fix: update ZeroBus plugin for platform compatibility and enhance code documentation

Added a fatal error message for Windows builds to indicate that the ZeroBus plugin is not supported. Enhanced code documentation by adding comments to clarify the purpose of several functions, including URL scheme validation, timestamp formatting, and plugin initialization and cleanup processes.

Author: mats16

plugins/out_zerobus/CMakeLists.txt

@@ -12,7 +12,11 @@ endif()
 target_link_libraries(flb-plugin-out_zerobus ${ZEROBUS_LIB_DIR}/libzerobus_ffi.a)
 
 # Platform-specific linker flags required by the Rust FFI static library
-if(APPLE)
+if(WIN32)
+  message(FATAL_ERROR
+    "out_zerobus does not support Windows builds. "
+    "Disable it with -DFLB_OUT_ZEROBUS=OFF")
+elseif(APPLE)
   target_link_libraries(flb-plugin-out_zerobus
     "-framework CoreFoundation"
     "-framework Security"

plugins/out_zerobus/zerobus.c

@@ -32,6 +32,7 @@
 
 #include "zerobus.h"
 
+/* Ensure the URL has an http:// or https:// scheme prefix. Returns a new sds string. */
 static flb_sds_t ensure_url_scheme(const char *url)
 {
     size_t url_len;
@@ -55,6 +56,7 @@ static flb_sds_t ensure_url_scheme(const char *url)
     return out;
 }
 
+/* Format a flb_time as an RFC 3339 timestamp with nanosecond precision into buf. */
 static int format_timestamp_rfc3339nano(struct flb_time *tm,
                                         char *buf, size_t size)
 {
@@ -71,6 +73,7 @@ static int format_timestamp_rfc3339nano(struct flb_time *tm,
                     (unsigned long) tm->tm.tv_nsec);
 }
 
+/* Return 1 if the given key matches any entry in the log_keys list, 0 otherwise. */
 static int key_in_log_keys(const char *key, int key_len,
                            struct mk_list *log_keys)
 {
@@ -87,6 +90,7 @@ static int key_in_log_keys(const char *key, int key_len,
     return 0;
 }
 
+/* Return true if msgpack object k is a string equal to name. */
 static inline int str_key_equals(const msgpack_object *k,
                                  const char *name, int name_len)
 {
@@ -241,6 +245,7 @@ static flb_sds_t record_to_json(struct flb_out_zerobus *ctx,
     return json;
 }
 
+/* Initialize the ZeroBus output plugin: validate config, create SDK and stream. */
 static int cb_zerobus_init(struct flb_output_instance *ins,
                            struct flb_config *config,
                            void *data)
@@ -358,6 +363,7 @@ static int cb_zerobus_init(struct flb_output_instance *ins,
     return -1;
 }
 
+/* Flush callback: convert log events to JSON and ingest them via ZeroBus. */
 static void cb_zerobus_flush(struct flb_event_chunk *event_chunk,
                              struct flb_output_flush *out_flush,
                              struct flb_input_instance *i_ins,
@@ -421,8 +427,16 @@ static void cb_zerobus_flush(struct flb_event_chunk *event_chunk,
             flb_sds_t *tmp = flb_realloc(json_records,
                                           sizeof(flb_sds_t) * new_cap);
             if (!tmp) {
+                flb_plg_error(ctx->ins,
+                              "realloc failed, retrying entire batch");
                 flb_sds_destroy(json);
-                break;
+                for (i = 0; i < num_records; i++) {
+                    flb_sds_destroy(json_records[i]);
+                }
+                flb_free(json_records);
+                msgpack_sbuffer_destroy(&sbuf);
+                flb_log_event_decoder_destroy(&log_decoder);
+                FLB_OUTPUT_RETURN(FLB_RETRY);
             }
             json_records = tmp;
             capacity     = new_cap;
@@ -480,6 +494,7 @@ static void cb_zerobus_flush(struct flb_event_chunk *event_chunk,
     FLB_OUTPUT_RETURN(ret);
 }
 
+/* Cleanup callback: close the stream, free SDK resources and plugin context. */
 static int cb_zerobus_exit(void *data, struct flb_config *config)
 {
     struct flb_out_zerobus *ctx = data;