filter: aws tags are not critical

allows to inject base metadata group into the logs even if tags were not
fetched

in this version fetching tags will be retried indefinitely with every
flush, where each retry is going to produce error logs

Signed-off-by: Mateusz Warzyński <mateusz@warzynski.pro>

plugins/filter_aws/aws.c

@@ -740,6 +740,7 @@ static int get_ec2_metadata_tags(struct flb_filter_aws *ctx)
 static int get_ec2_metadata(struct flb_filter_aws *ctx)
 {
     int ret;
+    int failures = 0;
 
     if (!ctx->metadata_groups[FLB_FILTER_AWS_METADATA_GROUP_BASE].done) {
         ret = get_ec2_metadata_base(ctx);
@@ -750,16 +751,23 @@ static int get_ec2_metadata(struct flb_filter_aws *ctx)
     }
 
     if (!ctx->metadata_groups[FLB_FILTER_AWS_METADATA_GROUP_TAGS].done) {
-        /* TODO: retries */
+        /* TODO: retries with Fixed Interval Rate */
+        /* at the moment it will retry with every flush */
         ret = get_ec2_metadata_tags(ctx);
-
-        if (ret < 0) {
+        if (ret == FLB_FILTER_AWS_CONFIGURATION_ERROR) {
             return ret;
         }
-        ctx->metadata_groups[FLB_FILTER_AWS_METADATA_GROUP_TAGS].done = FLB_TRUE;
+        if (ret == 0) {
+            ctx->metadata_groups[FLB_FILTER_AWS_METADATA_GROUP_TAGS].done = FLB_TRUE;
+        } else {
+            failures++;
+        }
+    }
+
+    if (failures == 0) {
+        ctx->metadata_retrieved = FLB_TRUE;
     }
 
-    ctx->metadata_retrieved = FLB_TRUE;
     return 0;
 }