vbf: implement vcl_backend_refresh logic

bin/varnishd/cache/cache_fetch.c

@@ -400,7 +400,7 @@ vbf_expected_304(struct busyobj *bo)
 static const struct fetch_step * v_matchproto_(vbf_state_f)
 vbf_stp_startfetch(struct worker *wrk, struct busyobj *bo)
 {
-	int i;
+	int i, skip_vbr = 0;
 	vtim_real now;
 	unsigned handling;
 	struct objcore *oc;
@@ -498,14 +498,37 @@ vbf_stp_startfetch(struct worker *wrk, struct busyobj *bo)
 	if (http_IsStatus(bo->beresp, 304)) {
 		if (!vbf_expected_304(bo))
 			return (F_STP_ERROR);
-		vbf_304_logic(bo);
+
+		bo->was_304 = 1;
+		VCL_backend_refresh_method(bo->vcl, wrk, NULL, bo, NULL);
+		switch (wrk->vpi->handling) {
+			case VCL_RET_MERGE:
+				vbf_304_logic(bo);
+				break;
+			case VCL_RET_BERESP:
+				break;
+			case VCL_RET_OBJ_STALE:
+				HTTP_Decode(bo->beresp, ObjGetAttr(bo->wrk, bo->stale_oc, OA_HEADERS, NULL));
+				break;
+			case VCL_RET_ERROR:
+				/* FALLTHROUGH */
+			case VCL_RET_ABANDON:
+				/* FALLTHROUGH */
+			case VCL_RET_FAIL:
+				/* FALLTHROUGH */
+			case VCL_RET_RETRY:
+				skip_vbr = 1;
+				break;
+			default:
+				WRONG("Illegal return from vcl_backend_refresh{}");
+		}
 	}
 
 	if (bo->htc != NULL && bo->htc->doclose == SC_NULL &&
 	    http_GetHdrField(bo->bereq, H_Connection, "close", NULL))
 		bo->htc->doclose = SC_REQ_CLOSE;
-
-	VCL_backend_response_method(bo->vcl, wrk, NULL, bo, NULL);
+	if (!skip_vbr)
+		VCL_backend_response_method(bo->vcl, wrk, NULL, bo, NULL);
 
 	if (bo->htc != NULL && bo->htc->doclose == SC_NULL &&
 	    http_GetHdrField(bo->beresp, H_Connection, "close", NULL))

bin/varnishtest/tests/b00082.vtc

@@ -0,0 +1,115 @@
+varnishtest "Test vcl_backend_refresh"
+
+server s1 {
+	rxreq
+	txresp -hdr "Etag: abcd" -hdr "from-bo: true" -bodylen 10
+	rxreq
+	expect req.http.if-none-match == "abcd"
+	txresp -status 304 -hdr "be304-1: true"
+	rxreq
+	expect req.http.if-none-match == "abcd"
+	txresp -status 304 -hdr "be304-2: true"
+	rxreq
+	expect req.http.if-none-match == "abcd"
+	txresp -status 304 -hdr "be304-3: true"
+} -start
+
+varnish v1 -vcl+backend {
+
+	sub vcl_backend_response {
+		set beresp.http.vbresp = "true";
+		set beresp.ttl = 0.01s;
+		set beresp.grace = 0s;
+		set beresp.keep = 10m;
+		set beresp.http.was-304 = beresp.was_304;
+	}
+
+	sub vcl_backend_refresh {
+		set beresp.http.vbref = "true";
+		return (merge);
+	}
+} -start
+
+client c1 {
+	txreq
+	rxresp
+	expect resp.status == 200
+	expect resp.http.was-304 == false
+	expect resp.http.vbref == <undef>
+	expect resp.http.vbresp == true
+	expect resp.http.from-bo == true
+} -run
+
+delay 0.01
+
+client c2 {
+	txreq
+	rxresp
+	expect resp.status == 200
+	expect resp.http.was-304 == true
+	expect resp.http.be304-1 == true
+	expect resp.http.vbref == true
+	expect resp.http.vbresp == true
+	expect resp.http.from-bo == true
+} -run
+
+varnish v1 -vcl+backend {
+
+	sub vcl_backend_response {
+		set beresp.http.vbresp = "true";
+		set beresp.ttl = 0.01s;
+		set beresp.grace = 0s;
+		set beresp.keep = 10m;
+		set beresp.http.was-304 = beresp.was_304;
+	}
+
+	sub vcl_backend_refresh {
+		set beresp.http.vbref = "true";
+		return (obj_stale);
+	}
+}
+
+delay 0.01
+
+client c3 {
+	txreq
+	rxresp
+	expect resp.status == 200
+	expect resp.http.was-304 == true
+	expect resp.http.be304-1 == true
+	expect resp.http.be304-2 == <undef>
+	expect resp.http.vbref == true
+	expect resp.http.vbresp == true
+	expect resp.http.from-bo == true
+} -run
+
+varnish v1 -vcl+backend {
+
+	sub vcl_backend_response {
+		set beresp.http.vbresp = "true";
+		set beresp.ttl = 0.01s;
+		set beresp.grace = 0s;
+		set beresp.keep = 10m;
+		set beresp.http.was-304 = beresp.was_304;
+	}
+
+	sub vcl_backend_refresh {
+		set beresp.http.vbref = "true";
+		return (beresp);
+	}
+}
+
+delay 0.01
+
+client c4 {
+	txreq
+	rxresp
+	expect resp.status == 304
+	expect resp.http.was-304 == true
+	expect resp.http.be304-1 == <undef>
+	expect resp.http.be304-2 == <undef>
+	expect resp.http.be304-3 == true
+	expect resp.http.vbref == true
+	expect resp.http.vbresp == true
+	expect resp.http.from-bo == <undef>
+} -run