Core: Add dump-config option to print read configuration on startup

src/config_format/flb_config_format.c

@@ -752,6 +752,10 @@ static void dump_section(struct flb_cf_section *s)
     struct cfl_kvpair *kv;
     struct flb_cf_group *g;
 
+    if (!s) {
+        return;
+    }
+
     printf("> section:\n  name: %s\n  type: %s\n",
            s->name, section_type_str(s->type));
 
@@ -793,6 +797,10 @@ static void dump_env(struct mk_list *list)
     struct mk_list *head;
     struct flb_kv *kv;
 
+    if (!list) {
+        return;
+    }
+
     if (mk_list_size(list) == 0) {
         return;
     }
@@ -810,6 +818,10 @@ static void dump_metas(struct mk_list *list)
     struct mk_list *head;
     struct flb_kv *kv;
 
+    if (!list) {
+        return;
+    }
+
     if (mk_list_size(list) == 0) {
         return;
     }
@@ -827,6 +839,10 @@ static void dump_section_list(struct mk_list *list)
     struct mk_list *head;
     struct flb_cf_section *s;
 
+    if (!list) {
+        return;
+    }
+
     mk_list_foreach(head, list) {
         s = mk_list_entry(head, struct flb_cf_section, _head);
         dump_section(s);

src/fluent-bit.c

@@ -165,6 +165,7 @@ static void flb_help(int rc, struct flb_config *config)
     print_opt("-q, --quiet", "quiet mode");
     print_opt("-S, --sosreport", "support report for Enterprise customers");
     print_opt("-Y, --enable-hot-reload", "enable for hot reloading");
+    print_opt("-a, --dump-config", "print configuration on startup");
     print_opt("-W, --disable-thread-safety-on-hot-reloading", "disable thread safety on hot reloading");
     print_opt("-V, --version", "show version number");
     print_opt("-h, --help", "print this help");
@@ -948,13 +949,17 @@ int flb_main(int argc, char **argv)
     int opt;
     int ret;
     flb_sds_t json;
+    int dump_cfg;
 
     /* handle plugin properties:  -1 = none, 0 = input, 1 = output */
     int last_plugin = -1;
 
     /* local variables to handle config options */
     char *cfg_file = NULL;
 
+    /* do not dump config file on default */
+    dump_cfg = FLB_FALSE;
+
     /* config format context */
     struct flb_cf *cf;
     struct flb_cf *tmp;
@@ -1024,6 +1029,7 @@ int flb_main(int argc, char **argv)
         { "http_listen",     required_argument, NULL, 'L' },
         { "http_port",       required_argument, NULL, 'P' },
 #endif
+        { "dump-config",    no_argument       , NULL, 'a' },
         { "enable-hot-reload",     no_argument, NULL, 'Y' },
 #ifdef FLB_HAVE_CHUNK_TRACE
         { "enable-chunk-trace",    no_argument, NULL, 'Z' },
@@ -1063,7 +1069,7 @@ int flb_main(int argc, char **argv)
     /* Parse the command line options */
     while ((opt = getopt_long(argc, argv,
                               "b:c:dDf:C:i:m:o:R:F:p:e:"
-                              "t:T:l:vw:qVhJL:HP:s:SWYZ",
+                              "t:T:l:vw:qVhJL:HP:s:SWaYZ",
                               long_opts, NULL)) != -1) {
 
         switch (opt) {
@@ -1221,6 +1227,9 @@ int flb_main(int argc, char **argv)
         case 'Y':
             flb_cf_section_property_add(cf_opts, service->properties, FLB_CONF_STR_HOT_RELOAD, 0, "on", 0);
             break;
+        case 'a':
+            dump_cfg = FLB_TRUE;
+            break;
         case 'W':
             flb_cf_section_property_add(cf_opts, service->properties,
                                         FLB_CONF_STR_HOT_RELOAD_ENSURE_THREAD_SAFETY, 0, "off", 0);
@@ -1314,6 +1323,16 @@ int flb_main(int argc, char **argv)
     cf = tmp;
 #endif
 
+    /* Print read config for debugging purposes */
+    if(dump_cfg) {
+            if (cf) {
+            fprintf(stderr, "[debug] read configuration:\n");
+            flb_cf_dump(cf);
+            fflush(stdout);
+            fflush(stderr);
+        }
+    }
+
     /* Check co-routine stack size */
     if (config->coro_stack_size < getpagesize()) {
         flb_cf_destroy(cf_opts);