MEDIUM: threads/filters: Add init/deinit callback per thread
Now, it is possible to define init_per_thread and deinit_per_thread callbacks to
deal with ressources allocation for each thread.
This is the filter responsibility to deal with concurrency. This is also the
filter responsibility to know if HAProxy is started with some threads. A good
way to do so is to check "global.nbthread" value. If it is greater than 1, then
_per_thread callbacks will be called.
diff --git a/doc/internals/filters.txt b/doc/internals/filters.txt
index dc55798..1e4d40a 100644
--- a/doc/internals/filters.txt
+++ b/doc/internals/filters.txt
@@ -1,6 +1,6 @@
-----------------------------------------
Filters Guide - version 1.8
- ( Last update: 2016-11-10 )
+ ( Last update: 2017-07-27 )
------------------------------------------
Author : Christopher Faulet
Contact : christopher dot faulet at capflam dot org
@@ -33,6 +33,7 @@
3.1. API Overview
3.2. Defining the filter name and its configuration
3.3. Managing the filter lifecycle
+ 3.3.1. Dealing with threads
3.4. Handling the streams activity
3.5. Analyzing the channels activity
3.6. Filtering the data exchanged
@@ -179,9 +180,11 @@
/*
* Callbacks to manage the filter lifecycle
*/
- 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);
+ 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);
+ int (*init_per_thread) (struct proxy *p, struct flt_conf *fconf);
+ void (*deinit_per_thread)(struct proxy *p, struct flt_conf *fconf);
/*
* Stream callbacks
@@ -473,7 +476,7 @@
----------------------------------
Once the configuration parsed and checked, filters are ready to by used. There
-are two callbacks to manage the filter lifecycle:
+are two main callbacks to manage the filter lifecycle:
* 'flt_ops.init': It initializes the filter for a proxy. You may define this
callback if you need to complete your filter configuration.
@@ -514,6 +517,30 @@
document it.
+3.3.1 DEALING WITH THREADS
+--------------------------
+
+When HAProxy is compiled with the threads support and started with more that one
+thread (global.nbthread > 1), then it is possible to manage the filter per
+thread with following callbacks:
+
+ * 'flt_ops.init_per_thread': It initializes the filter for each thread. It
+ works the same way than 'flt_ops.init' but in the
+ context of a thread. This callback is called
+ after the thread creation.
+
+ * 'flt_ops.deinit_per_thread': It cleans up what the init_per_thread callback
+ have done. It is called in the context of a
+ thread, before exiting it.
+
+This is the filter's responsibility to deal with concurrency. check, init and
+deinit callbacks are called on the main thread. All others are called on a
+"worker" thread (not always the same). This is also the filter's responsibility
+to know if HAProxy is started with more than one thread. If it is started with
+one thread (or compiled without the threads support), these callbacks will be
+silently ignored (in this case, global.nbthread will be always equal to one).
+
+
3.4. HANDLING THE STREAMS ACTIVITY
-----------------------------------
diff --git a/include/types/filters.h b/include/types/filters.h
index e6d0c2c..488a97f 100644
--- a/include/types/filters.h
+++ b/include/types/filters.h
@@ -62,6 +62,11 @@
* - deinit : Cleans up what the init function has done.
* - check : Check the filter config for a proxy. Returns the
* number of errors encountered.
+ * - init_per_thread : Initializes the filter for a proxy for a specific
+ * thread. Returns a negative value if an error
+ * occurs.
+ * - deinit_per_thread : Cleans up what the init_per_thread funcion has
+ * done.
*
*
* - attach : Called after a filter instance creation, when it is
@@ -150,9 +155,11 @@
/*
* Callbacks to manage the filter lifecycle
*/
- 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);
+ 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);
+ int (*init_per_thread) (struct proxy *p, struct flt_conf *fconf);
+ void (*deinit_per_thread)(struct proxy *p, struct flt_conf *fconf);
/*
* Stream callbacks
*/
diff --git a/src/filters.c b/src/filters.c
index 0d0e5e8..c1d3f87 100644
--- a/src/filters.c
+++ b/src/filters.c
@@ -18,6 +18,7 @@
#include <common/errors.h>
#include <common/namespace.h>
#include <common/standard.h>
+#include <common/hathreads.h>
#include <types/filters.h>
#include <types/proto_http.h>
@@ -263,6 +264,23 @@
return 0;
}
+/*
+ * Calls 'init_per_thread' callback for all filters attached to a proxy for each
+ * threads. This happens after the thread creation. Filters can finish to fill
+ * their config. Returns (ERR_ALERT|ERR_FATAL) if an error occurs, 0 otherwise.
+ */
+static int
+flt_init_per_thread(struct proxy *proxy)
+{
+ struct flt_conf *fconf;
+
+ list_for_each_entry(fconf, &proxy->filter_configs, list) {
+ if (fconf->ops->init_per_thread && fconf->ops->init_per_thread(proxy, fconf) < 0)
+ return ERR_ALERT|ERR_FATAL;
+ }
+ return 0;
+}
+
/* Calls flt_init() for all proxies, see above */
static int
flt_init_all()
@@ -281,6 +299,25 @@
return 0;
}
+/* Calls flt_init_per_thread() for all proxies, see above. Be carefull here, it
+ * returns 0 if an error occured. This is the opposite of flt_init_all. */
+static int
+flt_init_all_per_thread()
+{
+ struct proxy *px;
+ int err_code = 0;
+
+ for (px = proxy; px; px = px->next) {
+ err_code = flt_init_per_thread(px);
+ if (err_code & (ERR_ABORT|ERR_FATAL)) {
+ Alert("Failed to initialize filters for proxy '%s' for thread %u.\n",
+ px->id, tid);
+ return 0;
+ }
+ }
+ return 1;
+}
+
/*
* Calls 'check' callback for all filters attached to a proxy. This happens
* after the configuration parsing but before filters initialization. Returns
@@ -317,6 +354,32 @@
}
}
+/*
+ * Calls 'denit_per_thread' callback for all filters attached to a proxy for
+ * each threads. This happens before exiting a thread.
+ */
+void
+flt_deinit_per_thread(struct proxy *proxy)
+{
+ struct flt_conf *fconf, *back;
+
+ list_for_each_entry_safe(fconf, back, &proxy->filter_configs, list) {
+ if (fconf->ops->deinit_per_thread)
+ fconf->ops->deinit_per_thread(proxy, fconf);
+ }
+}
+
+
+/* Calls flt_deinit_per_thread() for all proxies, see above */
+static void
+flt_deinit_all_per_thread()
+{
+ struct proxy *px;
+
+ for (px = proxy; px; px = px->next)
+ flt_deinit_per_thread(px);
+}
+
/* Attaches a filter to a stream. Returns -1 if an error occurs, 0 otherwise. */
static int
flt_stream_add_filter(struct stream *s, struct flt_conf *fconf, unsigned int flags)
@@ -1124,6 +1187,8 @@
pool2_filter = create_pool("filter", sizeof(struct filter), MEM_F_SHARED);
cfg_register_keywords(&cfg_kws);
hap_register_post_check(flt_init_all);
+ hap_register_per_thread_init(flt_init_all_per_thread);
+ hap_register_per_thread_deinit(flt_deinit_all_per_thread);
}
__attribute__((destructor))