influxdb: allow stripping of tag prefix

Removes a configured prefix from measurement names

Signed-off-by: Ueli Graf <[email protected]>

Author: ueli-g

plugins/out_influxdb/influxdb.c

@@ -74,6 +74,8 @@ static int influxdb_format(struct flb_config *config,
     char *str = NULL;
     size_t str_size;
     char tmp[128];
+    int prefix_match = 0;
+    int prefix_offset = 0;
     msgpack_object map;
     struct flb_time tm;
     struct influxdb_bulk *bulk = NULL;
@@ -124,8 +126,16 @@ static int influxdb_format(struct flb_config *config,
             ctx->seq++;
         }
 
+        prefix_match = strncmp(tag, ctx->prefix, ctx->prefix_len);
+        if (prefix_match == 0) {
+            if (tag_len > ctx->prefix_len) {
+                prefix_offset = ctx->prefix_len;
+            }
+        }
+
         ret = influxdb_bulk_append_header(bulk_head,
-                                          tag, tag_len,
+                                          tag + prefix_offset,
+                                          tag_len - prefix_offset,
                                           seq,
                                           ctx->seq_name, ctx->seq_len);
         if (ret == -1) {
@@ -368,6 +378,15 @@ static int cb_influxdb_init(struct flb_output_instance *ins, struct flb_config *
     }
     ctx->seq_len = strlen(ctx->seq_name);
 
+    /* prefix */
+    tmp = flb_output_get_property("strip_prefix", ins);
+    if (!tmp) {
+        ctx->prefix = flb_strdup("");
+    } else {
+        ctx->prefix = flb_strdup(tmp);
+    }
+    ctx->prefix_len = strlen(ctx->prefix);
+
     if (ctx->custom_uri) {
         /* custom URI endpoint (e.g: Grafana */
         if (ctx->custom_uri[0] != '/') {
@@ -696,6 +715,12 @@ static struct flb_config_map config_map[] = {
      "Use influxdb line protocol's integer type suffix."
     },
 
+    {
+     FLB_CONFIG_MAP_STR, "strip_prefix", NULL,
+     0, FLB_FALSE, 0,
+     "Prefix to be removed from the record tag when writing influx measurements."
+    },
+
     /* EOF */
     {0}
 };

plugins/out_influxdb/influxdb.h

@@ -56,6 +56,10 @@ struct flb_influxdb {
     char *seq_name;
     int seq_len;
 
+    /* prefix */
+    char *prefix;
+    int prefix_len;
+
     /* auto_tags: on/off */
     int auto_tags;