/
streaming.go
174 lines (147 loc) · 4.03 KB
/
streaming.go
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package loki
import (
"context"
"encoding/json"
"fmt"
"net/url"
"os"
"os/signal"
"strings"
"time"
"github.com/gorilla/websocket"
"github.com/grafana/grafana-plugin-sdk-go/backend"
"github.com/grafana/grafana-plugin-sdk-go/data"
)
func (s *Service) SubscribeStream(ctx context.Context, req *backend.SubscribeStreamRequest) (*backend.SubscribeStreamResponse, error) {
dsInfo, err := s.getDSInfo(ctx, req.PluginContext)
if err != nil {
return &backend.SubscribeStreamResponse{
Status: backend.SubscribeStreamStatusNotFound,
}, err
}
// Expect tail/${key}
if !strings.HasPrefix(req.Path, "tail/") {
return &backend.SubscribeStreamResponse{
Status: backend.SubscribeStreamStatusNotFound,
}, fmt.Errorf("expected tail in channel path")
}
query, err := parseQueryModel(req.Data)
if err != nil {
return nil, err
}
if query.Expr == "" {
return &backend.SubscribeStreamResponse{
Status: backend.SubscribeStreamStatusNotFound,
}, fmt.Errorf("missing expr in channel (subscribe)")
}
dsInfo.streamsMu.RLock()
defer dsInfo.streamsMu.RUnlock()
cache, ok := dsInfo.streams[req.Path]
if ok {
msg, err := backend.NewInitialData(cache.Bytes(data.IncludeAll))
return &backend.SubscribeStreamResponse{
Status: backend.SubscribeStreamStatusOK,
InitialData: msg,
}, err
}
// nothing yet
return &backend.SubscribeStreamResponse{
Status: backend.SubscribeStreamStatusOK,
}, err
}
// Single instance for each channel (results are shared with all listeners)
func (s *Service) RunStream(ctx context.Context, req *backend.RunStreamRequest, sender *backend.StreamSender) error {
dsInfo, err := s.getDSInfo(ctx, req.PluginContext)
if err != nil {
return err
}
query, err := parseQueryModel(req.Data)
if err != nil {
return err
}
if query.Expr == "" {
return fmt.Errorf("missing expr in cuannel")
}
logger := logger.FromContext(ctx)
count := int64(0)
interrupt := make(chan os.Signal, 1)
signal.Notify(interrupt, os.Interrupt)
params := url.Values{}
params.Add("query", query.Expr)
wsurl, _ := url.Parse(dsInfo.URL)
wsurl.Path = "/loki/api/v2alpha/tail"
if wsurl.Scheme == "https" {
wsurl.Scheme = "wss"
} else {
wsurl.Scheme = "ws"
}
wsurl.RawQuery = params.Encode()
logger.Info("Connecting to websocket", "url", wsurl)
c, r, err := websocket.DefaultDialer.Dial(wsurl.String(), nil)
if err != nil {
logger.Error("Error connecting to websocket", "err", err)
return fmt.Errorf("error connecting to websocket")
}
defer func() {
dsInfo.streamsMu.Lock()
delete(dsInfo.streams, req.Path)
dsInfo.streamsMu.Unlock()
if r != nil {
_ = r.Body.Close()
}
err = c.Close()
logger.Error("Closing loki websocket", "err", err)
}()
prev := data.FrameJSONCache{}
// Read all messages
done := make(chan struct{})
go func() {
defer close(done)
for {
_, message, err := c.ReadMessage()
if err != nil {
logger.Error("Websocket read:", "err", err)
return
}
frame := &data.Frame{}
err = json.Unmarshal(message, &frame)
if err == nil && frame != nil {
next, _ := data.FrameToJSONCache(frame)
if next.SameSchema(&prev) {
err = sender.SendBytes(next.Bytes(data.IncludeDataOnly))
} else {
err = sender.SendFrame(frame, data.IncludeAll)
}
prev = next
// Cache the initial data
dsInfo.streamsMu.Lock()
dsInfo.streams[req.Path] = prev
dsInfo.streamsMu.Unlock()
}
if err != nil {
logger.Error("Websocket write:", "err", err, "raw", message)
return
}
}
}()
ticker := time.NewTicker(time.Second * 60) //.Step)
defer ticker.Stop()
for {
select {
case <-done:
logger.Info("Socket done")
return nil
case <-ctx.Done():
logger.Info("Stop streaming (context canceled)")
return nil
case t := <-ticker.C:
count++
logger.Error("Loki websocket ping?", "time", t, "count", count)
}
}
}
func (s *Service) PublishStream(_ context.Context, _ *backend.PublishStreamRequest) (*backend.PublishStreamResponse, error) {
return &backend.PublishStreamResponse{
Status: backend.PublishStreamStatusPermissionDenied,
}, nil
}