MINOR: ring: support arbitrary delimiters through ring_dispatch_messages()

In order to support delimiting output events with other characters than
just the LF, let's pass the delimiter through the API. The default remains
the LF, used by applet_append_line(), and ignored by the log forwarder.

include/haproxy/applet.h

@@ -58,7 +58,7 @@ size_t appctx_raw_snd_buf(struct appctx *appctx, struct buffer *buf, size_t coun
 size_t appctx_snd_buf(struct stconn *sc, struct buffer *buf, size_t count, unsigned int flags);
 
 int appctx_fastfwd(struct stconn *sc, unsigned int count, unsigned int flags);
-ssize_t applet_append_line(void *ctx, struct ist v1, struct ist v2, size_t ofs, size_t len);
+ssize_t applet_append_line(void *ctx, struct ist v1, struct ist v2, size_t ofs, size_t len, char delim);
 static forceinline void applet_fl_set(struct appctx *appctx, uint on);
 static forceinline void applet_fl_clr(struct appctx *appctx, uint off);
 

include/haproxy/log.h

@@ -144,7 +144,7 @@ void app_log(struct list *loggers, struct buffer *tag, int level, const char *fo
  */
 int add_to_logformat_list(char *start, char *end, int type, struct lf_expr *lf_expr, char **err);
 
-ssize_t syslog_applet_append_event(void *ctx, struct ist v1, struct ist v2, size_t ofs, size_t len);
+ssize_t syslog_applet_append_event(void *ctx, struct ist v1, struct ist v2, size_t ofs, size_t len, char delim);
 
 /*
  * Parse the log_format string and fill a linked list.

include/haproxy/ring.h

@@ -43,7 +43,8 @@ void cli_io_release_show_ring(struct appctx *appctx);
 
 size_t ring_max_payload(const struct ring *ring);
 int ring_dispatch_messages(struct ring *ring, void *ctx, size_t *ofs_ptr, size_t *last_ofs_ptr, uint flags,
-                           ssize_t (*msg_handler)(void *ctx, struct ist v1, struct ist v2, size_t ofs, size_t len),
+                           ssize_t (*msg_handler)(void *ctx, struct ist v1, struct ist v2, size_t ofs, size_t len, char delim),
+                           char delim,
                            size_t *processed);
 
 /* returns the ring storage's usable area */

src/applet.c

@@ -737,7 +737,7 @@ end:
 	return ret;
 }
 
-/* Atomically append a line to applet <ctx>'s output, appending a trailing LF.
+/* Atomically append a line to applet <ctx>'s output, appending a delimiter.
  * The line is read from vectors <v1> and <v2> at offset <ofs> relative to the
  * area's origin, for <len> bytes. It returns the number of bytes consumed from
  * the input vectors on success, -1 if it temporarily cannot (buffer full), -2
@@ -745,7 +745,7 @@ end:
  * The caller is responsible for making sure that there are at least ofs+len
  * bytes in the input vectors.
  */
-ssize_t applet_append_line(void *ctx, struct ist v1, struct ist v2, size_t ofs, size_t len)
+ssize_t applet_append_line(void *ctx, struct ist v1, struct ist v2, size_t ofs, size_t len, char delim)
 {
 	struct appctx *appctx = ctx;
 
@@ -757,7 +757,7 @@ ssize_t applet_append_line(void *ctx, struct ist v1, struct ist v2, size_t ofs,
 	chunk_reset(&trash);
 	vp_peek_ofs(v1, v2, ofs, trash.area, len);
 	trash.data += len;
-	trash.area[trash.data++] = '\n';
+	trash.area[trash.data++] = delim;
 	if (applet_putchk(appctx, &trash) == -1)
 		return -1;
 	return len;

src/log.c

@@ -5976,7 +5976,7 @@ static struct applet syslog_applet = {
  * large msg). The input vectors are not modified. The caller is responsible for
  * making sure that there are at least ofs+len bytes in the input buffer.
  */
-ssize_t syslog_applet_append_event(void *ctx, struct ist v1, struct ist v2, size_t ofs, size_t len)
+ssize_t syslog_applet_append_event(void *ctx, struct ist v1, struct ist v2, size_t ofs, size_t len, char delim)
 {
 	struct appctx *appctx = ctx;
 	char *p;

src/ring.c

@@ -550,7 +550,8 @@ int ring_attach_cli(struct ring *ring, struct appctx *appctx, uint flags)
  * processed by the function (even when the function returns 0)
  */
 int ring_dispatch_messages(struct ring *ring, void *ctx, size_t *ofs_ptr, size_t *last_ofs_ptr, uint flags,
-                           ssize_t (*msg_handler)(void *ctx, struct ist v1, struct ist v2, size_t ofs, size_t len),
+                           ssize_t (*msg_handler)(void *ctx, struct ist v1, struct ist v2, size_t ofs, size_t len, char delim),
+                           char delim,
                            size_t *processed)
 {
 	size_t head_ofs, tail_ofs, prev_ofs;
@@ -644,7 +645,7 @@ int ring_dispatch_messages(struct ring *ring, void *ctx, size_t *ofs_ptr, size_t
 
 		BUG_ON(msg_len + cnt + 1 > vp_size(v1, v2));
 
-		copied = msg_handler(ctx, v1, v2, cnt, msg_len);
+		copied = msg_handler(ctx, v1, v2, cnt, msg_len, delim);
 		if (copied == -2) {
 			/* too large a message to ever fit, let's skip it */
 			goto skip;
@@ -703,7 +704,7 @@ int cli_io_handler_show_ring(struct appctx *appctx)
 
 	MT_LIST_DELETE(&appctx->wait_entry);
 
-	ret = ring_dispatch_messages(ring, appctx, &ctx->ofs, &last_ofs, ctx->flags, applet_append_line, NULL);
+	ret = ring_dispatch_messages(ring, appctx, &ctx->ofs, &last_ofs, ctx->flags, applet_append_line, '\n', NULL);
 
 	if (ret && (ctx->flags & RING_WF_WAIT_MODE)) {
 		/* we've drained everything and are configured to wait for more

src/sink.c

@@ -412,7 +412,7 @@ void sink_setup_proxy(struct proxy *px)
 }
 
 static void _sink_forward_io_handler(struct appctx *appctx,
-                                     ssize_t (*msg_handler)(void *ctx, struct ist v1, struct ist v2, size_t ofs, size_t len))
+                                     ssize_t (*msg_handler)(void *ctx, struct ist v1, struct ist v2, size_t ofs, size_t len, char delim))
 {
 	struct stconn *sc = appctx_sc(appctx);
 	struct sink_forward_target *sft = appctx->svcctx;
@@ -446,7 +446,7 @@ static void _sink_forward_io_handler(struct appctx *appctx,
 	MT_LIST_DELETE(&appctx->wait_entry);
 
 	ret = ring_dispatch_messages(ring, appctx, &sft->ofs, &last_ofs, 0,
-	                             msg_handler, &processed);
+	                             msg_handler, '\n', &processed);
 	sft->e_processed += processed;
 
 	/* if server's max-reuse is set (>= 0), destroy the applet once the