engine: add logging for errors during engine initialization. (fluent#3723)

Signed-off-by: Phillip Whelan <[email protected]>

Author: pwhelan

src/flb_engine.c

@@ -485,6 +485,7 @@ int flb_engine_failed(struct flb_config *config)
 
     /* Check the channel is valid (enabled by library mode) */
     if (config->ch_notif[1] <= 0) {
+        flb_error("[engine] no channel to notify FAILED message");
         return -1;
     }
 
@@ -565,6 +566,7 @@ int flb_engine_start(struct flb_config *config)
     /* Create the event loop and set it in the global configuration */
     evl = mk_event_loop_create(256);
     if (!evl) {
+        fprintf(stderr, "[log] could not create event loop\n");
         return -1;
     }
     config->evl = evl;
@@ -604,6 +606,7 @@ int flb_engine_start(struct flb_config *config)
     /* Start the Logging service */
     ret = flb_engine_log_start(config);
     if (ret == -1) {
+        fprintf(stderr, "[engine] log start failed\n");
         return -1;
     }
 
@@ -639,6 +642,7 @@ int flb_engine_start(struct flb_config *config)
     /* Start the Storage engine */
     ret = flb_storage_create(config);
     if (ret == -1) {
+        flb_error("[engine] storage creation failed");
         return -1;
     }
 
@@ -661,12 +665,14 @@ int flb_engine_start(struct flb_config *config)
     /* Initialize input plugins */
     ret = flb_input_init_all(config);
     if (ret == -1) {
+        flb_error("[engine] input initialization failed");
         return -1;
     }
 
     /* Initialize filter plugins */
     ret = flb_filter_init_all(config);
     if (ret == -1) {
+        flb_error("[engine] filter initialization failed");
         return -1;
     }
 
@@ -676,6 +682,7 @@ int flb_engine_start(struct flb_config *config)
     /* Initialize output plugins */
     ret = flb_output_init_all(config);
     if (ret == -1) {
+        flb_error("[engine] output initialization failed");
         return -1;
     }
 

src/flb_log.c

@@ -428,6 +428,7 @@ void flb_log_print(int type, const char *file, int line, const char *fmt, ...)
     if (w) {
         int n = flb_pipe_write_all(w->log[1], &msg, sizeof(msg));
         if (n == -1) {
+            fprintf(stderr, "%s", (char *) msg.msg);
             perror("write");
         }
     }