Hi everyone,
newbie trying to get into Flight with Go here.
Invoking DoAction was pretty straight forward, but now I have problems with
DoExchange, namely:
```
rpc error: code = Unknown desc = Descriptor missing on first message
```
I managed wrapping flight.FlightServiceClient.DoExchange into a
flight.NewRecordWriter, but there is AFAIK no way to set the FlightDescriptor,
which lead me to the assumption, that the first message has to be sent manually
via DoEX.Send(<build FlightData here>).
Is there a preferred way/helper to build said FlightData? Am I on the right
track at all? I will keep digging into the source, but am thankful for any help.
Jasper
Complete client.go so far:
```
package main
import (
"context"
"fmt"
"time"
"github.com/apache/arrow/go/arrow"
"github.com/apache/arrow/go/arrow/array"
"github.com/apache/arrow/go/arrow/flight"
"github.com/apache/arrow/go/arrow/ipc"
"github.com/apache/arrow/go/arrow/memory"
"google.golang.org/grpc"
)
func main() {
conn, err := grpc.Dial("localhost:3001", grpc.WithInsecure(),
grpc.WithBlock())
c := flight.NewFlightServiceClient(conn)
ctx, cancel := context.WithTimeout(context.Background(),
100*time.Second)
defer cancel()
if err != nil {
panic(err)
}
defer conn.Close()
i := 0
doEX, err := c.DoExchange(ctx)
if err != nil {
panic(err)
}
// md := arrow.NewMetadata([]string{"f1-i64"}, []string{"v3"})
schema := arrow.NewSchema([]arrow.Field{
{Name: "f1-i64", Type: arrow.PrimitiveTypes.Int64},
}, nil)
pool := memory.NewGoAllocator()
w := flight.NewRecordWriter(doEX, ipc.WithSchema(schema),
ipc.WithAllocator(pool))
b := array.NewRecordBuilder(pool, schema)
defer b.Release()
for {
b.Field(0).(*array.Int64Builder).Append(int64(i))
r := b.NewRecord()
w.Write(r)
if err != nil {
panic(err)
}
fmt.Println(doEX.Recv())
defer r.Release()
time.Sleep(1 * time.Second)
i = i + 1
if i == 10 {
break
}
}
doEX.CloseSend()
}
```
