db: Allow empty service name in query

db/ping.go

@@ -3,18 +3,15 @@ package db
 import (
 	"time"
 
-	"github.com/jinzhu/gorm"
-
 	"status/check"
 )
 
 //PingEntry represents an entry of Ping that is persisted in the DB.
 type PingEntry struct {
-	gorm.Model
-	ServiceName string
-	Time        time.Time
-	Ping        int64
-	Status      check.Result
+	ServiceName string       `json:"service_name"`
+	Time        time.Time    `json:"query_time"`
+	Ping        int64        `json:"ping"`
+	Status      check.Result `json:"status"`
 }
 
 func (p PingEntry) AddToDB() {
@@ -24,8 +21,12 @@ func (p PingEntry) AddToDB() {
 	db.Create(&p)
 }
 
-func GetFromDB(serviceName string, from, to time.Time) []*PingEntry {
-	entries := make([]*PingEntry, 0)
-	db.Where("service_name = ? AND time BETWEEN ? AND ?", serviceName, from, to).Find(&entries)
+func GetFromDB(serviceName string, from, to time.Time) []PingEntry {
+	entries := make([]PingEntry, 0)
+	if serviceName == "" {
+		db.Where("time BETWEEN ? AND ?", from, to).Find(&entries)
+	} else {
+		db.Where("service_name = ? AND time BETWEEN ? AND ?", serviceName, from, to).Find(&entries)
+	}
 	return entries
 }