Prometheus web api connector (#8540)

* Fix the Prometheus web API code in the exporting engine

* Rename connector types

* Remove the conditional compilation of the exporting engine

* Use labels instead of tags

* Fix the exporter configuration

* Document functions

* Add unit tests

1 files changed, 20 insertions, 4 deletions

diff --git a/exporting/exporting_engine.h b/exporting/exporting_engine.h
index 1a3a3ecd09..8a46dd5d3d 100644
--- a/exporting/exporting_engine.h
+++ b/exporting/exporting_engine.h
@@ -14,10 +14,10 @@
 extern struct config exporting_config;
 
 #define EXPORTING_UPDATE_EVERY_OPTION_NAME "update every"
-#define EXPORTING_UPDATE_EVERY_DEFAULT     10
+#define EXPORTING_UPDATE_EVERY_DEFAULT 10
 
 typedef enum exporting_options {
-    EXPORTING_OPTION_NONE                   = 0,
+    EXPORTING_OPTION_NON                    = 0,
 
     EXPORTING_SOURCE_DATA_AS_COLLECTED      = (1 << 0),
     EXPORTING_SOURCE_DATA_AVERAGE           = (1 << 1),
@@ -42,10 +42,22 @@ typedef enum exporting_options {
      (instance->config.options & EXPORTING_OPTION_SEND_AUTOMATIC_LABELS &&                                             \
       label->label_source != LABEL_SOURCE_NETDATA_CONF))
 
+typedef enum exporting_connector_types {
+    EXPORTING_CONNECTOR_TYPE_UNKNOWN,                 // Invalid type
+    EXPORTING_CONNECTOR_TYPE_GRAPHITE,                // Send plain text to Graphite
+    EXPORTING_CONNECTOR_TYPE_OPENTSDB_USING_TELNET,   // Send data to OpenTSDB using telnet API
+    EXPORTING_CONNECTOR_TYPE_OPENTSDB_USING_HTTP,     // Send data to OpenTSDB using HTTP API
+    EXPORTING_CONNECTOR_TYPE_JSON,                    // Stores the data using JSON.
+    EXPORTING_CONNECTOR_TYPE_PROMETHEUS_REMOTE_WRITE, // The user selected to use Prometheus backend
+    EXPORTING_CONNECTOR_TYPE_KINESIS,                 // Send message to AWS Kinesis
+    EXPORTING_CONNECTOR_TYPE_MONGODB,                 // Send data to MongoDB collection
+    EXPORTING_CONNECTOR_TYPE_NUM                      // Number of backend types
+} EXPORTING_CONNECTOR_TYPE;
+
 struct engine;
 
 struct instance_config {
-    BACKEND_TYPE type;
+    EXPORTING_CONNECTOR_TYPE type;
 
     const char *name;
     const char *destination;
@@ -150,10 +162,12 @@ struct engine {
     struct instance *instance_root;
 };
 
+extern struct instance *prometheus_exporter_instance;
+
 void *exporting_main(void *ptr);
 
 struct engine *read_exporting_config();
-BACKEND_TYPE exporting_select_type(const char *type);
+EXPORTING_CONNECTOR_TYPE exporting_select_type(const char *type);
 
 int init_connectors(struct engine *engine);
 
@@ -187,4 +201,6 @@ void simple_connector_worker(void *instance_p);
 
 int send_internal_metrics(struct engine *engine);
 
+#include "exporting/prometheus/prometheus.h"
+
 #endif /* NETDATA_EXPORTING_ENGINE_H */