Exporting/send variables (#13221)

4 files changed, 94 insertions, 9 deletions

diff --git a/exporting/prometheus/remote_write/remote_write.c b/exporting/prometheus/remote_write/remote_write.c
index f6abaab36c..22b5c1d492 100644
--- a/exporting/prometheus/remote_write/remote_write.c
+++ b/exporting/prometheus/remote_write/remote_write.c
@@ -97,6 +97,7 @@ int init_prometheus_remote_write_instance(struct instance *instance)
     instance->start_chart_formatting = format_chart_prometheus_remote_write;
     instance->metric_formatting = format_dimension_prometheus_remote_write;
     instance->end_chart_formatting = NULL;
+    instance->variables_formatting = format_variables_prometheus_remote_write;
     instance->end_host_formatting = NULL;
     instance->end_batch_formatting = format_batch_prometheus_remote_write;
 
@@ -134,14 +135,6 @@ int init_prometheus_remote_write_instance(struct instance *instance)
     return 0;
 }
 
-/**
- * Format host data for Prometheus Remote Write connector
- *
- * @param instance an instance data structure.
- * @param host a data collecting host.
- * @return Always returns 0.
- */
-
 struct format_remote_write_label_callback {
     struct instance *instance;
     void *write_request;
@@ -161,6 +154,13 @@ static int format_remote_write_label_callback(const char *name, const char *valu
     return 1;
 }
 
+/**
+ * Format host data for Prometheus Remote Write connector
+ *
+ * @param instance an instance data structure.
+ * @param host a data collecting host.
+ * @return Always returns 0.
+ */
 int format_host_prometheus_remote_write(struct instance *instance, RRDHOST *host)
 {
     struct simple_connector_data *simple_connector_data =
@@ -177,7 +177,7 @@ int format_host_prometheus_remote_write(struct instance *instance, RRDHOST *host
     add_host_info(
         connector_specific_data->write_request,
         "netdata_info", hostname, host->program_name, host->program_version, now_realtime_usec() / USEC_PER_MS);
-
+    
     if (unlikely(sending_labels_configured(instance))) {
         struct format_remote_write_label_callback tmp = {
             .write_request = connector_specific_data->write_request,
@@ -321,6 +321,49 @@ int format_dimension_prometheus_remote_write(struct instance *instance, RRDDIM *
     return 0;
 }
 
+int format_variable_prometheus_remote_write_callback(RRDVAR *rv, void *data) {
+    struct prometheus_remote_write_variables_callback_options *opts = data;
+
+    if (rv->options & (RRDVAR_OPTION_CUSTOM_HOST_VAR | RRDVAR_OPTION_CUSTOM_CHART_VAR)) {        
+        RRDHOST *host = opts->host;
+        struct instance *instance = opts->instance;
+        struct simple_connector_data *simple_connector_data =
+            (struct simple_connector_data *)instance->connector_specific_data;
+        struct prometheus_remote_write_specific_data *connector_specific_data =
+            (struct prometheus_remote_write_specific_data *)simple_connector_data->connector_specific_data;
+
+        char name[PROMETHEUS_LABELS_MAX + 1];
+        char *suffix = "";
+
+        prometheus_name_copy(context, rv->name, PROMETHEUS_ELEMENT_MAX);
+        snprintf(name, PROMETHEUS_LABELS_MAX, "%s_%s%s", instance->config.prefix, context, suffix);
+
+        NETDATA_DOUBLE value = rrdvar2number(rv);
+        add_variable(connector_specific_data->write_request, name,
+            (host == localhost) ? instance->config.hostname : host->hostname, value, opts->now / USEC_PER_MS);
+    }
+
+    return 0;
+}
+
+/**
+ * Format a variable for Prometheus Remote Write connector
+ * 
+ * @param rv a variable.
+ * @param instance an instance data structure.
+ * @return Always returns 0.
+ */ 
+int format_variables_prometheus_remote_write(struct instance *instance, RRDHOST *host)
+{
+    struct prometheus_remote_write_variables_callback_options opt = {
+        .host = host,
+        .instance = instance,
+        .now = now_realtime_usec(),
+    };
+
+    return foreach_host_variable_callback(host, format_variable_prometheus_remote_write_callback, &opt);
+}
+
 /**
  * Format a batch for Prometheus Remote Write connector
  *
diff --git a/exporting/prometheus/remote_write/remote_write.h b/exporting/prometheus/remote_write/remote_write.h
index d738f5126f..4740772d06 100644
--- a/exporting/prometheus/remote_write/remote_write.h
+++ b/exporting/prometheus/remote_write/remote_write.h
@@ -11,12 +11,19 @@ struct prometheus_remote_write_specific_data {
     void *write_request;
 };
 
+struct prometheus_remote_write_variables_callback_options {
+    RRDHOST *host;
+    time_t now;
+    struct instance *instance;
+};
+
 int init_prometheus_remote_write_instance(struct instance *instance);
 extern void clean_prometheus_remote_write(struct instance *instance);
 
 int format_host_prometheus_remote_write(struct instance *instance, RRDHOST *host);
 int format_chart_prometheus_remote_write(struct instance *instance, RRDSET *st);
 int format_dimension_prometheus_remote_write(struct instance *instance, RRDDIM *rd);
+int format_variables_prometheus_remote_write(struct instance *instance, RRDHOST *host);
 int format_batch_prometheus_remote_write(struct instance *instance);
 
 void prometheus_remote_write_prepare_header(struct instance *instance);
diff --git a/exporting/prometheus/remote_write/remote_write_request.cc b/exporting/prometheus/remote_write/remote_write_request.cc
index cfd61271e6..ecfa11fa8a 100644
--- a/exporting/prometheus/remote_write/remote_write_request.cc
+++ b/exporting/prometheus/remote_write/remote_write_request.cc
@@ -138,6 +138,38 @@ void add_metric(
 }
 
 /**
+ * Adds a metric to a write request
+ *
+ * @param write_request_p the write request
+ * @param name the name of the metric
+ * @param instance the name of the host, the metric belongs to
+ * @param value the value of the metric
+ * @param timestamp the timestamp for the metric in milliseconds
+ */
+void add_variable(
+    void *write_request_p, const char *name, const char *instance, const double value, const int64_t timestamp)
+{
+    WriteRequest *write_request = (WriteRequest *)write_request_p;
+    TimeSeries *timeseries;
+    Sample *sample;
+    Label *label;
+
+    timeseries = write_request->add_timeseries();
+
+    label = timeseries->add_labels();
+    label->set_name("__name__");
+    label->set_value(name);
+
+    label = timeseries->add_labels();
+    label->set_name("instance");
+    label->set_value(instance);
+
+    sample = timeseries->add_samples();
+    sample->set_value(value);
+    sample->set_timestamp(timestamp);
+}
+
+/**
  * Gets the size of a write request
  *
  * @param write_request_p the write request
diff --git a/exporting/prometheus/remote_write/remote_write_request.h b/exporting/prometheus/remote_write/remote_write_request.h
index 5f242b9418..b253701336 100644
--- a/exporting/prometheus/remote_write/remote_write_request.h
+++ b/exporting/prometheus/remote_write/remote_write_request.h
@@ -20,6 +20,9 @@ void add_metric(
     const char *name, const char *chart, const char *family, const char *dimension,
     const char *instance, const double value, const int64_t timestamp);
 
+void add_variable(
+    void *write_request_p, const char *name, const char *instance, const double value, const int64_t timestamp);
+
 size_t get_write_request_size(void *write_request_p);
 
 int pack_and_clear_write_request(void *write_request_p, char *buffer, size_t *size);