MEDIUM: filters: Add attch/detach and stream_set_backend callbacks
New callbacks have been added to handle creation and destruction of filter
instances:
* 'attach' callback is called after a filter instance creation, when it is
attached to a stream. This happens when the stream is started for filters
defined on the stream's frontend and when the backend is set for filters
declared on the stream's backend. It is possible to ignore the filter, if
needed, by returning 0. This could be useful to have conditional filtering.
* 'detach' callback is called when a filter instance is detached from a stream,
before its destruction. This happens when the stream is stopped for filters
defined on the stream's frontend and when the analyze ends for filters defined
on the stream's backend.
In addition, the callback 'stream_set_backend' has been added to know when a
backend is set for a stream. It is only called when the frontend and the backend
are not the same. And it is called for all filters attached to a stream
(frontend and backend).
Finally, the TRACE filter has been updated.
diff --git a/include/types/filters.h b/include/types/filters.h
index 62fcfb1..62b457d 100644
--- a/include/types/filters.h
+++ b/include/types/filters.h
@@ -64,14 +64,32 @@
* number of errors encountered.
*
*
+ * - attach : Called after a filter instance creation, when it is
+ * attached to a stream. This happens when the stream
+ * is started for filters defined on the stream's
+ * frontend and when the backend is set for filters
+ * declared on the stream's backend.
+ * Returns a negative value if an error occurs, 0 if
+ * the filter must be ignored for the stream, any other
+ * value otherwise.
* - stream_start : Called when a stream is started. This callback will
- * only be called for filters defined on a proxy with
- * the frontend capability.
+ * only be called for filters defined on the stream's
+ * frontend.
+ * Returns a negative value if an error occurs, any
+ * other value otherwise.
+ * - stream_set_backend : Called when a backend is set for a stream. This
+ * callbacks will be called for all filters attached
+ * to a stream (frontend and backend).
* Returns a negative value if an error occurs, any
* other value otherwise.
* - stream_stop : Called when a stream is stopped. This callback will
- * only be called for filters defined on a proxy with
- * the frontend capability.
+ * only be called for filters defined on the stream's
+ * frontend.
+ * - detach : Called when a filter instance is detached from a
+ * stream, before its destruction. This happens when
+ * the stream is stopped for filters defined on the
+ * stream's frontend and when the analyze ends for
+ * filters defined on the stream's backend.
*
*
* - channel_start_analyze: Called when a filter starts to analyze a channel.
@@ -133,12 +151,14 @@
int (*init) (struct proxy *p, struct flt_conf *fconf);
void (*deinit)(struct proxy *p, struct flt_conf *fconf);
int (*check) (struct proxy *p, struct flt_conf *fconf);
-
/*
* Stream callbacks
*/
- int (*stream_start) (struct stream *s, struct filter *f);
- void (*stream_stop) (struct stream *s, struct filter *f);
+ int (*attach) (struct stream *s, struct filter *f);
+ int (*stream_start) (struct stream *s, struct filter *f);
+ int (*stream_set_backend)(struct stream *s, struct filter *f, struct proxy *be);
+ void (*stream_stop) (struct stream *s, struct filter *f);
+ void (*detach) (struct stream *s, struct filter *f);
/*
* Channel callbacks
diff --git a/src/filters.c b/src/filters.c
index 7f8fae4..a1b36ba 100644
--- a/src/filters.c
+++ b/src/filters.c
@@ -304,11 +304,21 @@
flt_stream_add_filter(struct stream *s, struct flt_conf *fconf, unsigned int flags)
{
struct filter *f = pool_alloc2(pool2_filter);
+
if (!f) /* not enough memory */
return -1;
memset(f, 0, sizeof(*f));
f->config = fconf;
f->flags |= flags;
+
+ if (FLT_OPS(f)->attach) {
+ int ret = FLT_OPS(f)->attach(s, f);
+ if (ret <= 0) {
+ pool_free2(pool2_filter, f);
+ return ret;
+ }
+ }
+
LIST_ADDQ(&strm_flt(s)->filters, &f->list);
strm_flt(s)->flags |= STRM_FLT_FL_HAS_FILTERS;
return 0;
@@ -345,6 +355,8 @@
list_for_each_entry_safe(filter, back, &strm_flt(s)->filters, list) {
if (!only_backend || (filter->flags & FLT_FL_IS_BACKEND_FILTER)) {
+ if (FLT_OPS(filter)->detach)
+ FLT_OPS(filter)->detach(s, filter);
LIST_DEL(&filter->list);
pool_free2(pool2_filter, filter);
}
@@ -387,21 +399,30 @@
/*
* Called when a backend is set for a stream. If the frontend and the backend
- * are the same, this function does nothing. Else it attaches all backend
- * filters to the stream. Returns -1 if an error occurs, 0 otherwise.
+ * are not the same, this function attaches all backend filters to the
+ * stream. Returns -1 if an error occurs, 0 otherwise.
*/
int
flt_set_stream_backend(struct stream *s, struct proxy *be)
{
struct flt_conf *fconf;
+ struct filter *filter;
if (strm_fe(s) == be)
- return 0;
+ goto end;
list_for_each_entry(fconf, &be->filter_configs, list) {
if (flt_stream_add_filter(s, fconf, FLT_FL_IS_BACKEND_FILTER) < 0)
return -1;
}
+
+ end:
+ list_for_each_entry(filter, &strm_flt(s)->filters, list) {
+ if (FLT_OPS(filter)->stream_set_backend &&
+ FLT_OPS(filter)->stream_set_backend(s, filter, be) < 0)
+ return -1;
+ }
+
return 0;
}
diff --git a/src/flt_trace.c b/src/flt_trace.c
index a052ab5..ce3bf5c 100644
--- a/src/flt_trace.c
+++ b/src/flt_trace.c
@@ -66,6 +66,12 @@
return (s->flags & SF_BE_ASSIGNED) ? "backend" : "frontend";
}
+static const char *
+filter_type(const struct filter *f)
+{
+ return (f->flags & FLT_FL_IS_BACKEND_FILTER) ? "backend" : "frontend";
+}
+
/***************************************************************************
* Hooks that manage the filter lifecycle (init/check/deinit)
**************************************************************************/
@@ -111,6 +117,28 @@
/**************************************************************************
* Hooks to handle start/stop of streams
*************************************************************************/
+/* Called when a filter instance is created and attach to a stream */
+static int
+trace_attach(struct stream *s, struct filter *filter)
+{
+ struct trace_config *conf = FLT_CONF(filter);
+
+ STRM_TRACE(conf, s, "%-25s: filter-type=%s",
+ __FUNCTION__, filter_type(filter));
+ return 1;
+}
+
+/* Called when a filter instance is detach from a stream, just before its
+ * destruction */
+static void
+trace_detach(struct stream *s, struct filter *filter)
+{
+ struct trace_config *conf = FLT_CONF(filter);
+
+ STRM_TRACE(conf, s, "%-25s: filter-type=%s",
+ __FUNCTION__, filter_type(filter));
+}
+
/* Called when a stream is created */
static int
trace_stream_start(struct stream *s, struct filter *filter)
@@ -122,6 +150,19 @@
return 0;
}
+
+/* Called when a backend is set for a stream */
+static int
+trace_stream_set_backend(struct stream *s, struct filter *filter,
+ struct proxy *be)
+{
+ struct trace_config *conf = FLT_CONF(filter);
+
+ STRM_TRACE(conf, s, "%-25s: backend=%s",
+ __FUNCTION__, be->id);
+ return 0;
+}
+
/* Called when a stream is destroyed */
static void
trace_stream_stop(struct stream *s, struct filter *filter)
@@ -410,8 +451,11 @@
.check = trace_check,
/* Handle start/stop of streams */
- .stream_start = trace_stream_start,
- .stream_stop = trace_stream_stop,
+ .attach = trace_attach,
+ .detach = trace_detach,
+ .stream_start = trace_stream_start,
+ .stream_set_backend = trace_stream_set_backend,
+ .stream_stop = trace_stream_stop,
/* Handle channels activity */
.channel_start_analyze = trace_chn_start_analyze,