Support in-memory telemetry/stats database

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
+}