Implement LB policy updates
diff --git a/src/core/ext/filters/client_channel/lb_policy/pick_first/pick_first.c b/src/core/ext/filters/client_channel/lb_policy/pick_first/pick_first.c
index b1c5dfc..b6f8625 100644
--- a/src/core/ext/filters/client_channel/lb_policy/pick_first/pick_first.c
+++ b/src/core/ext/filters/client_channel/lb_policy/pick_first/pick_first.c
@@ -37,11 +37,14 @@
#include "src/core/ext/filters/client_channel/lb_policy_registry.h"
#include "src/core/ext/filters/client_channel/subchannel.h"
+#include "src/core/ext/filters/client_channel/subchannel_index.h"
#include "src/core/lib/channel/channel_args.h"
#include "src/core/lib/iomgr/combiner.h"
#include "src/core/lib/iomgr/sockaddr_utils.h"
#include "src/core/lib/transport/connectivity_state.h"
+grpc_tracer_flag grpc_lb_pick_first_trace = GRPC_TRACER_INITIALIZER(false);
+
typedef struct pending_pick {
struct pending_pick *next;
uint32_t initial_metadata_flags;
@@ -54,7 +57,9 @@
grpc_lb_policy base;
/** all our subchannels */
grpc_subchannel **subchannels;
+ grpc_subchannel **new_subchannels;
size_t num_subchannels;
+ size_t num_new_subchannels;
grpc_closure connectivity_changed;
@@ -63,10 +68,19 @@
/** the selected channel */
grpc_connected_subchannel *selected;
+ /** the subchannel key for \a selected, or NULL if \a selected not set */
+ const grpc_subchannel_key *selected_key;
+
/** have we started picking? */
- int started_picking;
+ bool started_picking;
/** are we shut down? */
- int shutdown;
+ bool shutdown;
+ /** are we updating the selected subchannel? */
+ bool updating_selected;
+ /** are we updating the subchannel candidates? */
+ bool updating_subchannels;
+ /** args from the latest update received while already updating, or NULL */
+ grpc_lb_policy_args *pending_update_args;
/** which subchannel are we watching? */
size_t checking_subchannel;
/** what is the connectivity of that channel? */
@@ -80,23 +94,28 @@
static void pf_destroy(grpc_exec_ctx *exec_ctx, grpc_lb_policy *pol) {
pick_first_lb_policy *p = (pick_first_lb_policy *)pol;
- size_t i;
GPR_ASSERT(p->pending_picks == NULL);
- for (i = 0; i < p->num_subchannels; i++) {
- GRPC_SUBCHANNEL_UNREF(exec_ctx, p->subchannels[i], "pick_first");
+ for (size_t i = 0; i < p->num_subchannels; i++) {
+ GRPC_SUBCHANNEL_UNREF(exec_ctx, p->subchannels[i], "pick_first_destroy");
}
if (p->selected != NULL) {
- GRPC_CONNECTED_SUBCHANNEL_UNREF(exec_ctx, p->selected, "picked_first");
+ GRPC_CONNECTED_SUBCHANNEL_UNREF(exec_ctx, p->selected,
+ "picked_first_destroy");
}
grpc_connectivity_state_destroy(exec_ctx, &p->state_tracker);
+ if (p->pending_update_args != NULL) {
+ grpc_channel_args_destroy(exec_ctx, p->pending_update_args->args);
+ gpr_free(p->pending_update_args);
+ }
gpr_free(p->subchannels);
+ gpr_free(p->new_subchannels);
gpr_free(p);
}
static void pf_shutdown_locked(grpc_exec_ctx *exec_ctx, grpc_lb_policy *pol) {
pick_first_lb_policy *p = (pick_first_lb_policy *)pol;
pending_pick *pp;
- p->shutdown = 1;
+ p->shutdown = true;
pp = p->pending_picks;
p->pending_picks = NULL;
grpc_connectivity_state_set(
@@ -106,7 +125,7 @@
if (p->selected != NULL) {
grpc_connected_subchannel_notify_on_state_change(
exec_ctx, p->selected, NULL, NULL, &p->connectivity_changed);
- } else if (p->num_subchannels > 0) {
+ } else if (p->num_subchannels > 0 && p->started_picking) {
grpc_subchannel_notify_on_state_change(
exec_ctx, p->subchannels[p->checking_subchannel], NULL, NULL,
&p->connectivity_changed);
@@ -169,21 +188,25 @@
GRPC_ERROR_UNREF(error);
}
-static void start_picking(grpc_exec_ctx *exec_ctx, pick_first_lb_policy *p) {
- p->started_picking = 1;
- p->checking_subchannel = 0;
- p->checking_connectivity = GRPC_CHANNEL_IDLE;
- GRPC_LB_POLICY_WEAK_REF(&p->base, "pick_first_connectivity");
- grpc_subchannel_notify_on_state_change(
- exec_ctx, p->subchannels[p->checking_subchannel],
- p->base.interested_parties, &p->checking_connectivity,
- &p->connectivity_changed);
+static void start_picking_locked(grpc_exec_ctx *exec_ctx,
+ pick_first_lb_policy *p) {
+ p->started_picking = true;
+ if (p->subchannels != NULL) {
+ GPR_ASSERT(p->num_subchannels > 0);
+ p->checking_subchannel = 0;
+ p->checking_connectivity = GRPC_CHANNEL_IDLE;
+ GRPC_LB_POLICY_WEAK_REF(&p->base, "pick_first_connectivity");
+ grpc_subchannel_notify_on_state_change(
+ exec_ctx, p->subchannels[p->checking_subchannel],
+ p->base.interested_parties, &p->checking_connectivity,
+ &p->connectivity_changed);
+ }
}
static void pf_exit_idle_locked(grpc_exec_ctx *exec_ctx, grpc_lb_policy *pol) {
pick_first_lb_policy *p = (pick_first_lb_policy *)pol;
if (!p->started_picking) {
- start_picking(exec_ctx, p);
+ start_picking_locked(exec_ctx, p);
}
}
@@ -203,7 +226,7 @@
/* No subchannel selected yet, so try again */
if (!p->started_picking) {
- start_picking(exec_ctx, p);
+ start_picking_locked(exec_ctx, p);
}
pp = gpr_malloc(sizeof(*pp));
pp->next = p->pending_picks;
@@ -216,30 +239,290 @@
static void destroy_subchannels_locked(grpc_exec_ctx *exec_ctx,
pick_first_lb_policy *p) {
- size_t i;
size_t num_subchannels = p->num_subchannels;
- grpc_subchannel **subchannels;
+ grpc_subchannel **subchannels = p->subchannels;
- subchannels = p->subchannels;
p->num_subchannels = 0;
p->subchannels = NULL;
GRPC_LB_POLICY_WEAK_UNREF(exec_ctx, &p->base, "destroy_subchannels");
- for (i = 0; i < num_subchannels; i++) {
+ for (size_t i = 0; i < num_subchannels; i++) {
GRPC_SUBCHANNEL_UNREF(exec_ctx, subchannels[i], "pick_first");
}
-
gpr_free(subchannels);
}
+static grpc_connectivity_state pf_check_connectivity_locked(
+ grpc_exec_ctx *exec_ctx, grpc_lb_policy *pol, grpc_error **error) {
+ pick_first_lb_policy *p = (pick_first_lb_policy *)pol;
+ return grpc_connectivity_state_get(&p->state_tracker, error);
+}
+
+static void pf_notify_on_state_change_locked(grpc_exec_ctx *exec_ctx,
+ grpc_lb_policy *pol,
+ grpc_connectivity_state *current,
+ grpc_closure *notify) {
+ pick_first_lb_policy *p = (pick_first_lb_policy *)pol;
+ grpc_connectivity_state_notify_on_state_change(exec_ctx, &p->state_tracker,
+ current, notify);
+}
+
+static void pf_ping_one_locked(grpc_exec_ctx *exec_ctx, grpc_lb_policy *pol,
+ grpc_closure *closure) {
+ pick_first_lb_policy *p = (pick_first_lb_policy *)pol;
+ if (p->selected) {
+ grpc_connected_subchannel_ping(exec_ctx, p->selected, closure);
+ } else {
+ grpc_closure_sched(exec_ctx, closure,
+ GRPC_ERROR_CREATE_FROM_STATIC_STRING("Not connected"));
+ }
+}
+
+/* unsubscribe all subchannels */
+static void stop_connectivity_watchers(grpc_exec_ctx *exec_ctx,
+ pick_first_lb_policy *p) {
+ if (p->num_subchannels > 0) {
+ GPR_ASSERT(p->selected == NULL);
+ grpc_subchannel_notify_on_state_change(
+ exec_ctx, p->subchannels[p->checking_subchannel], NULL, NULL,
+ &p->connectivity_changed);
+ p->updating_subchannels = true;
+ } else if (p->selected != NULL) {
+ grpc_connected_subchannel_notify_on_state_change(
+ exec_ctx, p->selected, NULL, NULL, &p->connectivity_changed);
+ p->updating_selected = true;
+ }
+}
+
+/* true upon success */
+static void pf_update_locked(grpc_exec_ctx *exec_ctx, grpc_lb_policy *policy,
+ const grpc_lb_policy_args *args) {
+ pick_first_lb_policy *p = (pick_first_lb_policy *)policy;
+ /* Find the number of backend addresses. We ignore balancer
+ * addresses, since we don't know how to handle them. */
+ const grpc_arg *arg =
+ grpc_channel_args_find(args->args, GRPC_ARG_LB_ADDRESSES);
+ if (arg == NULL || arg->type != GRPC_ARG_POINTER) {
+ if (p->subchannels == NULL) {
+ // If we don't have a current subchannel list, go into TRANSIENT FAILURE.
+ grpc_connectivity_state_set(
+ exec_ctx, &p->state_tracker, GRPC_CHANNEL_TRANSIENT_FAILURE,
+ GRPC_ERROR_CREATE_FROM_STATIC_STRING("Missing update in args"),
+ "pf_update_missing");
+ } else {
+ // otherwise, keep using the current subchannel list (ignore this update).
+ gpr_log(GPR_ERROR,
+ "No valid LB addresses channel arg for Pick First %p update, "
+ "ignoring.",
+ (void *)p);
+ }
+ return;
+ }
+ const grpc_lb_addresses *addresses = arg->value.pointer.p;
+ size_t num_addrs = 0;
+ for (size_t i = 0; i < addresses->num_addresses; i++) {
+ if (!addresses->addresses[i].is_balancer) ++num_addrs;
+ }
+ if (num_addrs == 0) {
+ // Empty update. Unsubscribe from all current subchannels and put the
+ // channel in TRANSIENT_FAILURE.
+ grpc_connectivity_state_set(
+ exec_ctx, &p->state_tracker, GRPC_CHANNEL_TRANSIENT_FAILURE,
+ GRPC_ERROR_CREATE_FROM_STATIC_STRING("Empty update"),
+ "pf_update_empty");
+ stop_connectivity_watchers(exec_ctx, p);
+ return;
+ }
+ if (GRPC_TRACER_ON(grpc_lb_pick_first_trace)) {
+ gpr_log(GPR_INFO, "Pick First %p received update with %lu addresses",
+ (void *)p, (unsigned long)num_addrs);
+ }
+ grpc_subchannel_args *sc_args = gpr_zalloc(sizeof(*sc_args) * num_addrs);
+ /* We remove the following keys in order for subchannel keys belonging to
+ * subchannels point to the same address to match. */
+ static const char *keys_to_remove[] = {GRPC_ARG_SUBCHANNEL_ADDRESS,
+ GRPC_ARG_LB_ADDRESSES};
+ size_t sc_args_count = 0;
+
+ /* Create list of subchannel args for new addresses in \a args. */
+ for (size_t i = 0; i < addresses->num_addresses; i++) {
+ if (addresses->addresses[i].is_balancer) continue;
+ if (addresses->addresses[i].user_data != NULL) {
+ gpr_log(GPR_ERROR,
+ "This LB policy doesn't support user data. It will be ignored");
+ }
+ grpc_arg addr_arg =
+ grpc_create_subchannel_address_arg(&addresses->addresses[i].address);
+ grpc_channel_args *new_args = grpc_channel_args_copy_and_add_and_remove(
+ args->args, keys_to_remove, GPR_ARRAY_SIZE(keys_to_remove), &addr_arg,
+ 1);
+ gpr_free(addr_arg.value.string);
+ sc_args[sc_args_count++].args = new_args;
+ }
+
+ /* Check if p->selected is amongst them. If so, we are done. */
+ if (p->selected != NULL) {
+ GPR_ASSERT(p->selected_key != NULL);
+ for (size_t i = 0; i < sc_args_count; i++) {
+ grpc_subchannel_key *ith_sc_key = grpc_subchannel_key_create(&sc_args[i]);
+ const bool found_selected =
+ grpc_subchannel_key_compare(p->selected_key, ith_sc_key) == 0;
+ grpc_subchannel_key_destroy(exec_ctx, ith_sc_key);
+ if (found_selected) {
+ // The currently selected subchannel is in the update: we are done.
+ if (GRPC_TRACER_ON(grpc_lb_pick_first_trace)) {
+ gpr_log(GPR_INFO,
+ "Pick First %p found already selected subchannel %p amongst "
+ "updates. Update done.",
+ (void *)p, (void *)p->selected);
+ }
+ for (size_t j = 0; j < sc_args_count; j++) {
+ grpc_channel_args_destroy(exec_ctx,
+ (grpc_channel_args *)sc_args[j].args);
+ }
+ gpr_free(sc_args);
+ return;
+ }
+ }
+ }
+ // We only check for already running updates here because if the previous
+ // steps were successful, the update can be considered done without any
+ // interference (ie, no callbacks were scheduled).
+ if (p->updating_selected || p->updating_subchannels) {
+ if (GRPC_TRACER_ON(grpc_lb_pick_first_trace)) {
+ gpr_log(GPR_INFO,
+ "Update already in progress for pick first %p. Deferring update.",
+ (void *)p);
+ }
+ if (p->pending_update_args != NULL) {
+ grpc_channel_args_destroy(exec_ctx, p->pending_update_args->args);
+ gpr_free(p->pending_update_args);
+ }
+ p->pending_update_args = gpr_zalloc(sizeof(*p->pending_update_args));
+ p->pending_update_args->client_channel_factory =
+ args->client_channel_factory;
+ p->pending_update_args->args = grpc_channel_args_copy(args->args);
+ p->pending_update_args->combiner = args->combiner;
+ return;
+ }
+ /* Create the subchannels for the new subchannel args/addresses. */
+ grpc_subchannel **new_subchannels =
+ gpr_zalloc(sizeof(*new_subchannels) * sc_args_count);
+ size_t num_new_subchannels = 0;
+ for (size_t i = 0; i < sc_args_count; i++) {
+ grpc_subchannel *subchannel = grpc_client_channel_factory_create_subchannel(
+ exec_ctx, args->client_channel_factory, &sc_args[i]);
+ if (GRPC_TRACER_ON(grpc_lb_pick_first_trace)) {
+ char *address_uri =
+ grpc_sockaddr_to_uri(&addresses->addresses[i].address);
+ gpr_log(GPR_INFO,
+ "Pick First %p created subchannel %p for address uri %s",
+ (void *)p, (void *)subchannel, address_uri);
+ gpr_free(address_uri);
+ }
+ grpc_channel_args_destroy(exec_ctx, (grpc_channel_args *)sc_args[i].args);
+ if (subchannel != NULL) new_subchannels[num_new_subchannels++] = subchannel;
+ }
+ gpr_free(sc_args);
+ if (num_new_subchannels == 0) {
+ gpr_free(new_subchannels);
+ // Empty update. Unsubscribe from all current subchannels and put the
+ // channel in TRANSIENT_FAILURE.
+ grpc_connectivity_state_set(
+ exec_ctx, &p->state_tracker, GRPC_CHANNEL_TRANSIENT_FAILURE,
+ GRPC_ERROR_CREATE_FROM_STATIC_STRING("No valid addresses in update"),
+ "pf_update_no_valid_addresses");
+ stop_connectivity_watchers(exec_ctx, p);
+ return;
+ }
+
+ /* Destroy the current subchannels. Repurpose pf_shutdown/destroy. */
+ stop_connectivity_watchers(exec_ctx, p);
+
+ /* Save new subchannels. The switch over will happen in
+ * pf_connectivity_changed_locked */
+ if (p->updating_selected || p->updating_subchannels) {
+ p->num_new_subchannels = num_new_subchannels;
+ p->new_subchannels = new_subchannels;
+ } else { /* nothing is updating. Get things moving from here */
+ p->num_subchannels = num_new_subchannels;
+ p->subchannels = new_subchannels;
+ p->new_subchannels = NULL;
+ p->num_new_subchannels = 0;
+ if (p->started_picking) {
+ p->checking_subchannel = 0;
+ p->checking_connectivity = GRPC_CHANNEL_IDLE;
+ grpc_subchannel_notify_on_state_change(
+ exec_ctx, p->subchannels[p->checking_subchannel],
+ p->base.interested_parties, &p->checking_connectivity,
+ &p->connectivity_changed);
+ }
+ }
+}
+
static void pf_connectivity_changed_locked(grpc_exec_ctx *exec_ctx, void *arg,
grpc_error *error) {
pick_first_lb_policy *p = arg;
grpc_subchannel *selected_subchannel;
pending_pick *pp;
- GRPC_ERROR_REF(error);
+ bool restart = false;
+ if (p->updating_selected && error == GRPC_ERROR_CANCELLED) {
+ /* Captured the unsubscription for p->selected */
+ GPR_ASSERT(p->selected != NULL);
+ GRPC_CONNECTED_SUBCHANNEL_UNREF(exec_ctx, p->selected,
+ "pf_update_connectivity");
+ p->updating_selected = false;
+ if (p->num_new_subchannels == 0) {
+ p->selected = NULL;
+ return;
+ }
+ restart = true;
+ }
+ if (p->updating_subchannels && error == GRPC_ERROR_CANCELLED) {
+ /* Captured the unsubscription for the checking subchannel */
+ GPR_ASSERT(p->selected == NULL);
+ for (size_t i = 0; i < p->num_subchannels; i++) {
+ GRPC_SUBCHANNEL_UNREF(exec_ctx, p->subchannels[i],
+ "pf_update_connectivity");
+ }
+ gpr_free(p->subchannels);
+ p->subchannels = NULL;
+ p->num_subchannels = 0;
+ p->updating_subchannels = false;
+ if (p->num_new_subchannels == 0) return;
+ restart = true;
+ }
+ if (restart) {
+ p->selected = NULL;
+ p->selected_key = NULL;
+ GPR_ASSERT(p->new_subchannels != NULL);
+ GPR_ASSERT(p->num_new_subchannels > 0);
+ p->num_subchannels = p->num_new_subchannels;
+ p->subchannels = p->new_subchannels;
+ p->num_new_subchannels = 0;
+ p->new_subchannels = NULL;
+
+ if (p->started_picking) {
+ /* If we were picking, continue to do so over the new subchannels,
+ * starting from the 0th index. */
+ p->checking_subchannel = 0;
+ p->checking_connectivity = GRPC_CHANNEL_IDLE;
+ /* reuses the weak ref from start_picking_locked */
+ grpc_subchannel_notify_on_state_change(
+ exec_ctx, p->subchannels[p->checking_subchannel],
+ p->base.interested_parties, &p->checking_connectivity,
+ &p->connectivity_changed);
+ }
+ if (p->pending_update_args != NULL) {
+ const grpc_lb_policy_args *args = p->pending_update_args;
+ p->pending_update_args = NULL;
+ pf_update_locked(exec_ctx, &p->base, args);
+ }
+ return;
+ }
+ GRPC_ERROR_REF(error);
if (p->shutdown) {
GRPC_LB_POLICY_WEAK_UNREF(exec_ctx, &p->base, "pick_first_connectivity");
GRPC_ERROR_UNREF(error);
@@ -272,6 +555,11 @@
p->selected = GRPC_CONNECTED_SUBCHANNEL_REF(
grpc_subchannel_get_connected_subchannel(selected_subchannel),
"picked_first");
+
+ if (GRPC_TRACER_ON(grpc_lb_pick_first_trace)) {
+ gpr_log(GPR_INFO, "Selected subchannel %p", (void *)p->selected);
+ }
+ p->selected_key = grpc_subchannel_get_key(selected_subchannel);
/* drop the pick list: we are connected now */
GRPC_LB_POLICY_WEAK_REF(&p->base, "destroy_subchannels");
destroy_subchannels_locked(exec_ctx, p);
@@ -279,6 +567,11 @@
while ((pp = p->pending_picks)) {
p->pending_picks = pp->next;
*pp->target = GRPC_CONNECTED_SUBCHANNEL_REF(p->selected, "picked");
+ if (GRPC_TRACER_ON(grpc_lb_pick_first_trace)) {
+ gpr_log(GPR_INFO,
+ "Servicing pending pick with selected subchannel %p",
+ (void *)p->selected);
+ }
grpc_closure_sched(exec_ctx, pp->on_complete, GRPC_ERROR_NONE);
gpr_free(pp);
}
@@ -353,32 +646,6 @@
GRPC_ERROR_UNREF(error);
}
-static grpc_connectivity_state pf_check_connectivity_locked(
- grpc_exec_ctx *exec_ctx, grpc_lb_policy *pol, grpc_error **error) {
- pick_first_lb_policy *p = (pick_first_lb_policy *)pol;
- return grpc_connectivity_state_get(&p->state_tracker, error);
-}
-
-static void pf_notify_on_state_change_locked(grpc_exec_ctx *exec_ctx,
- grpc_lb_policy *pol,
- grpc_connectivity_state *current,
- grpc_closure *notify) {
- pick_first_lb_policy *p = (pick_first_lb_policy *)pol;
- grpc_connectivity_state_notify_on_state_change(exec_ctx, &p->state_tracker,
- current, notify);
-}
-
-static void pf_ping_one_locked(grpc_exec_ctx *exec_ctx, grpc_lb_policy *pol,
- grpc_closure *closure) {
- pick_first_lb_policy *p = (pick_first_lb_policy *)pol;
- if (p->selected) {
- grpc_connected_subchannel_ping(exec_ctx, p->selected, closure);
- } else {
- grpc_closure_sched(exec_ctx, closure,
- GRPC_ERROR_CREATE_FROM_STATIC_STRING("Not connected"));
- }
-}
-
static const grpc_lb_policy_vtable pick_first_lb_policy_vtable = {
pf_destroy,
pf_shutdown_locked,
@@ -388,7 +655,8 @@
pf_ping_one_locked,
pf_exit_idle_locked,
pf_check_connectivity_locked,
- pf_notify_on_state_change_locked};
+ pf_notify_on_state_change_locked,
+ pf_update_locked};
static void pick_first_factory_ref(grpc_lb_policy_factory *factory) {}
@@ -398,59 +666,8 @@
grpc_lb_policy_factory *factory,
grpc_lb_policy_args *args) {
GPR_ASSERT(args->client_channel_factory != NULL);
-
- /* Find the number of backend addresses. We ignore balancer
- * addresses, since we don't know how to handle them. */
- const grpc_arg *arg =
- grpc_channel_args_find(args->args, GRPC_ARG_LB_ADDRESSES);
- if (arg == NULL || arg->type != GRPC_ARG_POINTER) {
- return NULL;
- }
- grpc_lb_addresses *addresses = arg->value.pointer.p;
- size_t num_addrs = 0;
- for (size_t i = 0; i < addresses->num_addresses; i++) {
- if (!addresses->addresses[i].is_balancer) ++num_addrs;
- }
- if (num_addrs == 0) return NULL;
-
pick_first_lb_policy *p = gpr_zalloc(sizeof(*p));
-
- p->subchannels = gpr_zalloc(sizeof(grpc_subchannel *) * num_addrs);
- grpc_subchannel_args sc_args;
- size_t subchannel_idx = 0;
- for (size_t i = 0; i < addresses->num_addresses; i++) {
- /* Skip balancer addresses, since we only know how to handle backends. */
- if (addresses->addresses[i].is_balancer) continue;
-
- if (addresses->addresses[i].user_data != NULL) {
- gpr_log(GPR_ERROR,
- "This LB policy doesn't support user data. It will be ignored");
- }
-
- static const char *keys_to_remove[] = {GRPC_ARG_SUBCHANNEL_ADDRESS};
- memset(&sc_args, 0, sizeof(grpc_subchannel_args));
- grpc_arg addr_arg =
- grpc_create_subchannel_address_arg(&addresses->addresses[i].address);
- grpc_channel_args *new_args = grpc_channel_args_copy_and_add_and_remove(
- args->args, keys_to_remove, GPR_ARRAY_SIZE(keys_to_remove), &addr_arg,
- 1);
- gpr_free(addr_arg.value.string);
- sc_args.args = new_args;
- grpc_subchannel *subchannel = grpc_client_channel_factory_create_subchannel(
- exec_ctx, args->client_channel_factory, &sc_args);
- grpc_channel_args_destroy(exec_ctx, new_args);
-
- if (subchannel != NULL) {
- p->subchannels[subchannel_idx++] = subchannel;
- }
- }
- if (subchannel_idx == 0) {
- gpr_free(p->subchannels);
- gpr_free(p);
- return NULL;
- }
- p->num_subchannels = subchannel_idx;
-
+ pf_update_locked(exec_ctx, &p->base, args);
grpc_lb_policy_init(&p->base, &pick_first_lb_policy_vtable, args->combiner);
grpc_closure_init(&p->connectivity_changed, pf_connectivity_changed_locked, p,
grpc_combiner_scheduler(args->combiner, false));
@@ -472,6 +689,7 @@
void grpc_lb_policy_pick_first_init() {
grpc_register_lb_policy(pick_first_lb_factory_create());
+ grpc_register_tracer("pick_first", &grpc_lb_pick_first_trace);
}
void grpc_lb_policy_pick_first_shutdown() {}