header_rewrite: count operators and conditions run

plugins/header_rewrite/condition.h

@@ -49,6 +49,10 @@ class Condition : public Statement
   bool
   do_eval(const Resources &res)
   {
+    // In do_eval, so AND/OR short-circuited conditions aren't counted.
+    if (TS_ERROR != hrw_stat_conditions) {
+      TSStatIntIncrement(hrw_stat_conditions, 1);
+    }
     bool rt = eval(res);
 
     if (has_modifier(_mods, CondModifiers::NOT)) {

plugins/header_rewrite/header_rewrite.cc

@@ -569,6 +569,8 @@ TSPluginInit(int argc, const char *argv[])
     return;
   }
 
+  init_hrw_work_stats();
+
   std::string geoDBpath;
   int         inboundIpSource = 0;
   int         timezone        = 0;
@@ -663,6 +665,8 @@ TSRemapInit(TSRemapInterface *api_info, char *errbuf, int errbuf_size)
   CHECK_REMAP_API_COMPATIBILITY(api_info, errbuf, errbuf_size);
   Dbg(pi_dbg_ctl, "Remap plugin is successfully initialized");
 
+  init_hrw_work_stats();
+
   return TS_SUCCESS;
 }
 

plugins/header_rewrite/operator.h

@@ -78,6 +78,9 @@ class Operator : public Statement
   unsigned
   do_exec(const Resources &res) const
   {
+    if (TS_ERROR != hrw_stat_operators) {
+      TSStatIntIncrement(hrw_stat_operators, 1);
+    }
     unsigned no_reenable{exec(res) ? 0U : 1U};
     if (nullptr != _next) {
       no_reenable += static_cast<Operator *>(_next)->do_exec(res);

plugins/header_rewrite/statement.cc

@@ -21,6 +21,24 @@
 //
 #include "statement.h"
 
+int hrw_stat_operators  = TS_ERROR;
+int hrw_stat_conditions = TS_ERROR;
+
+void
+init_hrw_work_stats()
+{
+  // Plugin init is single-threaded, so the create-once guard is safe. header_rewrite.so can
+  // be loaded both globally and as a remap plugin; both must share one process-wide stat.
+  if (TS_ERROR == hrw_stat_operators) {
+    hrw_stat_operators = TSStatCreate("proxy.process.plugin.header_rewrite.operators", TS_RECORDDATATYPE_INT,
+                                      TS_STAT_NON_PERSISTENT, TS_STAT_SYNC_COUNT);
+  }
+  if (TS_ERROR == hrw_stat_conditions) {
+    hrw_stat_conditions = TSStatCreate("proxy.process.plugin.header_rewrite.conditions", TS_RECORDDATATYPE_INT,
+                                       TS_STAT_NON_PERSISTENT, TS_STAT_SYNC_COUNT);
+  }
+}
+
 void
 Statement::append(Statement *stmt)
 {

plugins/header_rewrite/statement.h

@@ -32,6 +32,13 @@
 #include "parser.h"
 #include "lulu.h"
 
+// Counters for the number of header_rewrite operators executed and conditions evaluated; the
+// bare hook invocation count cannot tell a small ruleset from a large one. Created once via
+// init_hrw_work_stats(); both are TS_ERROR until then, so increments are guarded.
+extern int hrw_stat_operators;
+extern int hrw_stat_conditions;
+void       init_hrw_work_stats();
+
 namespace header_rewrite_ns
 {
 constexpr int NUM_STATE_FLAGS = 16;

tests/gold_tests/autest-site/ats_replay.test.ext

@@ -323,14 +323,28 @@ def ATSReplayTest(obj, replay_file: str):
 
         for check in metric_checks:
             metric_name = check['metric']
-            expected_value = check['value']
-            check_tr = obj.AddTestRun(f'Verify {metric_name} == {expected_value}')
-            check_tr.Processes.Default.Command = f'traffic_ctl metric get {metric_name}'
-            check_tr.Processes.Default.Env = ts.Env
-            check_tr.Processes.Default.ReturnCode = 0
-            check_tr.Processes.Default.Streams.All = Testers.ContainsExpression(
-                f'^{re.escape(metric_name)}\\s+{expected_value}$', f'{metric_name} should be {expected_value}')
-            check_tr.StillRunningAfter = ts
+            if 'value' in check:
+                expected_value = check['value']
+                check_tr = obj.AddTestRun(f'Verify {metric_name} == {expected_value}')
+                check_tr.Processes.Default.Command = f'traffic_ctl metric get {metric_name}'
+                check_tr.Processes.Default.Env = ts.Env
+                check_tr.Processes.Default.ReturnCode = 0
+                check_tr.Processes.Default.Streams.All = Testers.ContainsExpression(
+                    f'^{re.escape(metric_name)}\\s+{expected_value}$', f'{metric_name} should be {expected_value}')
+                check_tr.StillRunningAfter = ts
+            elif 'min' in check:
+                minimum = check['min']
+                check_tr = obj.AddTestRun(f'Verify {metric_name} >= {minimum}')
+                # Fail if the metric value (field 2) is below the minimum, or absent.
+                # $$ escapes the awk field ref from autest's command templating.
+                check_tr.Processes.Default.Command = (
+                    f"traffic_ctl metric get {metric_name} | "
+                    f"awk 'BEGIN {{ rc = 1 }} {{ if ($$2 + 0 >= {minimum}) rc = 0 }} END {{ exit rc }}'")
+                check_tr.Processes.Default.Env = ts.Env
+                check_tr.Processes.Default.ReturnCode = 0
+                check_tr.StillRunningAfter = ts
+            else:
+                raise ValueError(f"metric_checks entry for '{metric_name}' must specify 'value' or 'min'")
 
     # wait for error log
     if log_validation and log_validation.get('error_log'):

tests/gold_tests/pluginTest/header_rewrite/header_rewrite_bundle.replay.yaml

@@ -176,6 +176,12 @@ autest:
             args:
               - "rules/rule_session_vars.conf"
 
+    metric_checks:
+      - metric: "proxy.process.plugin.header_rewrite.operators"
+        min: 1
+      - metric: "proxy.process.plugin.header_rewrite.conditions"
+        min: 1
+
     log_validation:
       traffic_out:
         excludes: