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test_udf.go
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test_udf.go
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package udf_test
import (
"bufio"
"io"
"log"
"github.com/influxdata/kapacitor/udf"
)
// IO implements a UDF process communication.
// Connect up to UDF server via In/Out pipes.
// Use Requests/Responses channels for reading
// and writing requests and responses for the UDF.
type IO struct {
inr *io.PipeReader
inw *io.PipeWriter
outr *io.PipeReader
brr udf.ByteReadReader
outw *io.PipeWriter
// Requests sent to the UDF
Requests chan *udf.Request
// Responses from the UDF
Responses chan *udf.Response
// Any error that may have occurred
ErrC chan error
}
func NewIO() *IO {
inr, inw := io.Pipe()
outr, outw := io.Pipe()
brr := bufio.NewReader(outr)
u := &IO{
Requests: make(chan *udf.Request),
Responses: make(chan *udf.Response),
ErrC: make(chan error, 1),
inr: inr,
inw: inw,
outr: outr,
brr: brr,
outw: outw,
}
go u.run()
return u
}
// Forcefully kill the command.
// This will likely cause a panic.
func (o *IO) Kill() {
close(o.Requests)
close(o.Responses)
close(o.ErrC)
o.inr.Close()
o.inw.Close()
o.outr.Close()
o.outw.Close()
}
func (o *IO) readRequests() error {
defer o.inr.Close()
defer close(o.Requests)
buf := bufio.NewReader(o.inr)
var b []byte
for {
req := &udf.Request{}
err := udf.ReadMessage(&b, buf, req)
if err == io.EOF {
return nil
}
if err != nil {
return err
}
o.Requests <- req
}
}
func (o *IO) writeResponses() error {
defer o.outw.Close()
for response := range o.Responses {
udf.WriteMessage(response, o.outw)
}
return nil
}
func (o *IO) run() {
readErrC := make(chan error, 1)
writeErrC := make(chan error, 1)
go func() {
readErrC <- o.readRequests()
}()
go func() {
writeErrC <- o.writeResponses()
}()
var readErr, writeErr error
for readErrC != nil || writeErrC != nil {
select {
case readErr = <-readErrC:
readErrC = nil
case writeErr = <-writeErrC:
writeErrC = nil
}
}
if readErr != nil {
o.ErrC <- readErr
} else {
o.ErrC <- writeErr
}
}
func (o *IO) In() io.WriteCloser {
return o.inw
}
func (o *IO) Out() udf.ByteReadReader {
return o.brr
}
type UDF struct {
*udf.Server
uio *IO
logger *log.Logger
}
func New(uio *IO, l *log.Logger) *UDF {
return &UDF{
uio: uio,
logger: l,
}
}
func (u *UDF) Open() error {
u.Server = udf.NewServer(u.uio.Out(), u.uio.In(), u.logger, 0, nil, nil)
return u.Server.Start()
}
func (u *UDF) Close() error {
return u.Server.Stop()
}