C - AVRO - Array of records

[Utsch Julian (AE-EB/ENS1)]

Hi together,

I'm trying to get familiar with 
AVRO<https://avro.apache.org/docs/1.8.1/spec.html> in C. I've defined an AVRO 
Schema (see below) with simple fields, which aren't the problem. But also there 
are an array of (sub)-records, which I can't access correctly. There are no 
compiler errors or other AVRO errors, but the AVRO file won't be filled with 
data... Without the array of (sub)-records, everything works fine.
Maybe some of you have an idea why my code isn't still working. Therefore I 
can't find any examples or documentations, which describe the procedure to fill 
subrecords with data.

PS: I've extracted only the important parts from the whole code; otherwise the 
code would be too long for here. So, I hope I didn't forget any necessary parts.

Thanks for your help. Best regards, Julian
Here the code:


const char METAFILE_SCHEMA[] =

"{\

  \"name\" : \"metafile\",\

  \"type\" : \"record\",\

  \"fields\" : [\

    { \"name\" : \"metaId\", \"type\" : \"long\" },\

    { \"name\" : \"logFilesCount\", \"type\" : \"int\" },\

    { \"name\" : \"logDataReference\", \"type\" : {\

        \"type\" : \"array\",\

        \"items\" : {\

          \"name\" : \"LogFileRef\",\

          \"type\" : \"record\",\

          \"fields\" : [\

            { \"name\" : \"deviceType\", \"type\" : \"int\" },\

            { \"name\" : \"deviceId\", \"type\" : \"int\" }\

            ]\

        }\

      }\

    },\

    { \"name\" : \"timestamp\", \"type\" : \"long\" }\

    ]\

}";



avro_file_writer_t file;



avro_schema_t metafile_schema;



avro_value_iface_t *metafile_iface;



avro_value_t metafile_record;



avro_value_t currentField;

avro_value_t element;

avro_value_t logDataReferenceArray;



if(avro_schema_from_json_literal(METAFILE_SCHEMA, &metafile_schema)) {

        fprintf(stderr, "Unable to parse metafile schema\n");

        exit(EXIT_FAILURE);

    }



 metafile_iface = avro_generic_class_from_schema(metafile_schema);

 try(avro_generic_value_new(metafile_iface, &metafile_record), "Error creating 
instance of metafile record");



 remove("metafile.avro");

 avro_file_writer_create("metafile.avro", metafile_schema, &file);



 int64_t metaId = 9999;

 avro_value_get_by_name(&metafile_record, "metaId", &currentField, NULL);

 avro_value_set_long(&currentField, metaId);



 avro_value_get_by_name(&metafile_record, "logDataReference", 
&logDataReferenceArray, NULL);

 try(avro_value_append(&logDataReferenceArray, &element, NULL), "Error in 
appending record in logdatareference array");

 avro_value_get_by_name(&element, "deviceType", &currentField, NULL);

 avro_value_set_int(&currentField, 2);

 avro_value_get_by_name(&element, "deviceId", &currentField, NULL);

 avro_value_set_int(&currentField, 3);



avro_file_writer_append_value(file, &metafile_record);



avro_file_writer_close(file);



avro_schema_decref(metafile_schema);



avro_value_decref(&metafile_record);



avro_value_iface_decref(metafile_iface);