Expose VCL probes to VMODs

doc/sphinx/reference/directors.rst

@@ -150,4 +150,5 @@ too is no longer needed. It is then Varnish that will take care of health
 probing and disabling the feature on cold VCL (see
 :ref:`ref-vmod-event-functions`).
 
-.. TODO document VCL_PROBE if patchwork #310 is merged
+Instead of initializing your own probe definition, you can get a ``VCL_PROBE``
+directly built from VCL (see :ref:`ref-vmod-vcl-c-types`).

doc/sphinx/reference/vmod.rst

@@ -193,7 +193,10 @@ PRIV_TOP
 PRIV_VCL
 	See :ref:`ref-vmod-private-pointers` below.
 
-.. TODO document PROBE if patchwork #310 is merged
+PROBE
+	C-type: ``const struct vrt_backend_probe *``
+
+	A named standalone backend probe definition.
 
 REAL
 	C-type: ``double``

include/vrt.h

@@ -67,20 +67,21 @@ struct ws;
  * (alphabetic order)
  */
 
-typedef const struct director *		VCL_BACKEND;
-typedef const struct vmod_priv *	VCL_BLOB;
-typedef unsigned			VCL_BOOL;
-typedef double				VCL_BYTES;
-typedef double				VCL_DURATION;
-typedef const char *			VCL_ENUM;
-typedef const struct gethdr_s *		VCL_HEADER;
-typedef struct http *			VCL_HTTP;
-typedef long				VCL_INT;
-typedef const struct suckaddr *		VCL_IP;
-typedef double				VCL_REAL;
-typedef const char *			VCL_STRING;
-typedef double				VCL_TIME;
-typedef void				VCL_VOID;
+typedef const struct director *			VCL_BACKEND;
+typedef const struct vmod_priv *		VCL_BLOB;
+typedef unsigned				VCL_BOOL;
+typedef double					VCL_BYTES;
+typedef double					VCL_DURATION;
+typedef const char *				VCL_ENUM;
+typedef const struct gethdr_s *			VCL_HEADER;
+typedef struct http *				VCL_HTTP;
+typedef long					VCL_INT;
+typedef const struct suckaddr *			VCL_IP;
+typedef const struct vrt_backend_probe *	VCL_PROBE;
+typedef double					VCL_REAL;
+typedef const char *				VCL_STRING;
+typedef double					VCL_TIME;
+typedef void					VCL_VOID;
 
 /***********************************************************************
  * This is the composite argument we pass to compiled VCL and VRT

lib/libvcc/vcc_backend.c

@@ -249,7 +249,7 @@ void
 vcc_ParseProbe(struct vcc *tl)
 {
 	struct token *t_probe;
-	int i;
+	struct symbol *sym;
 	char *p;
 
 	vcc_NextToken(tl);		/* ID: probe */
@@ -258,11 +258,18 @@ vcc_ParseProbe(struct vcc *tl)
 	ERRCHK(tl);
 	t_probe = tl->t;
 	vcc_NextToken(tl);
-	i = vcc_AddDef(tl, t_probe, SYM_PROBE);
-	if (i > 1) {
+
+	sym = VCC_GetSymbolTok(tl, t_probe, SYM_PROBE);
+	AN(sym);
+	if (sym->ndef > 0) {
 		VSB_printf(tl->sb, "Probe %.*s redefined\n", PF(t_probe));
 		vcc_ErrWhere(tl, t_probe);
+		return;
 	}
+	sym->fmt = PROBE;
+	sym->eval = vcc_Eval_Probe;
+	sym->ndef++;
+	ERRCHK(tl);
 
 	vcc_ParseProbeSpec(tl, t_probe, &p);
 	if (vcc_IdIs(t_probe, "default")) {

lib/libvcc/vcc_compile.h

@@ -280,6 +280,7 @@ sym_expr_t vcc_Eval_SymFunc;
 void vcc_Eval_Func(struct vcc *tl, const char *cfunc, const char *extra,
     const char *name, const char *args);
 sym_expr_t vcc_Eval_Backend;
+sym_expr_t vcc_Eval_Probe;
 
 /* vcc_obj.c */
 extern const struct var vcc_vars[];

lib/libvcc/vcc_expr.c

@@ -516,6 +516,23 @@ vcc_Eval_Backend(struct vcc *tl, struct expr **e, const struct symbol *sym)
 
 /*--------------------------------------------------------------------
  */
+
+void
+vcc_Eval_Probe(struct vcc *tl, struct expr **e, const struct symbol *sym)
+{
+
+	assert(sym->kind == SYM_PROBE);
+
+	vcc_ExpectCid(tl);
+	vcc_AddRef(tl, tl->t, SYM_PROBE);
+	*e = vcc_mk_expr(PROBE, "&vgc_probe_%.*s", PF(tl->t));
+	(*e)->constant = EXPR_VAR;      /* XXX ? */
+	vcc_NextToken(tl);
+}
+
+/*--------------------------------------------------------------------
+ */
+
 void
 vcc_Eval_Var(struct vcc *tl, struct expr **e, const struct symbol *sym)
 {
@@ -812,6 +829,8 @@ vcc_expr4(struct vcc *tl, struct expr **e, enum var_type fmt)
 		sym = NULL;
 		if (fmt == BACKEND)
 			sym = VCC_FindSymbol(tl, tl->t, SYM_BACKEND);
+		if (fmt == PROBE)
+			sym = VCC_FindSymbol(tl, tl->t, SYM_PROBE);
 		if (sym == NULL)
 			sym = VCC_FindSymbol(tl, tl->t, SYM_VAR);
 		if (sym == NULL)
@@ -831,6 +850,7 @@ vcc_expr4(struct vcc *tl, struct expr **e, enum var_type fmt)
 		case SYM_VAR:
 		case SYM_FUNC:
 		case SYM_BACKEND:
+		case SYM_PROBE:
 			AN(sym->eval);
 			AZ(*e);
 			sym->eval(tl, e, sym);

lib/libvcc/vmodtool.py

@@ -60,6 +60,7 @@ ctypes = {
 	'PRIV_VCL':	"struct vmod_priv *",
 	'PRIV_TASK':	"struct vmod_priv *",
 	'PRIV_TOP':	"struct vmod_priv *",
+	'PROBE':	"VCL_PROBE",
 	'REAL':		"VCL_REAL",
 	'STRING':	"VCL_STRING",
 	'STRING_LIST':	"const char *, ...",