A minimal (working ?) example of writing data with avro-c

test-avro.c

/* Compile with:
 *    gcc -std=c99 -Wall -Wextra -Werror $(pkg-config --cflags avro-c) -o test-avro test-avro.c $(pkg-config --libs avro-c)
 */

#include <avro.h>

#define OUTFILE "out.avro"
#define OUTCODEC "null"

#define SCHEMA \
"{"\
"    \"type\": \"record\","\
"    \"name\": \"engine\","\
"    \"fields\": ["\
"        {\"type\": [\"null\",\"double\"], \"name\": \"rpm\"},"\
"        {\"type\": [\"null\",\"double\"], \"name\": \"hours\"}"\
"    ]"\
"}"

static int add_record(avro_schema_t schema, avro_file_writer_t writer, double rpm)
{
    // Create some data
    avro_datum_t record = avro_record(schema);
    avro_datum_t engine_rpm = avro_double(rpm);
    if (avro_record_set(record, "rpm", engine_rpm)){
        fprintf(stderr, "Unable to add rpm into Avro record\n");
        return -1;
    }
    avro_datum_decref(engine_rpm);

    // Write data to file
    int res = avro_file_writer_append(writer, record);
    if (res){
        fprintf(stderr, "Unable to write Avro record to file: %s\n", avro_strerror());
    }
    avro_datum_decref(record);
    return res;
}

int main(int argc, const char **argv)
{
    (void) argc;
    (void) argv;

    // Load schema
    char schema_json_string[4096];
    strncpy(schema_json_string, SCHEMA, sizeof(schema_json_string));
    avro_schema_t schema;
    if (avro_schema_from_json(schema_json_string, 0, &schema, NULL)){
        fprintf(stderr, "Unable to load Avro schema: %s\n", avro_strerror());
        return -1;
    }

    // Open output file
    avro_file_writer_t writer;
    if (avro_file_writer_create_with_codec(OUTFILE, schema, &writer, OUTCODEC, 0)){
        fprintf(stderr, "Unable to create output file: %s\n", avro_strerror());
        return -1;
    }

    add_record(schema, writer, 723.5);

    // Cleanup
    avro_file_writer_close(writer);
    avro_schema_decref(schema);
    return 0;
}