 /* "location": "" */
 #define GRPC_MDELEM_LOCATION_EMPTY \
-  (GRPC_MAKE_MDELEM(&grpc_static_mdelem_table[57], GRPC_MDELEM_STORAGE_STATIC))
+  (GRPC_MAKE_MDELEM(&grpc_static_mdelem_table[58], GRPC_MDELEM_STORAGE_STATIC))
 /* "max-forwards": "" */
 #define GRPC_MDELEM_MAX_FORWARDS_EMPTY \
-  (GRPC_MAKE_MDELEM(&grpc_static_mdelem_table[58], GRPC_MDELEM_STORAGE_STATIC))
+  (GRPC_MAKE_MDELEM(&grpc_static_mdelem_table[59], GRPC_MDELEM_STORAGE_STATIC))
 /* "proxy-authenticate": "" */
 #define GRPC_MDELEM_PROXY_AUTHENTICATE_EMPTY \
-  (GRPC_MAKE_MDELEM(&grpc_static_mdelem_table[59], GRPC_MDELEM_STORAGE_STATIC))
+  (GRPC_MAKE_MDELEM(&grpc_static_mdelem_table[60], GRPC_MDELEM_STORAGE_STATIC))
 /* "proxy-authorization": "" */
 #define GRPC_MDELEM_PROXY_AUTHORIZATION_EMPTY \
-  (GRPC_MAKE_MDELEM(&grpc_static_mdelem_table[60], GRPC_MDELEM_STORAGE_STATIC))
+  (GRPC_MAKE_MDELEM(&grpc_static_mdelem_table[61], GRPC_MDELEM_STORAGE_STATIC))
 /* "range": "" */
 #define GRPC_MDELEM_RANGE_EMPTY \
-  (GRPC_MAKE_MDELEM(&grpc_static_mdelem_table[61], GRPC_MDELEM_STORAGE_STATIC))
+  (GRPC_MAKE_MDELEM(&grpc_static_mdelem_table[62], GRPC_MDELEM_STORAGE_STATIC))
 /* "referer": "" */
 #define GRPC_MDELEM_REFERER_EMPTY \
-  (GRPC_MAKE_MDELEM(&grpc_static_mdelem_table[62], GRPC_MDELEM_STORAGE_STATIC))
+  (GRPC_MAKE_MDELEM(&grpc_static_mdelem_table[63], GRPC_MDELEM_STORAGE_STATIC))
 /* "refresh": "" */
 #define GRPC_MDELEM_REFRESH_EMPTY \
-  (GRPC_MAKE_MDELEM(&grpc_static_mdelem_table[63], GRPC_MDELEM_STORAGE_STATIC))
+  (GRPC_MAKE_MDELEM(&grpc_static_mdelem_table[64], GRPC_MDELEM_STORAGE_STATIC))
 /* "retry-after": "" */
 #define GRPC_MDELEM_RETRY_AFTER_EMPTY \
-  (GRPC_MAKE_MDELEM(&grpc_static_mdelem_table[64], GRPC_MDELEM_STORAGE_STATIC))
+  (GRPC_MAKE_MDELEM(&grpc_static_mdelem_table[65], GRPC_MDELEM_STORAGE_STATIC))
 /* "server": "" */
 #define GRPC_MDELEM_SERVER_EMPTY \
-  (GRPC_MAKE_MDELEM(&grpc_static_mdelem_table[65], GRPC_MDELEM_STORAGE_STATIC))
+  (GRPC_MAKE_MDELEM(&grpc_static_mdelem_table[66], GRPC_MDELEM_STORAGE_STATIC))
 /* "set-cookie": "" */
 #define GRPC_MDELEM_SET_COOKIE_EMPTY \
-  (GRPC_MAKE_MDELEM(&grpc_static_mdelem_table[66], GRPC_MDELEM_STORAGE_STATIC))
+  (GRPC_MAKE_MDELEM(&grpc_static_mdelem_table[67], GRPC_MDELEM_STORAGE_STATIC))
 /* "strict-transport-security": "" */
 #define GRPC_MDELEM_STRICT_TRANSPORT_SECURITY_EMPTY \
-  (GRPC_MAKE_MDELEM(&grpc_static_mdelem_table[67], GRPC_MDELEM_STORAGE_STATIC))
+  (GRPC_MAKE_MDELEM(&grpc_static_mdelem_table[68], GRPC_MDELEM_STORAGE_STATIC))
 /* "transfer-encoding": "" */
 #define GRPC_MDELEM_TRANSFER_ENCODING_EMPTY \
-  (GRPC_MAKE_MDELEM(&grpc_static_mdelem_table[68], GRPC_MDELEM_STORAGE_STATIC))
+  (GRPC_MAKE_MDELEM(&grpc_static_mdelem_table[69], GRPC_MDELEM_STORAGE_STATIC))
 /* "user-agent": "" */
 #define GRPC_MDELEM_USER_AGENT_EMPTY \
-  (GRPC_MAKE_MDELEM(&grpc_static_mdelem_table[69], GRPC_MDELEM_STORAGE_STATIC))
+  (GRPC_MAKE_MDELEM(&grpc_static_mdelem_table[70], GRPC_MDELEM_STORAGE_STATIC))
 /* "vary": "" */
 #define GRPC_MDELEM_VARY_EMPTY \
-  (GRPC_MAKE_MDELEM(&grpc_static_mdelem_table[70], GRPC_MDELEM_STORAGE_STATIC))
+  (GRPC_MAKE_MDELEM(&grpc_static_mdelem_table[71], GRPC_MDELEM_STORAGE_STATIC))
 /* "via": "" */
 #define GRPC_MDELEM_VIA_EMPTY \
-  (GRPC_MAKE_MDELEM(&grpc_static_mdelem_table[71], GRPC_MDELEM_STORAGE_STATIC))
+  (GRPC_MAKE_MDELEM(&grpc_static_mdelem_table[72], GRPC_MDELEM_STORAGE_STATIC))
 /* "www-authenticate": "" */
 #define GRPC_MDELEM_WWW_AUTHENTICATE_EMPTY \
-  (GRPC_MAKE_MDELEM(&grpc_static_mdelem_table[72], GRPC_MDELEM_STORAGE_STATIC))
+  (GRPC_MAKE_MDELEM(&grpc_static_mdelem_table[73], GRPC_MDELEM_STORAGE_STATIC))
 /* "grpc-accept-encoding": "identity" */
 #define GRPC_MDELEM_GRPC_ACCEPT_ENCODING_IDENTITY \
-  (GRPC_MAKE_MDELEM(&grpc_static_mdelem_table[73], GRPC_MDELEM_STORAGE_STATIC))
+  (GRPC_MAKE_MDELEM(&grpc_static_mdelem_table[74], GRPC_MDELEM_STORAGE_STATIC))
 /* "grpc-accept-encoding": "deflate" */
 #define GRPC_MDELEM_GRPC_ACCEPT_ENCODING_DEFLATE \
-  (GRPC_MAKE_MDELEM(&grpc_static_mdelem_table[74], GRPC_MDELEM_STORAGE_STATIC))
+  (GRPC_MAKE_MDELEM(&grpc_static_mdelem_table[75], GRPC_MDELEM_STORAGE_STATIC))
 /* "grpc-accept-encoding": "identity,deflate" */
 #define GRPC_MDELEM_GRPC_ACCEPT_ENCODING_IDENTITY_COMMA_DEFLATE \
-  (GRPC_MAKE_MDELEM(&grpc_static_mdelem_table[75], GRPC_MDELEM_STORAGE_STATIC))
+  (GRPC_MAKE_MDELEM(&grpc_static_mdelem_table[76], GRPC_MDELEM_STORAGE_STATIC))
 /* "grpc-accept-encoding": "gzip" */
 #define GRPC_MDELEM_GRPC_ACCEPT_ENCODING_GZIP \
-  (GRPC_MAKE_MDELEM(&grpc_static_mdelem_table[76], GRPC_MDELEM_STORAGE_STATIC))
+  (GRPC_MAKE_MDELEM(&grpc_static_mdelem_table[77], GRPC_MDELEM_STORAGE_STATIC))
 /* "grpc-accept-encoding": "identity,gzip" */
 #define GRPC_MDELEM_GRPC_ACCEPT_ENCODING_IDENTITY_COMMA_GZIP \
-  (GRPC_MAKE_MDELEM(&grpc_static_mdelem_table[77], GRPC_MDELEM_STORAGE_STATIC))
+  (GRPC_MAKE_MDELEM(&grpc_static_mdelem_table[78], GRPC_MDELEM_STORAGE_STATIC))
 /* "grpc-accept-encoding": "deflate,gzip" */
 #define GRPC_MDELEM_GRPC_ACCEPT_ENCODING_DEFLATE_COMMA_GZIP \
-  (GRPC_MAKE_MDELEM(&grpc_static_mdelem_table[78], GRPC_MDELEM_STORAGE_STATIC))
+  (GRPC_MAKE_MDELEM(&grpc_static_mdelem_table[79], GRPC_MDELEM_STORAGE_STATIC))
 /* "grpc-accept-encoding": "identity,deflate,gzip" */
 #define GRPC_MDELEM_GRPC_ACCEPT_ENCODING_IDENTITY_COMMA_DEFLATE_COMMA_GZIP \
-  (GRPC_MAKE_MDELEM(&grpc_static_mdelem_table[79], GRPC_MDELEM_STORAGE_STATIC))
+  (GRPC_MAKE_MDELEM(&grpc_static_mdelem_table[80], GRPC_MDELEM_STORAGE_STATIC))
 
 grpc_mdelem grpc_static_mdelem_for_static_strings(int a, int b);
 typedef enum {
diff --git a/src/cpp/server/server_cc.cc b/src/cpp/server/server_cc.cc
index 75610d69cd..62ded0d239 100644
--- a/src/cpp/server/server_cc.cc
+++ b/src/cpp/server/server_cc.cc
@@ -503,7 +503,7 @@ int Server::AddListeningPort(const grpc::string& addr,
                              ServerCredentials* creds) {
   GPR_ASSERT(!started_);
   int port = creds->AddPortToServer(addr, server_);
-  global_callbacks_->AddPort(this, port);
+  global_callbacks_->AddPort(this, addr, creds, port);
   return port;
 }
 
diff --git a/src/cpp/server/server_context.cc b/src/cpp/server/server_context.cc
index afc9873c14..33ad0ae142 100644
--- a/src/cpp/server/server_context.cc
+++ b/src/cpp/server/server_context.cc
@@ -229,17 +229,9 @@ const struct census_context* ServerContext::census_context() const {
 void ServerContext::SetLoadReportingCosts(
     const std::vector<grpc::string>& cost_data) {
   if (call_ == nullptr) return;
-  grpc_load_reporting_cost_context* cost_ctx =
-      static_cast<grpc_load_reporting_cost_context*>(
-          gpr_malloc(sizeof(*cost_ctx)));
-  cost_ctx->values_count = cost_data.size();
-  cost_ctx->values = static_cast<grpc_slice*>(
-      gpr_malloc(sizeof(*cost_ctx->values) * cost_ctx->values_count));
-  for (size_t i = 0; i < cost_ctx->values_count; ++i) {
-    cost_ctx->values[i] =
-        grpc_slice_from_copied_buffer(cost_data[i].data(), cost_data[i].size());
+  for (const auto& cost_datum : cost_data) {
+    AddTrailingMetadata(GRPC_LB_COST_MD_KEY, cost_datum);
   }
-  grpc_call_set_load_reporting_cost_context(call_, cost_ctx);
 }
 
 }  // namespace grpc
diff --git a/src/csharp/Grpc.Core.Tests/AppDomainUnloadTest.cs b/src/csharp/Grpc.Core.Tests/AppDomainUnloadTest.cs
index d7ebdb4201..7858e77b27 100644
--- a/src/csharp/Grpc.Core.Tests/AppDomainUnloadTest.cs
+++ b/src/csharp/Grpc.Core.Tests/AppDomainUnloadTest.cs
@@ -72,10 +72,6 @@ namespace Grpc.Core.Tests
             public AppDomainTestClass()
             {
                 var helper = new MockServiceHelper(Host);
-                var server = helper.GetServer();
-                server.Start();
-                var channel = helper.GetChannel();
-
                 var readyToShutdown = new TaskCompletionSource<object>();
                 helper.DuplexStreamingHandler = new DuplexStreamingServerMethod<string, string>(async (requestStream, responseStream, context) =>
                 {
@@ -83,6 +79,10 @@ namespace Grpc.Core.Tests
                     await requestStream.ToListAsync();
                 });
 
+                var server = helper.GetServer();
+                server.Start();
+                var channel = helper.GetChannel();
+
                 var call = Calls.AsyncDuplexStreamingCall(helper.CreateDuplexStreamingCall());
                 readyToShutdown.Task.Wait();  // make sure handler is running
             }
diff --git a/src/csharp/Grpc.Core.Tests/UserAgentStringTest.cs b/src/csharp/Grpc.Core.Tests/UserAgentStringTest.cs
index cc830086a6..74b4997f69 100644
--- a/src/csharp/Grpc.Core.Tests/UserAgentStringTest.cs
+++ b/src/csharp/Grpc.Core.Tests/UserAgentStringTest.cs
@@ -63,10 +63,6 @@ namespace Grpc.Core.Tests
         public void DefaultUserAgentString()
         {
             helper = new MockServiceHelper(Host);
-            server = helper.GetServer();
-            server.Start();
-            channel = helper.GetChannel();
-
             helper.UnaryHandler = new UnaryServerMethod<string, string>((request, context) =>
             {
                 var userAgentString = context.RequestHeaders.First(m => (m.Key == "user-agent")).Value;
@@ -75,6 +71,11 @@ namespace Grpc.Core.Tests
                 Assert.IsTrue(parts[1].StartsWith("grpc-c/"));
                 return Task.FromResult("PASS");
             });
+
+            server = helper.GetServer();
+            server.Start();
+            channel = helper.GetChannel();
+
             Assert.AreEqual("PASS", Calls.BlockingUnaryCall(helper.CreateUnaryCall(), ""));
         }
 
@@ -83,11 +84,6 @@ namespace Grpc.Core.Tests
         {
             helper = new MockServiceHelper(Host,
                 channelOptions: new[] { new ChannelOption(ChannelOptions.PrimaryUserAgentString, "XYZ") });
-            server = helper.GetServer();
-            server.Start();
-            channel = helper.GetChannel();
-            
-            channel = helper.GetChannel();
             helper.UnaryHandler = new UnaryServerMethod<string, string>((request, context) =>
             {
                 var userAgentString = context.RequestHeaders.First(m => (m.Key == "user-agent")).Value;
@@ -95,6 +91,11 @@ namespace Grpc.Core.Tests
                 Assert.AreEqual("XYZ", parts[0]);
                 return Task.FromResult("PASS");
             });
+
+            server = helper.GetServer();
+            server.Start();
+            channel = helper.GetChannel();
+
             Assert.AreEqual("PASS", Calls.BlockingUnaryCall(helper.CreateUnaryCall(), ""));
         }
     }
diff --git a/src/objective-c/tests/InteropTestsLocalCleartext.m b/src/objective-c/tests/InteropTestsLocalCleartext.m
index 94cdf85965..cdcdd8a88c 100644
--- a/src/objective-c/tests/InteropTestsLocalCleartext.m
+++ b/src/objective-c/tests/InteropTestsLocalCleartext.m
@@ -36,7 +36,11 @@
 
 #import "InteropTests.h"
 
-static NSString * const kLocalCleartextHost = @"localhost:5050";
+// The server address is derived from preprocessor macro, which is
+// in turn derived from environment variable of the same name.
+#define NSStringize_helper(x) #x
+#define NSStringize(x) @NSStringize_helper(x)
+static NSString * const kLocalCleartextHost = NSStringize(HOST_PORT_LOCAL);
 
 // The Protocol Buffers encoding overhead of local interop server. Acquired
 // by experiment. Adjust this when server's proto file changes.
diff --git a/src/objective-c/tests/InteropTestsLocalSSL.m b/src/objective-c/tests/InteropTestsLocalSSL.m
index 3c78b65ede..45e62d29b9 100644
--- a/src/objective-c/tests/InteropTestsLocalSSL.m
+++ b/src/objective-c/tests/InteropTestsLocalSSL.m
@@ -35,8 +35,11 @@
 #import <GRPCClient/internal_testing/GRPCCall+InternalTests.h>
 
 #import "InteropTests.h"
-
-static NSString * const kLocalSSLHost = @"localhost:5051";
+// The server address is derived from preprocessor macro, which is
+// in turn derived from environment variable of the same name.
+#define NSStringize_helper(x) #x
+#define NSStringize(x) @NSStringize_helper(x)
+static NSString * const kLocalSSLHost = NSStringize(HOST_PORT_LOCALSSL);
 
 // The Protocol Buffers encoding overhead of local interop server. Acquired
 // by experiment. Adjust this when server's proto file changes.
diff --git a/src/objective-c/tests/InteropTestsRemote.m b/src/objective-c/tests/InteropTestsRemote.m
index ff1193302b..5260fe4570 100644
--- a/src/objective-c/tests/InteropTestsRemote.m
+++ b/src/objective-c/tests/InteropTestsRemote.m
@@ -36,7 +36,11 @@
 
 #import "InteropTests.h"
 
-static NSString * const kRemoteSSLHost = @"grpc-test.sandbox.googleapis.com";
+// The server address is derived from preprocessor macro, which is
+// in turn derived from environment variable of the same name.
+#define NSStringize_helper(x) #x
+#define NSStringize(x) @NSStringize_helper(x)
+static NSString * const kRemoteSSLHost = NSStringize(HOST_PORT_REMOTE);
 
 // The Protocol Buffers encoding overhead of remote interop server. Acquired
 // by experiment. Adjust this when server's proto file changes.
diff --git a/src/objective-c/tests/InteropTestsRemoteWithCronet/InteropTestsRemoteWithCronet.m b/src/objective-c/tests/InteropTestsRemoteWithCronet/InteropTestsRemoteWithCronet.m
index 9edfbc2639..a7f190d2b4 100644
--- a/src/objective-c/tests/InteropTestsRemoteWithCronet/InteropTestsRemoteWithCronet.m
+++ b/src/objective-c/tests/InteropTestsRemoteWithCronet/InteropTestsRemoteWithCronet.m
@@ -39,7 +39,12 @@
 
 #import "InteropTests.h"
 
-static NSString * const kRemoteSSLHost = @"grpc-test.sandbox.googleapis.com";
+// The server address is derived from preprocessor macro, which is
+// in turn derived from environment variable of the same name.
+#define NSStringize_helper(x) #x
+#define NSStringize(x) @NSStringize_helper(x)
+static NSString * const kRemoteSSLHost = NSStringize(HOST_PORT_REMOTE);
+
 
 // The Protocol Buffers encoding overhead of remote interop server. Acquired
 // by experiment. Adjust this when server's proto file changes.
diff --git a/src/objective-c/tests/Tests.xcodeproj/project.pbxproj b/src/objective-c/tests/Tests.xcodeproj/project.pbxproj
index 97de723a22..b01d5ffcea 100644
--- a/src/objective-c/tests/Tests.xcodeproj/project.pbxproj
+++ b/src/objective-c/tests/Tests.xcodeproj/project.pbxproj
@@ -1282,6 +1282,9 @@
 				GCC_PREPROCESSOR_DEFINITIONS = (
 					"DEBUG=1",
 					"$(inherited)",
+					"HOST_PORT_LOCALSSL=$(HOST_PORT_LOCALSSL)",
+					"HOST_PORT_LOCAL=$(HOST_PORT_LOCAL)",
+					"HOST_PORT_REMOTE=$(HOST_PORT_REMOTE)",
 				);
 				GCC_SYMBOLS_PRIVATE_EXTERN = NO;
 				GCC_TREAT_WARNINGS_AS_ERRORS = YES;
@@ -1565,6 +1568,7 @@
 				GCC_PREPROCESSOR_DEFINITIONS = (
 					"DEBUG=1",
 					"$(inherited)",
+					"HOST_PORT_REMOTE=$(HOST_PORT_REMOTE)",
 				);
 				GCC_SYMBOLS_PRIVATE_EXTERN = NO;
 				GCC_TREAT_WARNINGS_AS_ERRORS = YES;
diff --git a/src/objective-c/tests/run_tests.sh b/src/objective-c/tests/run_tests.sh
index 0e82bcaa44..2432209f4f 100755
--- a/src/objective-c/tests/run_tests.sh
+++ b/src/objective-c/tests/run_tests.sh
@@ -59,6 +59,9 @@ xcodebuild \
     -workspace Tests.xcworkspace \
     -scheme AllTests \
     -destination name="iPhone 6" \
+    HOST_PORT_LOCALSSL=localhost:5051 \
+    HOST_PORT_LOCAL=localhost:5050 \
+    HOST_PORT_REMOTE=grpc-test.sandbox.googleapis.com \
     test | xcpretty
 
 echo "TIME:  $(date)"
@@ -84,4 +87,5 @@ xcodebuild \
     -workspace Tests.xcworkspace \
     -scheme InteropTestsRemoteWithCronet \
     -destination name="iPhone 6" \
+    HOST_PORT_REMOTE=grpc-test.sandbox.googleapis.com \
     test | xcpretty
diff --git a/src/ruby/ext/grpc/rb_grpc_imports.generated.c b/src/ruby/ext/grpc/rb_grpc_imports.generated.c
index 063f92114c..f189e88198 100644
--- a/src/ruby/ext/grpc/rb_grpc_imports.generated.c
+++ b/src/ruby/ext/grpc/rb_grpc_imports.generated.c
@@ -110,7 +110,6 @@ grpc_channel_register_call_type grpc_channel_register_call_import;
 grpc_channel_create_registered_call_type grpc_channel_create_registered_call_import;
 grpc_call_start_batch_type grpc_call_start_batch_import;
 grpc_call_get_peer_type grpc_call_get_peer_import;
-grpc_call_set_load_reporting_cost_context_type grpc_call_set_load_reporting_cost_context_import;
 grpc_census_call_set_context_type grpc_census_call_set_context_import;
 grpc_census_call_get_context_type grpc_census_call_get_context_import;
 grpc_channel_get_target_type grpc_channel_get_target_import;
@@ -407,7 +406,6 @@ void grpc_rb_load_imports(HMODULE library) {
   grpc_channel_create_registered_call_import = (grpc_channel_create_registered_call_type) GetProcAddress(library, "grpc_channel_create_registered_call");
   grpc_call_start_batch_import = (grpc_call_start_batch_type) GetProcAddress(library, "grpc_call_start_batch");
   grpc_call_get_peer_import = (grpc_call_get_peer_type) GetProcAddress(library, "grpc_call_get_peer");
-  grpc_call_set_load_reporting_cost_context_import = (grpc_call_set_load_reporting_cost_context_type) GetProcAddress(library, "grpc_call_set_load_reporting_cost_context");
   grpc_census_call_set_context_import = (grpc_census_call_set_context_type) GetProcAddress(library, "grpc_census_call_set_context");
   grpc_census_call_get_context_import = (grpc_census_call_get_context_type) GetProcAddress(library, "grpc_census_call_get_context");
   grpc_channel_get_target_import = (grpc_channel_get_target_type) GetProcAddress(library, "grpc_channel_get_target");
diff --git a/src/ruby/ext/grpc/rb_grpc_imports.generated.h b/src/ruby/ext/grpc/rb_grpc_imports.generated.h
index e036ff7bd6..dcdc8063a2 100644
--- a/src/ruby/ext/grpc/rb_grpc_imports.generated.h
+++ b/src/ruby/ext/grpc/rb_grpc_imports.generated.h
@@ -281,9 +281,6 @@ extern grpc_call_start_batch_type grpc_call_start_batch_import;
 typedef char *(*grpc_call_get_peer_type)(grpc_call *call);
 extern grpc_call_get_peer_type grpc_call_get_peer_import;
 #define grpc_call_get_peer grpc_call_get_peer_import
-typedef void(*grpc_call_set_load_reporting_cost_context_type)(grpc_call *call, struct grpc_load_reporting_cost_context *context);
-extern grpc_call_set_load_reporting_cost_context_type grpc_call_set_load_reporting_cost_context_import;
-#define grpc_call_set_load_reporting_cost_context grpc_call_set_load_reporting_cost_context_import
 typedef void(*grpc_census_call_set_context_type)(grpc_call *call, struct census_context *context);
 extern grpc_census_call_set_context_type grpc_census_call_set_context_import;
 #define grpc_census_call_set_context grpc_census_call_set_context_import