From 89a5de0105957d6a78c392c24eaae6b7d0d6d74c Mon Sep 17 00:00:00 2001
From: Maddie Zhan <maddie.zhan@cynovan.com>
Date: Sat, 18 Sep 2021 02:19:14 +0800
Subject: [PATCH] Support in-memory telemetry/stats database

---
 README.md                 |  2 +-
 database/database.go      |  3 +++
 database/memory/memory.go | 51 +++++++++++++++++++++++++++++++++++++++
 settings.toml             |  2 +-
 4 files changed, 56 insertions(+), 2 deletions(-)
 create mode 100644 database/memory/memory.go

diff --git a/README.md b/README.md
index 8261592..6ed2d35 100644
--- a/README.md
+++ b/README.md
@@ -106,7 +106,7 @@ manually, you can install newer version of Go into your `GOPATH`:
     # redact IP addresses
     redact_ip_addresses=false
 
-    # database type for statistics data, currently supports: none, bolt, mysql, postgresql
+    # database type for statistics data, currently supports: none, memory, bolt, mysql, postgresql
     # if none is specified, no telemetry/stats will be recorded, and no result PNG will be generated
     database_type="postgresql"
     database_hostname="localhost"
diff --git a/database/database.go b/database/database.go
index e2d16ef..de2e7e7 100644
--- a/database/database.go
+++ b/database/database.go
@@ -3,6 +3,7 @@ package database
 import (
 	"github.com/librespeed/speedtest/config"
 	"github.com/librespeed/speedtest/database/bolt"
+	"github.com/librespeed/speedtest/database/memory"
 	"github.com/librespeed/speedtest/database/mysql"
 	"github.com/librespeed/speedtest/database/none"
 	"github.com/librespeed/speedtest/database/postgresql"
@@ -29,6 +30,8 @@ func SetDBInfo(conf *config.Config) {
 		DB = mysql.Open(conf.DatabaseHostname, conf.DatabaseUsername, conf.DatabasePassword, conf.DatabaseName)
 	case "bolt":
 		DB = bolt.Open(conf.DatabaseFile)
+	case "memory":
+		DB = memory.Open("")
 	case "none":
 		DB = none.Open("")
 	default:
diff --git a/database/memory/memory.go b/database/memory/memory.go
new file mode 100644
index 0000000..ac8bf1d
--- /dev/null
+++ b/database/memory/memory.go
@@ -0,0 +1,51 @@
+package memory
+
+import (
+	"errors"
+	"sync"
+	"time"
+
+	"github.com/librespeed/speedtest/database/schema"
+)
+
+const (
+	// just enough records to return for FetchLast100
+	maxRecords = 100
+)
+
+type Memory struct {
+	lock    sync.RWMutex
+	records []schema.TelemetryData
+}
+
+func Open(_ string) *Memory {
+	return &Memory{}
+}
+
+func (mem *Memory) Insert(data *schema.TelemetryData) error {
+	mem.lock.Lock()
+	defer mem.lock.Unlock()
+	data.Timestamp = time.Now()
+	mem.records = append(mem.records, *data)
+	if len(mem.records) > maxRecords {
+		mem.records = mem.records[len(mem.records)-maxRecords:]
+	}
+	return nil
+}
+
+func (mem *Memory) FetchByUUID(uuid string) (*schema.TelemetryData, error) {
+	mem.lock.RLock()
+	defer mem.lock.RUnlock()
+	for _, record := range mem.records {
+		if record.UUID == uuid {
+			return &record, nil
+		}
+	}
+	return nil, errors.New("record not found")
+}
+
+func (mem *Memory) FetchLast100() ([]schema.TelemetryData, error) {
+	mem.lock.RLock()
+	defer mem.lock.RUnlock()
+	return mem.records, nil
+}
diff --git a/settings.toml b/settings.toml
index fb081ac..79a1b8e 100644
--- a/settings.toml
+++ b/settings.toml
@@ -18,7 +18,7 @@ statistics_password="PASSWORD"
 # redact IP addresses
 redact_ip_addresses=false
 
-# database type for statistics data, currently supports: none, bolt, mysql, postgresql
+# database type for statistics data, currently supports: none, memory, bolt, mysql, postgresql
 # if none is specified, no telemetry/stats will be recorded, and no result PNG will be generated
 database_type="bolt"
 database_hostname=""