cache_ban: Add obj.last_hit

bin/varnishd/cache/cache_ban.c

@@ -498,7 +498,7 @@ ban_evaluate(struct worker *wrk, const uint8_t *bsarg, struct objcore *oc,
 	int rv;
 
 	/*
-	 * for ttl and age, fix the point in time such that banning refers to
+	 * for ttl, age and lru, fix the point in time such that banning refers to
 	 * the same point in time when the ban is evaluated
 	 *
 	 * for grace/keep, we assume that the absolute values are pola and that
@@ -546,6 +546,12 @@ ban_evaluate(struct worker *wrk, const uint8_t *bsarg, struct objcore *oc,
 			darg1 = oc->keep;
 			darg2 = bt.arg2_double;
 			break;
+		case BANS_ARG_OBJLASTHIT:
+			if (isnan(oc->last_lru))
+				return (0);
+			darg1 = 0.0 - oc->last_lru;
+			darg2 = 0.0 - (ban_time(bsarg) - bt.arg2_double);
+			break;
 		default:
 			WRONG("Wrong BAN_ARG code");
 		}

bin/varnishd/cache/cache_ban.h

@@ -97,7 +97,8 @@
 #define BANS_ARG_OBJAGE		0x1d
 #define BANS_ARG_OBJGRACE	0x1e
 #define BANS_ARG_OBJKEEP	0x1f
-#define BANS_ARG_LIM		(BANS_ARG_OBJKEEP + 1)
+#define BANS_ARG_OBJLASTHIT	0x20
+#define BANS_ARG_LIM		(BANS_ARG_OBJLASTHIT + 1)
 
 #define BAN_ARGIDX(x) ((x) - BANS_ARG_OFF_)
 #define BAN_ARGARRSZ  (BANS_ARG_LIM - BANS_ARG_OFF_)
@@ -116,7 +117,7 @@
 // has an arg2_double (BANS_FLAG_DURATION at build time)
 #define BANS_HAS_ARG2_DOUBLE(arg)	\
 	((arg) >= BANS_ARG_OBJTTL &&	\
-	 (arg) <= BANS_ARG_OBJKEEP)
+	 (arg) <= BANS_ARG_OBJLASTHIT)
 
 /*--------------------------------------------------------------------*/
 

bin/varnishtest/tests/c00059.vtc

@@ -3,6 +3,9 @@ varnishtest "test ban obj.* except obj.http.*"
 # see c00021.vtc for obj.http.* tests
 
 server s1 {
+	rxreq
+	expect req.url == "/old"
+	txresp -status 204
 	rxreq
 	txresp -bodylen 1
 	rxreq
@@ -15,11 +18,25 @@ server s1 {
 	txresp -bodylen 5
 	rxreq
 	txresp -bodylen 6
+	rxreq
+	txresp -bodylen 7
 } -start
 
-varnish v1 -vcl+backend {} -start
+varnish v1 -vcl+backend {
+	sub vcl_deliver {
+		set resp.http.hits = obj.hits;
+	}
+} -start
 
 client c1 {
+	txreq -url "/old"
+	rxresp
+	expect resp.status == 204
+
+	txreq -url "/old"
+	rxresp
+	expect resp.status == 204
+
 	txreq
 	rxresp
 	expect resp.bodylen == 1
@@ -55,7 +72,7 @@ client c1 {
 	expect resp.bodylen == 2
 } -run
 
-varnish v1 -cliok "ban obj.ttl <= 2m"
+varnish v1 -cliok "ban obj.status == 200 && obj.ttl <= 2m"
 
 client c1 {
 	txreq
@@ -75,7 +92,7 @@ client c1 {
 	expect resp.bodylen == 3
 } -run
 
-varnish v1 -cliok "ban obj.age < 1m"
+varnish v1 -cliok "ban obj.status == 200 && obj.age < 1m"
 
 client c1 {
 	txreq
@@ -95,7 +112,7 @@ client c1 {
 	expect resp.bodylen == 4
 } -run
 
-varnish v1 -cliok "ban obj.grace == 10s"
+varnish v1 -cliok "ban obj.status == 200 && obj.grace == 10s"
 
 client c1 {
 	txreq
@@ -115,12 +132,37 @@ client c1 {
 	expect resp.bodylen == 5
 } -run
 
-varnish v1 -cliok "ban obj.keep == 0s"
+varnish v1 -cli "param.set ban_lurker_age 0.1"
+varnish v1 -cliok "ban obj.status == 200 && obj.keep == 0s"
+delay 1
 
 client c1 {
 	txreq
 	rxresp
 	expect resp.bodylen == 6
+
+	txreq
+	rxresp
+	expect resp.bodylen == 6
+	expect resp.http.hits == 1
+} -run
+
+# now we should have two objects, /old from the beginning and the len==6 object
+varnish v1 -cliexpect { 2 C} "ban.list"
+varnish v1 -cli "param.set ban_lurker_age 600"
+varnish v1 -cliok "ban obj.last_hit < 1s"
+
+# /old survives, but len==6 gets removed
+client c1 {
+	txreq -url "/old"
+	rxresp
+	expect resp.http.age > 0
+	expect resp.http.hits == 2
+
+	txreq
+	rxresp
+	expect resp.bodylen == 7
+	expect resp.http.hits == 0
 } -run
 
 # duration formatting - 0s is being tested above

include/tbl/ban_arg_oper.h

@@ -52,6 +52,7 @@ ARGOPER(BANS_ARG_OBJTTL,	BANS_OPER_DURATION)
 ARGOPER(BANS_ARG_OBJAGE,	BANS_OPER_DURATION)
 ARGOPER(BANS_ARG_OBJGRACE,	BANS_OPER_DURATION)
 ARGOPER(BANS_ARG_OBJKEEP,	BANS_OPER_DURATION)
+ARGOPER(BANS_ARG_OBJLASTHIT,	BANS_OPER_DURATION)
 
 #undef ARGOPER
 #undef BANS_OPER_STRING

include/tbl/ban_vars.h

@@ -57,6 +57,9 @@ PVAR("obj.grace",
 PVAR("obj.keep",
      BANS_FLAG_OBJ | BANS_FLAG_DURATION,
      BANS_ARG_OBJKEEP)
+PVAR("obj.last_hit",
+     BANS_FLAG_OBJ | BANS_FLAG_DURATION | BANS_FLAG_NODEDUP,
+     BANS_ARG_OBJLASTHIT)
 #undef PVAR
 
 /*lint -restore */

vmod/vmod_std.vcc

@@ -612,10 +612,15 @@ The format of *STRING* is::
 
   * duration fields:
 
-    * ``obj.ttl``: Remaining ttl at the time the ban is issued
-    * ``obj.age``: Object age at the time the ban is issued
+    * ``obj.ttl``: Remaining ttl
+    * ``obj.age``: Object age
     * ``obj.grace``: The grace time of the object
     * ``obj.keep``: The keep time of the object
+    * ``obj.last_hit``: Time since the last hit
+
+    ``obj.ttl``, ``obj.age`` and ``obj.last_hit`` are relative to the submission
+    time of the ban, such that they represent a fixed point in time despite
+    being specified as a duration.
 
 
 * *<operator>*:
@@ -662,6 +667,19 @@ non-existing header, the operators ``==`` and ``~`` always evaluate as
 false, while the operators ``!=`` and ``!~`` always evaluate as true,
 respectively, for any value of *<arg>*.
 
+``obj.last_hit`` can be used almost as a "last accessed" time, so, for example,
+``ban obj.last_hit > 1d`` removes all objects which were last accessed more than
+one day ago. Also, it can be used to remove objects stuck at request bans by
+issuing ``ban obj.last_hit > X``, with X being slightly less than the time since
+the request ban.
+
+``obj.last_hit`` is based on an internal last LRU time, which might not be
+implemented by all storage engines. Where it is not available, ban expressions
+using ``obj.last_hit`` evaluate to ``false``, which means that the respective
+ban behaves as if it was not present. Where implemented, the last LRU time might
+only get updated by the ``lru_interval`` parameter, which therefore is the
+maximum precision of ``obj.last_hit`` bans.
+
 $Function STRING ban_error()
 
 Returns a textual error description of the last `std.ban()`_ call from