diff options
Diffstat (limited to 'src/core/ext/resolver/zookeeper/zookeeper_resolver.c')
| -rw-r--r-- | src/core/ext/resolver/zookeeper/zookeeper_resolver.c | 512 |
1 files changed, 512 insertions, 0 deletions
diff --git a/src/core/ext/resolver/zookeeper/zookeeper_resolver.c b/src/core/ext/resolver/zookeeper/zookeeper_resolver.c new file mode 100644 index 0000000000..5acb0940c6 --- /dev/null +++ b/src/core/ext/resolver/zookeeper/zookeeper_resolver.c @@ -0,0 +1,512 @@ +/* + * + * Copyright 2015, Google Inc. + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions are + * met: + * + * * Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * * Redistributions in binary form must reproduce the above + * copyright notice, this list of conditions and the following disclaimer + * in the documentation and/or other materials provided with the + * distribution. + * * Neither the name of Google Inc. nor the names of its + * contributors may be used to endorse or promote products derived from + * this software without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS + * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT + * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR + * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT + * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, + * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT + * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, + * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY + * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT + * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE + * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + * + */ + +#include <string.h> + +#include <grpc/support/alloc.h> +#include <grpc/support/string_util.h> + +#include <grpc/grpc_zookeeper.h> +#include <zookeeper/zookeeper.h> + +#include "src/core/lib/client_config/lb_policy_registry.h" +#include "src/core/lib/client_config/resolver_registry.h" +#include "src/core/lib/iomgr/resolve_address.h" +#include "src/core/lib/json/json.h" +#include "src/core/lib/support/string.h" +#include "src/core/lib/surface/api_trace.h" + +/** Zookeeper session expiration time in milliseconds */ +#define GRPC_ZOOKEEPER_SESSION_TIMEOUT 15000 + +typedef struct { + /** base class: must be first */ + grpc_resolver base; + /** refcount */ + gpr_refcount refs; + /** name to resolve */ + char *name; + /** subchannel factory */ + grpc_subchannel_factory *subchannel_factory; + /** load balancing policy name */ + char *lb_policy_name; + + /** mutex guarding the rest of the state */ + gpr_mu mu; + /** are we currently resolving? */ + int resolving; + /** which version of resolved_config have we published? */ + int published_version; + /** which version of resolved_config is current? */ + int resolved_version; + /** pending next completion, or NULL */ + grpc_closure *next_completion; + /** target config address for next completion */ + grpc_client_config **target_config; + /** current (fully resolved) config */ + grpc_client_config *resolved_config; + + /** zookeeper handle */ + zhandle_t *zookeeper_handle; + /** zookeeper resolved addresses */ + grpc_resolved_addresses *resolved_addrs; + /** total number of addresses to be resolved */ + int resolved_total; + /** number of addresses resolved */ + int resolved_num; +} zookeeper_resolver; + +static void zookeeper_destroy(grpc_exec_ctx *exec_ctx, grpc_resolver *r); + +static void zookeeper_start_resolving_locked(zookeeper_resolver *r); +static void zookeeper_maybe_finish_next_locked(grpc_exec_ctx *exec_ctx, + zookeeper_resolver *r); + +static void zookeeper_shutdown(grpc_exec_ctx *exec_ctx, grpc_resolver *r); +static void zookeeper_channel_saw_error(grpc_exec_ctx *exec_ctx, + grpc_resolver *r); +static void zookeeper_next(grpc_exec_ctx *exec_ctx, grpc_resolver *r, + grpc_client_config **target_config, + grpc_closure *on_complete); + +static const grpc_resolver_vtable zookeeper_resolver_vtable = { + zookeeper_destroy, zookeeper_shutdown, zookeeper_channel_saw_error, + zookeeper_next}; + +static void zookeeper_shutdown(grpc_exec_ctx *exec_ctx, + grpc_resolver *resolver) { + zookeeper_resolver *r = (zookeeper_resolver *)resolver; + grpc_closure *call = NULL; + gpr_mu_lock(&r->mu); + if (r->next_completion != NULL) { + *r->target_config = NULL; + call = r->next_completion; + r->next_completion = NULL; + } + zookeeper_close(r->zookeeper_handle); + gpr_mu_unlock(&r->mu); + if (call != NULL) { + call->cb(exec_ctx, call->cb_arg, 1); + } +} + +static void zookeeper_channel_saw_error(grpc_exec_ctx *exec_ctx, + grpc_resolver *resolver) { + zookeeper_resolver *r = (zookeeper_resolver *)resolver; + gpr_mu_lock(&r->mu); + if (r->resolving == 0) { + zookeeper_start_resolving_locked(r); + } + gpr_mu_unlock(&r->mu); +} + +static void zookeeper_next(grpc_exec_ctx *exec_ctx, grpc_resolver *resolver, + grpc_client_config **target_config, + grpc_closure *on_complete) { + zookeeper_resolver *r = (zookeeper_resolver *)resolver; + gpr_mu_lock(&r->mu); + GPR_ASSERT(r->next_completion == NULL); + r->next_completion = on_complete; + r->target_config = target_config; + if (r->resolved_version == 0 && r->resolving == 0) { + zookeeper_start_resolving_locked(r); + } else { + zookeeper_maybe_finish_next_locked(exec_ctx, r); + } + gpr_mu_unlock(&r->mu); +} + +/** Zookeeper global watcher for connection management + TODO: better connection management besides logs */ +static void zookeeper_global_watcher(zhandle_t *zookeeper_handle, int type, + int state, const char *path, + void *watcher_ctx) { + if (type == ZOO_SESSION_EVENT) { + if (state == ZOO_EXPIRED_SESSION_STATE) { + gpr_log(GPR_ERROR, "Zookeeper session expired"); + } else if (state == ZOO_AUTH_FAILED_STATE) { + gpr_log(GPR_ERROR, "Zookeeper authentication failed"); + } + } +} + +/** Zookeeper watcher triggered by changes to watched nodes + Once triggered, it tries to resolve again to get updated addresses */ +static void zookeeper_watcher(zhandle_t *zookeeper_handle, int type, int state, + const char *path, void *watcher_ctx) { + if (watcher_ctx != NULL) { + zookeeper_resolver *r = (zookeeper_resolver *)watcher_ctx; + if (state == ZOO_CONNECTED_STATE) { + gpr_mu_lock(&r->mu); + if (r->resolving == 0) { + zookeeper_start_resolving_locked(r); + } + gpr_mu_unlock(&r->mu); + } + } +} + +/** Callback function after getting all resolved addresses + Creates a subchannel for each address */ +static void zookeeper_on_resolved(grpc_exec_ctx *exec_ctx, void *arg, + grpc_resolved_addresses *addresses) { + zookeeper_resolver *r = arg; + grpc_client_config *config = NULL; + grpc_lb_policy *lb_policy; + + if (addresses != NULL) { + grpc_lb_policy_args lb_policy_args; + config = grpc_client_config_create(); + + lb_policy_args.addresses = addresses; + lb_policy_args.subchannel_factory = r->subchannel_factory; + lb_policy = + grpc_lb_policy_create(exec_ctx, r->lb_policy_name, &lb_policy_args); + + if (lb_policy != NULL) { + grpc_client_config_set_lb_policy(config, lb_policy); + GRPC_LB_POLICY_UNREF(exec_ctx, lb_policy, "construction"); + } + grpc_resolved_addresses_destroy(addresses); + } + gpr_mu_lock(&r->mu); + GPR_ASSERT(r->resolving == 1); + r->resolving = 0; + if (r->resolved_config != NULL) { + grpc_client_config_unref(exec_ctx, r->resolved_config); + } + r->resolved_config = config; + r->resolved_version++; + zookeeper_maybe_finish_next_locked(exec_ctx, r); + gpr_mu_unlock(&r->mu); + + GRPC_RESOLVER_UNREF(exec_ctx, &r->base, "zookeeper-resolving"); +} + +/** Callback function for each DNS resolved address */ +static void zookeeper_dns_resolved(grpc_exec_ctx *exec_ctx, void *arg, + grpc_resolved_addresses *addresses) { + size_t i; + zookeeper_resolver *r = arg; + int resolve_done = 0; + + gpr_mu_lock(&r->mu); + r->resolved_num++; + r->resolved_addrs->addrs = + gpr_realloc(r->resolved_addrs->addrs, + sizeof(grpc_resolved_address) * + (r->resolved_addrs->naddrs + addresses->naddrs)); + for (i = 0; i < addresses->naddrs; i++) { + memcpy(r->resolved_addrs->addrs[i + r->resolved_addrs->naddrs].addr, + addresses->addrs[i].addr, addresses->addrs[i].len); + r->resolved_addrs->addrs[i + r->resolved_addrs->naddrs].len = + addresses->addrs[i].len; + } + + r->resolved_addrs->naddrs += addresses->naddrs; + grpc_resolved_addresses_destroy(addresses); + + /** Wait for all addresses to be resolved */ + resolve_done = (r->resolved_num == r->resolved_total); + gpr_mu_unlock(&r->mu); + if (resolve_done) { + zookeeper_on_resolved(exec_ctx, r, r->resolved_addrs); + } +} + +/** Parses JSON format address of a zookeeper node */ +static char *zookeeper_parse_address(const char *value, size_t value_len) { + grpc_json *json; + grpc_json *cur; + const char *host; + const char *port; + char *buffer; + char *address = NULL; + + buffer = gpr_malloc(value_len); + memcpy(buffer, value, value_len); + json = grpc_json_parse_string_with_len(buffer, value_len); + if (json != NULL) { + host = NULL; + port = NULL; + for (cur = json->child; cur != NULL; cur = cur->next) { + if (!strcmp(cur->key, "host")) { + host = cur->value; + if (port != NULL) { + break; + } + } else if (!strcmp(cur->key, "port")) { + port = cur->value; + if (host != NULL) { + break; + } + } + } + if (host != NULL && port != NULL) { + gpr_asprintf(&address, "%s:%s", host, port); + } + grpc_json_destroy(json); + } + gpr_free(buffer); + + return address; +} + +static void zookeeper_get_children_node_completion(int rc, const char *value, + int value_len, + const struct Stat *stat, + const void *arg) { + char *address = NULL; + zookeeper_resolver *r = (zookeeper_resolver *)arg; + int resolve_done = 0; + grpc_exec_ctx exec_ctx = GRPC_EXEC_CTX_INIT; + + if (rc != 0) { + gpr_log(GPR_ERROR, "Error in getting a child node of %s", r->name); + grpc_exec_ctx_finish(&exec_ctx); + return; + } + + address = zookeeper_parse_address(value, (size_t)value_len); + if (address != NULL) { + /** Further resolves address by DNS */ + grpc_resolve_address(address, NULL, zookeeper_dns_resolved, r); + gpr_free(address); + } else { + gpr_log(GPR_ERROR, "Error in resolving a child node of %s", r->name); + gpr_mu_lock(&r->mu); + r->resolved_total--; + resolve_done = (r->resolved_num == r->resolved_total); + gpr_mu_unlock(&r->mu); + if (resolve_done) { + zookeeper_on_resolved(&exec_ctx, r, r->resolved_addrs); + } + } + + grpc_exec_ctx_finish(&exec_ctx); +} + +static void zookeeper_get_children_completion( + int rc, const struct String_vector *children, const void *arg) { + char *path; + int status; + int i; + zookeeper_resolver *r = (zookeeper_resolver *)arg; + + if (rc != 0) { + gpr_log(GPR_ERROR, "Error in getting zookeeper children of %s", r->name); + return; + } + + if (children->count == 0) { + gpr_log(GPR_ERROR, "Error in resolving zookeeper address %s", r->name); + return; + } + + r->resolved_addrs = gpr_malloc(sizeof(grpc_resolved_addresses)); + r->resolved_addrs->addrs = NULL; + r->resolved_addrs->naddrs = 0; + r->resolved_total = children->count; + + /** TODO: Replace expensive heap allocation with stack + if we can get maximum length of zookeeper path */ + for (i = 0; i < children->count; i++) { + gpr_asprintf(&path, "%s/%s", r->name, children->data[i]); + status = zoo_awget(r->zookeeper_handle, path, zookeeper_watcher, r, + zookeeper_get_children_node_completion, r); + gpr_free(path); + if (status != 0) { + gpr_log(GPR_ERROR, "Error in getting zookeeper node %s", path); + } + } +} + +static void zookeeper_get_node_completion(int rc, const char *value, + int value_len, + const struct Stat *stat, + const void *arg) { + int status; + char *address = NULL; + zookeeper_resolver *r = (zookeeper_resolver *)arg; + r->resolved_addrs = NULL; + r->resolved_total = 0; + r->resolved_num = 0; + + if (rc != 0) { + gpr_log(GPR_ERROR, "Error in getting zookeeper node %s", r->name); + return; + } + + /** If zookeeper node of path r->name does not have address + (i.e. service node), get its children */ + address = zookeeper_parse_address(value, (size_t)value_len); + if (address != NULL) { + r->resolved_addrs = gpr_malloc(sizeof(grpc_resolved_addresses)); + r->resolved_addrs->addrs = NULL; + r->resolved_addrs->naddrs = 0; + r->resolved_total = 1; + /** Further resolves address by DNS */ + grpc_resolve_address(address, NULL, zookeeper_dns_resolved, r); + gpr_free(address); + return; + } + + status = zoo_awget_children(r->zookeeper_handle, r->name, zookeeper_watcher, + r, zookeeper_get_children_completion, r); + if (status != 0) { + gpr_log(GPR_ERROR, "Error in getting zookeeper children of %s", r->name); + } +} + +static void zookeeper_resolve_address(zookeeper_resolver *r) { + int status; + status = zoo_awget(r->zookeeper_handle, r->name, zookeeper_watcher, r, + zookeeper_get_node_completion, r); + if (status != 0) { + gpr_log(GPR_ERROR, "Error in getting zookeeper node %s", r->name); + } +} + +static void zookeeper_start_resolving_locked(zookeeper_resolver *r) { + GRPC_RESOLVER_REF(&r->base, "zookeeper-resolving"); + GPR_ASSERT(r->resolving == 0); + r->resolving = 1; + zookeeper_resolve_address(r); +} + +static void zookeeper_maybe_finish_next_locked(grpc_exec_ctx *exec_ctx, + zookeeper_resolver *r) { + if (r->next_completion != NULL && + r->resolved_version != r->published_version) { + *r->target_config = r->resolved_config; + if (r->resolved_config != NULL) { + grpc_client_config_ref(r->resolved_config); + } + grpc_exec_ctx_enqueue(exec_ctx, r->next_completion, true, NULL); + r->next_completion = NULL; + r->published_version = r->resolved_version; + } +} + +static void zookeeper_destroy(grpc_exec_ctx *exec_ctx, grpc_resolver *gr) { + zookeeper_resolver *r = (zookeeper_resolver *)gr; + gpr_mu_destroy(&r->mu); + if (r->resolved_config != NULL) { + grpc_client_config_unref(exec_ctx, r->resolved_config); + } + grpc_subchannel_factory_unref(exec_ctx, r->subchannel_factory); + gpr_free(r->name); + gpr_free(r->lb_policy_name); + gpr_free(r); +} + +static grpc_resolver *zookeeper_create(grpc_resolver_args *args, + const char *lb_policy_name) { + zookeeper_resolver *r; + size_t length; + char *path = args->uri->path; + + if (0 == strcmp(args->uri->authority, "")) { + gpr_log(GPR_ERROR, "No authority specified in zookeeper uri"); + return NULL; + } + + /** Removes the trailing slash if exists */ + length = strlen(path); + if (length > 1 && path[length - 1] == '/') { + path[length - 1] = 0; + } + + r = gpr_malloc(sizeof(zookeeper_resolver)); + memset(r, 0, sizeof(*r)); + gpr_ref_init(&r->refs, 1); + gpr_mu_init(&r->mu); + grpc_resolver_init(&r->base, &zookeeper_resolver_vtable); + r->name = gpr_strdup(path); + + r->subchannel_factory = args->subchannel_factory; + grpc_subchannel_factory_ref(r->subchannel_factory); + + r->lb_policy_name = gpr_strdup(lb_policy_name); + + /** Initializes zookeeper client */ + zoo_set_debug_level(ZOO_LOG_LEVEL_WARN); + r->zookeeper_handle = + zookeeper_init(args->uri->authority, zookeeper_global_watcher, + GRPC_ZOOKEEPER_SESSION_TIMEOUT, 0, 0, 0); + if (r->zookeeper_handle == NULL) { + gpr_log(GPR_ERROR, "Unable to connect to zookeeper server"); + return NULL; + } + + return &r->base; +} + +/* + * FACTORY + */ + +static void zookeeper_factory_ref(grpc_resolver_factory *factory) {} + +static void zookeeper_factory_unref(grpc_resolver_factory *factory) {} + +static char *zookeeper_factory_get_default_hostname( + grpc_resolver_factory *factory, grpc_uri *uri) { + return NULL; +} + +static grpc_resolver *zookeeper_factory_create_resolver( + grpc_resolver_factory *factory, grpc_resolver_args *args) { + return zookeeper_create(args, "pick_first"); +} + +static const grpc_resolver_factory_vtable zookeeper_factory_vtable = { + zookeeper_factory_ref, zookeeper_factory_unref, + zookeeper_factory_create_resolver, zookeeper_factory_get_default_hostname, + "zookeeper"}; + +static grpc_resolver_factory zookeeper_resolver_factory = { + &zookeeper_factory_vtable}; + +static grpc_resolver_factory *zookeeper_resolver_factory_create() { + return &zookeeper_resolver_factory; +} + +static void zookeeper_plugin_init() { + grpc_register_resolver_type(zookeeper_resolver_factory_create()); +} + +void grpc_zookeeper_register() { + GRPC_API_TRACE("grpc_zookeeper_register(void)", 0, ()); + grpc_register_plugin(zookeeper_plugin_init, NULL); +} |