Implement the main flow for the Exporting Engine (#7149)

* Add top level tests

* Add a skeleton for preparing buffers

* Initialize graphite instance

* Prepare buffers for all instances

* Add Grafite collected value formatter

* Add support for exporting.conf read and parsing

* - Use new exporting_config instead of netdata_config

* Implement Grafite worker

* Disable exporting engine compilation if libuv is not available

* Add mutex locks

- Configure connectors as connector_<type> in sections of exporting.conf

- Change exporting_select_type to check for connector_ fields

* - Override exporting_config structure if there no exporting.conf so that
  look ups don't fail and we maintain backwards compatibility

* Separate fixtures in unit tests

* Test exporting_discard_responce

* Test response receiving

* Test buffer sending

* Test simple connector worker

- Instance section has the format connector:instance_name
  e.g graphite:my_graphite_instance

- Connectors with : in their name e.g graphite:plaintext are reserved
  So graphite:plaintext is not accepted because it would activate an
  instance with name "plaintext"
  It should be graphite:plaintext:instance_name

* - Enable the add_connector_instance to cleanup the internal structure
  by passing NULL,not NULL arguments

* Implement configurable update interval

- Add additional check to verify instance uniqueness across connectors

* Add host and chart filters

* Add the value calculation over a database series

* Add the calculated over stored data graphite connector

* Add tests for graphite connector

* Add JSON connector

* Add tests for JSON formatting functions

* Add OpenTSDB connector

* Add tests for the OpenTSDB connector

* Add temporaty notes to the documentation

1 files changed, 20 insertions, 0 deletions

diff --git a/configure.ac b/configure.ac
index 4ae08bffc9..6fcb3baeba 100644
--- a/configure.ac
+++ b/configure.ac
@@ -36,6 +36,7 @@ m4_ifdef([AM_SILENT_RULES], [
     ])
 AC_CANONICAL_HOST
 AC_PROG_CC
+AC_PROG_CC_C99
 AM_PROG_CC_C_O
 AC_PROG_CXX
 AC_PROG_INSTALL
@@ -408,6 +409,20 @@ AC_MSG_RESULT([${enable_https}])
 AM_CONDITIONAL([ENABLE_HTTPS], [test "${enable_https}" = "yes"])
 
 # -----------------------------------------------------------------------------
+# Exporting engine
+AC_MSG_CHECKING([if netdata exporting engine should be used])
+if test "${UV_LIBS}"; then
+    enable_exporting_engine="yes"
+    AC_DEFINE([ENABLE_EXPORTING], [1], [netdata exporting engine usability])
+    OPTIONAL_UV_CFLAGS="${UV_CFLAGS}"
+    OPTIONAL_UV_LIBS="${UV_LIBS}"
+else
+    enable_exporting_engine="no"
+fi
+AC_MSG_RESULT([${enable_exporting_engine}])
+AM_CONDITIONAL([ENABLE_EXPORTING], [test "${enable_exporting_engine}" = "yes"])
+
+# -----------------------------------------------------------------------------
 # JSON-C
 test "${enable_jsonc}" = "yes" -a -z "${JSONC_LIBS}" && \
     AC_MSG_ERROR([JSON-C required but not found. Try installing 'libjson-c-dev' or 'json-c'.])
@@ -1209,6 +1224,11 @@ AC_CONFIG_FILES([
     database/Makefile
     database/engine/Makefile
     diagrams/Makefile
+    exporting/Makefile
+    exporting/graphite/Makefile
+    exporting/json/Makefile
+    exporting/opentsdb/Makefile
+    exporting/tests/Makefile
     health/Makefile
     health/notifications/Makefile
     libnetdata/Makefile