Show previous query and don't require auth if token setting is empty

cmd/querycheck/main.go

···
 		&cli.StringFlag{
 			Name:    "auth-token",
 			Usage:   "auth token for accessing the querycheck api",
-			Value:   "localdev",
+			Value:   "",
 			EnvVars: []string{"AUTH_TOKEN"},
 		},
 	}
···
 
 	e.Use(func(next echo.HandlerFunc) echo.HandlerFunc {
 		return func(c echo.Context) error {
-			if c.Request().Header.Get("Authorization") != cctx.String("auth-token") {
+			if cctx.String("auth-token") != "" && c.Request().Header.Get("Authorization") != cctx.String("auth-token") {
 				return c.String(http.StatusUnauthorized, "unauthorized")
 			}
 			return next(c)

querycheck/check.go

···
 
 // Query is a query to check
 type Query struct {
-	Name        string
-	Query       string
-	LastPlan    *QueryPlan
-	LastChecked time.Time
-	LastError   error
-	CheckEvery  time.Duration
+	Name         string
+	Query        string
+	LatestPlan   *QueryPlan
+	PreviousPlan *QueryPlan
+	LastChecked  time.Time
+	LastError    error
+	CheckEvery   time.Duration
 
 	lk  sync.RWMutex
 	in  chan struct{}
···
 	for _, qu := range q.Queries {
 		if qu.Name == name {
 			return &Query{
-				Name:        qu.Name,
-				Query:       qu.Query,
-				LastPlan:    qu.LastPlan,
-				LastChecked: qu.LastChecked,
-				LastError:   qu.LastError,
-				CheckEvery:  qu.CheckEvery,
+				Name:         qu.Name,
+				Query:        qu.Query,
+				LatestPlan:   qu.LatestPlan,
+				PreviousPlan: qu.PreviousPlan,
+				LastChecked:  qu.LastChecked,
+				LastError:    qu.LastError,
+				CheckEvery:   qu.CheckEvery,
 			}
 		}
 	}
···
 	queries := make([]*Query, len(q.Queries))
 	for i, qu := range q.Queries {
 		queries[i] = &Query{
-			Name:        qu.Name,
-			Query:       qu.Query,
-			LastPlan:    qu.LastPlan,
-			LastChecked: qu.LastChecked,
-			LastError:   qu.LastError,
-			CheckEvery:  qu.CheckEvery,
+			Name:         qu.Name,
+			Query:        qu.Query,
+			LatestPlan:   qu.LatestPlan,
+			PreviousPlan: qu.PreviousPlan,
+			LastChecked:  qu.LastChecked,
+			LastError:    qu.LastError,
+			CheckEvery:   qu.CheckEvery,
 		}
 	}
 
···
 			ticker := time.NewTicker(query.CheckEvery)
 			defer ticker.Stop()
 
-			query.LastPlan, err = q.CheckQueryPlan(ctx, query.Query)
+			query.LatestPlan, err = q.CheckQueryPlan(ctx, query.Query)
 			if err != nil {
 				log.Errorf("failed to check query plan: %+v\n", err)
 			}
 
-			if query.LastPlan != nil {
-				log.Infof("Initial plan:\n%+v\n", query.LastPlan.String())
-				query.RecordPlanMetrics(*query.LastPlan)
+			if query.LatestPlan != nil {
+				log.Infof("Initial plan:\n%+v\n", query.LatestPlan.String())
+				query.RecordPlanMetrics(*query.LatestPlan)
 				query.LastChecked = time.Now()
 			}
 
···
 					}
 
 					query.lk.RLock()
-					lastPlan := *query.LastPlan
+					lastPlan := *query.LatestPlan
 					query.lk.RUnlock()
 
 					query.RecordPlanMetrics(*qp)
···
 						log.Infof("query plan has changed (%s%.03fms): \n%+v\n", sign, diff, qp.String())
 
 						query.lk.Lock()
-						query.LastPlan = qp
+						query.PreviousPlan = query.LatestPlan
+						query.LatestPlan = qp
 						query.lk.Unlock()
 					}
 				case <-query.in:

querycheck/handlers.go

···
 )
 
 type RetQuery struct {
-	Name        string     `json:"name"`
-	Query       string     `json:"query"`
-	LastPlan    *QueryPlan `json:"last_plan"`
-	LastChecked time.Time  `json:"last_checked"`
-	LastError   error      `json:"last_error"`
-	CheckEvery  string     `json:"check_every"`
+	Name         string     `json:"name"`
+	Query        string     `json:"query"`
+	LatestPlan   *QueryPlan `json:"latest_plan"`
+	PreviousPlan *QueryPlan `json:"previous_plan"`
+	LastChecked  time.Time  `json:"last_checked"`
+	LastError    error      `json:"last_error"`
+	CheckEvery   string     `json:"check_every"`
 }
 
 func (q *Querychecker) HandleGetQueries(c echo.Context) error {
···
 	retQueries := []RetQuery{}
 	for _, query := range queries {
 		retQueries = append(retQueries, RetQuery{
-			Name:        query.Name,
-			Query:       query.Query,
-			LastPlan:    query.LastPlan,
-			LastChecked: query.LastChecked,
-			LastError:   query.LastError,
-			CheckEvery:  query.CheckEvery.String(),
+			Name:         query.Name,
+			Query:        query.Query,
+			LatestPlan:   query.LatestPlan,
+			PreviousPlan: query.PreviousPlan,
+			LastChecked:  query.LastChecked,
+			LastError:    query.LastError,
+			CheckEvery:   query.CheckEvery.String(),
 		})
 	}
 
···
 	}
 
 	retQuery := RetQuery{
-		Name:        query.Name,
-		Query:       query.Query,
-		LastPlan:    query.LastPlan,
-		LastChecked: query.LastChecked,
-		LastError:   query.LastError,
-		CheckEvery:  query.CheckEvery.String(),
+		Name:         query.Name,
+		Query:        query.Query,
+		LatestPlan:   query.LatestPlan,
+		PreviousPlan: query.PreviousPlan,
+		LastChecked:  query.LastChecked,
+		LastError:    query.LastError,
+		CheckEvery:   query.CheckEvery.String(),
 	}
 
 	return c.JSON(200, retQuery)