lua: Added new executions counter to the Lua filter to track script execution count.

Signed-off-by: Anirban Nandi <[email protected]>

Author: AnirbanNandi

changelogs/current.yaml

@@ -158,5 +158,8 @@ new_features:
     Added QUIC protocol option :ref:`max_sessions_per_event_loop
     <envoy_v3_api_field_config.listener.v3.QuicProtocolOptions.max_sessions_per_event_loop>` to limit the maximum
     number of new QUIC sessions created per event loop. The default is 16, preserving the previous hardcoded limit.
+- area: lua
+  change: |
+    Added new executions counter to the Lua filter to track script execution count.
 
 deprecated:

docs/root/configuration/http/http_filters/lua_filter.rst

@@ -137,7 +137,8 @@ individual filter instance/script can be tracked by providing a per-filter
   :header: Name, Type, Description
   :widths: 1, 1, 2
 
-  error, Counter, Total script execution errors.
+  errors, Counter, Total script execution errors.
+  executions, Counter, Total number of times ``envoy_on_request`` and ``envoy_on_response`` was executed.
 
 Script examples
 ---------------

source/extensions/filters/http/lua/lua_filter.cc

@@ -891,6 +891,10 @@ Filter::doHeaders(StreamHandleRef& handle, Filters::Common::Lua::CoroutinePtr& c
 
   Http::FilterHeadersStatus status = Http::FilterHeadersStatus::Continue;
   TRY_NEEDS_AUDIT {
+    // The counter will increment twice if the supplied script has both request and response
+    // handles. This is intentionally kept so as to provide consistency with the way the 'errors'
+    // counter is incremented.
+    stats_.executions_.inc();
     status = handle.get()->start(function_ref);
     handle.markDead();
   }

source/extensions/filters/http/lua/lua_filter.h

@@ -20,7 +20,7 @@ namespace Lua {
 /**
  * All lua stats. @see stats_macros.h
  */
-#define ALL_LUA_FILTER_STATS(COUNTER) COUNTER(errors)
+#define ALL_LUA_FILTER_STATS(COUNTER) COUNTER(errors) COUNTER(executions)
 
 /**
  * Struct definition for all Lua stats. @see stats_macros.h