Re: C-API schema

[Alan Miller]

Here's a more concise example of what I'm doing.

BTW: I also don't see my "doc" object in the data file ( I also tried:
   "aliases": ["MyAlias"], )
so I'm at a loss as to how to write custom meta-data via the C-API

[alan@localhost]$ cat writer.c
#include "avro.h"
#include <stdio.h>
#include <stdlib.h>

int main(int argc, char *argv[])
{
int rval;
int written = 0;
avro_file_writer_t file_writer;
char avro_file[128];
char json_schema[16 * 1024];
avro_schema_t schema = NULL;
avro_schema_error_t schema_error = NULL;

FILE *fp = fopen("test.avsc", "r");
rval = fread(json_schema, 1, sizeof(json_schema) - 1, fp);
json_schema[rval] = '\0';
rval = avro_schema_from_json(json_schema, strlen(json_schema),
&schema, &schema_error);
fprintf(stderr, "Loaded avro schema. rval %d\n", rval);
fclose(fp);

snprintf(avro_file, sizeof(avro_file), "%s", "test.avro");
rval = avro_file_writer_create("test.avro", schema, &file_writer);
fprintf(stderr, "Created writer. rval %d\n", rval);

avro_datum_t mydatum = avro_record(schema);
avro_record_set(mydatum, "myname", avro_givestring("alan", NULL));
rval = avro_file_writer_append(file_writer, mydatum);
if (rval == 0) {
 fprintf(stderr, "Successfully appended datum to file. rval %d\n", rval);
 written ++;
} else {
fprintf(stderr, "Unable to append data to file!\n");
exit(EXIT_FAILURE);
}
avro_datum_decref(mydatum);

rval = avro_file_writer_close(file_writer);
fprintf(stderr, "Closed writer. rval %d\n", rval);
fprintf(stderr, "Wrote %d records to %s\n", written, "test.avro");

return 0;
}


[alan@localhost]$ make writer
building writer
gcc -Wall -g -I/opt/avro/include -L/opt/avro/lib -l avro -o writer writer.c

[alan@localhost]$ ./writer
Loaded avro schema. rval 0
Created writer. rval 0
Successfully appended datum to file. rval 0
Closed writer. rval 0
Wrote 1 records to test.avro

[alan@localhost]$ java -jar avro-tools-1.7.7.jar getmeta test.avro
avro.codec null
avro.schema 
{"type":"record","name":"MyRecord","namespace":"org.me","fields":[{"name":"myname","type":{"type":"string"}}]}

[alan@localhost]$ cat test.avsc
{
  "type" : "record",
  "name" : "MyRecord",
  "namespace": "org.me",
  "doc": "Version_0.1",
  "rev": "0.1",
  "fields" : [
    { "name": "myname",  "type": "string" }
  ]
}

[alan@localhost]$ avro cat test.avro
{"myname": "alan"}

[alan@localhost]$ avro cat --print-schema test.avro
{
    "namespace": "org.me",
    "type": "record",
    "name": "MyRecord",
    "fields": [
        {
            "type": {
                "type": "string"
            },
            "name": "myname"
        }
    ]
}

[alan@localhost]$ java -jar avro-tools-1.7.7.jar getmeta test.avro
avro.codec null
avro.schema 
{"type":"record","name":"MyRecord","namespace":"org.me","fields":[{"name":"myname","type":{"type":"string"}}]}

[alan@localhost]$ java -jar avro-tools-1.7.7.jar tojson  test.avro
{"myname":"alan"}


On Mon, Apr 27, 2015 at 3:10 PM, Alan Miller <alan.mill...@gmail.com> wrote:
> Is it possible to write custom meta-field with the C-API?
>
> I tried this:
> {
>   "type" : "record",
>   "name" : "MySchema",
>   "namespace": "org.my",
>   "aliases": ["Cerberus_address"],
>   "doc": "MYSCHEMA_V1",
>   "my.version": "v1",
>   "fields" : [
>     { "name": "name",  "type": "string"    }
> }
>
> And write a record with the C-API (v1.7.7) I only get this:
>
> java -jar /opt/avro/avro-tools-1.7.7.jar getmeta test.avro
> avro.codec null
> avro.schema 
> {"type":"record","name":"MySchema","namespace":"org.my","fields":[{"name":"name","type":{"type":"string"}]}]}
>
> Alan