Add zookeeper resolver

src/core/client_config/resolvers/zookeeper_resolver.c

+/*
+ *
+ * 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 "src/core/client_config/resolvers/zookeeper_resolver.h"
+
+#include <string.h>
+
+#include <grpc/support/alloc.h>
+#include <grpc/support/string_util.h>
+
+#include <zookeeper/zookeeper.h>
+
+#include "src/core/client_config/lb_policies/pick_first.h"
+#include "src/core/iomgr/resolve_address.h"
+#include "src/core/support/string.h"
+
+#define GRPC_ZOOKEEPER_MAX_SIZE 128
+#define GRPC_ZOOKEEPER_TIMEOUT 15000
+#define GRPC_ZOOKEEPER_WATCH 1
+
+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 factory */
+  grpc_lb_policy *(*lb_policy_factory)(grpc_subchannel **subchannels,
+                                       size_t num_subchannels);
+
+  /** 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_iomgr_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 connection state */
+  int zookeeper_state;
+
+} zookeeper_resolver;
+
+static void zookeeper_destroy(grpc_resolver *r);
+
+static void zookeeper_start_resolving_locked(zookeeper_resolver *r);
+static void zookeeper_maybe_finish_next_locked(zookeeper_resolver *r);
+
+static void zookeeper_shutdown(grpc_resolver *r);
+static void zookeeper_channel_saw_error(grpc_resolver *r,
+                                  struct sockaddr *failing_address,
+                                  int failing_address_len);
+static void zookeeper_next(grpc_resolver *r, grpc_client_config **target_config,
+                     grpc_iomgr_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_resolver *resolver) {
+  zookeeper_resolver *r = (zookeeper_resolver *)resolver;
+  gpr_mu_lock(&r->mu);
+  if (r->next_completion != NULL) {
+    *r->target_config = NULL;
+    grpc_iomgr_add_callback(r->next_completion);
+    r->next_completion = NULL;
+  }
+  zookeeper_close(r->zookeeper_handle);
+  gpr_mu_unlock(&r->mu);
+}
+
+static void zookeeper_channel_saw_error(grpc_resolver *resolver, struct sockaddr *sa,
+                                  int len) {
+  zookeeper_resolver *r = (zookeeper_resolver *)resolver;
+  gpr_mu_lock(&r->mu);
+  if (!r->resolving) {
+    zookeeper_start_resolving_locked(r);
+  }
+  gpr_mu_unlock(&r->mu);
+}
+
+static void zookeeper_next(grpc_resolver *resolver,
+                     grpc_client_config **target_config,
+                     grpc_iomgr_closure *on_complete) {
+  zookeeper_resolver *r = (zookeeper_resolver *)resolver;
+  gpr_mu_lock(&r->mu);
+  GPR_ASSERT(!r->next_completion);
+  r->next_completion = on_complete;
+  r->target_config = target_config;
+  if (r->resolved_version == 0 && !r->resolving) {
+    zookeeper_start_resolving_locked(r);
+  } else {
+    zookeeper_maybe_finish_next_locked(r);
+  }
+  gpr_mu_unlock(&r->mu);
+}
+
+static void zookeeper_on_resolved(void *arg, grpc_resolved_addresses *addresses) {
+  zookeeper_resolver *r = arg;
+  grpc_client_config *config = NULL;
+  grpc_subchannel **subchannels;
+  grpc_subchannel_args args;
+  grpc_lb_policy *lb_policy;
+  size_t i;
+  if (addresses) {
+    config = grpc_client_config_create();
+    subchannels = gpr_malloc(sizeof(grpc_subchannel *) * addresses->naddrs);
+    for (i = 0; i < addresses->naddrs; i++) {
+      memset(&args, 0, sizeof(args));
+      args.addr = (struct sockaddr *)(addresses->addrs[i].addr);
+      args.addr_len = addresses->addrs[i].len;
+      subchannels[i] = grpc_subchannel_factory_create_subchannel(
+          r->subchannel_factory, &args);
+    }
+    lb_policy = r->lb_policy_factory(subchannels, addresses->naddrs);
+    grpc_client_config_set_lb_policy(config, lb_policy);
+    GRPC_LB_POLICY_UNREF(lb_policy, "construction");
+    grpc_resolved_addresses_destroy(addresses);
+    gpr_free(subchannels);
+  }
+  gpr_mu_lock(&r->mu);
+  GPR_ASSERT(r->resolving);
+  r->resolving = 0;
+  if (r->resolved_config) {
+    grpc_client_config_unref(r->resolved_config);
+  }
+  r->resolved_config = config;
+  r->resolved_version++;
+  zookeeper_maybe_finish_next_locked(r);
+  gpr_mu_unlock(&r->mu);
+
+  GRPC_RESOLVER_UNREF(&r->base, "zookeeper-resolving");
+}
+
+/** Resolve address by zookeeper */
+static void zookeeper_resolve_address(zookeeper_resolver *r) {
+  struct String_vector children;
+  grpc_resolved_addresses *addrs;
+  int i, k;
+  int status;
+
+  char buffer[GRPC_ZOOKEEPER_MAX_SIZE];
+  int buffer_len;
+  
+  addrs = NULL;
+  status = zoo_get_children(r->zookeeper_handle, r->name, GRPC_ZOOKEEPER_WATCH, &children);
+  if (!status) {
+    addrs = gpr_malloc(sizeof(grpc_resolved_addresses));
+    addrs->naddrs = 0;
+    addrs->addrs = gpr_malloc(sizeof(grpc_resolved_address) * children.count);
+    
+    k = 0;
+    for (i = 0; i < children.count; i++) {
+      char path[GRPC_ZOOKEEPER_MAX_SIZE];
+      strcat(path, r->name);
+      strcat(path, "/");
+      strcat(path, children.data[i]);
+      
+      status = zoo_get(r->zookeeper_handle, path, GRPC_ZOOKEEPER_WATCH, buffer, &buffer_len, NULL);
+      if (!status) {
+        addrs->naddrs++;
+        memcpy(&addrs->addrs[k].addr, buffer, buffer_len);
+        addrs->addrs[k].len = buffer_len;
+        k++;
+      } else {
+        gpr_log(GPR_ERROR, "cannot resolve zookeeper address");
+      }
+    }
+  } else {
+    gpr_log(GPR_ERROR, "cannot resolve zookeeper address");
+  }
+
+  zookeeper_on_resolved(r, addrs);
+}
+
+static void zookeeper_start_resolving_locked(zookeeper_resolver *r) {
+  GRPC_RESOLVER_REF(&r->base, "zookeeper-resolving");
+  GPR_ASSERT(!r->resolving);
+  r->resolving = 1;
+
+  zookeeper_resolve_address(r);
+}
+
+static void zookeeper_maybe_finish_next_locked(zookeeper_resolver *r) {
+  if (r->next_completion != NULL &&
+      r->resolved_version != r->published_version) {
+    *r->target_config = r->resolved_config;
+    if (r->resolved_config) {
+      grpc_client_config_ref(r->resolved_config);
+    }
+    grpc_iomgr_add_callback(r->next_completion);
+    r->next_completion = NULL;
+    r->published_version = r->resolved_version;
+  }
+}
+
+static void zookeeper_destroy(grpc_resolver *gr) {
+  zookeeper_resolver *r = (zookeeper_resolver *)gr;
+  gpr_mu_destroy(&r->mu);
+  if (r->resolved_config) {
+    grpc_client_config_unref(r->resolved_config);
+  }
+  grpc_subchannel_factory_unref(r->subchannel_factory);
+  gpr_free(r->name);
+  gpr_free(r);
+}
+
+/** Zookeeper watcher function: handle any updates to watched nodes */
+static void zookeeper_watcher(zhandle_t *zookeeper_handle, int type, int state, const char* path, void* watcher_ctx) {
+
+}
+
+static grpc_resolver *zookeeper_create(
+    grpc_uri *uri,
+    grpc_lb_policy *(*lb_policy_factory)(grpc_subchannel **subchannels,
+                                         size_t num_subchannels),
+    grpc_subchannel_factory *subchannel_factory) {
+  zookeeper_resolver *r;
+  const char *path = uri->path;
+
+  if (0 == strcmp(uri->authority, "")) {
+    gpr_log(GPR_ERROR, "no authority specified in zookeeper uri");
+    return NULL;
+  }
+
+  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 = subchannel_factory;
+  r->lb_policy_factory = lb_policy_factory;
+  grpc_subchannel_factory_ref(subchannel_factory);
+
+  /** Initialize zookeeper client */
+  r->zookeeper_handle = zookeeper_init(uri->authority, zookeeper_watcher, GRPC_ZOOKEEPER_TIMEOUT, 0, 0, 0);
+  if (r->zookeeper_handle  == NULL) {
+    gpr_log(GPR_ERROR, "cannot connect to zookeeper servers");
+    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 grpc_resolver *zookeeper_factory_create_resolver(
+    grpc_resolver_factory *factory, grpc_uri *uri,
+    grpc_subchannel_factory *subchannel_factory) {
+  return zookeeper_create(uri, grpc_create_pick_first_lb_policy,
+                    subchannel_factory);
+}
+
+static const grpc_resolver_factory_vtable zookeeper_factory_vtable = {
+    zookeeper_factory_ref, zookeeper_factory_unref, zookeeper_factory_create_resolver};
+static grpc_resolver_factory zookeeper_resolver_factory = {&zookeeper_factory_vtable};
+
+grpc_resolver_factory *grpc_zookeeper_resolver_factory_create() {
+  return &zookeeper_resolver_factory;
+}
\ No newline at end of file

src/core/client_config/resolvers/zookeeper_resolver.h

+/*
+ *
+ * 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.
+ *
+ */
+
+#ifndef GRPC_INTERNAL_CORE_CLIENT_CONFIG_RESOLVERS_ZOOKEEPER_RESOLVER_H
+#define GRPC_INTERNAL_CORE_CLIENT_CONFIG_RESOLVERS_ZOOKEEPER_RESOLVER_H
+
+#include "src/core/client_config/resolver_factory.h"
+
+/** Create a zookeeper resolver for \a name */
+grpc_resolver_factory *grpc_zookeeper_resolver_factory_create(void);
+
+#endif /* GRPC_INTERNAL_CORE_CLIENT_CONFIG_RESOLVERS_ZOOKEEPER_RESOLVER_H */
\ No newline at end of file