Merging upstream version 1.29.0.

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 179 insertions, 919 deletions

diff --git a/streaming/rrdpush.c b/streaming/rrdpush.c
index e6d2aca0..f54fc609 100644
--- a/streaming/rrdpush.c
+++ b/streaming/rrdpush.c
@@ -1,6 +1,7 @@
 // SPDX-License-Identifier: GPL-3.0-or-later
 
 #include "rrdpush.h"
+#include "../parser/parser.h"
 
 /*
  * rrdpush
@@ -25,15 +26,9 @@
  *
  */
 
-#define START_STREAMING_PROMPT "Hit me baby, push them over..."
-
-typedef enum {
-    RRDPUSH_MULTIPLE_CONNECTIONS_ALLOW,
-    RRDPUSH_MULTIPLE_CONNECTIONS_DENY_NEW
-} RRDPUSH_MULTIPLE_CONNECTIONS_STRATEGY;
-
-static struct config stream_config = {
-        .sections = NULL,
+struct config stream_config = {
+        .first_section = NULL,
+        .last_section = NULL,
         .mutex = NETDATA_MUTEX_INITIALIZER,
         .index = {
                 .avl_tree = {
@@ -57,12 +52,12 @@ char *netdata_ssl_ca_file = NULL;
 static void load_stream_conf() {
     errno = 0;
     char *filename = strdupz_path_subpath(netdata_configured_user_config_dir, "stream.conf");
-    if(!appconfig_load(&stream_config, filename, 0)) {
+    if(!appconfig_load(&stream_config, filename, 0, NULL)) {
         info("CONFIG: cannot load user config '%s'. Will try stock config.", filename);
         freez(filename);
 
         filename = strdupz_path_subpath(netdata_configured_stock_config_dir, "stream.conf");
-        if(!appconfig_load(&stream_config, filename, 0))
+        if(!appconfig_load(&stream_config, filename, 0, NULL))
             info("CONFIG: cannot load stock config '%s'. Running with internal defaults.", filename);
     }
     freez(filename);
@@ -79,6 +74,7 @@ int rrdpush_init() {
     default_rrdpush_send_charts_matching      = appconfig_get(&stream_config, CONFIG_SECTION_STREAM, "send charts matching", "*");
     rrdhost_free_orphan_time    = config_get_number(CONFIG_SECTION_GLOBAL, "cleanup orphan hosts after seconds", rrdhost_free_orphan_time);
 
+
     if(default_rrdpush_enabled && (!default_rrdpush_destination || !*default_rrdpush_destination || !default_rrdpush_api_key || !*default_rrdpush_api_key)) {
         error("STREAM [send]: cannot enable sending thread - information is missing.");
         default_rrdpush_enabled = 0;
@@ -96,6 +92,7 @@ int rrdpush_init() {
     }
 
     char *invalid_certificate = appconfig_get(&stream_config, CONFIG_SECTION_STREAM, "ssl skip certificate verification", "no");
+
     if ( !strcmp(invalid_certificate,"yes")){
         if (netdata_validate_server == NETDATA_SSL_VALID_CERTIFICATE){
             info("Netdata is configured to accept invalid SSL certificate.");
@@ -110,8 +107,6 @@ int rrdpush_init() {
     return default_rrdpush_enabled;
 }
 
-#define CONNECTED_TO_SIZE 100
-
 // data collection happens from multiple threads
 // each of these threads calls rrdset_done()
 // which in turn calls rrdset_done_push()
@@ -126,8 +121,6 @@ int rrdpush_init() {
 // this is for the first iterations of each chart
 unsigned int remote_clock_resync_iterations = 60;
 
-#define rrdpush_buffer_lock(host) netdata_mutex_lock(&((host)->rrdpush_sender_buffer_mutex))
-#define rrdpush_buffer_unlock(host) netdata_mutex_unlock(&((host)->rrdpush_sender_buffer_mutex))
 
 static inline int should_send_chart_matching(RRDSET *st) {
     if(unlikely(!rrdset_flag_check(st, RRDSET_FLAG_ENABLED))) {
@@ -151,6 +144,25 @@ static inline int should_send_chart_matching(RRDSET *st) {
     return(rrdset_flag_check(st, RRDSET_FLAG_UPSTREAM_SEND));
 }
 
+int configured_as_parent() {
+    struct section *section = NULL;
+    int is_parent = 0;
+
+    appconfig_wrlock(&stream_config);
+    for (section = stream_config.first_section; section; section = section->next) {
+        uuid_t uuid;
+
+        if (uuid_parse(section->name, uuid) != -1 &&
+                appconfig_get_boolean_by_section(section, "enabled", 0)) {
+            is_parent = 1;
+            break;
+        }
+    }
+    appconfig_unlock(&stream_config);
+
+    return is_parent;
+}
+
 // checks if the current chart definition has been sent
 static inline int need_to_send_chart_definition(RRDSET *st) {
     rrdset_check_rdlock(st);
@@ -171,7 +183,8 @@ static inline int need_to_send_chart_definition(RRDSET *st) {
     return 0;
 }
 
-// sends the current chart definition
+// Send the current chart definition.
+// Assumes that collector thread has already called sender_start for mutex / buffer state.
 static inline void rrdpush_send_chart_definition_nolock(RRDSET *st) {
     RRDHOST *host = st->rrdhost;
 
@@ -190,11 +203,9 @@ static inline void rrdpush_send_chart_definition_nolock(RRDSET *st) {
         }
     }
 
-    // info("CHART '%s' '%s'", st->id, name);
-
     // send the chart
     buffer_sprintf(
-            host->rrdpush_sender_buffer
+            host->sender->build
             , "CHART \"%s\" \"%s\" \"%s\" \"%s\" \"%s\" \"%s\" \"%s\" %ld %d \"%s %s %s %s\" \"%s\" \"%s\"\n"
             , st->id
             , name
@@ -217,7 +228,7 @@ static inline void rrdpush_send_chart_definition_nolock(RRDSET *st) {
     RRDDIM *rd;
     rrddim_foreach_read(rd, st) {
         buffer_sprintf(
-                host->rrdpush_sender_buffer
+                host->sender->build
                 , "DIMENSION \"%s\" \"%s\" \"%s\" " COLLECTED_NUMBER_FORMAT " " COLLECTED_NUMBER_FORMAT " \"%s %s %s\"\n"
                 , rd->id
                 , rd->name
@@ -238,7 +249,7 @@ static inline void rrdpush_send_chart_definition_nolock(RRDSET *st) {
             calculated_number *value = (calculated_number *) rs->value;
 
             buffer_sprintf(
-                    host->rrdpush_sender_buffer
+                    host->sender->build
                     , "VARIABLE CHART %s = " CALCULATED_NUMBER_FORMAT "\n"
                     , rs->variable
                     , *value
@@ -250,25 +261,29 @@ static inline void rrdpush_send_chart_definition_nolock(RRDSET *st) {
 }
 
 // sends the current chart dimensions
-static inline void rrdpush_send_chart_metrics_nolock(RRDSET *st) {
+static inline void rrdpush_send_chart_metrics_nolock(RRDSET *st, struct sender_state *s) {
     RRDHOST *host = st->rrdhost;
-    buffer_sprintf(host->rrdpush_sender_buffer, "BEGIN \"%s\" %llu\n", st->id, (st->last_collected_time.tv_sec > st->upstream_resync_time)?st->usec_since_last_update:0);
+    buffer_sprintf(host->sender->build, "BEGIN \"%s\" %llu", st->id, (st->last_collected_time.tv_sec > st->upstream_resync_time)?st->usec_since_last_update:0);
+    if (s->version >= VERSION_GAP_FILLING)
+        buffer_sprintf(host->sender->build, " %ld\n", st->last_collected_time.tv_sec);
+    else
+        buffer_strcat(host->sender->build, "\n");
 
     RRDDIM *rd;
     rrddim_foreach_read(rd, st) {
         if(rd->updated && rd->exposed)
-            buffer_sprintf(host->rrdpush_sender_buffer
+            buffer_sprintf(host->sender->build
                            , "SET \"%s\" = " COLLECTED_NUMBER_FORMAT "\n"
                            , rd->id
                            , rd->collected_value
         );
     }
-
-    buffer_strcat(host->rrdpush_sender_buffer, "END\n");
+    buffer_strcat(host->sender->build, "END\n");
 }
 
 static void rrdpush_sender_thread_spawn(RRDHOST *host);
 
+// Called from the internal collectors to mark a chart obsolete.
 void rrdset_push_chart_definition_now(RRDSET *st) {
     RRDHOST *host = st->rrdhost;
 
@@ -276,9 +291,9 @@ void rrdset_push_chart_definition_now(RRDSET *st) {
         return;
 
     rrdset_rdlock(st);
-    rrdpush_buffer_lock(host);
+    sender_start(host->sender);
     rrdpush_send_chart_definition_nolock(st);
-    rrdpush_buffer_unlock(host);
+    sender_commit(host->sender);
     rrdset_unlock(st);
 }
 
@@ -288,18 +303,14 @@ void rrdset_done_push(RRDSET *st) {
 
     RRDHOST *host = st->rrdhost;
 
-    rrdpush_buffer_lock(host);
-
     if(unlikely(host->rrdpush_send_enabled && !host->rrdpush_sender_spawn))
         rrdpush_sender_thread_spawn(host);
 
-    if(unlikely(!host->rrdpush_sender_buffer || !host->rrdpush_sender_connected)) {
+    // Handle non-connected case
+    if(unlikely(!host->rrdpush_sender_connected)) {
         if(unlikely(!host->rrdpush_sender_error_shown))
             error("STREAM %s [send]: not ready - discarding collected metrics.", host->hostname);
-
         host->rrdpush_sender_error_shown = 1;
-
-        rrdpush_buffer_unlock(host);
         return;
     }
     else if(unlikely(host->rrdpush_sender_error_shown)) {
@@ -307,105 +318,82 @@ void rrdset_done_push(RRDSET *st) {
         host->rrdpush_sender_error_shown = 0;
     }
 
+    sender_start(host->sender);
+
     if(need_to_send_chart_definition(st))
         rrdpush_send_chart_definition_nolock(st);
 
-    rrdpush_send_chart_metrics_nolock(st);
+    rrdpush_send_chart_metrics_nolock(st, host->sender);
 
     // signal the sender there are more data
     if(host->rrdpush_sender_pipe[PIPE_WRITE] != -1 && write(host->rrdpush_sender_pipe[PIPE_WRITE], " ", 1) == -1)
         error("STREAM %s [send]: cannot write to internal pipe", host->hostname);
 
-    rrdpush_buffer_unlock(host);
+    sender_commit(host->sender);
 }
 
-// ----------------------------------------------------------------------------
-// rrdpush sender thread
-
-static inline void rrdpush_sender_add_host_variable_to_buffer_nolock(RRDHOST *host, RRDVAR *rv) {
-    calculated_number *value = (calculated_number *)rv->value;
+// labels
+void rrdpush_send_labels(RRDHOST *host) {
+    if (!host->labels.head || !(host->labels.labels_flag & LABEL_FLAG_UPDATE_STREAM) || (host->labels.labels_flag & LABEL_FLAG_STOP_STREAM))
+        return;
 
-    buffer_sprintf(
-            host->rrdpush_sender_buffer
-            , "VARIABLE HOST %s = " CALCULATED_NUMBER_FORMAT "\n"
-            , rv->name
-            , *value
-    );
+    sender_start(host->sender);
+    rrdhost_rdlock(host);
+    netdata_rwlock_rdlock(&host->labels.labels_rwlock);
 
-    debug(D_STREAM, "RRDVAR pushed HOST VARIABLE %s = " CALCULATED_NUMBER_FORMAT, rv->name, *value);
-}
+    struct label *label_i = host->labels.head;
+    while(label_i) {
+        buffer_sprintf(host->sender->build
+                , "LABEL \"%s\" = %d %s\n"
+                , label_i->key
+                , (int)label_i->label_source
+                , label_i->value);
 
-void rrdpush_sender_send_this_host_variable_now(RRDHOST *host, RRDVAR *rv) {
-    if(host->rrdpush_send_enabled && host->rrdpush_sender_spawn && host->rrdpush_sender_connected) {
-        rrdpush_buffer_lock(host);
-        rrdpush_sender_add_host_variable_to_buffer_nolock(host, rv);
-        rrdpush_buffer_unlock(host);
+        label_i = label_i->next;
     }
-}
-
-static int rrdpush_sender_thread_custom_host_variables_callback(void *rrdvar_ptr, void *host_ptr) {
-    RRDVAR *rv = (RRDVAR *)rrdvar_ptr;
-    RRDHOST *host = (RRDHOST *)host_ptr;
 
-    if(unlikely(rv->options & RRDVAR_OPTION_CUSTOM_HOST_VAR && rv->type == RRDVAR_TYPE_CALCULATED)) {
-        rrdpush_sender_add_host_variable_to_buffer_nolock(host, rv);
+    buffer_sprintf(host->sender->build
+            , "OVERWRITE %s\n", "labels");
 
-        // return 1, so that the traversal will return the number of variables sent
-        return 1;
-    }
-
-    // returning a negative number will break the traversal
-    return 0;
-}
+    netdata_rwlock_unlock(&host->labels.labels_rwlock);
+    rrdhost_unlock(host);
+    sender_commit(host->sender);
 
-static void rrdpush_sender_thread_send_custom_host_variables(RRDHOST *host) {
-    int ret = rrdvar_callback_for_all_host_variables(host, rrdpush_sender_thread_custom_host_variables_callback, host);
-    (void)ret;
+    if(host->rrdpush_sender_pipe[PIPE_WRITE] != -1 && write(host->rrdpush_sender_pipe[PIPE_WRITE], " ", 1) == -1)
+        error("STREAM %s [send]: cannot write to internal pipe", host->hostname);
 
-    debug(D_STREAM, "RRDVAR sent %d VARIABLES", ret);
+    host->labels.labels_flag &= ~LABEL_FLAG_UPDATE_STREAM;
 }
 
-// resets all the chart, so that their definitions
-// will be resent to the central netdata
-static void rrdpush_sender_thread_reset_all_charts(RRDHOST *host) {
-    rrdhost_rdlock(host);
-
-    RRDSET *st;
-    rrdset_foreach_read(st, host) {
-        rrdset_flag_clear(st, RRDSET_FLAG_UPSTREAM_EXPOSED);
+void rrdpush_claimed_id(RRDHOST *host)
+{
+    if(unlikely(!host->rrdpush_send_enabled || !host->rrdpush_sender_connected))
+        return;
+    
+    if(host->sender->version < STREAM_VERSION_CLAIM)
+        return;
 
-        st->upstream_resync_time = 0;
+    sender_start(host->sender);
+    rrdhost_aclk_state_lock(host);
 
-        rrdset_rdlock(st);
+    buffer_sprintf(host->sender->build, "CLAIMED_ID %s %s\n", host->machine_guid, (host->aclk_state.claimed_id ? host->aclk_state.claimed_id : "NULL") );
 
-        RRDDIM *rd;
-        rrddim_foreach_read(rd, st)
-            rd->exposed = 0;
+    rrdhost_aclk_state_unlock(host);
+    sender_commit(host->sender);
 
-        rrdset_unlock(st);
-    }
-
-    rrdhost_unlock(host);
+    // signal the sender there are more data
+    if(host->rrdpush_sender_pipe[PIPE_WRITE] != -1 && write(host->rrdpush_sender_pipe[PIPE_WRITE], " ", 1) == -1)
+        error("STREAM %s [send]: cannot write to internal pipe", host->hostname);
 }
 
-static inline void rrdpush_sender_thread_data_flush(RRDHOST *host) {
-    rrdpush_buffer_lock(host);
-
-    if(buffer_strlen(host->rrdpush_sender_buffer))
-        error("STREAM %s [send]: discarding %zu bytes of metrics already in the buffer.", host->hostname, buffer_strlen(host->rrdpush_sender_buffer));
-
-    buffer_flush(host->rrdpush_sender_buffer);
-
-    rrdpush_sender_thread_reset_all_charts(host);
-    rrdpush_sender_thread_send_custom_host_variables(host);
-
-    rrdpush_buffer_unlock(host);
-}
+// ----------------------------------------------------------------------------
+// rrdpush sender thread
 
+// Either the receiver lost the connection or the host is being destroyed.
+// The sender mutex guards thread creation, any spurious data is wiped on reconnection.
 void rrdpush_sender_thread_stop(RRDHOST *host) {
-    rrdpush_buffer_lock(host);
-    rrdhost_wrlock(host);
 
+    netdata_mutex_lock(&host->sender->mutex);
     netdata_thread_t thr = 0;
 
     if(host->rrdpush_sender_spawn) {
@@ -422,8 +410,7 @@ void rrdpush_sender_thread_stop(RRDHOST *host) {
         netdata_thread_cancel(host->rrdpush_sender_thread);
     }
 
-    rrdhost_unlock(host);
-    rrdpush_buffer_unlock(host);
+    netdata_mutex_unlock(&host->sender->mutex);
 
     if(thr != 0) {
         info("STREAM %s [send]: waiting for the sending thread to stop...", host->hostname);
@@ -433,828 +420,28 @@ void rrdpush_sender_thread_stop(RRDHOST *host) {
     }
 }
 
-static inline void rrdpush_sender_thread_close_socket(RRDHOST *host) {
-    host->rrdpush_sender_connected = 0;
-
-    if(host->rrdpush_sender_socket != -1) {
-        close(host->rrdpush_sender_socket);
-        host->rrdpush_sender_socket = -1;
-    }
-}
-
-//called from client side
-static int rrdpush_sender_thread_connect_to_master(RRDHOST *host, int default_port, int timeout, size_t *reconnects_counter, char *connected_to, size_t connected_to_size) {
-    struct timeval tv = {
-            .tv_sec = timeout,
-            .tv_usec = 0
-    };
-
-    // make sure the socket is closed
-    rrdpush_sender_thread_close_socket(host);
-
-    debug(D_STREAM, "STREAM: Attempting to connect...");
-    info("STREAM %s [send to %s]: connecting...", host->hostname, host->rrdpush_send_destination);
-
-    host->rrdpush_sender_socket = connect_to_one_of(
-            host->rrdpush_send_destination
-            , default_port
-            , &tv
-            , reconnects_counter
-            , connected_to
-            , connected_to_size
-    );
-
-    if(unlikely(host->rrdpush_sender_socket == -1)) {
-        error("STREAM %s [send to %s]: failed to connect", host->hostname, host->rrdpush_send_destination);
-        return 0;
-    }
-
-    info("STREAM %s [send to %s]: initializing communication...", host->hostname, connected_to);
-
-#ifdef ENABLE_HTTPS
-    if( netdata_client_ctx ){
-        host->ssl.flags = NETDATA_SSL_START;
-        if (!host->ssl.conn){
-            host->ssl.conn = SSL_new(netdata_client_ctx);
-            if(!host->ssl.conn){
-                error("Failed to allocate SSL structure.");
-                host->ssl.flags = NETDATA_SSL_NO_HANDSHAKE;
-            }
-        }
-        else{
-            SSL_clear(host->ssl.conn);
-        }
-
-        if (host->ssl.conn)
-        {
-            if (SSL_set_fd(host->ssl.conn, host->rrdpush_sender_socket) != 1) {
-                error("Failed to set the socket to the SSL on socket fd %d.", host->rrdpush_sender_socket);
-                host->ssl.flags = NETDATA_SSL_NO_HANDSHAKE;
-            } else{
-                host->ssl.flags = NETDATA_SSL_HANDSHAKE_COMPLETE;
-            }
-        }
-    }
-    else {
-        host->ssl.flags = NETDATA_SSL_NO_HANDSHAKE;
-    }
-#endif
-
-    #define HTTP_HEADER_SIZE 8192
-    char http[HTTP_HEADER_SIZE + 1];
-    int eol = snprintfz(http, HTTP_HEADER_SIZE,
-            "STREAM key=%s&hostname=%s&registry_hostname=%s&machine_guid=%s&update_every=%d&os=%s&timezone=%s&tags=%s"
-                    "&NETDATA_SYSTEM_OS_NAME=%s"
-                    "&NETDATA_SYSTEM_OS_ID=%s"
-                    "&NETDATA_SYSTEM_OS_ID_LIKE=%s"
-                    "&NETDATA_SYSTEM_OS_VERSION=%s"
-                    "&NETDATA_SYSTEM_OS_VERSION_ID=%s"
-                    "&NETDATA_SYSTEM_OS_DETECTION=%s"
-                    "&NETDATA_SYSTEM_KERNEL_NAME=%s"
-                    "&NETDATA_SYSTEM_KERNEL_VERSION=%s"
-                    "&NETDATA_SYSTEM_ARCHITECTURE=%s"
-                    "&NETDATA_SYSTEM_VIRTUALIZATION=%s"
-                    "&NETDATA_SYSTEM_VIRT_DETECTION=%s"
-                    "&NETDATA_SYSTEM_CONTAINER=%s"
-                    "&NETDATA_SYSTEM_CONTAINER_DETECTION=%s"
-                    " HTTP/1.1\r\n"
-                    "User-Agent: %s/%s\r\n"
-                    "Accept: */*\r\n\r\n"
-              , host->rrdpush_send_api_key
-              , host->hostname
-              , host->registry_hostname
-              , host->machine_guid
-              , default_rrd_update_every
-              , host->os
-              , host->timezone
-              , (host->tags) ? host->tags : ""
-              , (host->system_info->os_name) ? host->system_info->os_name : ""
-              , (host->system_info->os_id) ? host->system_info->os_id : ""
-              , (host->system_info->os_id_like) ? host->system_info->os_id_like : ""
-              , (host->system_info->os_version) ? host->system_info->os_version : ""
-              , (host->system_info->os_version_id) ? host->system_info->os_version_id : ""
-              , (host->system_info->os_detection) ? host->system_info->os_detection : ""
-              , (host->system_info->kernel_name) ? host->system_info->kernel_name : ""
-              , (host->system_info->kernel_version) ? host->system_info->kernel_version : ""
-              , (host->system_info->architecture) ? host->system_info->architecture : ""
-              , (host->system_info->virtualization) ? host->system_info->virtualization : ""
-              , (host->system_info->virt_detection) ? host->system_info->virt_detection : ""
-              , (host->system_info->container) ? host->system_info->container : ""
-              , (host->system_info->container_detection) ? host->system_info->container_detection : ""
-              , host->program_name
-              , host->program_version
-    );
-    http[eol] = 0x00;
-
-#ifdef ENABLE_HTTPS
-    if (!host->ssl.flags) {
-        ERR_clear_error();
-        SSL_set_connect_state(host->ssl.conn);
-        int err = SSL_connect(host->ssl.conn);
-        if (err != 1){
-            err = SSL_get_error(host->ssl.conn, err);
-            error("SSL cannot connect with the server:  %s ",ERR_error_string((long)SSL_get_error(host->ssl.conn,err),NULL));
-            if (netdata_use_ssl_on_stream == NETDATA_SSL_FORCE) {
-                rrdpush_sender_thread_close_socket(host);
-                return 0;
-            }else {
-                host->ssl.flags = NETDATA_SSL_NO_HANDSHAKE;
-            }
-        }
-        else {
-            if (netdata_use_ssl_on_stream == NETDATA_SSL_FORCE) {
-                if (netdata_validate_server == NETDATA_SSL_VALID_CERTIFICATE) {
-                    if ( security_test_certificate(host->ssl.conn)) {
-                        error("Closing the stream connection, because the server SSL certificate is not valid.");
-                        rrdpush_sender_thread_close_socket(host);
-                        return 0;
-                    }
-                }
-            }
-        }
-    }
-    if(send_timeout(&host->ssl,host->rrdpush_sender_socket, http, strlen(http), 0, timeout) == -1) {
-#else
-    if(send_timeout(host->rrdpush_sender_socket, http, strlen(http), 0, timeout) == -1) {
-#endif
-        error("STREAM %s [send to %s]: failed to send HTTP header to remote netdata.", host->hostname, connected_to);
-        rrdpush_sender_thread_close_socket(host);
-        return 0;
-    }
-
-    info("STREAM %s [send to %s]: waiting response from remote netdata...", host->hostname, connected_to);
-
-#ifdef ENABLE_HTTPS
-    if(recv_timeout(&host->ssl,host->rrdpush_sender_socket, http, HTTP_HEADER_SIZE, 0, timeout) == -1) {
-#else
-    if(recv_timeout(host->rrdpush_sender_socket, http, HTTP_HEADER_SIZE, 0, timeout) == -1) {
-#endif
-        error("STREAM %s [send to %s]: remote netdata does not respond.", host->hostname, connected_to);
-        rrdpush_sender_thread_close_socket(host);
-        return 0;
-    }
-
-    if(strncmp(http, START_STREAMING_PROMPT, strlen(START_STREAMING_PROMPT)) != 0) {
-        error("STREAM %s [send to %s]: server is not replying properly (is it a netdata?).", host->hostname, connected_to);
-        rrdpush_sender_thread_close_socket(host);
-        return 0;
-    }
-
-    info("STREAM %s [send to %s]: established communication - ready to send metrics...", host->hostname, connected_to);
-
-    if(sock_setnonblock(host->rrdpush_sender_socket) < 0)
-        error("STREAM %s [send to %s]: cannot set non-blocking mode for socket.", host->hostname, connected_to);
-
-    if(sock_enlarge_out(host->rrdpush_sender_socket) < 0)
-        error("STREAM %s [send to %s]: cannot enlarge the socket buffer.", host->hostname, connected_to);
-
-    debug(D_STREAM, "STREAM: Connected on fd %d...", host->rrdpush_sender_socket);
-
-    return 1;
-}
-
-static void rrdpush_sender_thread_cleanup_callback(void *ptr) {
-    RRDHOST *host = (RRDHOST *)ptr;
-
-    rrdpush_buffer_lock(host);
-    rrdhost_wrlock(host);
-
-    info("STREAM %s [send]: sending thread cleans up...", host->hostname);
-
-    rrdpush_sender_thread_close_socket(host);
-
-    // close the pipe
-    if(host->rrdpush_sender_pipe[PIPE_READ] != -1) {
-        close(host->rrdpush_sender_pipe[PIPE_READ]);
-        host->rrdpush_sender_pipe[PIPE_READ] = -1;
-    }
-
-    if(host->rrdpush_sender_pipe[PIPE_WRITE] != -1) {
-        close(host->rrdpush_sender_pipe[PIPE_WRITE]);
-        host->rrdpush_sender_pipe[PIPE_WRITE] = -1;
-    }
-
-    buffer_free(host->rrdpush_sender_buffer);
-    host->rrdpush_sender_buffer = NULL;
-
-    if(!host->rrdpush_sender_join) {
-        info("STREAM %s [send]: sending thread detaches itself.", host->hostname);
-        netdata_thread_detach(netdata_thread_self());
-    }
-
-    host->rrdpush_sender_spawn = 0;
-
-    info("STREAM %s [send]: sending thread now exits.", host->hostname);
-
-    rrdhost_unlock(host);
-    rrdpush_buffer_unlock(host);
-}
-
-void *rrdpush_sender_thread(void *ptr) {
-    RRDHOST *host = (RRDHOST *)ptr;
-
-    if(!host->rrdpush_send_enabled || !host->rrdpush_send_destination || !*host->rrdpush_send_destination || !host->rrdpush_send_api_key || !*host->rrdpush_send_api_key) {
-        error("STREAM %s [send]: thread created (task id %d), but host has streaming disabled.", host->hostname, gettid());
-        return NULL;
-    }
-
-#ifdef ENABLE_HTTPS
-    if (netdata_use_ssl_on_stream & NETDATA_SSL_FORCE ){
-        security_start_ssl(NETDATA_SSL_CONTEXT_STREAMING);
-        security_location_for_context(netdata_client_ctx, netdata_ssl_ca_file, netdata_ssl_ca_path);
-    }
-#endif
-
-    info("STREAM %s [send]: thread created (task id %d)", host->hostname, gettid());
-
-    int timeout = (int)appconfig_get_number(&stream_config, CONFIG_SECTION_STREAM, "timeout seconds", 60);
-    int default_port = (int)appconfig_get_number(&stream_config, CONFIG_SECTION_STREAM, "default port", 19999);
-    size_t max_size = (size_t)appconfig_get_number(&stream_config, CONFIG_SECTION_STREAM, "buffer size bytes", 1024 * 1024);
-    unsigned int reconnect_delay = (unsigned int)appconfig_get_number(&stream_config, CONFIG_SECTION_STREAM, "reconnect delay seconds", 5);
-    remote_clock_resync_iterations = (unsigned int)appconfig_get_number(&stream_config, CONFIG_SECTION_STREAM, "initial clock resync iterations", remote_clock_resync_iterations);
-    char connected_to[CONNECTED_TO_SIZE + 1] = "";
-
-    // initialize rrdpush globals
-    host->rrdpush_sender_buffer = buffer_create(1);
-    host->rrdpush_sender_connected = 0;
-    if(pipe(host->rrdpush_sender_pipe) == -1) fatal("STREAM %s [send]: cannot create required pipe.", host->hostname);
-
-    // initialize local variables
-    size_t begin = 0;
-    size_t reconnects_counter = 0;
-    size_t sent_bytes = 0;
-    size_t sent_bytes_on_this_connection = 0;
-    size_t send_attempts = 0;
-
-
-    time_t last_sent_t = 0;
-    struct pollfd fds[2], *ifd, *ofd;
-    nfds_t fdmax;
-
-    ifd = &fds[0];
-    ofd = &fds[1];
-
-    size_t not_connected_loops = 0;
-
-    netdata_thread_cleanup_push(rrdpush_sender_thread_cleanup_callback, host);
-
-        for(; host->rrdpush_send_enabled && !netdata_exit ;) {
-            // check for outstanding cancellation requests
-            netdata_thread_testcancel();
-
-            // if we don't have socket open, lets wait a bit
-            if(unlikely(host->rrdpush_sender_socket == -1)) {
-                send_attempts = 0;
-
-                if(not_connected_loops == 0 && sent_bytes_on_this_connection > 0) {
-                    // fast re-connection on first disconnect
-                    sleep_usec(USEC_PER_MS * 500); // milliseconds
-                }
-                else {
-                    // slow re-connection on repeating errors
-                    sleep_usec(USEC_PER_SEC * reconnect_delay); // seconds
-                }
-
-                if(rrdpush_sender_thread_connect_to_master(host, default_port, timeout, &reconnects_counter, connected_to, CONNECTED_TO_SIZE)) {
-                    last_sent_t = now_monotonic_sec();
-
-                    // reset the buffer, to properly send charts and metrics
-                    rrdpush_sender_thread_data_flush(host);
-
-                    // send from the beginning
-                    begin = 0;
-
-                    // make sure the next reconnection will be immediate
-                    not_connected_loops = 0;
-
-                    // reset the bytes we have sent for this session
-                    sent_bytes_on_this_connection = 0;
-
-                    // let the data collection threads know we are ready
-                    host->rrdpush_sender_connected = 1;
-                }
-                else {
-                    // increase the failed connections counter
-                    not_connected_loops++;
-
-                    // reset the number of bytes sent
-                    sent_bytes_on_this_connection = 0;
-                }
-
-                // loop through
-                continue;
-            }
-            else if(unlikely(now_monotonic_sec() - last_sent_t > timeout)) {
-                error("STREAM %s [send to %s]: could not send metrics for %d seconds - closing connection - we have sent %zu bytes on this connection via %zu send attempts.", host->hostname, connected_to, timeout, sent_bytes_on_this_connection, send_attempts);
-                rrdpush_sender_thread_close_socket(host);
-            }
-
-            ifd->fd = host->rrdpush_sender_pipe[PIPE_READ];
-            ifd->events = POLLIN;
-            ifd->revents = 0;
-
-            ofd->fd = host->rrdpush_sender_socket;
-            ofd->revents = 0;
-            if(ofd->fd != -1 && begin < buffer_strlen(host->rrdpush_sender_buffer)) {
-                debug(D_STREAM, "STREAM: Requesting data output on streaming socket %d...", ofd->fd);
-                ofd->events = POLLOUT;
-                fdmax = 2;
-                send_attempts++;
-            }
-            else {
-                debug(D_STREAM, "STREAM: Not requesting data output on streaming socket %d (nothing to send now)...", ofd->fd);
-                ofd->events = 0;
-                fdmax = 1;
-            }
-
-            debug(D_STREAM, "STREAM: Waiting for poll() events (current buffer length %zu bytes)...", buffer_strlen(host->rrdpush_sender_buffer));
-            if(unlikely(netdata_exit)) break;
-            int retval = poll(fds, fdmax, 1000);
-            if(unlikely(netdata_exit)) break;
-
-            if(unlikely(retval == -1)) {
-                debug(D_STREAM, "STREAM: poll() failed (current buffer length %zu bytes)...", buffer_strlen(host->rrdpush_sender_buffer));
-
-                if(errno == EAGAIN || errno == EINTR) {
-                    debug(D_STREAM, "STREAM: poll() failed with EAGAIN or EINTR...");
-                }
-                else {
-                    error("STREAM %s [send to %s]: failed to poll(). Closing socket.", host->hostname, connected_to);
-                    rrdpush_sender_thread_close_socket(host);
-                }
-
-                continue;
-            }
-            else if(likely(retval)) {
-                if (ifd->revents & POLLIN || ifd->revents & POLLPRI) {
-                    debug(D_STREAM, "STREAM: Data added to send buffer (current buffer length %zu bytes)...", buffer_strlen(host->rrdpush_sender_buffer));
-
-                    char buffer[1000 + 1];
-                    if (read(host->rrdpush_sender_pipe[PIPE_READ], buffer, 1000) == -1)
-                        error("STREAM %s [send to %s]: cannot read from internal pipe.", host->hostname, connected_to);
-                }
-
-                if (ofd->revents & POLLOUT) {
-                    if (begin < buffer_strlen(host->rrdpush_sender_buffer)) {
-                        debug(D_STREAM, "STREAM: Sending data (current buffer length %zu bytes, begin = %zu)...", buffer_strlen(host->rrdpush_sender_buffer), begin);
-
-                        // BEGIN RRDPUSH LOCKED SESSION
-
-                        // during this session, data collectors
-                        // will not be able to append data to our buffer
-                        // but the socket is in non-blocking mode
-                        // so, we will not block at send()
-
-                        netdata_thread_disable_cancelability();
-
-                        debug(D_STREAM, "STREAM: Getting exclusive lock on host...");
-                        rrdpush_buffer_lock(host);
-
-                        debug(D_STREAM, "STREAM: Sending data, starting from %zu, size %zu...", begin, buffer_strlen(host->rrdpush_sender_buffer));
-                        ssize_t ret;
-#ifdef ENABLE_HTTPS
-                        SSL *conn = host->ssl.conn ;
-                        if(conn && !host->ssl.flags) {
-                            ret = SSL_write(conn,&host->rrdpush_sender_buffer->buffer[begin], buffer_strlen(host->rrdpush_sender_buffer) - begin);
-                        } else {
-                            ret = send(host->rrdpush_sender_socket, &host->rrdpush_sender_buffer->buffer[begin], buffer_strlen(host->rrdpush_sender_buffer) - begin, MSG_DONTWAIT);
-                        }
-#else
-                        ret = send(host->rrdpush_sender_socket, &host->rrdpush_sender_buffer->buffer[begin], buffer_strlen(host->rrdpush_sender_buffer) - begin, MSG_DONTWAIT);
-#endif
-                        if (unlikely(ret == -1)) {
-                            if (errno != EAGAIN && errno != EINTR && errno != EWOULDBLOCK) {
-                                debug(D_STREAM, "STREAM: Send failed - closing socket...");
-                                error("STREAM %s [send to %s]: failed to send metrics - closing connection - we have sent %zu bytes on this connection.", host->hostname, connected_to, sent_bytes_on_this_connection);
-                                rrdpush_sender_thread_close_socket(host);
-                            }
-                            else {
-                                debug(D_STREAM, "STREAM: Send failed - will retry...");
-                            }
-                        }
-                        else if (likely(ret > 0)) {
-                            // DEBUG - dump the string to see it
-                            //char c = host->rrdpush_sender_buffer->buffer[begin + ret];
-                            //host->rrdpush_sender_buffer->buffer[begin + ret] = '\0';
-                            //debug(D_STREAM, "STREAM: sent from %zu to %zd:\n%s\n", begin, ret, &host->rrdpush_sender_buffer->buffer[begin]);
-                            //host->rrdpush_sender_buffer->buffer[begin + ret] = c;
-
-                            sent_bytes_on_this_connection += ret;
-                            sent_bytes += ret;
-                            begin += ret;
-
-                            if (begin == buffer_strlen(host->rrdpush_sender_buffer)) {
-                                // we send it all
-
-                                debug(D_STREAM, "STREAM: Sent %zd bytes (the whole buffer)...", ret);
-                                buffer_flush(host->rrdpush_sender_buffer);
-                                begin = 0;
-                            }
-                            else {
-                                debug(D_STREAM, "STREAM: Sent %zd bytes (part of the data buffer)...", ret);
-                            }
-
-                            last_sent_t = now_monotonic_sec();
-                        }
-                        else {
-                            debug(D_STREAM, "STREAM: send() returned %zd - closing the socket...", ret);
-                            error("STREAM %s [send to %s]: failed to send metrics (send() returned %zd) - closing connection - we have sent %zu bytes on this connection.",
-                                  host->hostname, connected_to, ret, sent_bytes_on_this_connection);
-                            rrdpush_sender_thread_close_socket(host);
-                        }
-
-                        debug(D_STREAM, "STREAM: Releasing exclusive lock on host...");
-                        rrdpush_buffer_unlock(host);
-
-                        netdata_thread_enable_cancelability();
-
-                        // END RRDPUSH LOCKED SESSION
-                    }
-                    else {
-                        debug(D_STREAM, "STREAM: we have sent the entire buffer, but we received POLLOUT...");
-                    }
-                }
-
-                if(host->rrdpush_sender_socket != -1) {
-                    char *error = NULL;
-
-                    if (unlikely(ofd->revents & POLLERR))
-                        error = "socket reports errors (POLLERR)";
-
-                    else if (unlikely(ofd->revents & POLLHUP))
-                        error = "connection closed by remote end (POLLHUP)";
-
-                    else if (unlikely(ofd->revents & POLLNVAL))
-                        error = "connection is invalid (POLLNVAL)";
-
-                    if(unlikely(error)) {
-                        debug(D_STREAM, "STREAM: %s - closing socket...", error);
-                        error("STREAM %s [send to %s]: %s - reopening socket - we have sent %zu bytes on this connection.", host->hostname, connected_to, error, sent_bytes_on_this_connection);
-                        rrdpush_sender_thread_close_socket(host);
-                    }
-                }
-            }
-            else {
-                debug(D_STREAM, "STREAM: poll() timed out.");
-            }
-
-            // protection from overflow
-            if(buffer_strlen(host->rrdpush_sender_buffer) > max_size) {
-                debug(D_STREAM, "STREAM: Buffer is too big (%zu bytes), bigger than the max (%zu) - flushing it...", buffer_strlen(host->rrdpush_sender_buffer), max_size);
-                errno = 0;
-                error("STREAM %s [send to %s]: too many data pending - buffer is %zu bytes long, %zu unsent - we have sent %zu bytes in total, %zu on this connection. Closing connection to flush the data.", host->hostname, connected_to, host->rrdpush_sender_buffer->len, host->rrdpush_sender_buffer->len - begin, sent_bytes, sent_bytes_on_this_connection);
-                rrdpush_sender_thread_close_socket(host);
-            }
-        }
-
-    netdata_thread_cleanup_pop(1);
-    return NULL;
-}
-
 
 // ----------------------------------------------------------------------------
 // rrdpush receiver thread
 
-static void log_stream_connection(const char *client_ip, const char *client_port, const char *api_key, const char *machine_guid, const char *host, const char *msg) {
+void log_stream_connection(const char *client_ip, const char *client_port, const char *api_key, const char *machine_guid, const char *host, const char *msg) {
     log_access("STREAM: %d '[%s]:%s' '%s' host '%s' api key '%s' machine guid '%s'", gettid(), client_ip, client_port, msg, host, api_key, machine_guid);
 }
 
-static RRDPUSH_MULTIPLE_CONNECTIONS_STRATEGY get_multiple_connections_strategy(struct config *c, const char *section, const char *name, RRDPUSH_MULTIPLE_CONNECTIONS_STRATEGY def) {
-    char *value;
-    switch(def) {
-        default:
-        case RRDPUSH_MULTIPLE_CONNECTIONS_ALLOW:
-            value = "allow";
-            break;
-
-        case RRDPUSH_MULTIPLE_CONNECTIONS_DENY_NEW:
-            value = "deny";
-            break;
-    }
-
-    value = appconfig_get(c, section, name, value);
-
-    RRDPUSH_MULTIPLE_CONNECTIONS_STRATEGY ret = def;
-
-    if(strcasecmp(value, "allow") == 0 || strcasecmp(value, "permit") == 0 || strcasecmp(value, "accept") == 0)
-        ret = RRDPUSH_MULTIPLE_CONNECTIONS_ALLOW;
-
-    else if(strcasecmp(value, "deny") == 0 || strcasecmp(value, "reject") == 0 || strcasecmp(value, "block") == 0)
-        ret = RRDPUSH_MULTIPLE_CONNECTIONS_DENY_NEW;
-
-    else
-        error("Invalid stream config value at section [%s], setting '%s', value '%s'", section, name, value);
-
-    return ret;
-}
-
-static int rrdpush_receive(int fd
-                           , const char *key
-                           , const char *hostname
-                           , const char *registry_hostname
-                           , const char *machine_guid
-                           , const char *os
-                           , const char *timezone
-                           , const char *tags
-                           , const char *program_name
-                           , const char *program_version
-                           , struct rrdhost_system_info *system_info
-                           , int update_every
-                           , char *client_ip
-                           , char *client_port
-#ifdef ENABLE_HTTPS
-                           , struct netdata_ssl *ssl
-#endif
-) {
-    RRDHOST *host;
-    int history = default_rrd_history_entries;
-    RRD_MEMORY_MODE mode = default_rrd_memory_mode;
-    int health_enabled = default_health_enabled;
-    int rrdpush_enabled = default_rrdpush_enabled;
-    char *rrdpush_destination = default_rrdpush_destination;
-    char *rrdpush_api_key = default_rrdpush_api_key;
-    char *rrdpush_send_charts_matching = default_rrdpush_send_charts_matching;
-    time_t alarms_delay = 60;
-    RRDPUSH_MULTIPLE_CONNECTIONS_STRATEGY rrdpush_multiple_connections_strategy = RRDPUSH_MULTIPLE_CONNECTIONS_ALLOW;
-
-    update_every = (int)appconfig_get_number(&stream_config, machine_guid, "update every", update_every);
-    if(update_every < 0) update_every = 1;
-
-    history = (int)appconfig_get_number(&stream_config, key, "default history", history);
-    history = (int)appconfig_get_number(&stream_config, machine_guid, "history", history);
-    if(history < 5) history = 5;
-
-    mode = rrd_memory_mode_id(appconfig_get(&stream_config, key, "default memory mode", rrd_memory_mode_name(mode)));
-    mode = rrd_memory_mode_id(appconfig_get(&stream_config, machine_guid, "memory mode", rrd_memory_mode_name(mode)));
-
-    health_enabled = appconfig_get_boolean_ondemand(&stream_config, key, "health enabled by default", health_enabled);
-    health_enabled = appconfig_get_boolean_ondemand(&stream_config, machine_guid, "health enabled", health_enabled);
-
-    alarms_delay = appconfig_get_number(&stream_config, key, "default postpone alarms on connect seconds", alarms_delay);
-    alarms_delay = appconfig_get_number(&stream_config, machine_guid, "postpone alarms on connect seconds", alarms_delay);
-
-    rrdpush_enabled = appconfig_get_boolean(&stream_config, key, "default proxy enabled", rrdpush_enabled);
-    rrdpush_enabled = appconfig_get_boolean(&stream_config, machine_guid, "proxy enabled", rrdpush_enabled);
-
-    rrdpush_destination = appconfig_get(&stream_config, key, "default proxy destination", rrdpush_destination);
-    rrdpush_destination = appconfig_get(&stream_config, machine_guid, "proxy destination", rrdpush_destination);
-
-    rrdpush_api_key = appconfig_get(&stream_config, key, "default proxy api key", rrdpush_api_key);
-    rrdpush_api_key = appconfig_get(&stream_config, machine_guid, "proxy api key", rrdpush_api_key);
-
-    rrdpush_multiple_connections_strategy = get_multiple_connections_strategy(&stream_config, key, "multiple connections", rrdpush_multiple_connections_strategy);
-    rrdpush_multiple_connections_strategy = get_multiple_connections_strategy(&stream_config, machine_guid, "multiple connections", rrdpush_multiple_connections_strategy);
-
-    rrdpush_send_charts_matching = appconfig_get(&stream_config, key, "default proxy send charts matching", rrdpush_send_charts_matching);
-    rrdpush_send_charts_matching = appconfig_get(&stream_config, machine_guid, "proxy send charts matching", rrdpush_send_charts_matching);
-
-    tags = appconfig_set_default(&stream_config, machine_guid, "host tags", (tags)?tags:"");
-    if(tags && !*tags) tags = NULL;
-
-    if (strcmp(machine_guid, localhost->machine_guid) == 0) {
-        log_stream_connection(client_ip, client_port, key, machine_guid, hostname, "DENIED - ATTEMPT TO RECEIVE METRICS FROM MACHINE_GUID IDENTICAL TO MASTER");
-        error("STREAM %s [receive from %s:%s]: denied to receive metrics, machine GUID [%s] is my own. Did you copy the master/proxy machine guid to a slave?", hostname, client_ip, client_port, machine_guid);
-        close(fd);
-        return 1;
-    }
-    else
-        host = rrdhost_find_or_create(
-                hostname
-                , registry_hostname
-                , machine_guid
-                , os
-                , timezone
-                , tags
-                , program_name
-                , program_version
-                , update_every
-                , history
-                , mode
-                , (unsigned int)(health_enabled != CONFIG_BOOLEAN_NO)
-                , (unsigned int)(rrdpush_enabled && rrdpush_destination && *rrdpush_destination && rrdpush_api_key && *rrdpush_api_key)
-                , rrdpush_destination
-                , rrdpush_api_key
-                , rrdpush_send_charts_matching
-                , system_info
-        );
-
-    if(!host) {
-        close(fd);
-        log_stream_connection(client_ip, client_port, key, machine_guid, hostname, "FAILED - CANNOT ACQUIRE HOST");
-        error("STREAM %s [receive from [%s]:%s]: failed to find/create host structure.", hostname, client_ip, client_port);
-        return 1;
-    }
-
-#ifdef NETDATA_INTERNAL_CHECKS
-    info("STREAM %s [receive from [%s]:%s]: client willing to stream metrics for host '%s' with machine_guid '%s': update every = %d, history = %ld, memory mode = %s, health %s, tags '%s'"
-         , hostname
-         , client_ip
-         , client_port
-         , host->hostname
-         , host->machine_guid
-         , host->rrd_update_every
-         , host->rrd_history_entries
-         , rrd_memory_mode_name(host->rrd_memory_mode)
-         , (health_enabled == CONFIG_BOOLEAN_NO)?"disabled":((health_enabled == CONFIG_BOOLEAN_YES)?"enabled":"auto")
-         , host->tags?host->tags:""
-    );
-#endif // NETDATA_INTERNAL_CHECKS
-
-    struct plugind cd = {
-            .enabled = 1,
-            .update_every = default_rrd_update_every,
-            .pid = 0,
-            .serial_failures = 0,
-            .successful_collections = 0,
-            .obsolete = 0,
-            .started_t = now_realtime_sec(),
-            .next = NULL,
-    };
-
-    // put the client IP and port into the buffers used by plugins.d
-    snprintfz(cd.id,           CONFIG_MAX_NAME,  "%s:%s", client_ip, client_port);
-    snprintfz(cd.filename,     FILENAME_MAX,     "%s:%s", client_ip, client_port);
-    snprintfz(cd.fullfilename, FILENAME_MAX,     "%s:%s", client_ip, client_port);
-    snprintfz(cd.cmd,          PLUGINSD_CMD_MAX, "%s:%s", client_ip, client_port);
-
-    info("STREAM %s [receive from [%s]:%s]: initializing communication...", host->hostname, client_ip, client_port);
-#ifdef ENABLE_HTTPS
-    host->stream_ssl.conn = ssl->conn;
-    host->stream_ssl.flags = ssl->flags;
-    if(send_timeout(ssl,fd, START_STREAMING_PROMPT, strlen(START_STREAMING_PROMPT), 0, 60) != strlen(START_STREAMING_PROMPT)) {
-#else
-    if(send_timeout(fd, START_STREAMING_PROMPT, strlen(START_STREAMING_PROMPT), 0, 60) != strlen(START_STREAMING_PROMPT)) {
-#endif
-        log_stream_connection(client_ip, client_port, key, host->machine_guid, host->hostname, "FAILED - CANNOT REPLY");
-        error("STREAM %s [receive from [%s]:%s]: cannot send ready command.", host->hostname, client_ip, client_port);
-        close(fd);
-        return 0;
-    }
-
-    // remove the non-blocking flag from the socket
-    if(sock_delnonblock(fd) < 0)
-        error("STREAM %s [receive from [%s]:%s]: cannot remove the non-blocking flag from socket %d", host->hostname, client_ip, client_port, fd);
-
-    // convert the socket to a FILE *
-    FILE *fp = fdopen(fd, "r");
-    if(!fp) {
-        log_stream_connection(client_ip, client_port, key, host->machine_guid, host->hostname, "FAILED - SOCKET ERROR");
-        error("STREAM %s [receive from [%s]:%s]: failed to get a FILE for FD %d.", host->hostname, client_ip, client_port, fd);
-        close(fd);
-        return 0;
-    }
-
-    rrdhost_wrlock(host);
-    if(host->connected_senders > 0) {
-        switch(rrdpush_multiple_connections_strategy) {
-            case RRDPUSH_MULTIPLE_CONNECTIONS_ALLOW:
-                info("STREAM %s [receive from [%s]:%s]: multiple streaming connections for the same host detected. If multiple netdata are pushing metrics for the same charts, at the same time, the result is unexpected.", host->hostname, client_ip, client_port);
-                break;
-
-            case RRDPUSH_MULTIPLE_CONNECTIONS_DENY_NEW:
-                rrdhost_unlock(host);
-                log_stream_connection(client_ip, client_port, key, host->machine_guid, host->hostname, "REJECTED - ALREADY CONNECTED");
-                info("STREAM %s [receive from [%s]:%s]: multiple streaming connections for the same host detected. Rejecting new connection.", host->hostname, client_ip, client_port);
-                fclose(fp);
-                return 0;
-        }
-    }
-
-    rrdhost_flag_clear(host, RRDHOST_FLAG_ORPHAN);
-    host->connected_senders++;
-    host->senders_disconnected_time = 0;
-    if(health_enabled != CONFIG_BOOLEAN_NO) {
-        if(alarms_delay > 0) {
-            host->health_delay_up_to = now_realtime_sec() + alarms_delay;
-            info("Postponing health checks for %ld seconds, on host '%s', because it was just connected."
-            , alarms_delay
-            , host->hostname
-            );
-        }
-    }
-    rrdhost_unlock(host);
-
-    // call the plugins.d processor to receive the metrics
-    info("STREAM %s [receive from [%s]:%s]: receiving metrics...", host->hostname, client_ip, client_port);
-    log_stream_connection(client_ip, client_port, key, host->machine_guid, host->hostname, "CONNECTED");
-
-    size_t count = pluginsd_process(host, &cd, fp, 1);
-
-    log_stream_connection(client_ip, client_port, key, host->machine_guid, host->hostname, "DISCONNECTED");
-    error("STREAM %s [receive from [%s]:%s]: disconnected (completed %zu updates).", host->hostname, client_ip, client_port, count);
-
-    rrdhost_wrlock(host);
-    host->senders_disconnected_time = now_realtime_sec();
-    host->connected_senders--;
-    if(!host->connected_senders) {
-        rrdhost_flag_set(host, RRDHOST_FLAG_ORPHAN);
-        if(health_enabled == CONFIG_BOOLEAN_AUTO)
-            host->health_enabled = 0;
-    }
-    rrdhost_unlock(host);
-
-    if(host->connected_senders == 0)
-        rrdpush_sender_thread_stop(host);
-
-    // cleanup
-    fclose(fp);
-
-    return (int)count;
-}
-
-struct rrdpush_thread {
-    int fd;
-    char *key;
-    char *hostname;
-    char *registry_hostname;
-    char *machine_guid;
-    char *os;
-    char *timezone;
-    char *tags;
-    char *client_ip;
-    char *client_port;
-    char *program_name;
-    char *program_version;
-    struct rrdhost_system_info *system_info;
-    int update_every;
-#ifdef ENABLE_HTTPS
-    struct netdata_ssl ssl;
-#endif
-};
-
-static void rrdpush_receiver_thread_cleanup(void *ptr) {
-    static __thread int executed = 0;
-    if(!executed) {
-        executed = 1;
-        struct rrdpush_thread *rpt = (struct rrdpush_thread *) ptr;
-
-        info("STREAM %s [receive from [%s]:%s]: receive thread ended (task id %d)", rpt->hostname, rpt->client_ip, rpt->client_port, gettid());
-
-        freez(rpt->key);
-        freez(rpt->hostname);
-        freez(rpt->registry_hostname);
-        freez(rpt->machine_guid);
-        freez(rpt->os);
-        freez(rpt->timezone);
-        freez(rpt->tags);
-        freez(rpt->client_ip);
-        freez(rpt->client_port);
-        freez(rpt->program_name);
-        freez(rpt->program_version);
-#ifdef ENABLE_HTTPS
-        if(rpt->ssl.conn){
-            SSL_free(rpt->ssl.conn);
-        }
-#endif
-        freez(rpt);
-
-    }
-}
-
-static void *rrdpush_receiver_thread(void *ptr) {
-    netdata_thread_cleanup_push(rrdpush_receiver_thread_cleanup, ptr);
-
-    struct rrdpush_thread *rpt = (struct rrdpush_thread *)ptr;
-    info("STREAM %s [%s]:%s: receive thread created (task id %d)", rpt->hostname, rpt->client_ip, rpt->client_port, gettid());
-
-    rrdpush_receive(
-	    rpt->fd
-	    , rpt->key
-	    , rpt->hostname
-	    , rpt->registry_hostname
-	    , rpt->machine_guid
-	    , rpt->os
-	    , rpt->timezone
-	    , rpt->tags
-	    , rpt->program_name
-	    , rpt->program_version
-        , rpt->system_info
-	    , rpt->update_every
-	    , rpt->client_ip
-	    , rpt->client_port
-#ifdef ENABLE_HTTPS
-	    , &rpt->ssl
-#endif
-    );
-
-    netdata_thread_cleanup_pop(1);
-    return NULL;
-}
 
 static void rrdpush_sender_thread_spawn(RRDHOST *host) {
-    rrdhost_wrlock(host);
+    netdata_mutex_lock(&host->sender->mutex);
 
     if(!host->rrdpush_sender_spawn) {
         char tag[NETDATA_THREAD_TAG_MAX + 1];
         snprintfz(tag, NETDATA_THREAD_TAG_MAX, "STREAM_SENDER[%s]", host->hostname);
 
-        if(netdata_thread_create(&host->rrdpush_sender_thread, tag, NETDATA_THREAD_OPTION_JOINABLE, rrdpush_sender_thread, (void *) host))
+        if(netdata_thread_create(&host->rrdpush_sender_thread, tag, NETDATA_THREAD_OPTION_JOINABLE, rrdpush_sender_thread, (void *) host->sender))
             error("STREAM %s [send]: failed to create new thread for client.", host->hostname);
         else
             host->rrdpush_sender_spawn = 1;
     }
-
-    rrdhost_unlock(host);
+    netdata_mutex_unlock(&host->sender->mutex);
 }
 
 int rrdpush_receiver_permission_denied(struct web_client *w) {
@@ -1273,13 +460,13 @@ int rrdpush_receiver_too_busy_now(struct web_client *w) {
     return 503;
 }
 
-int rrdpush_receiver_thread_spawn(RRDHOST *host, struct web_client *w, char *url) {
-    (void)host;
-
+void *rrdpush_receiver_thread(void *ptr);
+int rrdpush_receiver_thread_spawn(struct web_client *w, char *url) {
     info("clients wants to STREAM metrics.");
 
     char *key = NULL, *hostname = NULL, *registry_hostname = NULL, *machine_guid = NULL, *os = "unknown", *timezone = "unknown", *tags = NULL;
     int update_every = default_rrd_update_every;
+    uint32_t stream_version = UINT_MAX;
     char buf[GUID_LEN + 1];
 
     struct rrdhost_system_info *system_info = callocz(1, sizeof(struct rrdhost_system_info));
@@ -1308,12 +495,36 @@ int rrdpush_receiver_thread_spawn(RRDHOST *host, struct web_client *w, char *url
             timezone = value;
         else if(!strcmp(name, "tags"))
             tags = value;
-        else
-            if(unlikely(rrdhost_set_system_info_variable(system_info, name, value))) {
-                info("STREAM [receive from [%s]:%s]: request has parameter '%s' = '%s', which is not used.", w->client_ip, w->client_port, key, value);
+        else if(!strcmp(name, "ver"))
+            stream_version = MIN((uint32_t) strtoul(value, NULL, 0), STREAMING_PROTOCOL_CURRENT_VERSION);
+        else {
+            // An old Netdata child does not have a compatible streaming protocol, map to something sane.
+            if (!strcmp(name, "NETDATA_SYSTEM_OS_NAME"))
+                name = "NETDATA_HOST_OS_NAME";
+            else if (!strcmp(name, "NETDATA_SYSTEM_OS_ID"))
+                name = "NETDATA_HOST_OS_ID";
+            else if (!strcmp(name, "NETDATA_SYSTEM_OS_ID_LIKE"))
+                name = "NETDATA_HOST_OS_ID_LIKE";
+            else if (!strcmp(name, "NETDATA_SYSTEM_OS_VERSION"))
+                name = "NETDATA_HOST_OS_VERSION";
+            else if (!strcmp(name, "NETDATA_SYSTEM_OS_VERSION_ID"))
+                name = "NETDATA_HOST_OS_VERSION_ID";
+            else if (!strcmp(name, "NETDATA_SYSTEM_OS_DETECTION"))
+                name = "NETDATA_HOST_OS_DETECTION";
+            else if(!strcmp(name, "NETDATA_PROTOCOL_VERSION") && stream_version == UINT_MAX) {
+                stream_version = 1;
             }
+
+            if (unlikely(rrdhost_set_system_info_variable(system_info, name, value))) {
+                info("STREAM [receive from [%s]:%s]: request has parameter '%s' = '%s', which is not used.",
+                     w->client_ip, w->client_port, name, value);
+            }
+        }
     }
 
+    if (stream_version == UINT_MAX)
+        stream_version = 0;
+
     if(!key || !*key) {
         rrdhost_system_info_free(system_info);
         log_stream_connection(w->client_ip, w->client_port, (key && *key)?key:"-", (machine_guid && *machine_guid)?machine_guid:"-", (hostname && *hostname)?hostname:"-", "ACCESS DENIED - NO KEY");
@@ -1412,7 +623,56 @@ int rrdpush_receiver_thread_spawn(RRDHOST *host, struct web_client *w, char *url
         netdata_mutex_unlock(&stream_rate_mutex);
     }
 
-    struct rrdpush_thread *rpt = callocz(1, sizeof(struct rrdpush_thread));
+    /*
+     * Quick path for rejecting multiple connections. The lock taken is fine-grained - it only protects the receiver
+     * pointer within the host (if a host exists). This protects against multiple concurrent web requests hitting
+     * separate threads within the web-server and landing here. The lock guards the thread-shutdown sequence that
+     * detaches the receiver from the host. If the host is being created (first time-access) then we also use the
+     * lock to prevent race-hazard (two threads try to create the host concurrently, one wins and the other does a
+     * lookup to the now-attached structure).
+     */
+    struct receiver_state *rpt = callocz(1, sizeof(*rpt));
+
+    rrd_rdlock();
+    RRDHOST *host = rrdhost_find_by_guid(machine_guid, 0);
+    if (unlikely(host && rrdhost_flag_check(host, RRDHOST_FLAG_ARCHIVED))) /* Ignore archived hosts. */
+        host = NULL;
+    if (host) {
+        rrdhost_wrlock(host);
+        netdata_mutex_lock(&host->receiver_lock);
+        rrdhost_flag_clear(host, RRDHOST_FLAG_ORPHAN);
+        host->senders_disconnected_time = 0;
+        if (host->receiver != NULL) {
+            time_t age = now_realtime_sec() - host->receiver->last_msg_t;
+            if (age > 30) {
+                host->receiver->shutdown = 1;
+                shutdown(host->receiver->fd, SHUT_RDWR);
+                host->receiver = NULL;      // Thread holds reference to structure
+                info("STREAM %s [receive from [%s]:%s]: multiple connections for same host detected - existing connection is dead (%ld sec), accepting new connection.", host->hostname, w->client_ip, w->client_port, age);
+            }
+            else {
+                netdata_mutex_unlock(&host->receiver_lock);
+                rrdhost_unlock(host);
+                rrd_unlock();
+                log_stream_connection(w->client_ip, w->client_port, key, host->machine_guid, host->hostname,
+                                      "REJECTED - ALREADY CONNECTED");
+                info("STREAM %s [receive from [%s]:%s]: multiple connections for same host detected - existing connection is active (within last %ld sec), rejecting new connection.", host->hostname, w->client_ip, w->client_port, age);
+                // Have not set WEB_CLIENT_FLAG_DONT_CLOSE_SOCKET - caller should clean up
+                buffer_flush(w->response.data);
+                buffer_strcat(w->response.data, "This GUID is already streaming to this server");
+                freez(rpt);
+                return 409;
+            }
+        }
+        host->receiver = rpt;
+        netdata_mutex_unlock(&host->receiver_lock);
+        rrdhost_unlock(host);
+    }
+    rrd_unlock();
+
+    rpt->last_msg_t = now_realtime_sec();
+
+    rpt->host              = host;
     rpt->fd                = w->ifd;
     rpt->key               = strdupz(key);
     rpt->hostname          = strdupz(hostname);
@@ -1425,6 +685,7 @@ int rrdpush_receiver_thread_spawn(RRDHOST *host, struct web_client *w, char *url
     rpt->client_port       = strdupz(w->client_port);
     rpt->update_every      = update_every;
     rpt->system_info       = system_info;
+    rpt->stream_version    = stream_version;
 #ifdef ENABLE_HTTPS
     rpt->ssl.conn          = w->ssl.conn;
     rpt->ssl.flags         = w->ssl.flags;
@@ -1445,14 +706,13 @@ int rrdpush_receiver_thread_spawn(RRDHOST *host, struct web_client *w, char *url
     }
 
 
-    netdata_thread_t thread;
 
     debug(D_SYSTEM, "starting STREAM receive thread.");
 
     char tag[FILENAME_MAX + 1];
     snprintfz(tag, FILENAME_MAX, "STREAM_RECEIVER[%s,[%s]:%s]", rpt->hostname, w->client_ip, w->client_port);
 
-    if(netdata_thread_create(&thread, tag, NETDATA_THREAD_OPTION_DEFAULT, rrdpush_receiver_thread, (void *)rpt))
+    if(netdata_thread_create(&rpt->thread, tag, NETDATA_THREAD_OPTION_DEFAULT, rrdpush_receiver_thread, (void *)rpt))
         error("Failed to create new STREAM receive thread for client.");
 
     // prevent the caller from closing the streaming socket