Merge pull request #11878 from stanley-cheung/php-persistent-channel

PHP: persistent channels

13 files changed, 800 insertions, 75 deletions

diff --git a/src/php/ext/grpc/call.c b/src/php/ext/grpc/call.c
index 2f67e5cee7..c4997f720d 100644
--- a/src/php/ext/grpc/call.c
+++ b/src/php/ext/grpc/call.c
@@ -214,10 +214,12 @@ PHP_METHOD(Call, __construct) {
     return;
   }
   wrapped_grpc_channel *channel = Z_WRAPPED_GRPC_CHANNEL_P(channel_obj);
-  if (channel->wrapped == NULL) {
+  gpr_mu_lock(&channel->wrapper->mu);
+  if (channel->wrapper->wrapped == NULL) {
     zend_throw_exception(spl_ce_InvalidArgumentException,
                          "Call cannot be constructed from a closed Channel",
                          1 TSRMLS_CC);
+    gpr_mu_unlock(&channel->wrapper->mu);
     return;
   }
   add_property_zval(getThis(), "channel", channel_obj);
@@ -226,13 +228,15 @@ PHP_METHOD(Call, __construct) {
   grpc_slice host_slice = host_override != NULL ?
       grpc_slice_from_copied_string(host_override) : grpc_empty_slice();
   call->wrapped =
-    grpc_channel_create_call(channel->wrapped, NULL, GRPC_PROPAGATE_DEFAULTS,
+    grpc_channel_create_call(channel->wrapper->wrapped, NULL,
+                             GRPC_PROPAGATE_DEFAULTS,
                              completion_queue, method_slice,
                              host_override != NULL ? &host_slice : NULL,
                              deadline->wrapped, NULL);
   grpc_slice_unref(method_slice);
   grpc_slice_unref(host_slice);
   call->owned = true;
+  gpr_mu_unlock(&channel->wrapper->mu);
 }
 
 /**
diff --git a/src/php/ext/grpc/call_credentials.c b/src/php/ext/grpc/call_credentials.c
index a990206c08..f46091d709 100644
--- a/src/php/ext/grpc/call_credentials.c
+++ b/src/php/ext/grpc/call_credentials.c
@@ -109,8 +109,8 @@ PHP_METHOD(CallCredentials, createFromPlugin) {
   zend_fcall_info *fci;
   zend_fcall_info_cache *fci_cache;
 
-  fci = (zend_fcall_info *)emalloc(sizeof(zend_fcall_info));
-  fci_cache = (zend_fcall_info_cache *)emalloc(sizeof(zend_fcall_info_cache));
+  fci = (zend_fcall_info *)malloc(sizeof(zend_fcall_info));
+  fci_cache = (zend_fcall_info_cache *)malloc(sizeof(zend_fcall_info_cache));
   memset(fci, 0, sizeof(zend_fcall_info));
   memset(fci_cache, 0, sizeof(zend_fcall_info_cache));
 
@@ -123,7 +123,7 @@ PHP_METHOD(CallCredentials, createFromPlugin) {
   }
 
   plugin_state *state;
-  state = (plugin_state *)emalloc(sizeof(plugin_state));
+  state = (plugin_state *)malloc(sizeof(plugin_state));
   memset(state, 0, sizeof(plugin_state));
 
   /* save the user provided PHP callback function */
@@ -210,13 +210,13 @@ void plugin_get_metadata(void *ptr, grpc_auth_metadata_context context,
 /* Cleanup function for plugin creds API */
 void plugin_destroy_state(void *ptr) {
   plugin_state *state = (plugin_state *)ptr;
-  efree(state->fci);
-  efree(state->fci_cache);
+  free(state->fci);
+  free(state->fci_cache);
 #if PHP_MAJOR_VERSION < 7
   PHP_GRPC_FREE_STD_ZVAL(state->fci->params);
   PHP_GRPC_FREE_STD_ZVAL(state->fci->retval);
 #endif
-  efree(state);
+  free(state);
 }
 
 ZEND_BEGIN_ARG_INFO_EX(arginfo_createComposite, 0, 0, 2)
diff --git a/src/php/ext/grpc/channel.c b/src/php/ext/grpc/channel.c
index 6c432d2818..f1187e8722 100644
--- a/src/php/ext/grpc/channel.c
+++ b/src/php/ext/grpc/channel.c
@@ -25,6 +25,13 @@
 #include <php.h>
 #include <php_ini.h>
 #include <ext/standard/info.h>
+#include <ext/standard/php_var.h>
+#include <ext/standard/sha1.h>
+#if PHP_MAJOR_VERSION < 7
+#include <ext/standard/php_smart_str.h>
+#else
+#include <zend_smart_str.h>
+#endif
 #include <ext/spl/spl_exceptions.h>
 #include "php_grpc.h"
 
@@ -44,11 +51,25 @@ zend_class_entry *grpc_ce_channel;
 #if PHP_MAJOR_VERSION >= 7
 static zend_object_handlers channel_ce_handlers;
 #endif
+static gpr_mu global_persistent_list_mu;
+int le_plink;
 
 /* Frees and destroys an instance of wrapped_grpc_channel */
 PHP_GRPC_FREE_WRAPPED_FUNC_START(wrapped_grpc_channel)
-  if (p->wrapped != NULL) {
-    grpc_channel_destroy(p->wrapped);
+  if (p->wrapper != NULL) {
+    gpr_mu_lock(&p->wrapper->mu);
+    if (p->wrapper->wrapped != NULL) {
+      php_grpc_zend_resource *rsrc;
+      php_grpc_int key_len = strlen(p->wrapper->key);
+      // only destroy the channel here if not found in the persistent list
+      gpr_mu_lock(&global_persistent_list_mu);
+      if (!(PHP_GRPC_PERSISTENT_LIST_FIND(&EG(persistent_list), p->wrapper->key,
+                                          key_len, rsrc))) {
+        grpc_channel_destroy(p->wrapper->wrapped);
+      }
+      gpr_mu_unlock(&global_persistent_list_mu);
+    }
+    gpr_mu_unlock(&p->wrapper->mu);
   }
 PHP_GRPC_FREE_WRAPPED_FUNC_END()
 
@@ -62,15 +83,15 @@ php_grpc_zend_object create_wrapped_grpc_channel(zend_class_entry *class_type
   PHP_GRPC_FREE_CLASS_OBJECT(wrapped_grpc_channel, channel_ce_handlers);
 }
 
-void php_grpc_read_args_array(zval *args_array,
-                              grpc_channel_args *args TSRMLS_DC) {
+int php_grpc_read_args_array(zval *args_array,
+                             grpc_channel_args *args TSRMLS_DC) {
   HashTable *array_hash;
   int args_index;
   array_hash = Z_ARRVAL_P(args_array);
   if (!array_hash) {
     zend_throw_exception(spl_ce_InvalidArgumentException,
                          "array_hash is NULL", 1 TSRMLS_CC);
-    return;
+    return FAILURE;
   }
   args->num_args = zend_hash_num_elements(array_hash);
   args->args = ecalloc(args->num_args, sizeof(grpc_arg));
@@ -84,7 +105,7 @@ void php_grpc_read_args_array(zval *args_array,
     if (key_type != HASH_KEY_IS_STRING) {
       zend_throw_exception(spl_ce_InvalidArgumentException,
                            "args keys must be strings", 1 TSRMLS_CC);
-      return;
+      return FAILURE;
     }
     args->args[args_index].key = key;
     switch (Z_TYPE_P(data)) {
@@ -99,16 +120,78 @@ void php_grpc_read_args_array(zval *args_array,
     default:
       zend_throw_exception(spl_ce_InvalidArgumentException,
                            "args values must be int or string", 1 TSRMLS_CC);
-      return;
+      return FAILURE;
     }
     args_index++;
   PHP_GRPC_HASH_FOREACH_END()
+  return SUCCESS;
+}
+
+void generate_sha1_str(char *sha1str, char *str, php_grpc_int len) {
+  PHP_SHA1_CTX context;
+  unsigned char digest[20];
+  sha1str[0] = '\0';
+  PHP_SHA1Init(&context);
+  PHP_GRPC_SHA1Update(&context, str, len);
+  PHP_SHA1Final(digest, &context);
+  make_sha1_digest(sha1str, digest);
+}
+
+void create_channel(
+    wrapped_grpc_channel *channel,
+    char *target,
+    grpc_channel_args args,
+    wrapped_grpc_channel_credentials *creds) {
+  if (creds == NULL) {
+    channel->wrapper->wrapped = grpc_insecure_channel_create(target, &args,
+                                                             NULL);
+  } else {
+    channel->wrapper->wrapped =
+        grpc_secure_channel_create(creds->wrapped, target, &args, NULL);
+  }
+  efree(args.args);
+}
+
+void create_and_add_channel_to_persistent_list(
+    wrapped_grpc_channel *channel,
+    char *target,
+    grpc_channel_args args,
+    wrapped_grpc_channel_credentials *creds,
+    char *key,
+    php_grpc_int key_len) {
+  php_grpc_zend_resource new_rsrc;
+  channel_persistent_le_t *le;
+  // this links each persistent list entry to a destructor
+  new_rsrc.type = le_plink;
+  le = malloc(sizeof(channel_persistent_le_t));
+
+  create_channel(channel, target, args, creds);
+
+  le->channel = channel->wrapper;
+  new_rsrc.ptr = le;
+  gpr_mu_lock(&global_persistent_list_mu);
+  PHP_GRPC_PERSISTENT_LIST_UPDATE(&EG(persistent_list), key, key_len,
+                                  (void *)&new_rsrc);
+  gpr_mu_unlock(&global_persistent_list_mu);
 }
 
 /**
- * Construct an instance of the Channel class. If the $args array contains a
- * "credentials" key mapping to a ChannelCredentials object, a secure channel
- * will be created with those credentials.
+ * Construct an instance of the Channel class.
+ *
+ * By default, the underlying grpc_channel is "persistent". That is, given
+ * the same set of parameters passed to the constructor, the same underlying
+ * grpc_channel will be returned.
+ *
+ * If the $args array contains a "credentials" key mapping to a
+ * ChannelCredentials object, a secure channel will be created with those
+ * credentials.
+ *
+ * If the $args array contains a "force_new" key mapping to a boolean value
+ * of "true", a new underlying grpc_channel will be created regardless. If
+ * there are any opened channels on the same hostname, user must manually
+ * call close() on those dangling channels before the end of the PHP
+ * script.
+ *
  * @param string $target The hostname to associate with this channel
  * @param array $args_array The arguments to pass to the Channel
  */
@@ -121,6 +204,9 @@ PHP_METHOD(Channel, __construct) {
   grpc_channel_args args;
   HashTable *array_hash;
   wrapped_grpc_channel_credentials *creds = NULL;
+  php_grpc_zend_resource *rsrc;
+  bool force_new = false;
+  zval *force_new_obj = NULL;
 
   /* "sa" == 1 string, 1 array */
   if (zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, "sa", &target,
@@ -131,7 +217,7 @@ PHP_METHOD(Channel, __construct) {
   }
   array_hash = Z_ARRVAL_P(args_array);
   if (php_grpc_zend_hash_find(array_hash, "credentials", sizeof("credentials"),
-                     (void **)&creds_obj) == SUCCESS) {
+                              (void **)&creds_obj) == SUCCESS) {
     if (Z_TYPE_P(creds_obj) == IS_NULL) {
       creds = NULL;
       php_grpc_zend_hash_del(array_hash, "credentials", sizeof("credentials"));
@@ -146,14 +232,82 @@ PHP_METHOD(Channel, __construct) {
       php_grpc_zend_hash_del(array_hash, "credentials", sizeof("credentials"));
     }
   }
-  php_grpc_read_args_array(args_array, &args TSRMLS_CC);
-  if (creds == NULL) {
-    channel->wrapped = grpc_insecure_channel_create(target, &args, NULL);
+  if (php_grpc_zend_hash_find(array_hash, "force_new", sizeof("force_new"),
+                              (void **)&force_new_obj) == SUCCESS) {
+    if (PHP_GRPC_BVAL_IS_TRUE(force_new_obj)) {
+      force_new = true;
+    }
+    php_grpc_zend_hash_del(array_hash, "force_new", sizeof("force_new"));
+  }
+
+  // parse the rest of the channel args array
+  if (php_grpc_read_args_array(args_array, &args TSRMLS_CC) == FAILURE) {
+    return;
+  }
+
+  // Construct a hashkey for the persistent channel
+  // Currently, the hashkey contains 3 parts:
+  // 1. hostname
+  // 2. hash value of the channel args array (excluding "credentials"
+  //    and "force_new")
+  // 3. (optional) hash value of the ChannelCredentials object
+  php_serialize_data_t var_hash;
+  smart_str buf = {0};
+  PHP_VAR_SERIALIZE_INIT(var_hash);
+  PHP_GRPC_VAR_SERIALIZE(&buf, args_array, &var_hash);
+  PHP_VAR_SERIALIZE_DESTROY(var_hash);
+
+  char sha1str[41];
+  generate_sha1_str(sha1str, PHP_GRPC_SERIALIZED_BUF_STR(buf),
+                    PHP_GRPC_SERIALIZED_BUF_LEN(buf));
+
+  php_grpc_int key_len = target_length + strlen(sha1str);
+  if (creds != NULL && creds->hashstr != NULL) {
+    key_len += strlen(creds->hashstr);
+  }
+  char *key = malloc(key_len + 1);
+  strcpy(key, target);
+  strcat(key, sha1str);
+  if (creds != NULL && creds->hashstr != NULL) {
+    strcat(key, creds->hashstr);
+  }
+  channel->wrapper = malloc(sizeof(grpc_channel_wrapper));
+  channel->wrapper->key = key;
+  channel->wrapper->target = target;
+  channel->wrapper->args_hashstr = sha1str;
+  if (creds != NULL && creds->hashstr != NULL) {
+    channel->wrapper->creds_hashstr = creds->hashstr;
+  }
+  gpr_mu_init(&channel->wrapper->mu);
+  smart_str_free(&buf);
+
+  if (force_new) {
+    php_grpc_delete_persistent_list_entry(key, key_len TSRMLS_CC);
+  }
+
+  if (creds != NULL && creds->has_call_creds) {
+    // If the ChannelCredentials object was composed with a CallCredentials
+    // object, there is no way we can tell them apart. Do NOT persist
+    // them. They should be individually destroyed.
+    create_channel(channel, target, args, creds);
+  } else if (!(PHP_GRPC_PERSISTENT_LIST_FIND(&EG(persistent_list), key,
+                                             key_len, rsrc))) {
+    create_and_add_channel_to_persistent_list(
+        channel, target, args, creds, key, key_len);
   } else {
-    channel->wrapped =
-        grpc_secure_channel_create(creds->wrapped, target, &args, NULL);
+    // Found a previously stored channel in the persistent list
+    channel_persistent_le_t *le = (channel_persistent_le_t *)rsrc->ptr;
+    if (strcmp(target, le->channel->target) != 0 ||
+        strcmp(sha1str, le->channel->args_hashstr) != 0 ||
+        (creds != NULL && creds->hashstr != NULL &&
+         strcmp(creds->hashstr, le->channel->creds_hashstr) != 0)) {
+      // somehow hash collision
+      create_and_add_channel_to_persistent_list(
+          channel, target, args, creds, key, key_len);
+    } else {
+      channel->wrapper = le->channel;
+    }
   }
-  efree(args.args);
 }
 
 /**
@@ -162,7 +316,16 @@ PHP_METHOD(Channel, __construct) {
  */
 PHP_METHOD(Channel, getTarget) {
   wrapped_grpc_channel *channel = Z_WRAPPED_GRPC_CHANNEL_P(getThis());
-  PHP_GRPC_RETURN_STRING(grpc_channel_get_target(channel->wrapped), 1);
+  gpr_mu_lock(&channel->wrapper->mu);
+  if (channel->wrapper->wrapped == NULL) {
+    zend_throw_exception(spl_ce_RuntimeException,
+                         "Channel already closed", 1 TSRMLS_CC);
+    gpr_mu_unlock(&channel->wrapper->mu);
+    return;
+  }
+  char *target = grpc_channel_get_target(channel->wrapper->wrapped);
+  gpr_mu_unlock(&channel->wrapper->mu);
+  PHP_GRPC_RETURN_STRING(target, 1);
 }
 
 /**
@@ -172,6 +335,14 @@ PHP_METHOD(Channel, getTarget) {
  */
 PHP_METHOD(Channel, getConnectivityState) {
   wrapped_grpc_channel *channel = Z_WRAPPED_GRPC_CHANNEL_P(getThis());
+  gpr_mu_lock(&channel->wrapper->mu);
+  if (channel->wrapper->wrapped == NULL) {
+    zend_throw_exception(spl_ce_RuntimeException,
+                         "Channel already closed", 1 TSRMLS_CC);
+    gpr_mu_unlock(&channel->wrapper->mu);
+    return;
+  }
+
   bool try_to_connect = false;
 
   /* "|b" == 1 optional bool */
@@ -179,10 +350,18 @@ PHP_METHOD(Channel, getConnectivityState) {
       == FAILURE) {
     zend_throw_exception(spl_ce_InvalidArgumentException,
                          "getConnectivityState expects a bool", 1 TSRMLS_CC);
+    gpr_mu_unlock(&channel->wrapper->mu);
     return;
   }
-  RETURN_LONG(grpc_channel_check_connectivity_state(channel->wrapped,
-                                                    (int)try_to_connect));
+  int state = grpc_channel_check_connectivity_state(channel->wrapper->wrapped,
+                                                    (int)try_to_connect);
+  // this can happen if another shared Channel object close the underlying
+  // channel
+  if (state == GRPC_CHANNEL_SHUTDOWN) {
+    channel->wrapper->wrapped = NULL;
+  }
+  gpr_mu_unlock(&channel->wrapper->mu);
+  RETURN_LONG(state);
 }
 
 /**
@@ -194,25 +373,37 @@ PHP_METHOD(Channel, getConnectivityState) {
  */
 PHP_METHOD(Channel, watchConnectivityState) {
   wrapped_grpc_channel *channel = Z_WRAPPED_GRPC_CHANNEL_P(getThis());
+  gpr_mu_lock(&channel->wrapper->mu);
+  if (channel->wrapper->wrapped == NULL) {
+    zend_throw_exception(spl_ce_RuntimeException,
+                         "Channel already closed", 1 TSRMLS_CC);
+    gpr_mu_unlock(&channel->wrapper->mu);
+    return;
+  }
+
   php_grpc_long last_state;
   zval *deadline_obj;
 
   /* "lO" == 1 long 1 object */
   if (zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, "lO",
-          &last_state, &deadline_obj, grpc_ce_timeval) == FAILURE) {
+                            &last_state, &deadline_obj,
+                            grpc_ce_timeval) == FAILURE) {
     zend_throw_exception(spl_ce_InvalidArgumentException,
-        "watchConnectivityState expects 1 long 1 timeval", 1 TSRMLS_CC);
+                         "watchConnectivityState expects 1 long 1 timeval",
+                         1 TSRMLS_CC);
+    gpr_mu_unlock(&channel->wrapper->mu);
     return;
   }
 
   wrapped_grpc_timeval *deadline = Z_WRAPPED_GRPC_TIMEVAL_P(deadline_obj);
-  grpc_channel_watch_connectivity_state(channel->wrapped,
+  grpc_channel_watch_connectivity_state(channel->wrapper->wrapped,
                                         (grpc_connectivity_state)last_state,
                                         deadline->wrapped, completion_queue,
                                         NULL);
   grpc_event event =
-    grpc_completion_queue_pluck(completion_queue, NULL,
-                                gpr_inf_future(GPR_CLOCK_REALTIME), NULL);
+      grpc_completion_queue_pluck(completion_queue, NULL,
+                                  gpr_inf_future(GPR_CLOCK_REALTIME), NULL);
+  gpr_mu_unlock(&channel->wrapper->mu);
   RETURN_BOOL(event.success);
 }
 
@@ -222,10 +413,48 @@ PHP_METHOD(Channel, watchConnectivityState) {
  */
 PHP_METHOD(Channel, close) {
   wrapped_grpc_channel *channel = Z_WRAPPED_GRPC_CHANNEL_P(getThis());
-  if (channel->wrapped != NULL) {
-    grpc_channel_destroy(channel->wrapped);
-    channel->wrapped = NULL;
+  gpr_mu_lock(&channel->wrapper->mu);
+  if (channel->wrapper->wrapped != NULL) {
+    grpc_channel_destroy(channel->wrapper->wrapped);
+    channel->wrapper->wrapped = NULL;
+  }
+
+  php_grpc_delete_persistent_list_entry(channel->wrapper->key,
+                                        strlen(channel->wrapper->key)
+                                        TSRMLS_CC);
+  gpr_mu_unlock(&channel->wrapper->mu);
+}
+
+// Delete an entry from the persistent list
+// Note: this does not destroy or close the underlying grpc_channel
+void php_grpc_delete_persistent_list_entry(char *key, php_grpc_int key_len
+                                           TSRMLS_DC) {
+  php_grpc_zend_resource *rsrc;
+  gpr_mu_lock(&global_persistent_list_mu);
+  if (PHP_GRPC_PERSISTENT_LIST_FIND(&EG(persistent_list), key,
+                                    key_len, rsrc)) {
+    channel_persistent_le_t *le;
+    le = (channel_persistent_le_t *)rsrc->ptr;
+    le->channel = NULL;
+    php_grpc_zend_hash_del(&EG(persistent_list), key, key_len+1);
+  }
+  gpr_mu_unlock(&global_persistent_list_mu);
+}
+
+// A destructor associated with each list entry from the persistent list
+static void php_grpc_channel_plink_dtor(php_grpc_zend_resource *rsrc
+                                        TSRMLS_DC) {
+  channel_persistent_le_t *le = (channel_persistent_le_t *)rsrc->ptr;
+  if (le->channel != NULL) {
+    gpr_mu_lock(&le->channel->mu);
+    if (le->channel->wrapped != NULL) {
+      grpc_channel_destroy(le->channel->wrapped);
+      free(le->channel->key);
+      free(le->channel);
+    }
+    gpr_mu_unlock(&le->channel->mu);
   }
+  free(le);
 }
 
 ZEND_BEGIN_ARG_INFO_EX(arginfo_construct, 0, 0, 2)
@@ -262,10 +491,13 @@ static zend_function_entry channel_methods[] = {
   PHP_FE_END
 };
 
-void grpc_init_channel(TSRMLS_D) {
+GRPC_STARTUP_FUNCTION(channel) {
   zend_class_entry ce;
   INIT_CLASS_ENTRY(ce, "Grpc\\Channel", channel_methods);
   ce.create_object = create_wrapped_grpc_channel;
   grpc_ce_channel = zend_register_internal_class(&ce TSRMLS_CC);
+  le_plink = zend_register_list_destructors_ex(
+      NULL, php_grpc_channel_plink_dtor, "Persistent Channel", module_number);
   PHP_GRPC_INIT_HANDLER(wrapped_grpc_channel, channel_ce_handlers);
+  return SUCCESS;
 }
diff --git a/src/php/ext/grpc/channel.h b/src/php/ext/grpc/channel.h
index 45c9744135..69adc4782c 100755
--- a/src/php/ext/grpc/channel.h
+++ b/src/php/ext/grpc/channel.h
@@ -33,9 +33,18 @@
 /* Class entry for the PHP Channel class */
 extern zend_class_entry *grpc_ce_channel;
 
+typedef struct _grpc_channel_wrapper {
+  grpc_channel *wrapped;
+  char *key;
+  char *target;
+  char *args_hashstr;
+  char *creds_hashstr;
+  gpr_mu mu;
+} grpc_channel_wrapper;
+
 /* Wrapper struct for grpc_channel that can be associated with a PHP object */
 PHP_GRPC_WRAP_OBJECT_START(wrapped_grpc_channel)
-  grpc_channel *wrapped;
+  grpc_channel_wrapper *wrapper;
 PHP_GRPC_WRAP_OBJECT_END(wrapped_grpc_channel)
 
 #if PHP_MAJOR_VERSION < 7
@@ -57,10 +66,20 @@ static inline wrapped_grpc_channel
 #endif /* PHP_MAJOR_VERSION */
 
 /* Initializes the Channel class */
-void grpc_init_channel(TSRMLS_D);
+GRPC_STARTUP_FUNCTION(channel);
 
 /* Iterates through a PHP array and populates args with the contents */
-void php_grpc_read_args_array(zval *args_array, grpc_channel_args *args
-                              TSRMLS_DC);
+int php_grpc_read_args_array(zval *args_array, grpc_channel_args *args
+                             TSRMLS_DC);
+
+void generate_sha1_str(char *sha1str, char *str, php_grpc_int len);
+
+void php_grpc_delete_persistent_list_entry(char *key, php_grpc_int key_len
+                                           TSRMLS_DC);
+
+typedef struct _channel_persistent_le {
+  grpc_channel_wrapper *channel;
+} channel_persistent_le_t;
+
 
 #endif /* NET_GRPC_PHP_GRPC_CHANNEL_H_ */
diff --git a/src/php/ext/grpc/channel_credentials.c b/src/php/ext/grpc/channel_credentials.c
index 40629c8b00..19e1cefb6f 100644
--- a/src/php/ext/grpc/channel_credentials.c
+++ b/src/php/ext/grpc/channel_credentials.c
@@ -26,7 +26,9 @@
 #include <php.h>
 #include <php_ini.h>
 #include <ext/standard/info.h>
+#include <ext/standard/sha1.h>
 #include <ext/spl/spl_exceptions.h>
+#include "channel.h"
 #include "php_grpc.h"
 
 #include <zend_exceptions.h>
@@ -69,14 +71,17 @@ php_grpc_zend_object create_wrapped_grpc_channel_credentials(
                              channel_credentials_ce_handlers);
 }
 
-zval *grpc_php_wrap_channel_credentials(grpc_channel_credentials
-                                        *wrapped TSRMLS_DC) {
+zval *grpc_php_wrap_channel_credentials(grpc_channel_credentials *wrapped,
+                                        char *hashstr,
+                                        zend_bool has_call_creds TSRMLS_DC) {
   zval *credentials_object;
   PHP_GRPC_MAKE_STD_ZVAL(credentials_object);
   object_init_ex(credentials_object, grpc_ce_channel_credentials);
   wrapped_grpc_channel_credentials *credentials =
     Z_WRAPPED_GRPC_CHANNEL_CREDS_P(credentials_object);
   credentials->wrapped = wrapped;
+  credentials->hashstr = hashstr;
+  credentials->has_call_creds = has_call_creds;
   return credentials_object;
 }
 
@@ -106,7 +111,8 @@ PHP_METHOD(ChannelCredentials, setDefaultRootsPem) {
  */
 PHP_METHOD(ChannelCredentials, createDefault) {
   grpc_channel_credentials *creds = grpc_google_default_credentials_create();
-  zval *creds_object = grpc_php_wrap_channel_credentials(creds TSRMLS_CC);
+  zval *creds_object = grpc_php_wrap_channel_credentials(creds, NULL, false
+                                                         TSRMLS_CC);
   RETURN_DESTROY_ZVAL(creds_object);
 }
 
@@ -140,10 +146,24 @@ PHP_METHOD(ChannelCredentials, createSsl) {
                          "createSsl expects 3 optional strings", 1 TSRMLS_CC);
     return;
   }
+
+  php_grpc_int hashkey_len = root_certs_length + cert_chain_length;
+  char hashkey[hashkey_len];
+  if (root_certs_length > 0) {
+    strcpy(hashkey, pem_root_certs);
+  }
+  if (cert_chain_length > 0) {
+    strcpy(hashkey, pem_key_cert_pair.cert_chain);
+  }
+
+  char *hashstr = malloc(41);
+  generate_sha1_str(hashstr, hashkey, hashkey_len);
+
   grpc_channel_credentials *creds = grpc_ssl_credentials_create(
       pem_root_certs,
       pem_key_cert_pair.private_key == NULL ? NULL : &pem_key_cert_pair, NULL);
-  zval *creds_object = grpc_php_wrap_channel_credentials(creds TSRMLS_CC);
+  zval *creds_object = grpc_php_wrap_channel_credentials(creds, hashstr, false
+                                                         TSRMLS_CC);
   RETURN_DESTROY_ZVAL(creds_object);
 }
 
@@ -172,7 +192,9 @@ PHP_METHOD(ChannelCredentials, createComposite) {
   grpc_channel_credentials *creds =
       grpc_composite_channel_credentials_create(cred1->wrapped, cred2->wrapped,
                                                 NULL);
-  zval *creds_object = grpc_php_wrap_channel_credentials(creds TSRMLS_CC);
+  zval *creds_object =
+      grpc_php_wrap_channel_credentials(creds, cred1->hashstr, true
+                                        TSRMLS_CC);
   RETURN_DESTROY_ZVAL(creds_object);
 }
 
diff --git a/src/php/ext/grpc/channel_credentials.h b/src/php/ext/grpc/channel_credentials.h
index 28c7f2c1d3..357d732642 100755
--- a/src/php/ext/grpc/channel_credentials.h
+++ b/src/php/ext/grpc/channel_credentials.h
@@ -38,6 +38,8 @@ extern zend_class_entry *grpc_ce_channel_credentials;
  * with a PHP object */
 PHP_GRPC_WRAP_OBJECT_START(wrapped_grpc_channel_credentials) 
   grpc_channel_credentials *wrapped;
+  char *hashstr;
+  zend_bool has_call_creds;
 PHP_GRPC_WRAP_OBJECT_END(wrapped_grpc_channel_credentials)
 
 #if PHP_MAJOR_VERSION < 7
diff --git a/src/php/ext/grpc/php7_wrapper.h b/src/php/ext/grpc/php7_wrapper.h
index d4b4c262a7..96091f9dad 100644
--- a/src/php/ext/grpc/php7_wrapper.h
+++ b/src/php/ext/grpc/php7_wrapper.h
@@ -113,6 +113,20 @@ static inline int php_grpc_zend_hash_find(HashTable *ht, char *key, int len,
 }
 
 #define php_grpc_zend_hash_del zend_hash_del
+#define php_grpc_zend_resource zend_rsrc_list_entry
+
+#define PHP_GRPC_BVAL_IS_TRUE(zv) Z_LVAL_P(zv)
+#define PHP_GRPC_VAR_SERIALIZE(buf, zv, hash) \
+  php_var_serialize(buf, &zv, hash TSRMLS_CC)
+#define PHP_GRPC_SERIALIZED_BUF_STR(buf) buf.c
+#define PHP_GRPC_SERIALIZED_BUF_LEN(buf) buf.len
+#define PHP_GRPC_SHA1Update(cxt, str, len)     \
+  PHP_SHA1Update(cxt, (const unsigned char *)str, len)
+#define PHP_GRPC_PERSISTENT_LIST_FIND(plist, key, len, rsrc) \
+  zend_hash_find(plist, key, len+1, (void **)&rsrc) != FAILURE
+#define PHP_GRPC_PERSISTENT_LIST_UPDATE(plist, key, len, rsrc) \
+  zend_hash_update(plist, key, len+1, rsrc, sizeof(php_grpc_zend_resource), \
+                   NULL)
 
 #define PHP_GRPC_GET_CLASS_ENTRY(object) zend_get_class_entry(object TSRMLS_CC)
 
@@ -200,6 +214,20 @@ static inline int php_grpc_zend_hash_find(HashTable *ht, char *key, int len,
 static inline int php_grpc_zend_hash_del(HashTable *ht, char *key, int len) {
   return zend_hash_str_del(ht, key, len - 1);
 }
+#define php_grpc_zend_resource zend_resource
+
+#define PHP_GRPC_BVAL_IS_TRUE(zv) Z_TYPE_P(zv) == IS_TRUE
+#define PHP_GRPC_VAR_SERIALIZE(buf, zv, hash)   \
+  php_var_serialize(buf, zv, hash)
+#define PHP_GRPC_SERIALIZED_BUF_STR(buf) ZSTR_VAL(buf.s)
+#define PHP_GRPC_SERIALIZED_BUF_LEN(buf) ZSTR_LEN(buf.s)
+#define PHP_GRPC_SHA1Update(cxt, str, len)      \
+  PHP_SHA1Update(cxt, (unsigned char *)str, len)
+#define PHP_GRPC_PERSISTENT_LIST_FIND(plist, key, len, rsrc) \
+  (rsrc = zend_hash_str_find_ptr(plist, key, len)) != NULL
+#define PHP_GRPC_PERSISTENT_LIST_UPDATE(plist, key, len, rsrc) \
+  zend_hash_str_update_mem(plist, key, len, rsrc, \
+                           sizeof(php_grpc_zend_resource))
 
 #define PHP_GRPC_GET_CLASS_ENTRY(object) Z_OBJ_P(object)->ce
 
diff --git a/src/php/ext/grpc/php_grpc.c b/src/php/ext/grpc/php_grpc.c
index 281b9e6aba..a96daf7d9b 100644
--- a/src/php/ext/grpc/php_grpc.c
+++ b/src/php/ext/grpc/php_grpc.c
@@ -221,7 +221,7 @@ PHP_MINIT_FUNCTION(grpc) {
                          CONST_CS | CONST_PERSISTENT);
 
   grpc_init_call(TSRMLS_C);
-  grpc_init_channel(TSRMLS_C);
+  GRPC_STARTUP(channel);
   grpc_init_server(TSRMLS_C);
   grpc_init_timeval(TSRMLS_C);
   grpc_init_channel_credentials(TSRMLS_C);
diff --git a/src/php/ext/grpc/php_grpc.h b/src/php/ext/grpc/php_grpc.h
index ed846fdba4..32329178dc 100644
--- a/src/php/ext/grpc/php_grpc.h
+++ b/src/php/ext/grpc/php_grpc.h
@@ -74,4 +74,8 @@ ZEND_END_MODULE_GLOBALS(grpc)
 #define GRPC_G(v) (grpc_globals.v)
 #endif
 
+#define GRPC_STARTUP_FUNCTION(module)  ZEND_MINIT_FUNCTION(grpc_##module)
+#define GRPC_STARTUP(module)           \
+  ZEND_MODULE_STARTUP_N(grpc_##module)(INIT_FUNC_ARGS_PASSTHRU)
+
 #endif /* PHP_GRPC_H */
diff --git a/src/php/tests/unit_tests/CallTest.php b/src/php/tests/unit_tests/CallTest.php
index 3270e73f82..c5e1890a98 100644
--- a/src/php/tests/unit_tests/CallTest.php
+++ b/src/php/tests/unit_tests/CallTest.php
@@ -37,8 +37,7 @@ class CallTest extends PHPUnit_Framework_TestCase
 
     public function tearDown()
     {
-        unset($this->call);
-        unset($this->channel);
+        $this->channel->close();
     }
 
     public function testConstructor()
diff --git a/src/php/tests/unit_tests/ChannelTest.php b/src/php/tests/unit_tests/ChannelTest.php
index 34e6185031..400df0fb66 100644
--- a/src/php/tests/unit_tests/ChannelTest.php
+++ b/src/php/tests/unit_tests/ChannelTest.php
@@ -25,17 +25,15 @@ class ChannelTest extends PHPUnit_Framework_TestCase
 
     public function tearDown()
     {
-        unset($this->channel);
+        if (!empty($this->channel)) {
+            $this->channel->close();
+        }
     }
 
     public function testInsecureCredentials()
     {
-        $this->channel = new Grpc\Channel(
-            'localhost:0',
-            [
-                'credentials' => Grpc\ChannelCredentials::createInsecure(),
-            ]
-        );
+        $this->channel = new Grpc\Channel('localhost:0',
+            ['credentials' => Grpc\ChannelCredentials::createInsecure()]);
         $this->assertSame('Grpc\Channel', get_class($this->channel));
     }
 
@@ -111,7 +109,7 @@ class ChannelTest extends PHPUnit_Framework_TestCase
      */
     public function testInvalidConstructorWith()
     {
-        $this->channel = new Grpc\Channel('localhost', 'invalid');
+        $this->channel = new Grpc\Channel('localhost:0', 'invalid');
         $this->assertNull($this->channel);
     }
 
@@ -120,12 +118,8 @@ class ChannelTest extends PHPUnit_Framework_TestCase
      */
     public function testInvalidCredentials()
     {
-        $this->channel = new Grpc\Channel(
-            'localhost:0',
-            [
-                'credentials' => new Grpc\Timeval(100),
-            ]
-        );
+        $this->channel = new Grpc\Channel('localhost:0',
+            ['credentials' => new Grpc\Timeval(100)]);
     }
 
     /**
@@ -133,12 +127,8 @@ class ChannelTest extends PHPUnit_Framework_TestCase
      */
     public function testInvalidOptionsArray()
     {
-        $this->channel = new Grpc\Channel(
-            'localhost:0',
-            [
-                'abc' => [],
-            ]
-        );
+        $this->channel = new Grpc\Channel('localhost:0',
+            ['abc' => []]);
     }
 
     /**
@@ -170,4 +160,431 @@ class ChannelTest extends PHPUnit_Framework_TestCase
             ['credentials' => Grpc\ChannelCredentials::createInsecure()]);
         $this->channel->watchConnectivityState(1, 'hi');
     }
+
+
+    public function assertConnecting($state) {
+      $this->assertTrue($state == GRPC\CHANNEL_CONNECTING ||
+                        $state == GRPC\CHANNEL_TRANSIENT_FAILURE);
+    }
+
+    public function waitUntilNotIdle($channel) {
+        for ($i = 0; $i < 10; $i++) {
+            $now = Grpc\Timeval::now();
+            $deadline = $now->add(new Grpc\Timeval(1000));
+            if ($channel->watchConnectivityState(GRPC\CHANNEL_IDLE,
+                                                 $deadline)) {
+                return true;
+            }
+        }
+        $this->assertTrue(false);
+    }
+
+    public function testPersistentChannelSameHost()
+    {
+        $this->channel1 = new Grpc\Channel('localhost:1', []);
+        // the underlying grpc channel is the same by default
+        // when connecting to the same host
+        $this->channel2 = new Grpc\Channel('localhost:1', []);
+
+        // both channels should be IDLE
+        $state = $this->channel1->getConnectivityState();
+        $this->assertEquals(GRPC\CHANNEL_IDLE, $state);
+        $state = $this->channel2->getConnectivityState();
+        $this->assertEquals(GRPC\CHANNEL_IDLE, $state);
+
+        // try to connect on channel1
+        $state = $this->channel1->getConnectivityState(true);
+        $this->waitUntilNotIdle($this->channel1);
+
+        // both channels should now be in the CONNECTING state
+        $state = $this->channel1->getConnectivityState();
+        $this->assertConnecting($state);
+        $state = $this->channel2->getConnectivityState();
+        $this->assertConnecting($state);
+
+        $this->channel1->close();
+        $this->channel2->close();
+    }
+
+    public function testPersistentChannelDifferentHost()
+    {
+        // two different underlying channels because different hostname
+        $this->channel1 = new Grpc\Channel('localhost:1', []);
+        $this->channel2 = new Grpc\Channel('localhost:2', []);
+
+        // both channels should be IDLE
+        $state = $this->channel1->getConnectivityState();
+        $this->assertEquals(GRPC\CHANNEL_IDLE, $state);
+        $state = $this->channel2->getConnectivityState();
+        $this->assertEquals(GRPC\CHANNEL_IDLE, $state);
+
+        // try to connect on channel1
+        $state = $this->channel1->getConnectivityState(true);
+        $this->waitUntilNotIdle($this->channel1);
+
+        // channel1 should now be in the CONNECTING state
+        $state = $this->channel1->getConnectivityState();
+        $this->assertConnecting($state);
+        // channel2 should still be in the IDLE state
+        $state = $this->channel2->getConnectivityState();
+        $this->assertEquals(GRPC\CHANNEL_IDLE, $state);
+
+        $this->channel1->close();
+        $this->channel2->close();
+    }
+
+    public function testPersistentChannelSameArgs()
+    {
+        $this->channel1 = new Grpc\Channel('localhost:1', ["abc" => "def"]);
+        $this->channel2 = new Grpc\Channel('localhost:1', ["abc" => "def"]);
+
+        // try to connect on channel1
+        $state = $this->channel1->getConnectivityState(true);
+        $this->waitUntilNotIdle($this->channel1);
+
+        $state = $this->channel1->getConnectivityState();
+        $this->assertConnecting($state);
+        $state = $this->channel2->getConnectivityState();
+        $this->assertConnecting($state);
+
+        $this->channel1->close();
+        $this->channel2->close();
+    }
+
+    public function testPersistentChannelDifferentArgs()
+    {
+        $this->channel1 = new Grpc\Channel('localhost:1', []);
+        $this->channel2 = new Grpc\Channel('localhost:1', ["abc" => "def"]);
+
+        // try to connect on channel1
+        $state = $this->channel1->getConnectivityState(true);
+        $this->waitUntilNotIdle($this->channel1);
+
+        $state = $this->channel1->getConnectivityState();
+        $this->assertConnecting($state);
+        $state = $this->channel2->getConnectivityState();
+        $this->assertEquals(GRPC\CHANNEL_IDLE, $state);
+
+        $this->channel1->close();
+        $this->channel2->close();
+    }
+
+    public function testPersistentChannelSameChannelCredentials()
+    {
+        $creds1 = Grpc\ChannelCredentials::createSsl();
+        $creds2 = Grpc\ChannelCredentials::createSsl();
+
+        $this->channel1 = new Grpc\Channel('localhost:1',
+                                           ["credentials" => $creds1]);
+        $this->channel2 = new Grpc\Channel('localhost:1',
+                                           ["credentials" => $creds2]);
+
+        // try to connect on channel1
+        $state = $this->channel1->getConnectivityState(true);
+        $this->waitUntilNotIdle($this->channel1);
+
+        $state = $this->channel1->getConnectivityState();
+        $this->assertConnecting($state);
+        $state = $this->channel2->getConnectivityState();
+        $this->assertConnecting($state);
+
+        $this->channel1->close();
+        $this->channel2->close();
+    }
+
+    public function testPersistentChannelDifferentChannelCredentials()
+    {
+        $creds1 = Grpc\ChannelCredentials::createSsl();
+        $creds2 = Grpc\ChannelCredentials::createSsl(
+            file_get_contents(dirname(__FILE__).'/../data/ca.pem'));
+
+        $this->channel1 = new Grpc\Channel('localhost:1',
+                                           ["credentials" => $creds1]);
+        $this->channel2 = new Grpc\Channel('localhost:1',
+                                           ["credentials" => $creds2]);
+
+        // try to connect on channel1
+        $state = $this->channel1->getConnectivityState(true);
+        $this->waitUntilNotIdle($this->channel1);
+
+        $state = $this->channel1->getConnectivityState();
+        $this->assertConnecting($state);
+        $state = $this->channel2->getConnectivityState();
+        $this->assertEquals(GRPC\CHANNEL_IDLE, $state);
+
+        $this->channel1->close();
+        $this->channel2->close();
+    }
+
+    public function testPersistentChannelSameChannelCredentialsRootCerts()
+    {
+        $creds1 = Grpc\ChannelCredentials::createSsl(
+            file_get_contents(dirname(__FILE__).'/../data/ca.pem'));
+        $creds2 = Grpc\ChannelCredentials::createSsl(
+            file_get_contents(dirname(__FILE__).'/../data/ca.pem'));
+
+        $this->channel1 = new Grpc\Channel('localhost:1',
+                                           ["credentials" => $creds1]);
+        $this->channel2 = new Grpc\Channel('localhost:1',
+                                           ["credentials" => $creds2]);
+
+        // try to connect on channel1
+        $state = $this->channel1->getConnectivityState(true);
+        $this->waitUntilNotIdle($this->channel1);
+
+        $state = $this->channel1->getConnectivityState();
+        $this->assertConnecting($state);
+        $state = $this->channel2->getConnectivityState();
+        $this->assertConnecting($state);
+
+        $this->channel1->close();
+        $this->channel2->close();
+    }
+
+    public function testPersistentChannelDifferentSecureChannelCredentials()
+    {
+        $creds1 = Grpc\ChannelCredentials::createSsl();
+        $creds2 = Grpc\ChannelCredentials::createInsecure();
+
+        $this->channel1 = new Grpc\Channel('localhost:1',
+                                           ["credentials" => $creds1]);
+        $this->channel2 = new Grpc\Channel('localhost:1',
+                                           ["credentials" => $creds2]);
+
+        // try to connect on channel1
+        $state = $this->channel1->getConnectivityState(true);
+        $this->waitUntilNotIdle($this->channel1);
+
+        $state = $this->channel1->getConnectivityState();
+        $this->assertConnecting($state);
+        $state = $this->channel2->getConnectivityState();
+        $this->assertEquals(GRPC\CHANNEL_IDLE, $state);
+
+        $this->channel1->close();
+        $this->channel2->close();
+    }
+
+    /**
+     * @expectedException RuntimeException
+     */
+    public function testPersistentChannelSharedChannelClose()
+    {
+        // same underlying channel
+        $this->channel1 = new Grpc\Channel('localhost:1', []);
+        $this->channel2 = new Grpc\Channel('localhost:1', []);
+
+        // close channel1
+        $this->channel1->close();
+
+        // channel2 is now in SHUTDOWN state
+        $state = $this->channel2->getConnectivityState();
+        $this->assertEquals(GRPC\CHANNEL_FATAL_FAILURE, $state);
+
+        // calling it again will result in an exception because the
+        // channel is already closed
+        $state = $this->channel2->getConnectivityState();
+    }
+
+    public function testPersistentChannelCreateAfterClose()
+    {
+        $this->channel1 = new Grpc\Channel('localhost:1', []);
+
+        $this->channel1->close();
+
+        $this->channel2 = new Grpc\Channel('localhost:1', []);
+        $state = $this->channel2->getConnectivityState();
+        $this->assertEquals(GRPC\CHANNEL_IDLE, $state);
+
+        $this->channel2->close();
+    }
+
+    public function testPersistentChannelSharedMoreThanTwo()
+    {
+        $this->channel1 = new Grpc\Channel('localhost:1', []);
+        $this->channel2 = new Grpc\Channel('localhost:1', []);
+        $this->channel3 = new Grpc\Channel('localhost:1', []);
+
+        // try to connect on channel1
+        $state = $this->channel1->getConnectivityState(true);
+        $this->waitUntilNotIdle($this->channel1);
+
+        // all 3 channels should be in CONNECTING state
+        $state = $this->channel1->getConnectivityState();
+        $this->assertConnecting($state);
+        $state = $this->channel2->getConnectivityState();
+        $this->assertConnecting($state);
+        $state = $this->channel3->getConnectivityState();
+        $this->assertConnecting($state);
+
+        $this->channel1->close();
+    }
+
+    public function callbackFunc($context)
+    {
+        return [];
+    }
+
+    public function callbackFunc2($context)
+    {
+        return ["k1" => "v1"];
+    }
+
+    public function testPersistentChannelWithCallCredentials()
+    {
+        $creds = Grpc\ChannelCredentials::createSsl();
+        $callCreds = Grpc\CallCredentials::createFromPlugin(
+            [$this, 'callbackFunc']);
+        $credsWithCallCreds = Grpc\ChannelCredentials::createComposite(
+            $creds, $callCreds);
+
+        // If a ChannelCredentials object is composed with a
+        // CallCredentials object, the underlying grpc channel will
+        // always be created new and NOT persisted.
+        $this->channel1 = new Grpc\Channel('localhost:1',
+                                           ["credentials" =>
+                                            $credsWithCallCreds]);
+        $this->channel2 = new Grpc\Channel('localhost:1',
+                                           ["credentials" =>
+                                            $credsWithCallCreds]);
+
+        // try to connect on channel1
+        $state = $this->channel1->getConnectivityState(true);
+        $this->waitUntilNotIdle($this->channel1);
+
+        $state = $this->channel1->getConnectivityState();
+        $this->assertConnecting($state);
+        $state = $this->channel2->getConnectivityState();
+        $this->assertEquals(GRPC\CHANNEL_IDLE, $state);
+
+        $this->channel1->close();
+        $this->channel2->close();
+    }
+
+    public function testPersistentChannelWithDifferentCallCredentials()
+    {
+        $callCreds1 = Grpc\CallCredentials::createFromPlugin(
+            [$this, 'callbackFunc']);
+        $callCreds2 = Grpc\CallCredentials::createFromPlugin(
+            [$this, 'callbackFunc2']);
+
+        $creds1 = Grpc\ChannelCredentials::createSsl();
+        $creds2 = Grpc\ChannelCredentials::createComposite(
+            $creds1, $callCreds1);
+        $creds3 = Grpc\ChannelCredentials::createComposite(
+            $creds1, $callCreds2);
+
+        // Similar to the test above, anytime a ChannelCredentials
+        // object is composed with a CallCredentials object, the
+        // underlying grpc channel will always be separate and not
+        // persisted
+        $this->channel1 = new Grpc\Channel('localhost:1',
+                                           ["credentials" => $creds1]);
+        $this->channel2 = new Grpc\Channel('localhost:1',
+                                           ["credentials" => $creds2]);
+        $this->channel3 = new Grpc\Channel('localhost:1',
+                                           ["credentials" => $creds3]);
+
+        // try to connect on channel1
+        $state = $this->channel1->getConnectivityState(true);
+        $this->waitUntilNotIdle($this->channel1);
+
+        $state = $this->channel1->getConnectivityState();
+        $this->assertConnecting($state);
+        $state = $this->channel2->getConnectivityState();
+        $this->assertEquals(GRPC\CHANNEL_IDLE, $state);
+        $state = $this->channel3->getConnectivityState();
+        $this->assertEquals(GRPC\CHANNEL_IDLE, $state);
+
+        $this->channel1->close();
+        $this->channel2->close();
+        $this->channel3->close();
+    }
+
+    public function testPersistentChannelForceNew()
+    {
+        $this->channel1 = new Grpc\Channel('localhost:1', []);
+        // even though all the channel params are the same, channel2
+        // has a new and different underlying channel
+        $this->channel2 = new Grpc\Channel('localhost:1',
+                                           ["force_new" => true]);
+
+        // try to connect on channel1
+        $state = $this->channel1->getConnectivityState(true);
+        $this->waitUntilNotIdle($this->channel1);
+
+        $state = $this->channel1->getConnectivityState();
+        $this->assertConnecting($state);
+        $state = $this->channel2->getConnectivityState();
+        $this->assertEquals(GRPC\CHANNEL_IDLE, $state);
+
+        // any dangling old connection to the same host must be
+        // manually closed
+        $this->channel1->close();
+        $this->channel2->close();
+    }
+
+    public function testPersistentChannelForceNewOldChannelIdle()
+    {
+
+        $this->channel1 = new Grpc\Channel('localhost:1', []);
+        $this->channel2 = new Grpc\Channel('localhost:1',
+                                           ["force_new" => true]);
+        $this->channel3 = new Grpc\Channel('localhost:1', []);
+
+        // try to connect on channel2
+        $state = $this->channel2->getConnectivityState(true);
+        $this->waitUntilNotIdle($this->channel2);
+
+        $state = $this->channel1->getConnectivityState();
+        $this->assertEquals(GRPC\CHANNEL_IDLE, $state);
+        $state = $this->channel2->getConnectivityState();
+        $this->assertConnecting($state);
+        $state = $this->channel3->getConnectivityState();
+        $this->assertConnecting($state);
+
+        $this->channel1->close();
+        $this->channel2->close();
+    }
+
+    public function testPersistentChannelForceNewOldChannelClose()
+    {
+
+        $this->channel1 = new Grpc\Channel('localhost:1', []);
+        $this->channel2 = new Grpc\Channel('localhost:1',
+                                           ["force_new" => true]);
+        $this->channel3 = new Grpc\Channel('localhost:1', []);
+
+        $this->channel1->close();
+
+        $state = $this->channel2->getConnectivityState();
+        $this->assertEquals(GRPC\CHANNEL_IDLE, $state);
+        $state = $this->channel3->getConnectivityState();
+        $this->assertEquals(GRPC\CHANNEL_IDLE, $state);
+
+        $this->channel2->close();
+        $this->channel3->close();
+    }
+
+    public function testPersistentChannelForceNewNewChannelClose()
+    {
+
+        $this->channel1 = new Grpc\Channel('localhost:1', []);
+        $this->channel2 = new Grpc\Channel('localhost:1',
+                                           ["force_new" => true]);
+        $this->channel3 = new Grpc\Channel('localhost:1', []);
+
+        $this->channel2->close();
+
+        $state = $this->channel1->getConnectivityState();
+        $this->assertEquals(GRPC\CHANNEL_IDLE, $state);
+
+        // can still connect on channel1
+        $state = $this->channel1->getConnectivityState(true);
+        $this->waitUntilNotIdle($this->channel1);
+
+        $state = $this->channel1->getConnectivityState();
+        $this->assertConnecting($state);
+
+        $this->channel1->close();
+    }
 }
diff --git a/src/php/tests/unit_tests/EndToEndTest.php b/src/php/tests/unit_tests/EndToEndTest.php
index 43d54d9ee6..b54f1d87c9 100644
--- a/src/php/tests/unit_tests/EndToEndTest.php
+++ b/src/php/tests/unit_tests/EndToEndTest.php
@@ -28,8 +28,7 @@ class EndToEndTest extends PHPUnit_Framework_TestCase
 
     public function tearDown()
     {
-        unset($this->channel);
-        unset($this->server);
+        $this->channel->close();
     }
 
     public function testSimpleRequestBody()
@@ -516,7 +515,7 @@ class EndToEndTest extends PHPUnit_Framework_TestCase
         $this->assertTrue($idle_state == Grpc\CHANNEL_IDLE);
 
         $now = Grpc\Timeval::now();
-        $delta = new Grpc\Timeval(500000); // should timeout
+        $delta = new Grpc\Timeval(50000); // should timeout
         $deadline = $now->add($delta);
 
         $this->assertFalse($this->channel->watchConnectivityState(
@@ -545,7 +544,7 @@ class EndToEndTest extends PHPUnit_Framework_TestCase
         $this->assertTrue($idle_state == Grpc\CHANNEL_IDLE);
 
         $now = Grpc\Timeval::now();
-        $delta = new Grpc\Timeval(100000);
+        $delta = new Grpc\Timeval(50000);
         $deadline = $now->add($delta);
 
         $this->assertFalse($this->channel->watchConnectivityState(
diff --git a/src/php/tests/unit_tests/SecureEndToEndTest.php b/src/php/tests/unit_tests/SecureEndToEndTest.php
index 0fecbfb3dd..dff4e878ea 100644
--- a/src/php/tests/unit_tests/SecureEndToEndTest.php
+++ b/src/php/tests/unit_tests/SecureEndToEndTest.php
@@ -43,8 +43,7 @@ class SecureEndToEndTest extends PHPUnit_Framework_TestCase
 
     public function tearDown()
     {
-        unset($this->channel);
-        unset($this->server);
+        $this->channel->close();
     }
 
     public function testSimpleRequestBody()