From 490ac3be1ccaa52fdf97569576b1492078336b27 Mon Sep 17 00:00:00 2001
From: Sandeep Sukhani <sandeep.d.sukhani@gmail.com>
Date: Thu, 16 May 2019 16:04:56 +0530
Subject: [PATCH] Change tail response for backward compatibilty with future
 changes (#590)

Changed it to dict with single key called "streams" and value set to list of logproto.Stream
---
 cmd/logcli/tail.go  | 40 +++++++++++++++++++++-------------------
 pkg/querier/http.go | 11 ++++++++++-
 2 files changed, 31 insertions(+), 20 deletions(-)

diff --git a/cmd/logcli/tail.go b/cmd/logcli/tail.go
index 27331aa58a10..3f9a6806251a 100644
--- a/cmd/logcli/tail.go
+++ b/cmd/logcli/tail.go
@@ -4,9 +4,9 @@ import (
 	"log"
 	"strings"
 
-	"github.com/fatih/color"
+	"github.com/grafana/loki/pkg/querier"
 
-	"github.com/grafana/loki/pkg/logproto"
+	"github.com/fatih/color"
 )
 
 func tailQuery() {
@@ -15,7 +15,7 @@ func tailQuery() {
 		log.Fatalf("Tailing logs failed: %+v", err)
 	}
 
-	stream := new(logproto.Stream)
+	tailReponse := new(querier.TailResponse)
 
 	if len(*ignoreLabelsKey) > 0 {
 		log.Println("Ingoring labels key:", color.RedString(strings.Join(*ignoreLabelsKey, ",")))
@@ -26,36 +26,38 @@ func tailQuery() {
 	}
 
 	for {
-		err := conn.ReadJSON(stream)
+		err := conn.ReadJSON(tailReponse)
 		if err != nil {
 			log.Println("Error reading stream:", err)
 			return
 		}
 
 		labels := ""
-		if !*noLabels {
+		for _, stream := range tailReponse.Streams {
+			if !*noLabels {
 
-			if len(*ignoreLabelsKey) > 0 || len(*showLabelsKey) > 0 {
+				if len(*ignoreLabelsKey) > 0 || len(*showLabelsKey) > 0 {
 
-				ls := mustParseLabels(stream.GetLabels())
+					ls := mustParseLabels(stream.GetLabels())
 
-				if len(*showLabelsKey) > 0 {
-					ls = ls.MatchLabels(true, *showLabelsKey...)
-				}
+					if len(*showLabelsKey) > 0 {
+						ls = ls.MatchLabels(true, *showLabelsKey...)
+					}
 
-				if len(*ignoreLabelsKey) > 0 {
-					ls = ls.MatchLabels(false, *ignoreLabelsKey...)
-				}
+					if len(*ignoreLabelsKey) > 0 {
+						ls = ls.MatchLabels(false, *ignoreLabelsKey...)
+					}
 
-				labels = ls.String()
+					labels = ls.String()
 
-			} else {
+				} else {
 
-				labels = stream.Labels
+					labels = stream.Labels
+				}
+			}
+			for _, entry := range stream.Entries {
+				printLogEntry(entry.Timestamp, labels, entry.Line)
 			}
-		}
-		for _, entry := range stream.Entries {
-			printLogEntry(entry.Timestamp, labels, entry.Line)
 		}
 	}
 }
diff --git a/pkg/querier/http.go b/pkg/querier/http.go
index c57b8e979659..3161ff6f619d 100644
--- a/pkg/querier/http.go
+++ b/pkg/querier/http.go
@@ -25,6 +25,11 @@ const (
 	defaulSince       = 1 * time.Hour
 )
 
+// TailResponse represents response for tail query
+type TailResponse struct {
+	Streams []*logproto.Stream `json:"streams"`
+}
+
 // nolint
 func intParam(values url.Values, name string, def int) (int, error) {
 	value := values.Get(name)
@@ -161,13 +166,17 @@ func (q *Querier) TailHandler(w http.ResponseWriter, r *http.Request) {
 	// heap until connection to websocket stays open
 	queryRequest := *queryRequestPtr
 	itr := q.tailQuery(r.Context(), &queryRequest)
+
 	stream := logproto.Stream{}
+	tailResponse := TailResponse{[]*logproto.Stream{
+		&stream,
+	}}
 
 	for itr.Next() {
 		stream.Entries = []logproto.Entry{itr.Entry()}
 		stream.Labels = itr.Labels()
 
-		err := conn.WriteJSON(stream)
+		err := conn.WriteJSON(tailResponse)
 		if err != nil {
 			level.Error(util.Logger).Log("Error writing to websocket", fmt.Sprintf("%v", err))
 			if err := conn.WriteMessage(websocket.CloseMessage, websocket.FormatCloseMessage(websocket.CloseInternalServerErr, err.Error())); err != nil {