I need to send several MB to a spawned Go process. I followed the directions at https://gobyexample.com/spawning-processes, but my data is too large to send that way. I thought I could chunk the data. Here is the code I ended up with:
doit := exec.Command("/bin/bash", "-c", cmd) // cmd reads stdin
doit_stdin,_ := doit.StdinPipe()
doit_stdout,_ := doit.StdoutPipe()
doit.Start()
go func() {
w := bufio.NewWriter(doit_stdin)
for i := 0; i < nchunks; i++ {
w.Write(input_data[chunk_begin[i]:chunk_begin[i+1]])
w.Flush()
}
doit_stdin.Close()
}()
rc,_ := ioutil.ReadAll(doit_stdout)
doit.Wait()
Where input_data
is []byte
and chunk_begin
is an array of break points computed elsewhere. Everything works just fine. cmd
gets all the data sent to it, detects EOF, sends results back and exits. ReadAll
gets all the info sent back from cmd. But do it.Wait()
blocks. I cannot understand why doit.Wait
is blocking.
Or if there is some other standard way of transferring larger amounts of data, that would be fine too. I do need to control the break points because the data has internal structure.
Any help would be greatly appreciated.