Send host labels via exporting connectors (#7554)

* Add labels to the JSON exporting connector

* Add labels to the Graphite exporting connector

* Add labels to the OpenTSDB telnet exporting connector

* Add labels to the OpenTSDB HTTP exporting connector

* Replace control characters in JSON strings

* Add unit tests

11 files changed, 437 insertions, 48 deletions

diff --git a/exporting/exporting_engine.h b/exporting/exporting_engine.h
index 02d0c89bfe..d45397b448 100644
--- a/exporting/exporting_engine.h
+++ b/exporting/exporting_engine.h
@@ -13,44 +13,62 @@
 
 extern struct config exporting_config;
 
-#define EXPORTER_DATA_SOURCE                 "data source"
-#define EXPORTER_DATA_SOURCE_DEFAULT         "average"
+#define EXPORTER_DATA_SOURCE                    "data source"
+#define EXPORTER_DATA_SOURCE_DEFAULT            "average"
 
-#define EXPORTER_DESTINATION                "destination"
-#define EXPORTER_DESTINATION_DEFAULT        "localhost"
+#define EXPORTER_DESTINATION                    "destination"
+#define EXPORTER_DESTINATION_DEFAULT            "localhost"
 
-#define EXPORTER_UPDATE_EVERY               "update every"
-#define EXPORTER_UPDATE_EVERY_DEFAULT       10
+#define EXPORTER_UPDATE_EVERY                   "update every"
+#define EXPORTER_UPDATE_EVERY_DEFAULT           10
 
-#define EXPORTER_BUF_ONFAIL                 "buffer on failures"
-#define EXPORTER_BUF_ONFAIL_DEFAULT         10
+#define EXPORTER_BUF_ONFAIL                     "buffer on failures"
+#define EXPORTER_BUF_ONFAIL_DEFAULT             10
 
-#define EXPORTER_TIMEOUT_MS                 "timeout ms"
-#define EXPORTER_TIMEOUT_MS_DEFAULT         10000
+#define EXPORTER_TIMEOUT_MS                     "timeout ms"
+#define EXPORTER_TIMEOUT_MS_DEFAULT             10000
 
-#define EXPORTER_SEND_CHART_MATCH           "send charts matching"
-#define EXPORTER_SEND_CHART_MATCH_DEFAULT   "*"
+#define EXPORTER_SEND_CHART_MATCH               "send charts matching"
+#define EXPORTER_SEND_CHART_MATCH_DEFAULT       "*"
 
-#define EXPORTER_SEND_HOST_MATCH            "send hosts matching"
-#define EXPORTER_SEND_HOST_MATCH_DEFAULT    "localhost *"
+#define EXPORTER_SEND_HOST_MATCH                "send hosts matching"
+#define EXPORTER_SEND_HOST_MATCH_DEFAULT        "localhost *"
 
-#define EXPORTER_SEND_NAMES                 "send names instead of ids"
-#define EXPORTER_SEND_NAMES_DEFAULT         CONFIG_BOOLEAN_YES
+#define EXPORTER_SEND_CONFIGURED_LABELS         "send configured labels"
+#define EXPORTER_SEND_CONFIGURED_LABELS_DEFAULT CONFIG_BOOLEAN_YES
+
+#define EXPORTER_SEND_AUTOMATIC_LABELS          "send automatic labels"
+#define EXPORTER_SEND_AUTOMATIC_LABELS_DEFAULT  CONFIG_BOOLEAN_NO
+
+#define EXPORTER_SEND_NAMES                     "send names instead of ids"
+#define EXPORTER_SEND_NAMES_DEFAULT             CONFIG_BOOLEAN_YES
 
 typedef enum exporting_options {
-    EXPORTING_OPTION_NONE              = 0,
+    EXPORTING_OPTION_NONE                   = 0,
+
+    EXPORTING_SOURCE_DATA_AS_COLLECTED      = (1 << 0),
+    EXPORTING_SOURCE_DATA_AVERAGE           = (1 << 1),
+    EXPORTING_SOURCE_DATA_SUM               = (1 << 2),
 
-    EXPORTING_SOURCE_DATA_AS_COLLECTED = (1 << 0),
-    EXPORTING_SOURCE_DATA_AVERAGE      = (1 << 1),
-    EXPORTING_SOURCE_DATA_SUM          = (1 << 2),
+    EXPORTING_OPTION_SEND_CONFIGURED_LABELS = (1 << 3),
+    EXPORTING_OPTION_SEND_AUTOMATIC_LABELS  = (1 << 4),
 
-    EXPORTING_OPTION_SEND_NAMES        = (1 << 16)
+    EXPORTING_OPTION_SEND_NAMES             = (1 << 16)
 } EXPORTING_OPTIONS;
 
 #define EXPORTING_OPTIONS_SOURCE_BITS                                                                                  \
     (EXPORTING_SOURCE_DATA_AS_COLLECTED | EXPORTING_SOURCE_DATA_AVERAGE | EXPORTING_SOURCE_DATA_SUM)
 #define EXPORTING_OPTIONS_DATA_SOURCE(exporting_options) (exporting_options & EXPORTING_OPTIONS_SOURCE_BITS)
 
+#define sending_labels_configured(instance)                                                                            \
+    (instance->config.options & (EXPORTING_OPTION_SEND_CONFIGURED_LABELS | EXPORTING_OPTION_SEND_AUTOMATIC_LABELS))
+
+#define should_send_label(instance, label)                                                                             \
+    ((instance->config.options & EXPORTING_OPTION_SEND_CONFIGURED_LABELS &&                                            \
+      label->label_source == LABEL_SOURCE_NETDATA_CONF) ||                                                             \
+     (instance->config.options & EXPORTING_OPTION_SEND_AUTOMATIC_LABELS &&                                             \
+      label->label_source != LABEL_SOURCE_NETDATA_CONF))
+
 struct engine;
 
 struct instance_config {
@@ -107,6 +125,8 @@ struct instance {
     int skip_host;
     int skip_chart;
 
+    BUFFER *labels;
+
     time_t after;
     time_t before;
 
@@ -174,6 +194,7 @@ int metric_formatting(struct engine *engine, RRDDIM *rd);
 int end_chart_formatting(struct engine *engine, RRDSET *st);
 int end_host_formatting(struct engine *engine, RRDHOST *host);
 int end_batch_formatting(struct engine *engine);
+int flush_host_labels(struct instance *instance, RRDHOST *host);
 
 int exporting_discard_response(BUFFER *buffer, struct instance *instance);
 void simple_connector_receive_response(int *sock, struct instance *instance);
diff --git a/exporting/graphite/graphite.c b/exporting/graphite/graphite.c
index ec36b298e4..71f833a018 100644
--- a/exporting/graphite/graphite.c
+++ b/exporting/graphite/graphite.c
@@ -28,7 +28,7 @@ int init_graphite_connector(struct connector *connector)
 int init_graphite_instance(struct instance *instance)
 {
     instance->start_batch_formatting = NULL;
-    instance->start_host_formatting = NULL;
+    instance->start_host_formatting = format_host_labels_graphite_plaintext;
     instance->start_chart_formatting = NULL;
 
     if (EXPORTING_OPTIONS_DATA_SOURCE(instance->config.options) == EXPORTING_SOURCE_DATA_AS_COLLECTED)
@@ -37,7 +37,7 @@ int init_graphite_instance(struct instance *instance)
         instance->metric_formatting = format_dimension_stored_graphite_plaintext;
 
     instance->end_chart_formatting = NULL;
-    instance->end_host_formatting = NULL;
+    instance->end_host_formatting = flush_host_labels;
     instance->end_batch_formatting = NULL;
 
     instance->buffer = (void *)buffer_create(0);
@@ -52,6 +52,60 @@ int init_graphite_instance(struct instance *instance)
 }
 
 /**
+ * Copy a label value and substitute underscores in place of charachters which can't be used in Graphite output
+ *
+ * @param dst a destination string.
+ * @param src a source string.
+ * @param len the maximum number of characters copied.
+ */
+
+void sanitize_graphite_label_value(char *dst, char *src, size_t len)
+{
+    while (*src != '\0' && len) {
+        if (isspace(*src) || *src == ';' || *src == '~')
+            *dst++ = '_';
+        else
+            *dst++ = *src;
+        src++;
+        len--;
+    }
+    *dst = '\0';
+}
+
+/**
+ * Format host labels for JSON connector
+ *
+ * @param instance an instance data structure.
+ * @param host a data collecting host.
+ * @return Always returns 0.
+ */
+int format_host_labels_graphite_plaintext(struct instance *instance, RRDHOST *host)
+{
+    if (!instance->labels)
+        instance->labels = buffer_create(1024);
+
+    if (unlikely(!sending_labels_configured(instance)))
+        return 0;
+
+    netdata_rwlock_rdlock(&host->labels_rwlock);
+    for (struct label *label = host->labels; label; label = label->next) {
+        if (!should_send_label(instance, label))
+            continue;
+
+        char value[CONFIG_MAX_VALUE + 1];
+        sanitize_graphite_label_value(value, label->value, CONFIG_MAX_VALUE);
+
+        if (*value) {
+            buffer_strcat(instance->labels, ";");
+            buffer_sprintf(instance->labels, "%s=%s", label->key, value);
+        }
+    }
+    netdata_rwlock_unlock(&host->labels_rwlock);
+
+    return 0;
+}
+
+/**
  * Format dimension using collected data for Graphite connector
  *
  * @param instance an instance data structure.
@@ -78,13 +132,14 @@ int format_dimension_collected_graphite_plaintext(struct instance *instance, RRD
 
     buffer_sprintf(
         instance->buffer,
-        "%s.%s.%s.%s%s%s " COLLECTED_NUMBER_FORMAT " %llu\n",
+        "%s.%s.%s.%s%s%s%s " COLLECTED_NUMBER_FORMAT " %llu\n",
         engine->config.prefix,
         engine->config.hostname,
         chart_name,
         dimension_name,
         (host->tags) ? ";" : "",
         (host->tags) ? host->tags : "",
+        (instance->labels) ? buffer_tostring(instance->labels) : "",
         rd->last_collected_value,
         (unsigned long long)rd->last_collected_time.tv_sec);
 
@@ -124,13 +179,14 @@ int format_dimension_stored_graphite_plaintext(struct instance *instance, RRDDIM
 
     buffer_sprintf(
         instance->buffer,
-        "%s.%s.%s.%s%s%s " CALCULATED_NUMBER_FORMAT " %llu\n",
+        "%s.%s.%s.%s%s%s%s " CALCULATED_NUMBER_FORMAT " %llu\n",
         engine->config.prefix,
         engine->config.hostname,
         chart_name,
         dimension_name,
         (host->tags) ? ";" : "",
         (host->tags) ? host->tags : "",
+        (instance->labels) ? buffer_tostring(instance->labels) : "",
         value,
         (unsigned long long)last_t);
 
diff --git a/exporting/graphite/graphite.h b/exporting/graphite/graphite.h
index e5a2001c28..cc3767003a 100644
--- a/exporting/graphite/graphite.h
+++ b/exporting/graphite/graphite.h
@@ -7,6 +7,10 @@
 
 int init_graphite_connector(struct connector *connector);
 int init_graphite_instance(struct instance *instance);
+
+void sanitize_graphite_label_value(char *dst, char *src, size_t len);
+int format_host_labels_graphite_plaintext(struct instance *instance, RRDHOST *host);
+
 int format_dimension_collected_graphite_plaintext(struct instance *instance, RRDDIM *rd);
 int format_dimension_stored_graphite_plaintext(struct instance *instance, RRDDIM *rd);
 
diff --git a/exporting/json/json.c b/exporting/json/json.c
index 59ceb046be..6499218df9 100644
--- a/exporting/json/json.c
+++ b/exporting/json/json.c
@@ -28,7 +28,7 @@ int init_json_connector(struct connector *connector)
 int init_json_instance(struct instance *instance)
 {
     instance->start_batch_formatting = NULL;
-    instance->start_host_formatting = NULL;
+    instance->start_host_formatting = format_host_labels_json_plaintext;
     instance->start_chart_formatting = NULL;
 
     if (EXPORTING_OPTIONS_DATA_SOURCE(instance->config.options) == EXPORTING_SOURCE_DATA_AS_COLLECTED)
@@ -37,7 +37,7 @@ int init_json_instance(struct instance *instance)
         instance->metric_formatting = format_dimension_stored_json_plaintext;
 
     instance->end_chart_formatting = NULL;
-    instance->end_host_formatting = NULL;
+    instance->end_host_formatting = flush_host_labels;
     instance->end_batch_formatting = NULL;
 
     instance->buffer = (void *)buffer_create(0);
@@ -52,6 +52,44 @@ int init_json_instance(struct instance *instance)
 }
 
 /**
+ * Format host labels for JSON connector
+ *
+ * @param instance an instance data structure.
+ * @param host a data collecting host.
+ * @return Always returns 0.
+ */
+int format_host_labels_json_plaintext(struct instance *instance, RRDHOST *host)
+{
+    if (!instance->labels)
+        instance->labels = buffer_create(1024);
+
+    if (unlikely(!sending_labels_configured(instance)))
+        return 0;
+
+    buffer_strcat(instance->labels, "\"labels\":{");
+
+    int count = 0;
+    netdata_rwlock_rdlock(&host->labels_rwlock);
+    for (struct label *label = host->labels; label; label = label->next) {
+        if (!should_send_label(instance, label))
+            continue;
+
+        char value[CONFIG_MAX_VALUE * 2 + 1];
+        sanitize_json_string(value, label->value, CONFIG_MAX_VALUE);
+        if (count > 0)
+            buffer_strcat(instance->labels, ",");
+        buffer_sprintf(instance->labels, "\"%s\":\"%s\"", label->key, value);
+
+        count++;
+    }
+    netdata_rwlock_unlock(&host->labels_rwlock);
+
+    buffer_strcat(instance->labels, "},");
+
+    return 0;
+}
+
+/**
  * Format dimension using collected data for JSON connector
  *
  * @param instance an instance data structure.
@@ -80,28 +118,32 @@ int format_dimension_collected_json_plaintext(struct instance *instance, RRDDIM
 
     buffer_sprintf(
         instance->buffer,
+
         "{"
         "\"prefix\":\"%s\","
         "\"hostname\":\"%s\","
         "%s%s%s"
+        "%s"
 
         "\"chart_id\":\"%s\","
         "\"chart_name\":\"%s\","
         "\"chart_family\":\"%s\","
-        "\"chart_context\": \"%s\","
+        "\"chart_context\":\"%s\","
         "\"chart_type\":\"%s\","
-        "\"units\": \"%s\","
+        "\"units\":\"%s\","
 
         "\"id\":\"%s\","
         "\"name\":\"%s\","
         "\"value\":" COLLECTED_NUMBER_FORMAT ","
 
-        "\"timestamp\": %llu}\n",
+        "\"timestamp\":%llu}\n",
+
         engine->config.prefix,
         engine->config.hostname,
         tags_pre,
         tags,
         tags_post,
+        instance->labels ? buffer_tostring(instance->labels) : "",
 
         st->id,
         st->name,
@@ -158,6 +200,7 @@ int format_dimension_stored_json_plaintext(struct instance *instance, RRDDIM *rd
         "\"prefix\":\"%s\","
         "\"hostname\":\"%s\","
         "%s%s%s"
+        "%s"
 
         "\"chart_id\":\"%s\","
         "\"chart_name\":\"%s\","
@@ -171,11 +214,13 @@ int format_dimension_stored_json_plaintext(struct instance *instance, RRDDIM *rd
         "\"value\":" CALCULATED_NUMBER_FORMAT ","
 
         "\"timestamp\": %llu}\n",
+
         engine->config.prefix,
         engine->config.hostname,
         tags_pre,
         tags,
         tags_post,
+        instance->labels ? buffer_tostring(instance->labels) : "",
 
         st->id,
         st->name,
diff --git a/exporting/json/json.h b/exporting/json/json.h
index 8827c42237..4a5c876934 100644
--- a/exporting/json/json.h
+++ b/exporting/json/json.h
@@ -7,6 +7,9 @@
 
 int init_json_connector(struct connector *connector);
 int init_json_instance(struct instance *instance);
+
+int format_host_labels_json_plaintext(struct instance *instance, RRDHOST *host);
+
 int format_dimension_collected_json_plaintext(struct instance *instance, RRDDIM *rd);
 int format_dimension_stored_json_plaintext(struct instance *instance, RRDDIM *rd);
 
diff --git a/exporting/opentsdb/opentsdb.c b/exporting/opentsdb/opentsdb.c
index b216c76b44..a1e810de93 100644
--- a/exporting/opentsdb/opentsdb.c
+++ b/exporting/opentsdb/opentsdb.c
@@ -28,7 +28,7 @@ int init_opentsdb_connector(struct connector *connector)
 int init_opentsdb_telnet_instance(struct instance *instance)
 {
     instance->start_batch_formatting = NULL;
-    instance->start_host_formatting = NULL;
+    instance->start_host_formatting = format_host_labels_opentsdb_telnet;
     instance->start_chart_formatting = NULL;
 
     if (EXPORTING_OPTIONS_DATA_SOURCE(instance->config.options) == EXPORTING_SOURCE_DATA_AS_COLLECTED)
@@ -37,7 +37,7 @@ int init_opentsdb_telnet_instance(struct instance *instance)
         instance->metric_formatting = format_dimension_stored_opentsdb_telnet;
 
     instance->end_chart_formatting = NULL;
-    instance->end_host_formatting = NULL;
+    instance->end_host_formatting = flush_host_labels;
     instance->end_batch_formatting = NULL;
 
     instance->buffer = (void *)buffer_create(0);
@@ -60,7 +60,7 @@ int init_opentsdb_telnet_instance(struct instance *instance)
 int init_opentsdb_http_instance(struct instance *instance)
 {
     instance->start_batch_formatting = NULL;
-    instance->start_host_formatting = NULL;
+    instance->start_host_formatting = format_host_labels_opentsdb_http;
     instance->start_chart_formatting = NULL;
 
     if (EXPORTING_OPTIONS_DATA_SOURCE(instance->config.options) == EXPORTING_SOURCE_DATA_AS_COLLECTED)
@@ -69,7 +69,7 @@ int init_opentsdb_http_instance(struct instance *instance)
         instance->metric_formatting = format_dimension_stored_opentsdb_http;
 
     instance->end_chart_formatting = NULL;
-    instance->end_host_formatting = NULL;
+    instance->end_host_formatting = flush_host_labels;
     instance->end_batch_formatting = NULL;
 
     instance->buffer = (void *)buffer_create(0);
@@ -84,6 +84,58 @@ int init_opentsdb_http_instance(struct instance *instance)
 }
 
 /**
+ * Copy a label value and substitute underscores in place of charachters which can't be used in OpenTSDB output
+ *
+ * @param dst a destination string.
+ * @param src a source string.
+ * @param len the maximum number of characters copied.
+ */
+
+void sanitize_opentsdb_label_value(char *dst, char *src, size_t len)
+{
+    while (*src != '\0' && len) {
+        if (isalpha(*src) || isdigit(*src) || *src == '-' || *src == '_' || *src == '.' || *src == '/' || IS_UTF8_BYTE(*src))
+            *dst++ = *src;
+        else
+            *dst++ = '_';
+        src++;
+        len--;
+    }
+    *dst = '\0';
+}
+
+/**
+ * Format host labels for JSON connector
+ *
+ * @param instance an instance data structure.
+ * @param host a data collecting host.
+ * @return Always returns 0.
+ */
+int format_host_labels_opentsdb_telnet(struct instance *instance, RRDHOST *host)
+{
+    if (!instance->labels)
+        instance->labels = buffer_create(1024);
+
+    if (unlikely(!sending_labels_configured(instance)))
+        return 0;
+
+    netdata_rwlock_rdlock(&host->labels_rwlock);
+    for (struct label *label = host->labels; label; label = label->next) {
+        if (!should_send_label(instance, label))
+            continue;
+
+        char value[CONFIG_MAX_VALUE + 1];
+        sanitize_opentsdb_label_value(value, label->value, CONFIG_MAX_VALUE);
+
+        if (*value)
+            buffer_sprintf(instance->labels, " %s=%s", label->key, value);
+    }
+    netdata_rwlock_unlock(&host->labels_rwlock);
+
+    return 0;
+}
+
+/**
  * Format dimension using collected data for OpenTSDB telnet connector
  *
  * @param instance an instance data structure.
@@ -110,7 +162,7 @@ int format_dimension_collected_opentsdb_telnet(struct instance *instance, RRDDIM
 
     buffer_sprintf(
         instance->buffer,
-        "put %s.%s.%s %llu " COLLECTED_NUMBER_FORMAT " host=%s%s%s\n",
+        "put %s.%s.%s %llu " COLLECTED_NUMBER_FORMAT " host=%s%s%s%s\n",
         engine->config.prefix,
         chart_name,
         dimension_name,
@@ -118,7 +170,8 @@ int format_dimension_collected_opentsdb_telnet(struct instance *instance, RRDDIM
         rd->last_collected_value,
         engine->config.hostname,
         (host->tags) ? " " : "",
-        (host->tags) ? host->tags : "");
+        (host->tags) ? host->tags : "",
+        (instance->labels) ? buffer_tostring(instance->labels) : "");
 
     return 0;
 }
@@ -156,7 +209,7 @@ int format_dimension_stored_opentsdb_telnet(struct instance *instance, RRDDIM *r
 
     buffer_sprintf(
         instance->buffer,
-        "put %s.%s.%s %llu " CALCULATED_NUMBER_FORMAT " host=%s%s%s\n",
+        "put %s.%s.%s %llu " CALCULATED_NUMBER_FORMAT " host=%s%s%s%s\n",
         engine->config.prefix,
         chart_name,
         dimension_name,
@@ -164,7 +217,8 @@ int format_dimension_stored_opentsdb_telnet(struct instance *instance, RRDDIM *r
         value,
         engine->config.hostname,
         (host->tags) ? " " : "",
-        (host->tags) ? host->tags : "");
+        (host->tags) ? host->tags : "",
+        (instance->labels) ? buffer_tostring(instance->labels) : "");
 
     return 0;
 }
@@ -193,6 +247,42 @@ static inline void opentsdb_build_message(BUFFER *buffer, char *message, const c
 }
 
 /**
+ * Format host labels for OpenTSDB HTTP connector
+ *
+ * @param instance an instance data structure.
+ * @param host a data collecting host.
+ * @return Always returns 0.
+ */
+int format_host_labels_opentsdb_http(struct instance *instance, RRDHOST *host)
+{
+    if (!instance->labels)
+        instance->labels = buffer_create(1024);
+
+    if (unlikely(!sending_labels_configured(instance)))
+        return 0;
+
+    netdata_rwlock_rdlock(&host->labels_rwlock);
+    for (struct label *label = host->labels; label; label = label->next) {
+        if (!should_send_label(instance, label))
+            continue;
+
+        char escaped_value[CONFIG_MAX_VALUE * 2 + 1];
+        sanitize_json_string(escaped_value, label->value, CONFIG_MAX_VALUE);
+
+        char value[CONFIG_MAX_VALUE + 1];
+        sanitize_opentsdb_label_value(value, escaped_value, CONFIG_MAX_VALUE);
+
+        if (*value) {
+            buffer_strcat(instance->labels, ",");
+            buffer_sprintf(instance->labels, "\"%s\":\"%s\"", label->key, value);
+        }
+    }
+    netdata_rwlock_unlock(&host->labels_rwlock);
+
+    return 0;
+}
+
+/**
  * Format dimension using collected data for OpenTSDB HTTP connector
  *
  * @param instance an instance data structure.
@@ -226,7 +316,7 @@ int format_dimension_collected_opentsdb_http(struct instance *instance, RRDDIM *
         "  \"timestamp\": %llu,"
         "  \"value\": " COLLECTED_NUMBER_FORMAT ","
         "  \"tags\": {"
-        "    \"host\": \"%s%s%s\""
+        "    \"host\": \"%s%s%s\"%s"
         "  }"
         "}",
         engine->config.prefix,
@@ -236,7 +326,8 @@ int format_dimension_collected_opentsdb_http(struct instance *instance, RRDDIM *
         rd->last_collected_value,
         engine->config.hostname,
         (host->tags) ? " " : "",
-        (host->tags) ? host->tags : "");
+        (host->tags) ? host->tags : "",
+        instance->labels ? buffer_tostring(instance->labels) : "");
 
     if (length > 0) {
         opentsdb_build_message(instance->buffer, message, engine->config.hostname, length);
@@ -285,7 +376,7 @@ int format_dimension_stored_opentsdb_http(struct instance *instance, RRDDIM *rd)
         "  \"timestamp\": %llu,"
         "  \"value\": " CALCULATED_NUMBER_FORMAT ","
         "  \"tags\": {"
-        "    \"host\": \"%s%s%s\""
+        "    \"host\": \"%s%s%s\"%s"
         "  }"
         "}",
         engine->config.prefix,
@@ -295,7 +386,8 @@ int format_dimension_stored_opentsdb_http(struct instance *instance, RRDDIM *rd)
         value,
         engine->config.hostname,
         (host->tags) ? " " : "",
-        (host->tags) ? host->tags : "");
+        (host->tags) ? host->tags : "",
+        instance->labels ? buffer_tostring(instance->labels) : "");
 
     if (length > 0) {
         opentsdb_build_message(instance->buffer, message, engine->config.hostname, length);
diff --git a/exporting/opentsdb/opentsdb.h b/exporting/opentsdb/opentsdb.h
index 929f49b1bb..df99356e92 100644
--- a/exporting/opentsdb/opentsdb.h
+++ b/exporting/opentsdb/opentsdb.h
@@ -9,6 +9,10 @@ int init_opentsdb_connector(struct connector *connector);
 int init_opentsdb_telnet_instance(struct instance *instance);
 int init_opentsdb_http_instance(struct instance *instance);
 
+void sanitize_opentsdb_label_value(char *dst, char *src, size_t len);
+int format_host_labels_opentsdb_telnet(struct instance *instance, RRDHOST *host);
+int format_host_labels_opentsdb_http(struct instance *instance, RRDHOST *host);
+
 int format_dimension_collected_opentsdb_telnet(struct instance *instance, RRDDIM *rd);
 int format_dimension_stored_opentsdb_telnet(struct instance *instance, RRDDIM *rd);
 
diff --git a/exporting/process_data.c b/exporting/process_data.c
index 07b9f59560..f38231f6ca 100644
--- a/exporting/process_data.c
+++ b/exporting/process_data.c
@@ -389,6 +389,23 @@ int prepare_buffers(struct engine *engine)
 }
 
 /**
+ * Flush a buffer with host labels
+ *
+ * @param instance an instance data structure.
+ * @param host a data collecting host.
+ * @return Always returns 0.
+ */
+int flush_host_labels(struct instance *instance, RRDHOST *host)
+{
+    (void)host;
+
+    if (instance->labels)
+        buffer_flush(instance->labels);
+
+    return 0;
+}
+
+/**
  * Notify workers
  *
  * Notify exporting connector instance working threads that data is ready to send.
diff --git a/exporting/read_config.c b/exporting/read_config.c
index 84c7828f93..5675187d21 100644
--- a/exporting/read_config.c
+++ b/exporting/read_config.c
@@ -318,6 +318,18 @@ struct engine *read_exporting_config()
 
                 tmp_instance->config.options = exporting_parse_data_source(data_source, tmp_instance->config.options);
 
+                if (exporter_get_boolean(
+                        instance_name, EXPORTER_SEND_CONFIGURED_LABELS, EXPORTER_SEND_CONFIGURED_LABELS_DEFAULT))
+                    tmp_instance->config.options |= EXPORTING_OPTION_SEND_CONFIGURED_LABELS;
+                else
+                    tmp_instance->config.options &= ~EXPORTING_OPTION_SEND_CONFIGURED_LABELS;
+
+                if (exporter_get_boolean(
+                        instance_name, EXPORTER_SEND_AUTOMATIC_LABELS, EXPORTER_SEND_AUTOMATIC_LABELS_DEFAULT))
+                    tmp_instance->config.options |= EXPORTING_OPTION_SEND_AUTOMATIC_LABELS;
+                else
+                    tmp_instance->config.options &= ~EXPORTING_OPTION_SEND_AUTOMATIC_LABELS;
+
                 if (exporter_get_boolean(instance_name, EXPORTER_SEND_NAMES, EXPORTER_SEND_NAMES_DEFAULT))
                     tmp_instance->config.options |= EXPORTING_OPTION_SEND_NAMES;
                 else
diff --git a/exporting/tests/exporting_fixtures.c b/exporting/tests/exporting_fixtures.c
index 9668e5ab2d..f92575e337 100644
--- a/exporting/tests/exporting_fixtures.c
+++ b/exporting/tests/exporting_fixtures.c
@@ -39,6 +39,18 @@ int setup_rrdhost()
 
     localhost->tags = strdupz("TAG1=VALUE1 TAG2=VALUE2");
 
+    struct label *label = calloc(1, sizeof(struct label));
+    label->key = strdupz("key1");
+    label->value = strdupz("value1");
+    label->label_source = LABEL_SOURCE_NETDATA_CONF;
+    localhost->labels = label;
+
+    label = calloc(1, sizeof(struct label));
+    label->key = strdupz("key2");
+    label->value = strdupz("value2");
+    label->label_source = LABEL_SOURCE_AUTO;
+    localhost->labels->next = label;
+
     localhost->rrdset_root = calloc(1, sizeof(RRDSET));
     RRDSET *st = localhost->rrdset_root;
     st->rrdhost = localhost;
@@ -80,6 +92,13 @@ int teardown_rrdhost()
     free((void *)st->name);
     free(st);
 
+    free(localhost->labels->next->key);
+    free(localhost->labels->next->value);
+    free(localhost->labels->next);
+    free(localhost->labels->key);
+    free(localhost->labels->value);
+    free(localhost->labels);
+
     free((void *)localhost->tags);
     free(localhost);
 
@@ -103,6 +122,7 @@ int teardown_initialized_engine(void **state)
     struct engine *engine = *state;
 
     teardown_rrdhost();
+    buffer_free(engine->connector_root->instance_root->labels);
     buffer_free(engine->connector_root->instance_root->buffer);
     teardown_configured_engine(state);
 
diff --git a/exporting/tests/test_exporting_engine.c b/exporting/tests/test_exporting_engine.c
index 95e1a3707f..7ba517a495 100644
--- a/exporting/tests/test_exporting_engine.c
+++ b/exporting/tests/test_exporting_engine.c
@@ -61,7 +61,9 @@ static void test_exporting_engine(void **state)
     expect_memory(__wrap_send_internal_metrics, engine, engine, sizeof(struct engine));
     will_return(__wrap_send_internal_metrics, 0);
 
-    void *ptr = malloc(sizeof(int));
+    expect_function_call(__wrap_info_int);
+
+    void *ptr = malloc(sizeof(struct netdata_static_thread));
     assert_ptr_equal(exporting_main(ptr), NULL);
     assert_int_equal(engine->now, 2);
     free(ptr);
@@ -118,11 +120,11 @@ static void test_init_connectors(void **state)
     assert_ptr_equal(instance->next, NULL);
     assert_int_equal(instance->index, 0);
     assert_ptr_equal(instance->start_batch_formatting, NULL);
-    assert_ptr_equal(instance->start_host_formatting, NULL);
+    assert_ptr_equal(instance->start_host_formatting, format_host_labels_graphite_plaintext);
     assert_ptr_equal(instance->start_chart_formatting, NULL);
     assert_ptr_equal(instance->metric_formatting, format_dimension_collected_graphite_plaintext);
     assert_ptr_equal(instance->end_chart_formatting, NULL);
-    assert_ptr_equal(instance->end_host_formatting, NULL);
+    assert_ptr_equal(instance->end_host_formatting, flush_host_labels);
     assert_ptr_equal(instance->end_batch_formatting, NULL);
 
     BUFFER *buffer = instance->buffer;
@@ -460,8 +462,8 @@ static void test_format_dimension_collected_json_plaintext(void **state)
         buffer_tostring(engine->connector_root->instance_root->buffer),
         "{\"prefix\":\"netdata\",\"hostname\":\"test-host\",\"host_tags\":\"TAG1=VALUE1 TAG2=VALUE2\","
         "\"chart_id\":\"chart_id\",\"chart_name\":\"chart_name\",\"chart_family\":\"(null)\","
-        "\"chart_context\": \"(null)\",\"chart_type\":\"(null)\",\"units\": \"(null)\",\"id\":\"dimension_id\","
-        "\"name\":\"dimension_name\",\"value\":123000321,\"timestamp\": 15051}\n");
+        "\"chart_context\":\"(null)\",\"chart_type\":\"(null)\",\"units\":\"(null)\",\"id\":\"dimension_id\","
+        "\"name\":\"dimension_name\",\"value\":123000321,\"timestamp\":15051}\n");
 }
 
 static void test_format_dimension_stored_json_plaintext(void **state)
@@ -678,6 +680,103 @@ static void test_simple_connector_worker(void **state)
     simple_connector_worker(instance);
 }
 
+static void test_sanitize_json_string(void **state)
+{
+    (void)state;
+
+    char *src = "check \t\\\" string";
+    char dst[19 + 1];
+
+    sanitize_json_string(dst, src, 19);
+
+    assert_string_equal(dst, "check _\\\\\\\" string");
+}
+
+static void test_sanitize_graphite_label_value(void **state)
+{
+    (void)state;
+
+    char *src = "check ;~ string";
+    char dst[15 + 1];
+
+    sanitize_graphite_label_value(dst, src, 15);
+
+    assert_string_equal(dst, "check____string");
+}
+
+static void test_sanitize_opentsdb_label_value(void **state)
+{
+    (void)state;
+
+    char *src = "check \t\\\" #&$? -_./ string";
+    char dst[26 + 1];
+
+    sanitize_opentsdb_label_value(dst, src, 26);
+
+    assert_string_equal(dst, "check__________-_./_string");
+}
+
+static void test_format_host_labels_json_plaintext(void **state)
+{
+    struct engine *engine = *state;
+    struct instance *instance = engine->connector_root->instance_root;
+
+    instance->config.options |= EXPORTING_OPTION_SEND_CONFIGURED_LABELS;
+    instance->config.options |= EXPORTING_OPTION_SEND_AUTOMATIC_LABELS;
+
+    assert_int_equal(format_host_labels_json_plaintext(instance, localhost), 0);
+    assert_string_equal(buffer_tostring(instance->labels), "\"labels\":{\"key1\":\"value1\",\"key2\":\"value2\"},");
+}
+
+static void test_format_host_labels_graphite_plaintext(void **state)
+{
+    struct engine *engine = *state;
+    struct instance *instance = engine->connector_root->instance_root;
+
+    instance->config.options |= EXPORTING_OPTION_SEND_CONFIGURED_LABELS;
+    instance->config.options |= EXPOR