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vcl: Make 'none' a reserved keyword and use it for probes #4309

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vcl: Make 'none' a reserved keyword and use it for probes #4309

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20e99de
vcc_symb: Improve error message for 'default'
dridi Apr 3, 2025
829c804
vcc: Make 'none' a reserved word
dridi Apr 3, 2025
10bbd83
vrt: Use a sentinel value for none backends
dridi Apr 4, 2025
bf1f80d
vrt: Use a sentinel value for none probes
dridi Apr 4, 2025
760d063
vcc: Set backend probe to none
dridi Apr 4, 2025
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2 changes: 2 additions & 0 deletions bin/varnishd/cache/cache_backend.c
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Expand Up @@ -893,6 +893,8 @@ VRT_new_backend_clustered(VRT_CTX, struct vsmw_cluster *vc,
vbp = vrt->probe;
if (vbp == NULL)
vbp = VCL_DefaultProbe(vcl);
if (vbp != NULL && vbp->window == ~0U) /* none probe */
vbp = NULL;

if (vbp != NULL) {
VBP_Insert(be, vbp, be->conn_pool);
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8 changes: 8 additions & 0 deletions bin/varnishd/cache/cache_vrt.c
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Expand Up @@ -65,6 +65,14 @@ const struct vrt_blob *vrt_null_blob = &(struct vrt_blob){
.blob = "\0"
};

const struct director *const vrt_none_backend = NULL;

const struct vrt_backend_probe *const vrt_none_probe =
&(const struct vrt_backend_probe){
.magic = VRT_BACKEND_PROBE_MAGIC,
.window = ~0U,
};

/*--------------------------------------------------------------------*/

VCL_VOID
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20 changes: 20 additions & 0 deletions bin/varnishtest/tests/c00136.vtc
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@@ -0,0 +1,20 @@
varnishtest "none probe"

server s0 {
rxreq
txresp -status 500
} -dispatch

varnish v1 -vcl {
probe default {
.interval = 100ms;
}
backend s0 {
.host = "${s0_sock}";
.probe = none;
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@nigoroll nigoroll Apr 15, 2025

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Can we also make sure please that this also works for a VCL_PROBE vmod function/method argument?

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@dridi dridi Apr 15, 2025

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I don't think we can pass none for a backends either, that would be a subsequent change (among a couple others) should this one be approved.

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@nigoroll nigoroll Apr 15, 2025

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We can always define a none backend and then pass that, so that is not so important. For probes we don't have that option.

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@dridi dridi Apr 15, 2025

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Right, so you'd like to align this change with backend definitions?

probe disabled none;

backend improbable {
       .probe = none;
}

backend also_improbable {
       .probe = disabled;
}

That would increase overall consistency, good idea.

}
} -start

delay 1

varnish v1 -cliexpect healthy "backend.list -p"
6 changes: 3 additions & 3 deletions bin/varnishtest/tests/m00000.vtc
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Expand Up @@ -142,7 +142,7 @@ varnish v1 -errvcl {Symbol not found: 'obj'} {

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@nigoroll nigoroll Apr 15, 2025

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On the commit message:
As with other versioning questions, I think we should only increase the major version for silent breaking changes. In this case a VCL compilation failure ensures that VCL authors become aware of the change, so we do not need a VCL version bump.

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@dridi dridi Apr 15, 2025

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In this case I think we should consider it a bug fix, we should never have authorized none to persist as a usable symbol name once we gave it a special meaning.

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@nigoroll nigoroll Apr 15, 2025

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Yes

varnish v1 -errvcl {rot13: VFP already registered (per-vcl)} {
import debug;
backend none none;
backend be none;
sub vcl_init {
debug.rot104();
}
Expand All @@ -167,7 +167,7 @@ varnish v1 -errvcl {Failed from VCL} {

varnish v1 -errvcl {Failed initialization} {
import debug;
backend none none;
backend be none;
sub vcl_init {
new fails = debug.obj("fail");
}
Expand All @@ -177,7 +177,7 @@ shell {
cat >${tmpdir}/f1 <<-EOF
vcl 4.1;
import debug;
backend none none;
backend be none;
sub vcl_init {
new fails = debug.obj("fail");
}
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2 changes: 1 addition & 1 deletion bin/varnishtest/tests/m00048.vtc
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Expand Up @@ -82,7 +82,7 @@ client c1 -repeat 2 {

varnish v1 -vcl {
import debug;
backend none none;
backend be none;

sub vcl_recv {
return (synth(200));
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4 changes: 2 additions & 2 deletions bin/varnishtest/tests/r03940.vtc
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Expand Up @@ -7,7 +7,7 @@ varnishtest "test startup_timeout vs. stevedore init / open"
# startup_timeout used, delay in stevedore init
varnish v1 -arg "-sdebug=debug,dinit=5s -pstartup_timeout=3s -pcli_timeout=2s" \
-arg "-p feature=+no_coredump" \
-vcl "backend none none;" \
-vcl "backend be none;" \
-expectexit 0x40
varnish v1 -cliexpect \
"Child failed on launch within startup_timeout=3.00s" \
Expand All @@ -31,7 +31,7 @@ shell {grep -q "Child failed on launch within startup_timeout=3.00s" ${p1_out}}

varnish v2 -arg "-sdebug=debug,dopen=5s -pstartup_timeout=2s -pcli_timeout=3s" \
-arg "-p feature=+no_coredump" \
-vcl "backend none none;" \
-vcl "backend be none;" \
-expectexit 0x40
varnish v2 -cliexpect \
"launch within cli_timeout=3.00s .tip: set startup_" \
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2 changes: 1 addition & 1 deletion bin/varnishtest/tests/t02027.vtc
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@@ -1,7 +1,7 @@
varnishtest "H2 RxStuff conditions"

varnish v1 -arg "-p feature=+http2" -arg "-p debug=+syncvsl" -vcl {
backend none none;
backend be none;
sub vcl_recv {
return (synth(200));
}
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4 changes: 2 additions & 2 deletions bin/varnishtest/tests/u00002.vtc
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Expand Up @@ -6,15 +6,15 @@ server s1 -repeat 4 {
} -start

varnish v1 -vcl+backend {
backend none none;
backend be none;

sub vcl_backend_fetch {
# XXX would like to do everything in v_b_e, but
# return(pass(x)) is not supported
if (bereq.url == "/hitpass") {
set bereq.backend = s1;
} else {
set bereq.backend = none;
set bereq.backend = be;
}
}

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18 changes: 10 additions & 8 deletions bin/varnishtest/tests/v00021.vtc
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Expand Up @@ -95,14 +95,6 @@ varnish v1 -errvcl {Unused sub foo, defined:} {
}
}

# deliberately testing for name "none"
varnish v1 -errvcl {Unused sub none, defined:} {
backend b { .host = "${localhost}"; }

sub none {
}
}

varnish v1 -errvcl {Invalid return "deliver"} {
backend b { .host = "${localhost}"; }

Expand Down Expand Up @@ -172,6 +164,16 @@ varnish v1 -errvcl {Symbol 'default' is a reserved word.} {
}
}

varnish v1 -errvcl {Symbol 'default' is a reserved word.} {
import debug;
sub vcl_init { new default = debug.obj(); }
}

varnish v1 -errvcl {Symbol 'none' is a reserved word.} {
import debug;
sub vcl_init { new none = debug.obj(); }
}

varnish v1 -syntax 4.1 -errvcl {(Only available when VCL syntax <= 4.0)} {
sub vcl_recv {
set req.esi = false;
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4 changes: 4 additions & 0 deletions include/vrt.h
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Expand Up @@ -529,6 +529,7 @@ typedef int vmod_event_f(VRT_CTX, struct vmod_priv *, enum vcl_event_e);
int VRT_acl_match(VRT_CTX, VCL_ACL, VCL_IP);

/* VCL_BACKEND */
extern VCL_BACKEND const vrt_none_backend;
VCL_BACKEND VRT_DirectorResolve(VRT_CTX, VCL_BACKEND);

/* VCL_BLOB */
Expand All @@ -542,6 +543,9 @@ int VRT_VSA_GetPtr(VRT_CTX, VCL_IP sua, const unsigned char ** dst);
VCL_BOOL VRT_ipcmp(VRT_CTX, VCL_IP, VCL_IP);
void VRT_Format_Proxy(struct vsb *, VCL_INT, VCL_IP, VCL_IP, VCL_STRING);

/* VCL_PROBE */
extern VCL_PROBE const vrt_none_probe;

/* VCL_REAL */
int VRT_REAL_is_valid(VCL_REAL);

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27 changes: 27 additions & 0 deletions lib/libvcc/vcc_backend.c
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Expand Up @@ -363,6 +363,25 @@ vcc_ParseProbe(struct vcc *tl)
free(p);
}

/*--------------------------------------------------------------------
*/

static void
vcc_EmitNoneProbe(struct vcc *tl)
{
static unsigned emitted = 0;

if (emitted)
return;

Fh(tl, 0,
"static const struct vrt_backend_probe vgc_probe_none[] = {{\n"
"\t.magic = VRT_BACKEND_PROBE_MAGIC,\n"
"\t.window = ~0U,\n"
"}};\n");
emitted = 1;
}

/*--------------------------------------------------------------------
* Parse and emit a backend host definition
*
Expand Down Expand Up @@ -403,6 +422,7 @@ vcc_ParseHostDef(struct vcc *tl, struct symbol *sym,
ifp = New_IniFin(tl);
VSB_printf(ifp->ini, "\t(void)%s;", vgcname);
VSB_printf(ifp->fin, "\t\t(void)%s;", vgcname);
sym->rname = "vrt_none_backend";
return;
}

Expand Down Expand Up @@ -534,6 +554,13 @@ vcc_ParseHostDef(struct vcc *tl, struct symbol *sym,
ERRCHK(tl);
} else if (vcc_IdIs(t_field, "probe") && tl->t->tok == ID) {
t_probe = tl->t;
if (vcc_IdIs(t_probe, "none")) {
vcc_EmitNoneProbe(tl);
Fb(tl, 0, "\t.probe = vgc_probe_none,\n");
vcc_NextToken(tl);
SkipToken(tl, ';');
continue;
}
pb = VCC_SymbolGet(tl, SYM_MAIN, SYM_PROBE,
SYMTAB_EXISTING, XREF_REF);
ERRCHK(tl);
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22 changes: 19 additions & 3 deletions lib/libvcc/vcc_expr.c
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Expand Up @@ -1599,10 +1599,8 @@ static void v_matchproto_(sym_expr_t)
vcc_Eval_Default(struct vcc *tl, struct expr **e, struct token *t,
struct symbol *sym, vcc_type_t fmt)
{
(void)e;
(void)fmt;

(void)sym;
(void)t;

if (fmt->default_sym == NULL) {
VSB_cat(tl->sb, "Symbol 'default' is a reserved word.\n");
Expand All @@ -1613,6 +1611,19 @@ vcc_Eval_Default(struct vcc *tl, struct expr **e, struct token *t,
*e = vcc_mk_expr(fmt, "%s", fmt->default_sym->rname);
}

static void v_matchproto_(sym_expr_t)
vcc_Eval_None(struct vcc *tl, struct expr **e, struct token *t,
struct symbol *sym, vcc_type_t fmt)
{

(void)e;
(void)fmt;
(void)sym;

VSB_cat(tl->sb, "'none' is a reserved word.\n");
vcc_ErrWhere(tl, t);
}

/*--------------------------------------------------------------------
*/

Expand Down Expand Up @@ -1649,4 +1660,9 @@ vcc_Expr_Init(struct vcc *tl)
AN(sym);
sym->type = DEFAULT;
sym->eval = vcc_Eval_Default;

sym = VCC_MkSym(tl, "none", SYM_MAIN, SYM_FUNC, VCL_LOW, VCL_HIGH);
AN(sym);
sym->type = DEFAULT;
sym->eval = vcc_Eval_None;
}
11 changes: 8 additions & 3 deletions lib/libvcc/vcc_symb.c
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Expand Up @@ -604,9 +604,14 @@ VCC_HandleSymbol(struct vcc *tl, vcc_type_t fmt)
vcc_ErrWhere(tl, sym->def_b);
return (sym);
} else if (sym != NULL && sym->kind != kind) {
VSB_printf(tl->sb,
"Name %.*s must have type '%s'.\n",
PF(t), sym->kind->name);
if (sym->type == DEFAULT) {
VSB_printf(tl->sb,
"Symbol '%.*s' is a reserved word.\n", PF(t));
} else {
VSB_printf(tl->sb,
"Name %.*s must have type '%s'.\n",
PF(t), sym->kind->name);
}
vcc_ErrWhere(tl, t);
return (sym);
}
Expand Down