send alert messages to an events channel when a channel is created or...

send alert messages to an events channel when a channel is created or destroyed and when a client subscribe or unsubscribe a channel

README.textile

@@ -152,6 +152,7 @@ h1(#directives). Directives
 | "push_stream_max_number_of_channels":push_stream_max_number_of_channels |   - |   x |   - |   - |   - |   - |
 | "push_stream_max_number_of_wildcard_channels":push_stream_max_number_of_wildcard_channels |   - |   x |   - |   - |   - |   - |
 | "push_stream_wildcard_channel_prefix":push_stream_wildcard_channel_prefix |   - |   x |   - |   - |   - |   - |
+| "push_stream_events_channel_id":push_stream_events_channel_id |   - |   x |   - |   - |   - |   - |
 | "push_stream_channels_path":push_stream_channels_path |   - |   - |   x |   x |   x |   x |
 | "push_stream_store_messages":push_stream_store_messages |   - |   - |   - |   x |   - |   x |
 | "push_stream_channel_info_on_publish":push_stream_channel_info_on_publish |   - |   - |   - |   x |   - |   - |
@@ -171,6 +172,7 @@ h1(#directives). Directives
 | "push_stream_user_agent":push_stream_user_agent |   - |   - |   x |   - |   - |   - |
 | "push_stream_padding_by_user_agent":push_stream_padding_by_user_agent |   - |   - |   x |   - |   - |   - |
 | "push_stream_allowed_origins":push_stream_allowed_origins |   - |   - |   x |   - |   - |   - |
+| "push_stream_allow_connections_to_events_channel":push_stream_allow_connections_to_events_channel |   - |   - |   x |   - |   - |   x |
 
 h1(#installation). Installation <a name="installation" href="#">&nbsp;</a>
 
@@ -258,6 +260,7 @@ h1(#contributors). Contributors
 [push_stream_max_number_of_channels]docs/directives/main.textile#push_stream_max_number_of_channels
 [push_stream_max_number_of_wildcard_channels]docs/directives/main.textile#push_stream_max_number_of_wildcard_channels
 [push_stream_wildcard_channel_prefix]docs/directives/main.textile#push_stream_wildcard_channel_prefix
+[push_stream_events_channel_id]docs/directives/main.textile#push_stream_events_channel_id
 [push_stream_channels_path]docs/directives/subscribers.textile#push_stream_channels_path
 [push_stream_authorized_channels_only]docs/directives/subscribers.textile#push_stream_authorized_channels_only
 [push_stream_header_template_file]docs/directives/subscribers.textile#push_stream_header_template_file
@@ -278,5 +281,6 @@ h1(#contributors). Contributors
 [push_stream_channel_info_on_publish]docs/directives/publishers.textile#push_stream_channel_info_on_publish
 [push_stream_allowed_origins]docs/directives/subscribers.textile#push_stream_allowed_origins
 [push_stream_websocket_allow_publish]docs/directives/subscribers.textile#push_stream_websocket_allow_publish
+[push_stream_allow_connections_to_events_channel]docs/directives/subscribers.textile#push_stream_allow_connections_to_events_channel
 [wiki]https://github.com/wandenberg/nginx-push-stream-module/wiki/_pages
 [nginx_debugging]http://wiki.nginx.org/Debugging

docs/directives/main.textile

@@ -134,4 +134,25 @@ The string prefix used to identify a wildcard channel, example: when you set thi
 A wildcard channel is technically equals to a normal one. It is intended to be used when the "push_stream_authorized_channels_only":push_stream_authorized_channels_only is set to on.
 
 
+h2(#push_stream_events_channel_id). push_stream_events_channel_id <a name="push_stream_events_channel_id" href="#">&nbsp;</a>
+
+*syntax:* _push_stream_events_channel_id string_
+
+*default:* _none_
+
+*context:* _http_
+
+*release version:* _0.6.0_
+
+The string identify an events channel where some control messages will be published.
+Examples:
+{"type": "channel_created", "channel": "CHANNEL_ID"}
+{"type": "channel_destroyed", "channel": "CHANNEL_ID"}
+{"type": "client_subscribed", "channel": "CHANNEL_ID"}
+{"type": "client_unsubscribed", "channel": "CHANNEL_ID"}
+
+By default this channel is not available to subscription. To allow subscriptions to it is necessary set "push_stream_allow_connections_to_events_channel":push_stream_allow_connections_to_events_channel to on.
+
+
 [push_stream_authorized_channels_only]subscribers.textile#push_stream_authorized_channels_only
+[push_stream_allow_connections_to_events_channel]subscribers.textile#push_stream_allow_connections_to_events_channel

docs/directives/subscribers.textile

@@ -221,6 +221,19 @@ h2(#push_stream_websocket_allow_publish). push_stream_websocket_allow_publish <a
 Enable a WebSocket subscriber send messages to the channel(s) it is connected through the same connection it is receiving the messages, using _send_ method from WebSocket interface.
 
 
+h2(#push_stream_allow_connections_to_events_channel). push_stream_allow_connections_to_events_channel <a name="push_stream_allow_connections_to_events_channel" href="#">&nbsp;</a>
+
+*syntax:* _push_stream_allow_connections_to_events_channel on | off_
+
+*default:* _off_
+
+*context:* _location_
+
+*release version:* _0.6.0_
+
+Enable subscriptions to events channel.
+
+
 h2(#push_stream_last_received_message_time). push_stream_last_received_message_time <a name="push_stream_last_received_message_time" href="#">&nbsp;</a>
 
 *syntax:* _push_stream_last_received_message_time string_

include/ngx_http_push_stream_module.h

@@ -76,6 +76,7 @@ typedef struct {
 typedef struct ngx_http_push_stream_msg_s ngx_http_push_stream_msg_t;
 typedef struct ngx_http_push_stream_shm_data_s ngx_http_push_stream_shm_data_t;
 typedef struct ngx_http_push_stream_global_shm_data_s ngx_http_push_stream_global_shm_data_t;
+typedef struct ngx_http_push_stream_channel_s ngx_http_push_stream_channel_t;
 
 typedef struct {
     ngx_flag_t                      enabled;
@@ -92,6 +93,8 @@ typedef struct {
     ngx_uint_t                      max_channel_id_length;
     ngx_queue_t                     msg_templates;
     ngx_flag_t                      timeout_with_body;
+    ngx_str_t                       events_channel_id;
+    ngx_http_push_stream_channel_t *events_channel;
     ngx_regex_t                    *backtrack_parser_regex;
     ngx_http_push_stream_msg_t     *ping_msg;
     ngx_http_push_stream_msg_t     *longpooling_timeout_msg;
@@ -115,6 +118,7 @@ typedef struct {
     ngx_msec_t                      longpolling_connection_ttl;
     ngx_flag_t                      websocket_allow_publish;
     ngx_flag_t                      channel_info_on_publish;
+    ngx_flag_t                      allow_connections_to_events_channel;
     ngx_http_complex_value_t       *last_received_message_time;
     ngx_http_complex_value_t       *last_received_message_tag;
     ngx_http_complex_value_t       *last_event_id;
@@ -156,8 +160,7 @@ typedef struct {
     ngx_uint_t                          subscribers;
 } ngx_http_push_stream_pid_queue_t;
 
-// our typecast-friendly rbtree node (channel)
-typedef struct {
+struct ngx_http_push_stream_channel_s {
     ngx_rbtree_node_t                   node;
     ngx_queue_t                         queue;
     ngx_str_t                           id;
@@ -171,9 +174,10 @@ typedef struct {
     time_t                              expires;
     ngx_flag_t                          deleted;
     ngx_flag_t                          wildcard;
+    char                                for_events;
     ngx_http_push_stream_msg_t         *channel_deleted_message;
     ngx_shmtx_t                        *mutex;
-} ngx_http_push_stream_channel_t;
+};
 
 typedef struct {
     ngx_queue_t                         queue;
@@ -295,6 +299,8 @@ struct ngx_http_push_stream_shm_data_s {
     ngx_shmtx_sh_t                          channels_lock[10];
     ngx_shmtx_t                             cleanup_mutex;
     ngx_shmtx_sh_t                          cleanup_lock;
+    ngx_shmtx_t                             events_channel_mutex;
+    ngx_shmtx_sh_t                          events_channel_lock;
 };
 
 ngx_shm_zone_t     *ngx_http_push_stream_global_shm_zone = NULL;
@@ -319,6 +325,8 @@ static const ngx_str_t NGX_HTTP_PUSH_STREAM_TOO_MUCH_WILDCARD_CHANNELS = ngx_str
 static const ngx_str_t NGX_HTTP_PUSH_STREAM_TOO_SUBSCRIBERS_PER_CHANNEL = ngx_string("Subscribers limit per channel has been exceeded.");
 static const ngx_str_t NGX_HTTP_PUSH_STREAM_CANNOT_CREATE_CHANNELS = ngx_string("Subscriber could not create channels.");
 static const ngx_str_t NGX_HTTP_PUSH_STREAM_NUMBER_OF_CHANNELS_EXCEEDED_MESSAGE = ngx_string("Number of channels were exceeded.");
+static const ngx_str_t NGX_HTTP_PUSH_STREAM_INTERNAL_ONLY_EVENTS_CHANNEL_MESSAGE = ngx_string("Only internal routines can change events channel.");
+static const ngx_str_t NGX_HTTP_PUSH_STREAM_SUBSCRIPTION_EVENTS_CHANNEL_FORBIDDEN_MESSAGE = ngx_string("Subscription to events channel is not allowed.");
 static const ngx_str_t NGX_HTTP_PUSH_STREAM_NO_MANDATORY_HEADERS_MESSAGE = ngx_string("Don't have at least one of the mandatory headers: Connection, Upgrade, Sec-WebSocket-Key and Sec-WebSocket-Version");
 static const ngx_str_t NGX_HTTP_PUSH_STREAM_WRONG_WEBSOCKET_VERSION_MESSAGE = ngx_string("Version not supported. Supported versions: 8, 13");
 static const ngx_str_t NGX_HTTP_PUSH_STREAM_CHANNEL_DELETED = ngx_string("Channel deleted.");

include/ngx_http_push_stream_module_setup.h

@@ -50,6 +50,8 @@ static time_t NGX_HTTP_PUSH_STREAM_DEFAULT_CHANNEL_INACTIVITY_TIME        = 30;
 
 #define NGX_HTTP_PUSH_STREAM_DEFAULT_WILDCARD_CHANNEL_PREFIX ""
 
+#define NGX_HTTP_PUSH_STREAM_DEFAULT_EVENTS_CHANNEL_ID ""
+
 static char *       ngx_http_push_stream_channels_statistics(ngx_conf_t *cf, ngx_command_t *cmd, void *conf);
 
 // publisher

include/ngx_http_push_stream_module_utils.h

@@ -222,6 +222,13 @@ static const ngx_str_t  NGX_HTTP_PUSH_STREAM_CALLBACK_CONTENT_TYPE = ngx_string(
 
 static const ngx_str_t  NGX_HTTP_PUSH_STREAM_PADDING_BY_USER_AGENT_PATTERN = ngx_string("([^:]+),(\\d+),(\\d+)");
 
+#define NGX_HTTP_PUSH_STREAM_EVENT_TEMPLATE "{\"type\": \"%V\", \"channel\": \"%V\"}%Z"
+static ngx_str_t  NGX_HTTP_PUSH_STREAM_EVENT_TYPE_CHANNEL_CREATED = ngx_string("channel_created");
+static ngx_str_t  NGX_HTTP_PUSH_STREAM_EVENT_TYPE_CHANNEL_DESTROYED = ngx_string("channel_destroyed");
+static ngx_str_t  NGX_HTTP_PUSH_STREAM_EVENT_TYPE_CLIENT_SUBSCRIBED = ngx_string("client_subscribed");
+static ngx_str_t  NGX_HTTP_PUSH_STREAM_EVENT_TYPE_CLIENT_UNSUBSCRIBED = ngx_string("client_unsubscribed");
+
+
 ngx_event_t         ngx_http_push_stream_memory_cleanup_event;
 ngx_event_t         ngx_http_push_stream_buffer_cleanup_event;
 
@@ -253,7 +260,8 @@ static void                 ngx_http_push_stream_unescape_uri(ngx_str_t *value);
 static void                 ngx_http_push_stream_complex_value(ngx_http_request_t *r, ngx_http_complex_value_t *val, ngx_str_t *value);
 
 
-ngx_int_t                   ngx_http_push_stream_add_msg_to_channel(ngx_http_request_t *r, ngx_http_push_stream_channel_t *channel, u_char *text, size_t len, ngx_str_t *event_id, ngx_str_t *event_type, ngx_pool_t *temp_pool);
+ngx_int_t                   ngx_http_push_stream_add_msg_to_channel(ngx_http_push_stream_main_conf_t *mcf, ngx_log_t *log, ngx_http_push_stream_channel_t *channel, u_char *text, size_t len, ngx_str_t *event_id, ngx_str_t *event_type, ngx_flag_t store_messages, ngx_pool_t *temp_pool);
+ngx_int_t                   ngx_http_push_stream_send_event(ngx_http_push_stream_main_conf_t *mcf, ngx_log_t *log, ngx_http_push_stream_channel_t *channel, ngx_str_t *event_id, ngx_pool_t *temp_pool);
 
 static void                 ngx_http_push_stream_ping_timer_wake_handler(ngx_event_t *ev);
 static void                 ngx_http_push_stream_disconnect_timer_wake_handler(ngx_event_t *ev);
@@ -264,7 +272,7 @@ static void                 ngx_http_push_stream_timer_set(ngx_msec_t timer_inte
 static void                 ngx_http_push_stream_timer_reset(ngx_msec_t timer_interval, ngx_event_t *timer_event);
 
 #define ngx_http_push_stream_memory_cleanup_timer_set(void) ngx_http_push_stream_timer_set(NGX_HTTP_PUSH_STREAM_DEFAULT_SHM_MEMORY_CLEANUP_INTERVAL, &ngx_http_push_stream_memory_cleanup_event, ngx_http_push_stream_memory_cleanup_timer_wake_handler, 1);
-#define ngx_http_push_stream_buffer_cleanup_timer_set(pslcf) ngx_http_push_stream_timer_set(NGX_HTTP_PUSH_STREAM_MESSAGE_BUFFER_CLEANUP_INTERVAL, &ngx_http_push_stream_buffer_cleanup_event, ngx_http_push_stream_buffer_timer_wake_handler, pslcf->store_messages);
+#define ngx_http_push_stream_buffer_cleanup_timer_set(void) ngx_http_push_stream_timer_set(NGX_HTTP_PUSH_STREAM_MESSAGE_BUFFER_CLEANUP_INTERVAL, &ngx_http_push_stream_buffer_cleanup_event, ngx_http_push_stream_buffer_timer_wake_handler, 1);
 
 static void                 ngx_http_push_stream_worker_subscriber_cleanup(ngx_http_push_stream_subscriber_t *worker_subscriber);
 static ngx_str_t *          ngx_http_push_stream_create_str(ngx_pool_t *pool, uint len);

misc/spec/nginx_configuration.rb

@@ -59,6 +59,9 @@ module NginxConfiguration
       :channels_path_for_pub => '$arg_id',
       :channels_path => '$1',
 
+      :events_channel_id => nil,
+      :allow_connections_to_events_channel => nil,
+
       :extra_location => '',
       :extra_configuration => ''
     }
@@ -152,6 +155,9 @@ http {
   <%= write_directive("push_stream_ping_message_text", ping_message_text) %>
   <%= write_directive("push_stream_channel_inactivity_time", channel_inactivity_time) %>
 
+  <%= write_directive("push_stream_events_channel_id", events_channel_id) %>
+  <%= write_directive("push_stream_allow_connections_to_events_channel", allow_connections_to_events_channel) %>
+
   server {
     listen        <%= nginx_port %>;
     server_name   <%= nginx_host %>;

src/ngx_http_push_stream_module_publisher.c

@@ -106,10 +106,14 @@ ngx_http_push_stream_publisher_handler(ngx_http_request_t *r)
                 ngx_log_error(NGX_LOG_ERR, r->connection->log, 0, "push stream module: number of channels were exceeded");
                 return ngx_http_push_stream_send_only_header_response(r, NGX_HTTP_FORBIDDEN, &NGX_HTTP_PUSH_STREAM_NUMBER_OF_CHANNELS_EXCEEDED_MESSAGE);
             }
-
         } else {
             requested_channel->channel = ngx_http_push_stream_find_channel(requested_channel->id, r->connection->log, mcf);
         }
+
+        if ((r->method != NGX_HTTP_GET) && (requested_channel->channel != NULL) && requested_channel->channel->for_events) {
+            ngx_log_error(NGX_LOG_ERR, r->connection->log, 0, "push stream module: only internal routines can change events channel");
+            return ngx_http_push_stream_send_only_header_response(r, NGX_HTTP_FORBIDDEN, &NGX_HTTP_PUSH_STREAM_INTERNAL_ONLY_EVENTS_CHANNEL_MESSAGE);
+        }
     }
 
     ctx->requested_channels = requested_channels;
@@ -236,6 +240,7 @@ ngx_http_push_stream_publisher_body_handler(ngx_http_request_t *r)
 {
     ngx_str_t                              *event_id, *event_type;
     ngx_http_push_stream_module_ctx_t      *ctx = ngx_http_get_module_ctx(r, ngx_http_push_stream_module);
+    ngx_http_push_stream_main_conf_t       *mcf = ngx_http_get_module_main_conf(r, ngx_http_push_stream_module);
     ngx_http_push_stream_loc_conf_t        *cf = ngx_http_get_module_loc_conf(r, ngx_http_push_stream_module);
     ngx_buf_t                              *buf = NULL;
 
@@ -263,7 +268,7 @@ ngx_http_push_stream_publisher_body_handler(ngx_http_request_t *r)
     for (q = ngx_queue_head(&ctx->requested_channels->queue); q != ngx_queue_sentinel(&ctx->requested_channels->queue); q = ngx_queue_next(q)) {
         requested_channel = ngx_queue_data(q, ngx_http_push_stream_requested_channel_t, queue);
 
-        if (ngx_http_push_stream_add_msg_to_channel(r, requested_channel->channel, buf->pos, ngx_buf_size(buf), event_id, event_type, r->pool) != NGX_OK) {
+        if (ngx_http_push_stream_add_msg_to_channel(mcf, r->connection->log, requested_channel->channel, buf->pos, ngx_buf_size(buf), event_id, event_type, cf->store_messages, r->pool) != NGX_OK) {
             ngx_http_finalize_request(r, NGX_HTTP_INTERNAL_SERVER_ERROR);
             return;
         }

src/ngx_http_push_stream_module_setup.c

@@ -121,6 +121,12 @@ static ngx_command_t    ngx_http_push_stream_commands[] = {
         NGX_HTTP_MAIN_CONF_OFFSET,
         offsetof(ngx_http_push_stream_main_conf_t, wildcard_channel_prefix),
         NULL },
+    { ngx_string("push_stream_events_channel_id"),
+        NGX_HTTP_MAIN_CONF|NGX_CONF_TAKE1,
+        ngx_conf_set_str_slot,
+        NGX_HTTP_MAIN_CONF_OFFSET,
+        offsetof(ngx_http_push_stream_main_conf_t, events_channel_id),
+        NULL },
 
     /* Location directives */
     { ngx_string("push_stream_channels_path"),
@@ -237,6 +243,13 @@ static ngx_command_t    ngx_http_push_stream_commands[] = {
         NGX_HTTP_LOC_CONF_OFFSET,
         offsetof(ngx_http_push_stream_loc_conf_t, allowed_origins),
         NULL },
+    { ngx_string("push_stream_allow_connections_to_events_channel"),
+        NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_HTTP_LIF_CONF|NGX_CONF_TAKE1,
+        ngx_conf_set_flag_slot,
+        NGX_HTTP_LOC_CONF_OFFSET,
+        offsetof(ngx_http_push_stream_loc_conf_t, allow_connections_to_events_channel),
+        NULL },
+
     ngx_null_command
 };
 
@@ -450,6 +463,8 @@ ngx_http_push_stream_create_main_conf(ngx_conf_t *cf)
     mcf->max_messages_stored_per_channel = NGX_CONF_UNSET_UINT;
     mcf->qtd_templates = 0;
     mcf->timeout_with_body = NGX_CONF_UNSET;
+    ngx_str_null(&mcf->events_channel_id);
+    mcf->events_channel = NULL;
     mcf->ping_msg = NULL;
     mcf->longpooling_timeout_msg = NULL;
     ngx_queue_init(&mcf->msg_templates);
@@ -472,6 +487,7 @@ ngx_http_push_stream_init_main_conf(ngx_conf_t *cf, void *parent)
     ngx_conf_merge_str_value(conf->channel_deleted_message_text, conf->channel_deleted_message_text, NGX_HTTP_PUSH_STREAM_CHANNEL_DELETED_MESSAGE_TEXT);
     ngx_conf_merge_str_value(conf->ping_message_text, conf->ping_message_text, NGX_HTTP_PUSH_STREAM_PING_MESSAGE_TEXT);
     ngx_conf_merge_str_value(conf->wildcard_channel_prefix, conf->wildcard_channel_prefix, NGX_HTTP_PUSH_STREAM_DEFAULT_WILDCARD_CHANNEL_PREFIX);
+    ngx_conf_merge_str_value(conf->events_channel_id, conf->events_channel_id, NGX_HTTP_PUSH_STREAM_DEFAULT_EVENTS_CHANNEL_ID);
     ngx_conf_init_value(conf->timeout_with_body, 0);
 
     // sanity checks
@@ -565,6 +581,7 @@ ngx_http_push_stream_create_loc_conf(ngx_conf_t *cf)
     lcf->longpolling_connection_ttl = NGX_CONF_UNSET_MSEC;
     lcf->websocket_allow_publish = NGX_CONF_UNSET_UINT;
     lcf->channel_info_on_publish = NGX_CONF_UNSET_UINT;
+    lcf->allow_connections_to_events_channel = NGX_CONF_UNSET_UINT;
     lcf->last_received_message_time = NULL;
     lcf->last_received_message_tag = NULL;
     lcf->last_event_id = NULL;
@@ -594,6 +611,7 @@ ngx_http_push_stream_merge_loc_conf(ngx_conf_t *cf, void *parent, void *child)
     ngx_conf_merge_msec_value(conf->longpolling_connection_ttl, prev->longpolling_connection_ttl, conf->subscriber_connection_ttl);
     ngx_conf_merge_value(conf->websocket_allow_publish, prev->websocket_allow_publish, 0);
     ngx_conf_merge_value(conf->channel_info_on_publish, prev->channel_info_on_publish, 1);
+    ngx_conf_merge_value(conf->allow_connections_to_events_channel, prev->allow_connections_to_events_channel, 0);
     ngx_conf_merge_str_value(conf->padding_by_user_agent, prev->padding_by_user_agent, NGX_HTTP_PUSH_STREAM_DEFAULT_PADDING_BY_USER_AGENT);
     ngx_conf_merge_uint_value(conf->location_type, prev->location_type, NGX_CONF_UNSET_UINT);
 
@@ -1111,5 +1129,18 @@ ngx_http_push_stream_init_shm_zone(ngx_shm_zone_t *shm_zone, void *data)
 
     d->mutex_round_robin = 0;
 
+    if (mcf->events_channel_id.len > 0) {
+        if ((mcf->events_channel = ngx_http_push_stream_get_channel(&mcf->events_channel_id, ngx_cycle->log, mcf)) == NULL) {
+            ngx_log_error(NGX_LOG_ERR, ngx_cycle->log, 0, "push stream module: unable to create events channel");
+            return NGX_ERROR;
+        }
+
+        if (ngx_http_push_stream_create_shmtx(&d->events_channel_mutex, &d->events_channel_lock, (u_char *) "push_stream_events_channel") != NGX_OK) {
+            return NGX_ERROR;
+        }
+
+        mcf->events_channel->mutex = &d->events_channel_mutex;
+    }
+
     return NGX_OK;
 }

src/ngx_http_push_stream_module_subscriber.c

@@ -330,6 +330,14 @@ ngx_http_push_stream_validate_channels(ngx_http_request_t *r, ngx_http_push_stre
             *explain_error_message = (ngx_str_t *) &NGX_HTTP_PUSH_STREAM_TOO_SUBSCRIBERS_PER_CHANNEL;
             return NGX_ERROR;
         }
+
+        // check if is allowed to connect to events channel
+        if (!cf->allow_connections_to_events_channel && (requested_channel->channel != NULL) && requested_channel->channel->for_events) {
+            ngx_log_error(NGX_LOG_ERR, r->connection->log, 0, "push stream module: subscription to events channel is not allowed");
+            *status_code = NGX_HTTP_FORBIDDEN;
+            *explain_error_message = (ngx_str_t *) &NGX_HTTP_PUSH_STREAM_SUBSCRIPTION_EVENTS_CHANNEL_FORBIDDEN_MESSAGE;
+            return NGX_ERROR;
+        }
     }
 
     // check if number of subscribed wildcard channels is acceptable
@@ -635,6 +643,9 @@ ngx_http_push_stream_assing_subscription_to_channel(ngx_slab_pool_t *shpool, ngx
     ngx_queue_insert_tail(&worker_subscribers_sentinel->subscriptions, &subscription->channel_worker_queue);
     subscription->channel_worker_sentinel = worker_subscribers_sentinel;
     ngx_shmtx_unlock(channel->mutex);
+
+    ngx_http_push_stream_send_event(mcf, log, channel, &NGX_HTTP_PUSH_STREAM_EVENT_TYPE_CLIENT_SUBSCRIBED, NULL);
+
     return NGX_OK;
 }
 

src/ngx_http_push_stream_module_utils.c

@@ -82,6 +82,7 @@ ngx_http_push_stream_delete_channels(void)
 void
 ngx_http_push_stream_delete_channels_data(ngx_http_push_stream_shm_data_t *data)
 {
+    ngx_http_push_stream_main_conf_t            *mcf = data->mcf;
     ngx_http_push_stream_channel_t              *channel;
     ngx_http_push_stream_pid_queue_t            *worker;
     ngx_queue_t                                 *cur_worker, *cur;
@@ -113,6 +114,8 @@ ngx_http_push_stream_delete_channels_data(ngx_http_push_stream_shm_data_t *data)
                         // remove the subscription for the channel from worker
                         ngx_queue_remove(&subscription->channel_worker_queue);
 
+                        ngx_http_push_stream_send_event(mcf, ngx_cycle->log, subscription->channel, &NGX_HTTP_PUSH_STREAM_EVENT_TYPE_CLIENT_UNSUBSCRIBED, subscriber->request->pool);
+
                         if (subscriber->longpolling) {
                             ngx_http_push_stream_add_polling_headers(subscriber->request, ngx_time(), 0, subscriber->request->pool);
                             ngx_http_send_header(subscriber->request);
@@ -139,9 +142,15 @@ ngx_http_push_stream_delete_channels_data(ngx_http_push_stream_shm_data_t *data)
 void
 ngx_http_push_stream_collect_deleted_channels_data(ngx_http_push_stream_shm_data_t *data)
 {
+    ngx_http_push_stream_main_conf_t            *mcf = data->mcf;
     ngx_http_push_stream_channel_t              *channel;
     ngx_queue_t                                 *q;
     ngx_uint_t                                   qtd_removed;
+    ngx_pool_t                                  *temp_pool = NULL;
+
+    if (mcf->events_channel_id.len > 0) {
+        temp_pool = ngx_create_pool(4096, ngx_cycle->log);
+    }
 
     ngx_shmtx_lock(&data->channels_to_delete_mutex);
     for (q = ngx_queue_head(&data->channels_to_delete); q != ngx_queue_sentinel(&data->channels_to_delete);) {
@@ -166,9 +175,15 @@ ngx_http_push_stream_collect_deleted_channels_data(ngx_http_push_stream_shm_data
             ngx_queue_insert_tail(&data->channels_trash, &channel->queue);
             data->channels_in_trash++;
             ngx_shmtx_unlock(&data->channels_trash_mutex);
+
+            ngx_http_push_stream_send_event(mcf, ngx_cycle->log, channel, &NGX_HTTP_PUSH_STREAM_EVENT_TYPE_CHANNEL_DESTROYED, temp_pool);
         }
     }
     ngx_shmtx_unlock(&data->channels_to_delete_mutex);
+
+    if (temp_pool != NULL) {
+        ngx_destroy_pool(temp_pool);
+    }
 }
 
 
@@ -357,10 +372,8 @@ ngx_http_push_stream_convert_char_to_msg_on_shared(ngx_http_push_stream_main_con
 
 
 ngx_int_t
-ngx_http_push_stream_add_msg_to_channel(ngx_http_request_t *r, ngx_http_push_stream_channel_t *channel, u_char *text, size_t len, ngx_str_t *event_id, ngx_str_t *event_type, ngx_pool_t *temp_pool)
+ngx_http_push_stream_add_msg_to_channel(ngx_http_push_stream_main_conf_t *mcf, ngx_log_t *log, ngx_http_push_stream_channel_t *channel, u_char *text, size_t len, ngx_str_t *event_id, ngx_str_t *event_type, ngx_flag_t store_messages, ngx_pool_t *temp_pool)
 {
-    ngx_http_push_stream_main_conf_t       *mcf = ngx_http_get_module_main_conf(r, ngx_http_push_stream_module);
-    ngx_http_push_stream_loc_conf_t        *cf = ngx_http_get_module_loc_conf(r, ngx_http_push_stream_module);
     ngx_http_push_stream_shm_data_t        *data = mcf->shm_data;
     ngx_http_push_stream_msg_t             *msg;
     ngx_uint_t                              qtd_removed;
@@ -368,7 +381,7 @@ ngx_http_push_stream_add_msg_to_channel(ngx_http_request_t *r, ngx_http_push_str
     // create a buffer copy in shared mem
     msg = ngx_http_push_stream_convert_char_to_msg_on_shared(mcf, text, len, channel, channel->last_message_id + 1, event_id, event_type, temp_pool);
     if (msg == NULL) {
-        ngx_log_error(NGX_LOG_ERR, r->connection->log, 0, "push stream module: unable to allocate message in shared memory");
+        ngx_log_error(NGX_LOG_ERR, log, 0, "push stream module: unable to allocate message in shared memory");
         return NGX_ERROR;
     }
 
@@ -383,7 +396,7 @@ ngx_http_push_stream_add_msg_to_channel(ngx_http_request_t *r, ngx_http_push_str
     channel->expires = ngx_time() + mcf->channel_inactivity_time;
 
     // put messages on the queue
-    if (cf->store_messages) {
+    if (store_messages) {
         ngx_queue_insert_tail(&channel->message_queue, &msg->queue);
         channel->stored_messages++;
     }
@@ -392,26 +405,54 @@ ngx_http_push_stream_add_msg_to_channel(ngx_http_request_t *r, ngx_http_push_str
     // now see if the queue is too big
     qtd_removed = ngx_http_push_stream_ensure_qtd_of_messages(data, channel, mcf->max_messages_stored_per_channel, 0);
 
-    ngx_shmtx_lock(&data->channels_queue_mutex);
-    data->published_messages++;
+    if (!channel->for_events) {
+        ngx_shmtx_lock(&data->channels_queue_mutex);
+        data->published_messages++;
 
-    if (msg->time >= data->last_message_time) {
-        data->last_message_time = msg->time;
-        data->last_message_tag = msg->tag;
-    }
+        if (msg->time >= data->last_message_time) {
+            data->last_message_time = msg->time;
+            data->last_message_tag = msg->tag;
+        }
 
-    NGX_HTTP_PUSH_STREAM_DECREMENT_COUNTER_BY(data->stored_messages, qtd_removed);
+        NGX_HTTP_PUSH_STREAM_DECREMENT_COUNTER_BY(data->stored_messages, qtd_removed);
 
-    if (cf->store_messages) {
-        data->stored_messages++;
+        if (store_messages) {
+            data->stored_messages++;
+        }
+        ngx_shmtx_unlock(&data->channels_queue_mutex);
     }
-    ngx_shmtx_unlock(&data->channels_queue_mutex);
 
     // send an alert to workers
-    ngx_http_push_stream_broadcast(channel, msg, r->connection->log, mcf);
+    ngx_http_push_stream_broadcast(channel, msg, log, mcf);
 
     // turn on timer to cleanup buffer of old messages
-    ngx_http_push_stream_buffer_cleanup_timer_set(cf);
+    ngx_http_push_stream_buffer_cleanup_timer_set();
+
+    return NGX_OK;
+}
+
+
+ngx_int_t
+ngx_http_push_stream_send_event(ngx_http_push_stream_main_conf_t *mcf, ngx_log_t *log, ngx_http_push_stream_channel_t *channel, ngx_str_t *event_type, ngx_pool_t *received_temp_pool)
+{
+    ngx_pool_t *temp_pool = received_temp_pool;
+
+    if ((temp_pool == NULL) && ((temp_pool = ngx_create_pool(4096, log)) == NULL)) {
+        return NGX_ERROR;
+    }
+
+    if ((mcf->events_channel_id.len > 0) && !channel->for_events) {
+        size_t len = ngx_strlen(NGX_HTTP_PUSH_STREAM_EVENT_TEMPLATE) + event_type->len + channel->id.len;
+        ngx_str_t *event = ngx_http_push_stream_create_str(temp_pool, len);
+        if (event != NULL) {
+            ngx_sprintf(event->data, NGX_HTTP_PUSH_STREAM_EVENT_TEMPLATE, event_type, &channel->id);
+            ngx_http_push_stream_add_msg_to_channel(mcf, log, mcf->events_channel, event->data, ngx_strlen(event->data), NULL, event_type, 1, temp_pool);
+        }
+    }
+
+    if ((received_temp_pool == NULL) && (temp_pool != NULL)) {
+        ngx_destroy_pool(temp_pool);
+    }
 
     return NGX_OK;
 }
@@ -942,8 +983,17 @@ ngx_http_push_stream_collect_expired_messages_and_empty_channels(ngx_flag_t forc
 void
 ngx_http_push_stream_collect_expired_messages_and_empty_channels_data(ngx_http_push_stream_shm_data_t *data, ngx_flag_t force)
 {
+    ngx_http_push_stream_main_conf_t   *mcf = data->mcf;
     ngx_http_push_stream_channel_t     *channel;
     ngx_queue_t                        *q;
+    ngx_pool_t                         *temp_pool = NULL;
+
+    if (mcf->events_channel_id.len > 0) {
+        if ((temp_pool = ngx_create_pool(4096, ngx_cycle->log)) == NULL) {
+            ngx_log_error(NGX_LOG_ERR, ngx_cycle->log, 0, "push stream module: unable to allocate memory to temporary pool");
+            return;
+        }
+    }
 
     ngx_http_push_stream_collect_expired_messages_data(data, force);
 
@@ -952,8 +1002,7 @@ ngx_http_push_stream_collect_expired_messages_and_empty_channels_data(ngx_http_p
         channel = ngx_queue_data(q, ngx_http_push_stream_channel_t, queue);
         q = ngx_queue_next(q);
 
-        if ((channel->stored_messages == 0) && (channel->subscribers == 0) && (channel->expires < ngx_time())) {
-
+        if ((channel->stored_messages == 0) && (channel->subscribers == 0) && (channel->expires < ngx_time()) && !channel->for_events) {
             channel->deleted = 1;
             channel->expires = ngx_time() + NGX_HTTP_PUSH_STREAM_DEFAULT_SHM_MEMORY_CLEANUP_OBJECTS_TTL;
             (channel->wildcard) ? NGX_HTTP_PUSH_STREAM_DECREMENT_COUNTER(data->wildcard_channels) : NGX_HTTP_PUSH_STREAM_DECREMENT_COUNTER(data->channels);
@@ -965,9 +1014,15 @@ ngx_http_push_stream_collect_expired_messages_and_empty_channels_data(ngx_http_p
             ngx_queue_insert_tail(&data->channels_trash, &channel->queue);
             data->channels_in_trash++;
             ngx_shmtx_unlock(&data->channels_trash_mutex);
+
+            ngx_http_push_stream_send_event(mcf, ngx_cycle->log, channel, &NGX_HTTP_PUSH_STREAM_EVENT_TYPE_CHANNEL_DESTROYED, temp_pool);
         }
     }
     ngx_shmtx_unlock(&data->channels_queue_mutex);
+
+    if (temp_pool != NULL) {
+        ngx_destroy_pool(temp_pool);
+    }
 }
 
 
@@ -1475,6 +1530,8 @@ ngx_http_push_stream_worker_subscriber_cleanup(ngx_http_push_stream_subscriber_t
         ngx_queue_remove(&subscription->channel_worker_queue);
         ngx_queue_remove(&subscription->queue);
         ngx_shmtx_unlock(subscription->channel->mutex);
+
+        ngx_http_push_stream_send_event(mcf, ngx_cycle->log, subscription->channel, &NGX_HTTP_PUSH_STREAM_EVENT_TYPE_CLIENT_UNSUBSCRIBED, worker_subscriber->request->pool);
     }
 
     ngx_shmtx_lock(&shpool->mutex);

src/ngx_http_push_stream_module_websocket.c

@@ -180,6 +180,7 @@ ngx_http_push_stream_generate_websocket_accept_value(ngx_http_request_t *r, ngx_
 void
 ngx_http_push_stream_websocket_reading(ngx_http_request_t *r)
 {
+    ngx_http_push_stream_main_conf_t  *mcf = ngx_http_get_module_main_conf(r, ngx_http_push_stream_module);
     ngx_http_push_stream_loc_conf_t   *cf = ngx_http_get_module_loc_conf(r, ngx_http_push_stream_module);
     ngx_http_push_stream_module_ctx_t *ctx = ngx_http_get_module_ctx(r, ngx_http_push_stream_module);
     ngx_int_t                          rc = NGX_OK;
@@ -288,7 +289,12 @@ ngx_http_push_stream_websocket_reading(ngx_http_request_t *r)
 
                         for (q = ngx_queue_head(&ctx->subscriber->subscriptions); q != ngx_queue_sentinel(&ctx->subscriber->subscriptions); q = ngx_queue_next(q)) {
                             ngx_http_push_stream_subscription_t *subscription = ngx_queue_data(q, ngx_http_push_stream_subscription_t, queue);
-                            if (ngx_http_push_stream_add_msg_to_channel(r, subscription->channel, ctx->frame->payload, ctx->frame->payload_len, NULL, NULL, ctx->temp_pool) != NGX_OK) {
+                            if (subscription->channel->for_events) {
+                                // skip events channel on publish by websocket connections
+                                continue;
+                            }
+
+                            if (ngx_http_push_stream_add_msg_to_channel(mcf, r->connection->log, subscription->channel, ctx->frame->payload, ctx->frame->payload_len, NULL, NULL, cf->store_messages, ctx->temp_pool) != NGX_OK) {
                                 goto finalize;
                             }
                         }

src/ngx_http_push_stream_rbtree_util.c

@@ -151,6 +151,7 @@ ngx_http_push_stream_get_channel(ngx_str_t *id, ngx_log_t *log, ngx_http_push_st
     channel->stored_messages = 0;
     channel->subscribers = 0;
     channel->deleted = 0;
+    channel->for_events = ((mcf->events_channel_id.len > 0) && (channel->id.len == mcf->events_channel_id.len) && (ngx_strncmp(channel->id.data, mcf->events_channel_id.data, mcf->events_channel_id.len) == 0));
     channel->expires = ngx_time() + mcf->channel_inactivity_time;
 
     ngx_queue_init(&channel->message_queue);
@@ -164,6 +165,9 @@ ngx_http_push_stream_get_channel(ngx_str_t *id, ngx_log_t *log, ngx_http_push_st
     channel->mutex = &data->channels_mutex[data->mutex_round_robin++ % 9];
 
     ngx_shmtx_unlock(&data->channels_queue_mutex);
+
+    ngx_http_push_stream_send_event(mcf, log, channel, &NGX_HTTP_PUSH_STREAM_EVENT_TYPE_CHANNEL_CREATED, NULL);
+
     return channel;
 }