From 1621c26c1ec49207e994e4b11671fb8fb38225ba Mon Sep 17 00:00:00 2001
From: "Mark D. Roth" <roth@google.com>
Date: Thu, 15 Sep 2016 12:51:29 -0700
Subject: [PATCH] Allow resolver to pass channel args to LB policy.
---
src/core/ext/client_config/client_channel.c | 2 ++
.../ext/client_config/lb_policy_factory.h | 3 +++
src/core/ext/client_config/resolver_result.c | 15 +++++++++++--
src/core/ext/client_config/resolver_result.h | 21 ++++++++++++++++---
.../ext/resolver/dns/native/dns_resolver.c | 2 +-
.../ext/resolver/sockaddr/sockaddr_resolver.c | 2 +-
6 files changed, 38 insertions(+), 7 deletions(-)
diff --git a/src/core/ext/client_config/client_channel.c b/src/core/ext/client_config/client_channel.c
index 2e6f253d38..0343a5e254 100644
--- a/src/core/ext/client_config/client_channel.c
+++ b/src/core/ext/client_config/client_channel.c
@@ -179,6 +179,8 @@ static void on_resolver_result_changed(grpc_exec_ctx *exec_ctx, void *arg,
grpc_lb_policy_args lb_policy_args;
lb_policy_args.addresses =
grpc_resolver_result_get_addresses(chand->resolver_result);
+ lb_policy_args.additional_args =
+ grpc_resolver_result_get_lb_policy_args(chand->resolver_result);
lb_policy_args.client_channel_factory = chand->client_channel_factory;
lb_policy = grpc_lb_policy_create(
exec_ctx,
diff --git a/src/core/ext/client_config/lb_policy_factory.h b/src/core/ext/client_config/lb_policy_factory.h
index 6919b1eb98..e2364c31a8 100644
--- a/src/core/ext/client_config/lb_policy_factory.h
+++ b/src/core/ext/client_config/lb_policy_factory.h
@@ -47,9 +47,12 @@ struct grpc_lb_policy_factory {
const grpc_lb_policy_factory_vtable *vtable;
};
+// TODO(roth, ctiller): Consider replacing this struct with
+// grpc_channel_args. See comment in resolver_result.h for details.
typedef struct grpc_lb_policy_args {
grpc_addresses *addresses;
grpc_client_channel_factory *client_channel_factory;
+ grpc_channel_args *additional_args;
} grpc_lb_policy_args;
struct grpc_lb_policy_factory_vtable {
diff --git a/src/core/ext/client_config/resolver_result.c b/src/core/ext/client_config/resolver_result.c
index ac263b9a46..f97dc467e1 100644
--- a/src/core/ext/client_config/resolver_result.c
+++ b/src/core/ext/client_config/resolver_result.c
@@ -36,6 +36,8 @@
#include <grpc/support/alloc.h>
#include <grpc/support/string_util.h>
+#include "src/core/lib/channel/channel_args.h"
+
grpc_addresses* grpc_addresses_create(size_t num_addresses) {
grpc_addresses* addresses = gpr_malloc(sizeof(grpc_addresses));
addresses->num_addresses = num_addresses;
@@ -71,15 +73,18 @@ struct grpc_resolver_result {
gpr_refcount refs;
grpc_addresses* addresses;
char* lb_policy_name;
+ grpc_channel_args* lb_policy_args;
};
-grpc_resolver_result* grpc_resolver_result_create(grpc_addresses* addresses,
- const char* lb_policy_name) {
+grpc_resolver_result* grpc_resolver_result_create(
+ grpc_addresses* addresses, const char* lb_policy_name,
+ grpc_channel_args* lb_policy_args) {
grpc_resolver_result* result = gpr_malloc(sizeof(*result));
memset(result, 0, sizeof(*result));
gpr_ref_init(&result->refs, 1);
result->addresses = addresses;
result->lb_policy_name = gpr_strdup(lb_policy_name);
+ result->lb_policy_args = lb_policy_args;
return result;
}
@@ -92,6 +97,7 @@ void grpc_resolver_result_unref(grpc_exec_ctx* exec_ctx,
if (gpr_unref(&result->refs)) {
grpc_addresses_destroy(result->addresses);
gpr_free(result->lb_policy_name);
+ grpc_channel_args_destroy(result->lb_policy_args);
gpr_free(result);
}
}
@@ -105,3 +111,8 @@ const char* grpc_resolver_result_get_lb_policy_name(
grpc_resolver_result* result) {
return result->lb_policy_name;
}
+
+grpc_channel_args* grpc_resolver_result_get_lb_policy_args(
+ grpc_resolver_result* result) {
+ return result->lb_policy_args;
+}
diff --git a/src/core/ext/client_config/resolver_result.h b/src/core/ext/client_config/resolver_result.h
index fa60c8cc6d..821208f709 100644
--- a/src/core/ext/client_config/resolver_result.h
+++ b/src/core/ext/client_config/resolver_result.h
@@ -37,6 +37,16 @@
#include "src/core/ext/client_config/lb_policy.h"
#include "src/core/lib/iomgr/resolve_address.h"
+// TODO(roth, ctiller): In the long term, we are considering replacing
+// the resolver_result data structure with grpc_channel_args. The idea is
+// that the resolver will return a set of channel args that contains the
+// information that is currently in the resolver_result struct. For
+// example, there will be specific args indicating the set of addresses
+// and the name of the LB policy to instantiate. Note that if we did
+// this, we would probably want to change the data structure of
+// grpc_channel_args such to a hash table or AVL or some other data
+// structure that does not require linear search to find keys.
+
/// Used to represent addresses returned by the resolver.
typedef struct grpc_address {
grpc_resolved_address address;
@@ -63,9 +73,10 @@ void grpc_addresses_destroy(grpc_addresses* addresses);
/// Results reported from a grpc_resolver.
typedef struct grpc_resolver_result grpc_resolver_result;
-/// Takes ownership of \a addresses.
-grpc_resolver_result* grpc_resolver_result_create(grpc_addresses* addresses,
- const char* lb_policy_name);
+/// Takes ownership of \a addresses and \a lb_policy_args.
+grpc_resolver_result* grpc_resolver_result_create(
+ grpc_addresses* addresses, const char* lb_policy_name,
+ grpc_channel_args* lb_policy_args);
void grpc_resolver_result_ref(grpc_resolver_result* result);
void grpc_resolver_result_unref(grpc_exec_ctx* exec_ctx,
grpc_resolver_result* result);
@@ -78,4 +89,8 @@ grpc_addresses* grpc_resolver_result_get_addresses(
const char* grpc_resolver_result_get_lb_policy_name(
grpc_resolver_result* result);
+/// Caller does NOT take ownership of result.
+grpc_channel_args* grpc_resolver_result_get_lb_policy_args(
+ grpc_resolver_result* result);
+
#endif /* GRPC_CORE_EXT_CLIENT_CONFIG_RESOLVER_RESULT_H */
diff --git a/src/core/ext/resolver/dns/native/dns_resolver.c b/src/core/ext/resolver/dns/native/dns_resolver.c
index 78a996788d..103d3effbd 100644
--- a/src/core/ext/resolver/dns/native/dns_resolver.c
+++ b/src/core/ext/resolver/dns/native/dns_resolver.c
@@ -174,7 +174,7 @@ static void dns_on_resolved(grpc_exec_ctx *exec_ctx, void *arg,
false /* is_balancer */);
}
grpc_resolved_addresses_destroy(r->addresses);
- result = grpc_resolver_result_create(addresses, r->lb_policy_name);
+ result = grpc_resolver_result_create(addresses, r->lb_policy_name, NULL);
} else {
gpr_timespec now = gpr_now(GPR_CLOCK_MONOTONIC);
gpr_timespec next_try = gpr_backoff_step(&r->backoff_state, now);
diff --git a/src/core/ext/resolver/sockaddr/sockaddr_resolver.c b/src/core/ext/resolver/sockaddr/sockaddr_resolver.c
index 5c59e4397a..fb67f1a227 100644
--- a/src/core/ext/resolver/sockaddr/sockaddr_resolver.c
+++ b/src/core/ext/resolver/sockaddr/sockaddr_resolver.c
@@ -121,7 +121,7 @@ static void sockaddr_maybe_finish_next_locked(grpc_exec_ctx *exec_ctx,
if (r->next_completion != NULL && !r->published) {
r->published = true;
*r->target_result = grpc_resolver_result_create(
- grpc_addresses_copy(r->addresses), r->lb_policy_name);
+ grpc_addresses_copy(r->addresses), r->lb_policy_name, NULL);
grpc_exec_ctx_sched(exec_ctx, r->next_completion, GRPC_ERROR_NONE, NULL);
r->next_completion = NULL;
}
--
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