MEDIUM: trace: create a new "trace" statement in the "global" section

The exact same commands as those from the CLI may be pre-loaded at boot
time by passing them one per line after the "trace" keyword in the global
section; i.e. just copy-pasting all commands directly there will do the
job. Note that if a ring is mentioned, it needs to be declared before the
global section. Another option is to append another global section after
"ring".

For now the keyword is marked as experimental to discourage its broad
adoption by default. "expose-experimental-directives" needs to be placed
in the global section to expose it.

diff --git a/doc/configuration.txt b/doc/configuration.txt
index 4883295a7aea66243ec328f7f770558cbd04087d..6c7d7470da70a1fd485fcd1465beeda579024d3c 100644 (file)
--- a/doc/configuration.txt
+++ b/doc/configuration.txt
@@ -2328,6 +2328,25 @@ thread-groups <number>
   since up to 64 threads per group may be configured. The maximum number of
   groups is configured at compile time and defaults to 16. See also "nbthread".
 
+trace <args...>
+  This command configures one "trace" subsystem statement. Each of them can be
+  found in the management manual, and follow the exact same syntax. Only one
+  statement per line is permitted (i.e. if some long trace configurations using
+  semi-colons are to be imported, they must be placed one per line). Any output
+  that the "trace" command would produce will be emitted during the parsing
+  step of the section. Most of the time these will be errors and warnings, but
+  certain incomplete commands might list permissible choices. This command is
+  not meant for regular use, it will generally only be suggested by developers
+  along complex debugging sessions. For this reason it is internally marked as
+  experimental, meaning that "expose-experimental-directives" must appear on a
+  line before any "trace" statement. Note that these directives are parsed on
+  the fly, so referencing a ring buffer that is only declared further will not
+  work. For such use cases it is suggested to place another "global" section
+  with only the "trace" statements after the declaration of that ring. It is
+  important to keep in mind that depending on the trace level and details,
+  enabling traces can severely degrade the global performance. Please refer to
+  the management manual for the statements syntax.
+
 uid <number>
   Changes the process's user ID to <number>. It is recommended that the user ID
   is dedicated to HAProxy or to a small set of similar daemons. HAProxy must

diff --git a/src/trace.c b/src/trace.c
index 243174ab0527493c3671095bb9541f6bfd3d86da..9c0b3f2057311002dd76fcab004e84dabd233dfc 100644 (file)
--- a/src/trace.c
+++ b/src/trace.c
@@ -21,6 +21,7 @@
 #include <import/ist.h>
 #include <haproxy/api.h>
 #include <haproxy/buf.h>
+#include <haproxy/cfgparse.h>
 #include <haproxy/cli.h>
 #include <haproxy/errors.h>
 #include <haproxy/istbuf.h>
@@ -675,6 +676,28 @@ static int trace_parse_statement(char **args, const char **msg)
 
 }
 
+/* parse a "trace" statement in the "global" section, returns 1 if a message is returned, otherwise zero */
+static int cfg_parse_trace(char **args, int section_type, struct proxy *curpx,
+                          const struct proxy *defpx, const char *file, int line,
+                          char **err)
+{
+       const char *msg;
+       int severity;
+
+       severity = trace_parse_statement(args, &msg);
+       if (msg) {
+               if (severity >= LOG_NOTICE)
+                       ha_notice("parsing [%s:%d] : '%s': %s\n", file, line, args[0], msg);
+               else if (severity >= LOG_WARNING)
+                       ha_warning("parsing [%s:%d] : '%s': %s\n", file, line, args[0], msg);
+               else {
+                       ha_alert("parsing [%s:%d] : '%s': %s\n", file, line, args[0], msg);
+                       return -1;
+               }
+       }
+       return 0;
+}
+
 /* parse the command, returns 1 if a message is returned, otherwise zero */
 static int cli_parse_trace(char **args, char *payload, struct appctx *appctx, void *private)
 {
@@ -754,6 +777,13 @@ static struct cli_kw_list cli_kws = {{ },{
 
 INITCALL1(STG_REGISTER, cli_register_kw, &cli_kws);
 
+static struct cfg_kw_list cfg_kws = {ILH, {
+       { CFG_GLOBAL, "trace", cfg_parse_trace, KWF_EXPERIMENTAL },
+       { /* END */ },
+}};
+
+INITCALL1(STG_REGISTER, cfg_register_keywords, &cfg_kws);
+
 /*
  * Local variables:
  *  c-indent-level: 8